Patent Publication Number: US-11658578-B2

Title: DC-DC auto-converter module

Description:
REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 17/397,892, filed Aug. 9, 2021, entitled DC-DC Auto-Converter Module, which claims priority of U.S. provisional patent application Ser. No. 63/063,800, entitled Systems, Methods and Apparatuses for Enhanced DC-DC Electrical Converters, filed Aug. 10, 2020, and hereby incorporates this provisional patent application by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     Embodiments of the technology relate, in general, to systems, apparatuses and methods providing technical solutions for enhanced direct current to direct current (DC-DC) converters. 
     BACKGROUND 
     DC-DC converters are widely used to efficiently produce a regulated voltage from a source that may or may not be well controlled to a load that may or may not be constant. A DC-to-DC converter is an electronic circuit or electromechanical device that converts DC voltage from one voltage level to another. Common topologies include buck and boost converters. A buck converter steps a voltage down, producing a voltage lower than the input voltage. A boost converter steps a voltage up, producing a voltage higher than the input voltage. DC-DC converters come in non-isolated and isolated varieties. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       It is believed that certain embodiments will be better understood from the following description taken in conjunction with the accompanying drawings in which: 
         FIG.  1    is a schematic view depicting a conventional DC-DC converter associated with a DC power source and a DC load; 
         FIG.  2    is a schematic view depicting a DC-DC auto-converter module, in accordance with one embodiment; 
         FIG.  3    is a schematic view depicting a DC-DC auto-converter module, in accordance with another embodiment; 
         FIG.  4    is a schematic view depicting a DC-DC auto-converter module, in accordance with another embodiment; 
         FIG.  5    is a schematic view depicting a DC-DC auto-converter module, in accordance with yet another embodiment; 
         FIG.  6    is a schematic view depicting a DC-DC auto-converter module, in accordance with yet another embodiment; 
         FIG.  7    is a schematic view depicting a DC-DC auto-converter module, in accordance with yet another embodiment; 
         FIG.  8    is a schematic view depicting a DC-DC auto-converter module, in accordance with yet another embodiment; 
         FIG.  9    is a schematic view depicting a DC-DC auto-converter module, in accordance with yet another embodiment; 
         FIG.  10    is a schematic view depicting a DC-DC auto-converter module, in accordance with yet another embodiment; 
         FIG.  11    is a schematic view depicting a DC-DC auto-converter module, in accordance with yet another embodiment; 
         FIG.  12    is a schematic view depicting a DC-DC auto-converter module, in accordance with yet another embodiment; 
         FIG.  13    is a schematic view depicting a DC-DC auto-converter module, in accordance with yet another embodiment; 
         FIG.  14    is a schematic view depicting a DC-DC auto-converter module, in accordance with yet another embodiment; 
         FIG.  15    is a schematic view depicting a DC-DC auto-converter module, in accordance with yet another embodiment; 
         FIG.  16    is a schematic view depicting a DC-DC auto-converter module, in accordance with yet another embodiment; and 
         FIG.  17    is a schematic view depicting a DC-DC auto-converter module, in accordance with yet another embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Various non-limiting embodiments of the present disclosure will now be described to provide an overall understanding of the principles of the structure, function, and use of the apparatuses, systems, methods, and processes disclosed herein. One or more examples of these non-limiting embodiments are illustrated in the accompanying drawings. Those of ordinary skill in the art will understand that systems and methods specifically described herein and illustrated in the accompanying drawings are non-limiting embodiments. The features illustrated or described in connection with one non-limiting embodiment may be combined with the features of other non-limiting embodiments. Such modifications and variations are intended to be included within the scope of the present disclosure. 
     Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” “some example embodiments,” “one example embodiment,” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with any embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” “some example embodiments,” “one example embodiment,” or “in an embodiment” in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments. In various embodiments disclosed herein, a single component can be replaced by multiple components and multiple components can be replaced by a single component to perform a given function or functions. Except where such substitution would not be operative, such substitution is within the intended scope of the embodiments. 
     The examples discussed herein are examples only and are provided to assist in the explanation of the apparatuses, devices, systems and methods described herein. None of the features or components shown in the drawings or discussed below should be taken as mandatory for any specific implementation of any of these the apparatuses, devices, systems or methods unless specifically designated as mandatory. For ease of reading and clarity, certain components, modules, or methods may be described solely in connection with a specific figure. Any failure to specifically describe a combination or sub-combination of components should not be understood as an indication that any combination or sub-combination is not possible. Also, for any methods described, regardless of whether the method is described in conjunction with a flow diagram, it should be understood that unless otherwise specified or required by context, any explicit or implicit ordering of steps performed in the execution of a method does not imply that those steps must be performed in the order presented but instead may be performed in a different order or in parallel. 
     Technical solutions to enhance the operating capabilities of DC-DC converters can be achieved by the systems, apparatuses and methods of the present disclosure. The disclosed systems, apparatuses and methods achieve improvements to base DC-DC converters to have greatly increased efficiency and power capability. 
     In general, the disclosed systems, apparatuses and methods enable base DC-DC converters (referred to herein as “base modules”), including state-of-the-art DC-DC converters, to be installed in configurations, referred to herein as “auto-connections,” that can greatly increase efficiency and power capability, or reduce cost, size, weight, and/or footprint for the same power level. The apparatus disclosed is referred to herein as an “auto-converter,” and the systems and methods relate to auto-converter technology. Disclosed is a representative family of auto-converter configurations applicable to DC-DC converters that enhance their operating capabilities. Of the various configurations identified in the disclosure, some result in improved efficiency and increase the power throughput by, for example, as much as an order of magnitude. Other configurations have a more modest impact on efficiency and power rating but can be useful in applications where large voltage ratios are required. 
     Auto-converter technology can incorporate existing or custom-built base modules. In one embodiment, the auto-converter can be a retrofit or aftermarket technology that allows a commercial-off-the-shelf (COTS) isolated DC-DC converter to be reconfigured by means of galvanically connecting certain terminals together to form a non-isolated DC-DC converter with increased efficiency and power capability. The technology can also encompass new design paradigms and tools to facilitate the repurposing of existing DC-DC products for solutions with higher power and efficiency, and/or with lower cost. The auto-converter and its associated engineering tools constitute a unique after-market product that can be employed across the entire field of power electronics. 
     The examples discussed herein are examples only and are provided to assist in the explanation of the apparatuses, devices, systems and methods described herein. None of the features or components shown in the drawings or discussed below should be taken as mandatory for any specific implementation of any of these the apparatuses, devices, systems or methods unless specifically designated as mandatory. For ease of reading and clarity, certain components, modules, or methods may be described solely in connection with a specific figure. Any failure to specifically describe a combination or sub-combination of components should not be understood as an indication that any combination or sub-combination is not possible. Also, for any methods described, regardless of whether the method is described in conjunction with a flow diagram, it should be understood that unless otherwise specified or required by context, any explicit or implicit ordering of steps performed in the execution of a method does not imply that those steps must be performed in the order presented but instead may be performed in a different order or in parallel. 
     Embodiments are hereinafter described in detail in connection with the views and examples of  FIGS.  1 - 17   , wherein like numbers indicate the same or corresponding elements throughout the views.  FIG.  1    illustrates a conventional isolated DC-DC converter  20  that includes an input circuit  22  and an output circuit  24  that are galvanically isolated from each other. It is to be appreciated that input and output circuits described as being galvanically isolated from each other can be understood to mean that there is no direct current (DC) electrical conduction path provided between the input and output terminals such that no DC electric current is conducted between the input and output terminals during normal (e.g., non-fault) operation of the isolated DC-DC converter. 
     The input circuit  22  can include positive input terminal  26  and a negative input terminal  28  that are electrically coupled to a DC power source  30 . The output circuit  24  can include a positive output terminal  32  and a negative output terminal  34  that are electrically coupled with a DC load  36 . The DC power source  30  can be configured to provide DC input power S in  to the conventional isolated DC-DC converter  20  in the form of an input current I in  through the input circuit  22  and an input voltage V in  across the positive and negative input terminals  26 ,  28 . The conventional isolated DC-DC converter  20  can be configured to convert the DC input power S in  into DC output power S b  that is delivered to the DC load  36  in the form of an output current I out  through the output circuit  24  and an output voltage V out  across the positive and negative output terminals  32 ,  34 . 
     The input circuit  22  and the output circuit  24  can have a voltage ratio n that describes the operation of the conventional isolated DC-DC converter  20  and the output voltage V out  that is provided across the across the positive and negative output terminals  32 ,  34 . The DC-DC converter can have a voltage gain G v  (defined as V out /V in ), a current gain G i  (defined as I m am), and an efficiency η b  (defined as S b /S in ). The voltage gain G v  and the current gain G i  can be dependent on the voltage ratio n. Under ideal circumstances, the efficiency η b  of the conventional isolated DC-DC converter  20  is 100%. However, in reality, the conventional isolated DC-DC converter  20  is subject to internal losses such that the efficiency η b  is less than 100%, and is typically between 85% and 95%. 
     In one embodiment, the voltage ratio of the DC-DC converter can be n:1, where n is greater than 1 such that the conventional isolated DC-DC converter  20  is considered a “step-down” converter. In such an embodiment, the voltage gain G v  is equal to 1/n and the ideal current gain is equal to n. In another embodiment, the voltage ratio of the DC-DC converter can be 1:n, where n is greater than 1 such that the conventional isolated DC-DC converter  20  is considered a “step-up” converter. In such an embodiment, the voltage gain G v  is equal to n and the ideal current gain is equal to 1/n. It is to be appreciated that the input current I in  is shown to flow into the conventional isolated DC-DC converter  20  and the output current I out  is shown to flow out of the conventional isolated DC-DC converter  20 . The conventional isolated DC-DC converter  20  can accordingly be configured as a “forward” converter. However, if the input and output currents I in , I out  were to flow in the opposite direction (e.g., with the output current I out  flowing into the conventional isolated DC-DC converter  20  and the input current I in  flowing out of the conventional isolated DC-DC converter  20 ), the conventional isolated DC-DC converter  20  can instead be configured as a “reverse” converter. In some embodiments, the isolated DC-DC converter can be configured as a reverse converter by installing a forward converter backwards. 
     The conventional isolated DC-DC converter  20  can utilize any conventional topology, including but not limited to circuits utilizing resonant operation, ZVS, ZCS, and SAC. The input current I in  and the output current I out  of the DC-DC converter  20  can be considered to be DC, with minimal harmonic content. That is, any filter elements that may be utilized to stabilize the operation of the DC-DC converter  20  (e.g., according to a manufacturer&#39;s specifications) can be understood to be incorporated into the input circuit  22  and the output circuit  24  and are thus not illustrated in  FIG.  1   . 
     In other embodiments, the DC-DC converter  20  can be configured to conduct current in both forward and reverse directions, resulting in a bidirectional DC-DC converter. In some embodiments, the DC power source  30  and the DC load  36  can be configured to supply and absorb power, respectively. In other embodiments the load can be regenerative and the DC power source  30  and the DC load  36  can absorb and supply power, respectively. 
       FIG.  2    illustrates one embodiment of a DC-DC auto-converter module  140  (hereinafter auto-converter  140 ) that includes an isolated DC-DC converter  120  is the same as the isolated DC-DC converter illustrated in  FIG.  1    and is configured as a step down converter (i.e., with a voltage ratio of n:1). For example, the isolated DC-DC converter  120  can include input circuit  122  and output circuit  124 . The input circuit  122  can include a positive input terminal  126  and a negative input terminal  128 . The output circuit  124  can include a positive output terminal  132  and a negative output terminal  134 . An input current I in  can be present at the positive input terminal  126  and an output current I out  can be present at the positive output terminal  132 . 
     The auto-converter  140  can be electrically coupled with a DC power source  130  and a DC load  136 . The auto-converter  140  can include a positive source terminal  142  and a negative source terminal  144  that cooperate with each other to facilitate connection of the DC power source  130  to the auto-converter  140 . The auto-converter  140  can include a positive load terminal  146  and a negative load terminal  148  that cooperate with each other to facilitate connection of the DC load  136  to the auto-converter  140 . The negative source terminal  144  and the negative load terminal  148  can be galvanically connected together via a ground bus  150  that provides an electrical ground for the auto-converter  140 . It is to be appreciated that components described as being galvanically connected together can be understood to have a DC resistance that is low enough such that the voltage drop across the galvanic connection when the auto-converter is operating at rated DC current is reasonably small (e.g., less than 2% of the rated input or output voltage, whichever is smaller). For low power auto-converters (e.g., less than 10 W), this value could be less than 100 mΩ. For high power auto-converters (e.g., greater than 10 kW), or auto-converters with very high current ratings (e.g., 400 A), the DC resistance could be less than 10 mΩ. Suitable resistance values can be established by anyone skilled in the art. The galvanic connections are described herein in terms of their DC impedance, but it is to be appreciated that the galvanic connections can also be understood to have an AC impedance that is also low enough such that any AC harmonics present at the galvanic connection do not adversely affect the performance of the auto-converter. 
     The DC power source  130  can be configured to provide DC input power S in1  to the isolated DC-DC converter  120  in the form of an input current I in1  that flows into the positive source terminal  142  at an input voltage V in1  provided across the positive and negative source terminals  142 ,  144 . The auto-converter  140  can be configured to convert the DC input power Sini into DC output power S a1  that is delivered to the DC load  136  in the form of an output current I out1  that flows out of the positive load terminal  146  at an output voltage V out1  provided across the positive and negative load terminals  146 ,  148 . It is to be appreciated that the DC power source  130  can be any of variety of suitable DC power sources that are configured to generate DC power, such as, for example, a DC motor, a battery, a photovoltaic cell, or an AC/DC converter. It is also to be appreciated that the DC load  136  can be any of a variety of loads that are capable of receiving DC power, such as, for example, a DC motor, a rechargeable DC battery, a light bulb, or a DC/AC converter. 
     The auto-converter  140  can have a voltage gain G v1  (defined as V out i/V in1 ), a current gain G i1  (defined as I out1 /I in1 ), a power gain G a1  (defined as S a1 /S b ), and an efficiency rating η a1  (defined as S a1 /S in1 ). The power gain G a1  can be understood to be distinct from the efficiency η a1 . While the efficiency η b  of the DC/DC converter  120  is always less than 1, the power gain G a1  can be significantly larger than unity. The efficiency rating η a1  of the auto-converter  140  can accordingly exceed the efficiency η b  of the DC/DC converter  120  which can enable the efficiency of the auto-converter  140  to approach unity more effectively than the DC/DC converter  120 . 
     The positive source terminal  142 , the negative source terminal  144 , the positive load terminal  146 , and the negative load terminal  148  (collectively “terminals”) can allow for easy connection of the DC power source  130  and the DC load  136  to the auto-converter  140 . As such, the auto-converter  140  can be readily employed in any of a variety of electrical applications that utilize a DC-DC converter. In one embodiment, each of the terminals  142 ,  144 ,  146 ,  148  can comprise terminal blocks (not shown) that are configured to allow for electrical connection to the auto-converter  140  with screws or other similar releasable fasteners. It is to be appreciated that the terminals  142 ,  144 ,  146 ,  148  can include be any of a variety of suitable alternative releasable electrical connection arrangements, such as, for example, a plug, or any of a variety of suitable non-releasable electrical connection arrangements, such as a soldering terminal or a pin that is provided through a printed circuit board. Terminals  144  and  148  can also be the same terminal, making the auto-converter a 3-terminal device. 
     The isolated DC-DC converter  120  can be wired together and to the terminals  142 ,  144 ,  146 ,  148  within the auto-converter  140  in a configuration that is different from the conventional arrangement illustrated in  FIG.  1    and that enhances the performance of the auto-converter  140  over conventional converter topologies. Still referring to  FIG.  2   , the positive input terminal  126  of the isolated DC-DC converter  120  can be galvanically connected to the positive source terminal  142  at location  152 . The negative input terminal  128  of the isolated DC-DC converter  120  can be galvanically connected to the ground bus  150  at location  154 . The positive output terminal  132  of the isolated DC-DC converter  120  can be galvanically connected the positive load terminal  146 . The negative output terminal  134  of the isolated DC-DC converter  120  can be galvanically connected to the positive input terminal  126  such that the positive input terminal  126 , the negative output terminal  134 , and the positive source terminal  142  are all galvanically connected together. During operation, a current I 1  can be generated that flows into the negative output terminal  134  such that the currents are added on the high voltage side of the isolated DC-DC converter which can be beneficial for the overall power throughput and efficiency of the auto-converter  140 . It is to be appreciated that these galvanic connections have sufficiently low impedance to DC currents that they don&#39;t introduce significant losses. On the contrary, the galvanic connections can allow the rated losses of the auto-converter  140  to effectively be the same as the rated losses of the isolated DC-DC converter  120  even while the auto-converter has significantly higher power throughput. This can lead to a dramatic improvement in efficiency. 
     By wiring the isolated DC-DC converter  120  in this manner, the auto-converter  140  can have the performance characteristics listed in Table 1 listed as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
             
            
               
                   
                 Voltage Gain G v1   
                 
                   
                     
                       
                         
                           n 
                           + 
                           1 
                         
                         n 
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Current Gain G i1   
                 
                   
                     
                       
                         ( 
                         
                           n 
                           
                             n 
                             + 
                             
                               1 
                               / 
                               
                                 η 
                                 b 
                               
                             
                           
                         
                         ) 
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Power Gain G a1   
                 n + 1 
               
               
                   
                   
               
               
                   
                 Efficiency Rating η a1   
                 
                   
                     
                       
                         ( 
                         
                           
                             n 
                             + 
                             1 
                           
                           
                             n 
                             + 
                             
                               1 
                               / 
                               
                                 η 
                                 b 
                               
                             
                           
                         
                         ) 
                       
                     
                   
                 
               
               
                   
                   
               
            
           
         
       
     
     When the output voltage V out  of the isolated DC-DC converter  120  is 1 VDC, the performance characteristics listed in Table 2 can be achieved as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
             
            
               
                   
                 Input Voltage V in   
                 n 
               
               
                   
                 Input Voltage V in1   
                 n 
               
               
                   
                 Output Voltage V out1   
                 n + 1 
               
               
                   
                   
               
               
                   
                 Input current I in1   
                 
                   
                     
                       
                         
                           ( 
                           
                             n 
                             + 
                             1 
                           
                           ) 
                         
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Input current I in   
                 
                   
                     
                       
                         1 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Output current I out1   
                 n 
               
               
                   
                 Output current I out   
                 n 
               
               
                   
                 Current I 1   
                 n 
               
               
                   
                   
               
            
           
         
       
     
     The auto-converter  140  can have a larger power gain G a1 , higher efficiency η a1 , and smaller voltage gain G v1  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases the power gain G a1  increases, the efficiency η a1  approaches unity, and the voltage gain G v1  approaches unity. The efficiency η a1  can dramatically increase for larger n values. The auto-converter  140  can effectively be a small boost positive converter. The auto-converter  140  can provide higher power throughput and better efficiency than conventional topologies and can be smaller, more lightweight, and less expensive. This can especially be true for larger n values (e.g., n≥6). 
       FIG.  3    illustrates an alternative embodiment of an auto-converter  240  that is similar to, or the same in many respects as, the auto-converter  140  of  FIG.  2   . For example, the auto-converter  240  can include an isolated DC-DC converter  220  that includes an input circuit  222  and an output circuit  224  that has a voltage ratio of n:1. The input circuit  222  can include a positive input terminal  226  and a negative input terminal  228 . The output circuit  224  can include a positive output terminal  232  and a negative output terminal  234 . An input current I in  can be present at the positive input terminal  226  and an output current I out  can be present at the positive output terminal  232 . The auto-converter  240  can include a positive source terminal  242 , a negative source terminal  244 , a positive load terminal  246 , a negative load terminal  248 , and a ground bus  250 . A DC power source  230  can provide DC input power S in2  to the auto-converter  240  in the form of an input current I in2  at the positive source terminal  242  at an input voltage V in2  provided across the positive and negative source terminals  242 ,  244 . 
     DC output power S a2  can be delivered to a DC load  236  in the form of an output current I out2  at the positive load terminal  246  at an output voltage V out2  provided across the positive and negative load terminals  246 ,  248 . The auto-converter  240  can have a voltage gain G v2  (defined as V out2 /V in2 ), a current gain G i2  (defined as I out2 /I in2 ), a power gain G a2  (defined as S a2 /S b ), and an efficiency rating η a2  (S a2 /S in ) which ideally is unity but, in reality, is less than unity. 
     Similar to the auto-converter  140 , the negative input terminal  228  of the isolated DC-DC converter  220  can be galvanically connected to the ground bus  250  at location  254 . However, the positive output terminal  232  of the isolated DC-DC converter  220  can be galvanically connected to the positive input terminal  226  at location  252  such that the positive input terminal  226 , the positive output terminal  232 , and the positive source terminal  242  are all galvanically connected together. The negative output terminal  234  of the isolated DC-DC converter  120  can be galvanically connected to the positive load terminal  246 . A current I 2  can flow into the positive output terminal  232  such that the currents are added on the high voltage side of the isolated DC-DC converter  220 . 
     By wiring the isolated DC-DC converter  220  in this manner, the auto-converter  240  can have the performance characteristics listed in Table 3 listed as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
             
            
               
                   
                 Voltage Gain G v2   
                 
                   
                     
                       
                         
                           n 
                           - 
                           1 
                         
                         n 
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Current Gain G i2   
                 
                   
                     
                       
                         n 
                         
                           n 
                           - 
                           
                             η 
                             b 
                           
                         
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Power Gain G a2   
                 n − 1  
               
               
                   
                   
               
               
                   
                 Efficiency Rating η a2   
                 
                   
                     
                       
                         
                           n 
                           - 
                           1 
                         
                         
                           n 
                           - 
                           
                             η 
                             b 
                           
                         
                       
                     
                   
                 
               
               
                   
                   
               
            
           
         
       
     
     When the output voltage V out  of the isolated DC-DC converter  220  is 1 VDC, the performance characteristics listed in Table 4 can be achieved as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 4 
               
               
                   
                   
               
             
            
               
                   
                 Input Voltage V in   
                 n 
               
               
                   
                 Input Voltage V in2   
                 n 
               
               
                   
                 Output Voltage V out2   
                 n − 1 
               
               
                   
                 Input current I in2   
                 n − η b   
               
               
                   
                 Input current I in   
                 η b   
               
               
                   
                 Output current I out2   
                 n 
               
               
                   
                 Output current I out   
                 n 
               
               
                   
                 Current I 2   
                 n 
               
               
                   
                   
               
            
           
         
       
     
     The auto-converter  240  can have a larger power gain G a2 , higher efficiency η a2 , and smaller voltage gain G v2  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases the power gain G a1  increases, the efficiency η a2  approaches unity, and the voltage gain G v2  approaches unity. The efficiency η a2  can dramatically increase for larger n values. The auto-converter  240  can effectively be a small buck negative converter and because the input and output currents I in  and I out  flow in reverse (e.g., with the output current I out  flowing into the isolated DC-DC converter  220  and the input current I in  flowing out of the isolated DC-DC converter  220 ), the isolated DC-DC converter  220  can instead be configured as a reverse converter. The auto-converter  240  can provide higher power throughput and better efficiency than conventional topologies and can be smaller, more lightweight, and less expensive. 
       FIG.  4    illustrates an alternative embodiment of an auto-converter  340  that is similar to, or the same in many respects as, the auto-converter  140  of  FIG.  2   . For example, the auto-converter  340  can include an isolated DC-DC converter  320  that includes an input circuit  322  and an output circuit  324 . The input circuit  322  can include a positive input terminal  326  and a negative input terminal  328 . The output circuit  324  can include a positive output terminal  332  and a negative output terminal  334 . An input current I in  can be present at the positive input terminal  326  and an output current I out  can be present at the positive output terminal  332 . The auto-converter  340  can include a positive source terminal  342 , a negative source terminal  344 , a positive load terminal  346 , a negative load terminal  348 , and a ground bus  350 . A DC power source  330  can provide DC input power S in3  to the auto-converter  340  in the form of an input current I in3  at the positive source terminal  342  at an input voltage V in3  provided across the positive and negative source terminals  342 ,  344 . 
     DC output power S a3  can be delivered to a DC load  336  in the form of an output current I out3  at the positive load terminal  346  at an output voltage V out3  provided across the positive and negative load terminals  346 ,  348 . The auto-converter  340  can have a voltage gain G v3  (defined as V out3 /V in3 ), a current gain G i3  (defined as I out3 /I in3 ), a power gain G a3  (defined as S a3 /S b ), and an efficiency rating η a3  (S a3 /S in3 ) which ideally is unity but, in reality, is less than unity. 
     The auto-converter  340  can be different from the auto-converter  140  in that the input circuit  322  and the output circuit  324  has a voltage ratio of 1:n. In addition, the negative output terminal  334  of the isolated DC-DC converter  320  can be galvanically connected to the ground bus  350  at location  354 . The negative input terminal  328  of the isolated DC-DC converter  320  can be galvanically connected to the positive output terminal  332  such that the negative input terminal  328 , the positive output terminal  332 , and the positive load terminal  346  are all galvanically connected together at location  352 . A current I 3  can flow out of the negative input terminal  328  such that the currents are added on the high voltage side of the isolated DC-DC converter  320  which can be beneficial for the overall power throughput and efficiency of the auto-converter  340 . It is to be appreciated that these galvanic connections can allow the rated losses of the auto-converter  340  to effectively be the same as the isolated DC-DC converter  320 . 
     By wiring the isolated DC-DC converter  320  in this manner, the auto-converter  340  can have the performance characteristics listed in Table 5 listed as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 5 
               
               
                   
                   
               
             
            
               
                   
                 Voltage Gain G v3   
                 
                   
                     
                       
                         n 
                         
                           n 
                           + 
                           1 
                         
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Current Gain G i3   
                 
                   
                     
                       
                         1 
                         + 
                         
                           
                             η 
                             b 
                           
                           n 
                         
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Power Gain G p3   
                 
                   
                     
                       
                         
                           n 
                           
                             η 
                             b 
                           
                         
                         + 
                         1 
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Efficiency Rating η a3   
                 
                   
                     
                       
                         
                           n 
                           + 
                           
                             η 
                             b 
                           
                         
                         
                           n 
                           + 
                           1 
                         
                       
                     
                   
                 
               
               
                   
                   
               
            
           
         
       
     
     When the output voltage V in  of the isolated DC-DC converter  320  is 1 VDC, the performance characteristics listed in Table 6 can be achieved as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 6 
               
               
                   
                   
               
             
            
               
                   
                 Output Voltage V out   
                 n 
               
               
                   
                 Input Voltage V in3   
                 n + 1 
               
               
                   
                 Output Voltage V out3   
                 n 
               
               
                   
                   
               
               
                   
                 Input current I in3   
                 
                   
                     
                       
                         n 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Input current I in   
                 
                   
                     
                       
                         n 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Output current I out3   
                 
                   
                     
                       
                         
                           n 
                           
                             η 
                             b 
                           
                         
                         + 
                         1 
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Output current I out   
                 1 
               
               
                   
                   
               
               
                   
                 Current I 3   
                 
                   
                     
                       
                         n 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
                   
               
            
           
         
       
     
     The auto-converter  340  can have a larger power gain Go, higher efficiency η a3 , and smaller voltage gain G v3  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases the power gain Go increases, the efficiency η a3  approaches unity, and the voltage gain G v3  approaches unity. The efficiency η a3  can dramatically increase for larger n values. The auto-converter  340  can effectively be a small buck positive converter. 
       FIG.  5    illustrates an alternative embodiment of an auto-converter  440  that is similar to, or the same in many respects as, the auto-converter  140  of  FIG.  2   . For example, the auto-converter  440  can include an isolated DC-DC converter  420  that includes an input circuit  422  and an output circuit  424  that has a voltage ratio of 1:n. The input circuit  422  can include a positive input terminal  426  and a negative input terminal  428 . The output circuit  424  can include a positive output terminal  432  and a negative output terminal  434 . An input current Tin can be present at the positive input terminal  426  and an output current I out  can be present at the positive output terminal  432 . The auto-converter  440  can include a positive source terminal  442 , a negative source terminal  444 , a positive load terminal  446 , a negative load terminal  448 , and a ground bus  450 . A DC power source  430  can provide DC input power Sino to the auto-converter  440  in the form of an input current I in4  at the positive source terminal  442  at an input voltage Vino provided across the positive and negative source terminals  442 ,  444 . 
     DC output power S a4  can be delivered to a DC load  436  in the form of an output current I out4  at the positive load terminal  446  at an output voltage V out4  provided across the positive and negative load terminals  446 ,  448 . The auto-converter  440  can have a voltage gain G v4  (defined as V in4 /V in4 ), a current gain G i4  (defined as I out4 /I in4 ), a power gain G a4  (defined as S a4 /S b ), and an efficiency rating η a4  (S a4 /S in4 ) which ideally is unity but, in reality, is less than unity. 
     The auto-converter  440  can be different from the auto-converter  140  in that the input circuit  422  and the output circuit  424  has a voltage ratio of 1:n. In addition, the positive source terminal  442  can be galvanically coupled with the negative input terminal  428 . The negative output terminal  434  of the isolated DC-DC converter  420  can be galvanically connected to the ground bus  450  at location  454 . The positive input terminal  426  of the isolated DC-DC converter  420  can be galvanically connected to the positive output terminal  432  such that the positive input terminal  426 , the positive output terminal  432 , and the positive load terminal  446  are all galvanically connected together at location  452 . A current I 4  can flow out of the positive input terminal  426  such that the currents are added on the high voltage side of the isolated DC-DC converter  420 . 
     By wiring the isolated DC-DC converter  420  in this manner, the auto-converter  440  can have the performance characteristics listed in Table 7 listed as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 7 
               
               
                   
                   
               
             
            
               
                   
                 Voltage Gain G v4   
                 
                   
                     
                       
                         n 
                         
                           n 
                           - 
                           1 
                         
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Current Gain G i4   
                 
                   
                     
                       
                         
                           n 
                           - 
                           
                             1 
                             
                               η 
                               b 
                             
                           
                         
                         n 
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Power Gain G a4   
                 n * η b  − 1 
               
               
                   
                   
               
               
                   
                 Efficiency Rating η a4   
                 
                   
                     
                       
                         
                           n 
                           - 
                           
                             1 
                             
                               η 
                               b 
                             
                           
                         
                         
                           n 
                           - 
                           1 
                         
                       
                     
                   
                 
               
               
                   
                   
               
            
           
         
       
     
     When the output voltage V in  of the isolated DC-DC converter  420  is n VDC, the performance characteristics listed in Table 8 can be achieved as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 8 
               
               
                   
                   
               
             
            
               
                   
                 Output Voltage V out   
                 n 
               
               
                   
                 Input Voltage V in4   
                 n − 1 
               
               
                   
                 Output Voltage V out4   
                 n 
               
               
                   
                 Input current I in4   
                 n * η b   
               
               
                   
                 Input current I in   
                 n * η b   
               
               
                   
                 Output current I out4   
                 n * η b   − l 
               
               
                   
                 Output current I out   
                 1 
               
               
                   
                 Current I 4   
                 n * η b   
               
               
                   
                   
               
            
           
         
       
     
     The auto-converter  440  can have a larger power gain G a4 , higher efficiency η a4 , and smaller voltage gain G v4  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases the power gain G a1  increases, the efficiency η a4  approaches unity, and the voltage gain G v4  approaches unity. The efficiency η a4  can dramatically increase for larger n values. The auto-converter  440  can effectively be a small boost negative converter and because the output current I out  flows into the isolated DC-DC converter  420  and the input current I in  flows out of the isolated DC-DC converter  420 , the isolated DC-DC converter  420  can instead be configured as a reverse converter. 
       FIG.  6    illustrates an alternative embodiment of an auto-converter  540  that is similar to, or the same in many respects as, the auto-converter  140  of  FIG.  2   . For example, the auto-converter  540  can include an isolated DC-DC converter  520  that includes an input circuit  522  and an output circuit  524 . The input circuit  522  can include a positive input terminal  526  and a negative input terminal  528 . The output circuit  524  can include a positive output terminal  532  and a negative output terminal  534 . An input current I in  can be present at the positive input terminal  526  and an output current I out  can be present at the positive output terminal  532 . The auto-converter  540  can include a positive source terminal  542 , a negative source terminal  544 , a positive load terminal  546 , a negative load terminal  548 , and a ground bus  550 . A DC power source  530  can provide DC input power S in5  to the auto-converter  540  in the form of an input current Tins at the positive source terminal  542  at an input voltage V in5  provided across the positive and negative source terminals  542 ,  544 . During operation, a current Is can be generated. 
     DC output power S a5  can be delivered to a DC load  536  in the form of an output current I out5  at the positive load terminal  546  at an output voltage V out5  provided across the positive and negative load terminals  546 ,  548 . The auto-converter  540  can have a voltage gain G v5  (defined as V out5 /V in5 ), a current gain G i5  (defined as I out5 /I in5 ), a power gain G a5  (defined as S a5 /S b ), and an efficiency rating η a5  (S a5 /S in5 ) which ideally is unity but, in reality, is less than unity. The auto-converter  540  can be different from the auto-converter  140  in that the input circuit  522  and the output circuit  524  has a voltage ratio of 1:n. 
     By wiring the isolated DC-DC converter  520  in this manner, the auto-converter  540  can have the performance characteristics listed in Table 9 listed as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 9 
               
               
                   
                   
               
             
            
               
                   
                 Voltage Gain G v5   
                 n + 1 
               
               
                   
                   
               
               
                   
                 Current Gain G i5   
                 
                   
                     
                       
                         1 
                         
                           
                             n 
                             
                               η 
                               b 
                             
                           
                           + 
                           1 
                         
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Power Gain G a5   
                 
                   
                     
                       
                         
                           n 
                           + 
                           1 
                         
                         n 
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Efficiency Rating η a5   
                 
                   
                     
                       
                         
                           n 
                           + 
                           1 
                         
                         
                           
                             n 
                             / 
                             
                               η 
                               b 
                             
                           
                           + 
                           1 
                         
                       
                     
                   
                 
               
               
                   
                   
               
            
           
         
       
     
     When the input voltage V in  of the isolated DC-DC converter  520  is 1 VDC, the performance characteristics listed in Table 10 can be achieved as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 10 
               
               
                   
                   
               
             
            
               
                   
                 Output Voltage V out   
                 n 
               
               
                   
                 Input Voltage V in5   
                 1 
               
               
                   
                 Output Voltage V out5   
                 n + 1 
               
               
                   
                   
               
               
                   
                 Input current I in5   
                 
                   
                     
                       
                         
                           n 
                           
                             η 
                             b 
                           
                         
                         + 
                         1 
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Input current I in   
                 
                   
                     
                       
                         n 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Output current I out5   
                 1 
               
               
                   
                 Output current I out   
                 1 
               
               
                   
                 Current I 5   
                 1 
               
               
                   
                   
               
            
           
         
       
     
     The auto-converter  540  can have a smaller power gain G a5  (e.g., closer to unity) and an efficiency η a5  that approaches the efficiency rib of the isolated DC-DC converter  520  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases, the power gain G a5  decreases (e.g., towards unity) and the efficiency η a5  of the auto-converter  540  approaches the efficiency η b  of the isolated DC-DC converter  520 . 
       FIG.  7    illustrates an alternative embodiment of an auto-converter  640  that is similar to, or the same in many respects as, the auto-converter  240  of  FIG.  3   . For example, the auto-converter  640  can include an isolated DC-DC converter  620  that includes an input circuit  622  and an output circuit  624 . The input circuit  622  can include a positive input terminal  626  and a negative input terminal  628 . The output circuit  624  can include a positive output terminal  632  and a negative output terminal  634 . An input current I in  can be present at the positive input terminal  626  and an output current I out  can be present at the positive output terminal  632 . The auto-converter  640  can include a positive source terminal  642 , a negative source terminal  644 , a positive load terminal  646 , a negative load terminal  648 , and a ground bus  650 . A DC power source  630  can provide DC input power S in6  to the auto-converter  640  in the form of an input current I in6  at the positive source terminal  642  at an input voltage V in6  provided across the positive and negative source terminals  642 ,  644 . During operation, a current I 6  can be generated. 
     DC output power S a6  can be delivered to a DC load  636  in the form of an output current I out6  at the positive load terminal  646  at an output voltage V out6  provided across the positive and negative load terminals  646 ,  648 . The auto-converter  640  can have a voltage gain G v6  (defined as V out6 /V in6 ), a current gain G i6  (defined as I out6 /I in6 ), a power gain G a6  (defined as S a6 /S b ), and an efficiency rating η a6  (S a6 /S in ) which ideally is unity but, in reality, is less than unity. The auto-converter  640  can be different from the auto-converter  240  in that the input circuit  622  and the output circuit  624  has a voltage ratio of 1:n. 
     By wiring the isolated DC-DC converter  620  in this manner, the auto-converter  640  can have the performance characteristics listed in Table 11 listed as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 11 
               
               
                   
                   
               
             
            
               
                   
                 Voltage Gain G v6   
                 −(n − 1) 
               
               
                   
                 Current Gain G i6   
                 
                   
                     
                       
                         - 
                         
                           1 
                           
                             
                               n 
                               * 
                               
                                 η 
                                 b 
                               
                             
                             - 
                             1 
                           
                         
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Power Gain G a6   
                 
                   
                     
                       
                         
                           - 
                           
                             ( 
                             
                               n 
                               - 
                               1 
                             
                             ) 
                           
                         
                         n 
                       
                     
                   
                 
               
               
                   
                   
               
               
                   
                 Efficiency Rating η a6   
                 
                   
                     
                       
                         
                           
                             n 
                             * 
                             
                               η 
                               b 
                             
                           
                           - 
                           1 
                         
                         
                           n 
                           - 
                           1 
                         
                       
                     
                   
                 
               
               
                   
                   
               
            
           
         
       
     
     When the input voltage V in  of the isolated DC-DC converter  620  is 1 VDC, the performance characteristics listed in Table 12 can be achieved as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 12 
               
               
                   
                   
               
             
            
               
                   
                 Output Voltage V out   
                 n 
               
               
                   
                 Input Voltage V in6   
                 1 
               
               
                   
                 Output Voltage V out6   
                 —(n − 1) 
               
               
                   
                 Input current I in6   
                 —(n * η b  − 1) 
               
               
                   
                 Input current I in   
                 n * η b   
               
               
                   
                 Output current T out   
                 1 
               
               
                   
                 Output current I out   
                 1 
               
               
                   
                 Current I 6   
                 1 
               
               
                   
                   
               
            
           
         
       
     
     The auto-converter  640  can have a smaller power gain G a6  (e.g., closer to unity) and an efficiency η a6  that approaches the efficiency η b  of the isolated DC-DC converter  620  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases, the power gain G a6  decreases (e.g., towards unity) and the efficiency nab of the auto-converter  640  approaches the efficiency η b  of the isolated DC-DC converter  620 . 
       FIG.  8    illustrates an alternative embodiment of an auto-converter  740  that is similar to, or the same in many respects as, the auto-converter  340  of  FIG.  4   . For example, the auto-converter  740  can include an isolated DC-DC converter  720  that includes an input circuit  722  and an output circuit  724 . The input circuit  722  can include a positive input terminal  726  and a negative input terminal  728 . The output circuit  724  can include a positive output terminal  732  and a negative output terminal  734 . An input current I in  can be present at the positive input terminal  726  and an output current I out  can be present at the positive output terminal  732 . The auto-converter  740  can include a positive source terminal  742 , a negative source terminal  744 , a positive load terminal  746 , a negative load terminal  748 , and a ground bus  750 . A DC power source  730  can provide DC input power S in7  to the auto-converter  740  in the form of an input current I in7  at the positive source terminal  742  at an input voltage V in7  provided across the positive and negative source terminals  742 ,  744 . During operation, a current I 7  can be generated. 
     DC output power S a7  can be delivered to a DC load  736  in the form of an output current I out7  at the positive load terminal  746  at an output voltage V out7  provided across the positive and negative load terminals  746 ,  748 . The auto-converter  740  can have a voltage gain G v7  (defined as V out7 /V in7 ), a current gain G i7  (defined as I out7 /I in7 ), a power gain G a7  (defined as S a7 /S b ), and an efficiency rating η a7  (S a7 /S in7 ) which ideally is unity but, in reality, is less than unity. The auto-converter  740  can be different from the auto-converter  340  in that the input circuit  722  and the output circuit  724  has a voltage ratio of n:1. 
     By wiring the isolated DC-DC converter  720  in this manner, the auto-converter  740  can have the performance characteristics listed in Table 13 listed as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 13 
               
               
                   
               
             
            
               
                 Voltage Gain G v7   
                 
                   
                     
                       
                         1 
                         
                           ( 
                           
                             n 
                             + 
                             1 
                           
                           ) 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Current Gain G i7   
                 n * η b  + 1 
               
               
                   
               
               
                 Power Gain G a7   
                 
                   
                     
                       
                         1 
                         + 
                         
                           1 
                           
                             n 
                             * 
                             
                               η 
                               b 
                             
                           
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Efficiency Rating η a7   
                 
                   
                     
                       
                         
                           
                             n 
                             * 
                             
                               η 
                               b 
                             
                           
                           + 
                           1 
                         
                         
                           n 
                           + 
                           1 
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     When the output voltage V out  of the isolated DC-DC converter  720  is 1 VDC, the performance characteristics listed in Table 14 can be achieved as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 14 
               
               
                   
               
             
            
               
                 Input Voltage V in   
                 n 
               
               
                   
               
               
                 Input Voltage V in7   
                 n + 1 
               
               
                   
               
               
                 Output Voltage V out7   
                 1 
               
               
                   
               
               
                 Input current I in7   
                 
                   
                     
                       
                         1 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Input current I in   
                 
                   
                     
                       
                         1 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Output current I out7   
                 
                   
                     
                       
                         n 
                         + 
                         
                           1 
                           
                             η 
                             b 
                           
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Output current I out   
                 n 
               
               
                   
               
               
                 Current I 7   
                 
                   
                     
                       
                         1 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     The auto-converter  740  can have a smaller power gain G a7  (e.g., closer to unity) and an efficiency η a7  that approaches the efficiency η b  of the isolated DC-DC converter  720  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases, the power gain G a7  decreases (e.g., towards unity) and the efficiency η a7  of the auto-converter  740  approaches the efficiency η b  of the isolated DC-DC converter  720 . 
       FIG.  9    illustrates an alternative embodiment of an auto-converter  840  that is similar to, or the same in many respects as, the auto-converter  440  of  FIG.  5   . For example, the auto-converter  840  can include an isolated DC-DC converter  820  that includes an input circuit  822  and an output circuit  824 . The input circuit  822  can include a positive input terminal  826  and a negative input terminal  828 . The output circuit  824  can include a positive output terminal  832  and a negative output terminal  834 . An input current I in  can be present at the positive input terminal  826  and an output current I out  can be present at the positive output terminal  832 . The auto-converter  840  can include a positive source terminal  842 , a negative source terminal  844 , a positive load terminal  846 , a negative load terminal  848 , and a ground bus  850 . A DC power source  830  can provide DC input power Sing to the auto-converter  840  in the form of an input current I in8  at the positive source terminal  842  at an input voltage V in8  provided across the positive and negative source terminals  842 ,  844 . During operation, a current I 8  can be generated. 
     DC output power S a8  can be delivered to a DC load  836  in the form of an output current I out8  at the positive load terminal  846  at an output voltage V out8  provided across the positive and negative load terminals  846 ,  848 . The auto-converter  840  can have a voltage gain G v8  (defined as V out8 /V in8 ), a current gain G i8  (defined as I out8 /I in8 ), a power gain G a8  (defined as S a8 /S b ), and an efficiency rating η a8  (S a8 /S in8 ) which ideally is unity but, in reality, is less than unity. The auto-converter  840  can be different from the auto-converter  440  in that the input circuit  822  and the output circuit  824  has a voltage ratio of n:1. 
     By wiring the isolated DC-DC converter  820  in this manner, the auto-converter  840  can have the performance characteristics listed in Table 15 listed as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 15 
               
               
                   
               
             
            
               
                 Voltage Gain G v8   
                 
                   
                     
                       
                         
                           - 
                           1 
                         
                         
                           n 
                           - 
                           1 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Current Gain G i8   
                 
                   
                     
                       
                         1 
                         - 
                         
                           n 
                           
                             η 
                             b 
                           
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Power Gain G a8   
                 
                   
                     
                       
                         
                           
                             η 
                             b 
                           
                           n 
                         
                         - 
                         1 
                       
                     
                   
                 
               
               
                   
               
               
                 Efficiency Rating η a8   
                 
                   
                     
                       
                         
                           n 
                           - 
                           1 
                         
                         
                           
                             n 
                             
                               η 
                               b 
                             
                           
                           - 
                           1 
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     When the output voltage V out  of the isolated DC-DC converter  820  is 1 VDC, the performance characteristics listed in Table 16 can be achieved as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 16 
               
               
                   
                   
               
             
            
               
                   
                 Input Voltage V in   
                 n 
               
               
                   
                 Input Voltage V in8   
                 —(n − 1) 
               
               
                   
                 Output Voltage V out8   
                 1 
               
               
                   
                 Input current I in8   
                 η b   
               
               
                   
                 Input current I in   
                 η b   
               
               
                   
                 Output current I out8   
                 —(n − η b ) 
               
               
                   
                 Output current I out   
                 n 
               
               
                   
                 Current I 8   
                 η b   
               
               
                   
                   
               
            
           
         
       
     
     The auto-converter  840  can have a smaller power gain G a8  (e.g., closer to unity) and an efficiency η a8  that approaches the efficiency η b  of the isolated DC-DC converter  820  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases, the power gain G a8  decreases (e.g., towards unity) and the efficiency η a8  of the auto-converter  840  approaches the efficiency η b  of the isolated DC-DC converter  820 . 
       FIG.  10    illustrates an alternative embodiment of an auto-converter  940  that is similar to, or the same in many respects as, the auto-converter  140  of  FIG.  2   . For example, the auto-converter  940  can include an isolated DC-DC converter  920  that includes an input circuit  922  and an output circuit  924  that has a voltage ratio of n:1. The input circuit  922  can include a positive input terminal  926  and a negative input terminal  928 . The output circuit  924  can include a positive output terminal  932  and a negative output terminal  934 . The auto-converter  940  can include a positive source terminal  942 , a negative source terminal  944 , a positive load terminal  946 , and a negative load terminal  948 . The negative source terminal  944  can provide an electrical ground for the auto-converter  940 . 
     A DC power source  930  can provide DC input power S in9  to the auto-converter  940  in the form of an input current I in9  at the negative source terminal  944  at an input voltage V in9  provided across the positive and negative source terminals  942 ,  944 . The input current I in9  can flow out of the negative source terminal  944  and towards the DC power source  930 . DC output power S a9  can be delivered to a DC load  936  in the form of an output current I out9  at the negative load terminal  948  at an output voltage V out9  provided across the positive and negative load terminals  946 ,  948 . The output current I out9  can flow out of the DC load  936  and towards the negative load terminal  948 . The auto-converter  940  can have a voltage gain G v9  (defined as V out9 /V in9 ), a current gain G i9  (defined as I out9 /I in9 ), a power gain G a9  (defined as S a9 /S b ), and an efficiency rating η a9  (S a9 /S in9 ) which ideally is unity but, in reality, is less than unity. 
     The auto-converter  940  can be different from the auto-converter  140  in that the auto-converter  940  can include a main bus  951  that is galvanically connected to the positive source terminal  942  and the positive load terminal  946 . The positive input terminal  926  of the isolated DC-DC converter  920  can be galvanically connected to the main bus  951  at location  952 . The negative input terminal  928  of the isolated DC-DC converter  920  can be galvanically connected to the negative source terminal  944 . The positive output terminal  932  of the isolated DC-DC converter  920  can be galvanically connected to the negative input terminal  928  such that the negative input terminal  928 , the positive output terminal  932 , and the negative source terminal  944  are galvanically connected together at location  954 . The negative output terminal  934  can be galvanically connected to the negative load terminal  948 . A current I 9  can flow out of the positive output terminal  932  into the location  954  such that the currents are added on the high voltage side of the isolated DC-DC converter  920 . 
     By wiring the isolated DC-DC converter  920  in this manner, the auto-converter  940  can have the performance characteristics listed in Table 17 listed as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 17 
               
               
                   
               
             
            
               
                 Voltage Gain G v9   
                 
                   
                     
                       
                         
                           n 
                           + 
                           1 
                         
                         n 
                       
                     
                   
                 
               
               
                   
               
               
                 Current Gain G i9   
                 
                   
                     
                       
                         ( 
                         
                           n 
                           
                             n 
                             + 
                             
                               1 
                               / 
                               
                                 η 
                                 b 
                               
                             
                           
                         
                         ) 
                       
                     
                   
                 
               
               
                   
               
               
                 Power Gain G a9   
                 n + 1 
               
               
                   
               
               
                 Efficiency Rating η a9   
                 
                   
                     
                       
                         
                           n 
                           + 
                           1 
                         
                         
                           n 
                           + 
                           
                             1 
                             / 
                             
                               η 
                               b 
                             
                           
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     When the output voltage V out  of the isolated DC-DC converter  920  is 1 VDC, the output voltage V out9  across the load terminals  946 ,  948  can have a −1 VDC offset and the performance characteristics listed in Table 18 can be achieved as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 18 
               
               
                   
               
             
            
               
                 Input Voltage V in   
                 n 
               
               
                 Input Voltage V in9   
                 n 
               
               
                 Output Voltage V out9   
                 n + 1 
               
               
                   
               
               
                 Input current I in9   
                 
                   
                     
                       
                         n 
                         + 
                         
                           1 
                           
                             η 
                             b 
                           
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Input current I in   
                 
                   
                     
                       
                         1 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Output current I out9   
                 n 
               
               
                 Output current I out   
                 n 
               
               
                 Current I 9   
                 n 
               
               
                   
               
            
           
         
       
     
     The auto-converter  940  can have a larger power gain G a9 , higher efficiency nag, and smaller voltage gain G v9  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases the power gain G a9  increases, the efficiency η a9  approaches unity, and the voltage gain G v9  approaches unity. The efficiency η a9  can dramatically increase for larger n values. The auto-converter  940  can effectively be a small boost positive converter. The auto-converter  940  can provide higher power throughput and better efficiency than conventional topologies and can be smaller, more lightweight, and less expensive. 
       FIG.  11    illustrates an alternative embodiment of an auto-converter  1040  that is similar to, or the same in many respects as, the auto-converter  940  of  FIG.  10   . For example, the auto-converter  1040  can include an isolated DC-DC converter  1020  that includes an input circuit  1022  and an output circuit  1024  that has a voltage ratio of n:1. The input circuit  1022  can include a positive input terminal  1026  and a negative input terminal  1028 . The output circuit  1024  can include a positive output terminal  1032  and a negative output terminal  1034 . The auto-converter  1040  can include a positive source terminal  1042 , a negative source terminal  1044 , a positive load terminal  1046 , and a negative load terminal  1048 . 
     A DC power source  1030  can provide DC input power S in10  to the auto-converter  1040  in the form of an input current Ingo at the negative source terminal  1044  at an input voltage V in10  provided across the positive and negative source terminals  1042 ,  1044 . The input current Lao can flow out of the negative source terminal  1044  and towards the DC power source  1030 . DC output power S a10  can be delivered to a DC load  1036  in the form of an output current I out10  at the negative load terminal  1046  at an output voltage V out10  provided across the positive and negative load terminals  1046 ,  1048 . The output current I out10  can flow out of the DC load  1036  and towards the negative load terminal  1048 . The auto-converter  1040  can have a voltage gain G v10  (defined as V out10 /V in10 ), a current gain G i10  (defined as I out10 /I in10 ), a power gain G a10  (defined as S a10 /S b ), and an efficiency rating η a10  (S a10 /S in10 ) which ideally is unity but, in reality, is less than unity. 
     The positive input terminal  1026  of the isolated DC-DC converter  1020  can be galvanically connected to the main bus  1051  at location  1052 . The negative input terminal  1028  of the isolated DC-DC converter  1020  can be galvanically connected to the negative source terminal  1044 . Different from the auto-converter  940 , however, the positive output terminal  1032  of the isolated DC-DC converter  1020  can be galvanically connected to the negative load terminal  1048 . The negative output terminal  1034  can be galvanically connected to the negative input terminal  1028  such that the negative input terminal  1028 , the negative output terminal  1034 , and the negative source terminal  1044  are galvanically connected together at location  1054 . The positive output terminal  1032  can be galvanically connected to the negative load terminal  1048 . A current I 10  can flow out of the negative output terminal  1034  into the location  1054  such that the currents are added on the high voltage side of the isolated DC-DC converter  1020 . 
     By wiring the isolated DC-DC converter  1020  in this manner, the auto-converter  1040  can have the performance characteristics listed in Table 19 listed as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 19 
               
               
                   
               
             
            
               
                 Voltage Gain G v10   
                 
                   
                     
                       
                         
                           n 
                           - 
                           1 
                         
                         n 
                       
                     
                   
                 
               
               
                   
               
               
                 Current Gain G i10   
                 
                   
                     
                       
                         n 
                         
                           n 
                           - 
                           
                             η 
                             b 
                           
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Power Gain G a10   
                 n − 1 
               
               
                   
               
               
                 Efficiency Rating η a10   
                 
                   
                     
                       
                         
                           n 
                           - 
                           1 
                         
                         
                           n 
                           - 
                           
                             η 
                             b 
                           
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     When the output voltage V out  of the isolated DC-DC converter  1020  is 1 VDC, the output voltage V out10  across the load terminals can have a 1 VDC offset and the performance characteristics listed in Table 20 can be achieved as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 20 
               
               
                   
                   
               
             
            
               
                   
                 Input Voltage V in   
                 n 
               
               
                   
                 Input Voltage V in10   
                 n 
               
               
                   
                 Output Voltage 
                 n − 1 
               
               
                   
                 V out10   
                   
               
               
                   
                 Input current I in10   
                 n − η b   
               
               
                   
                 Input current I in   
                 η b   
               
               
                   
                 Output current I out10   
                 n 
               
               
                   
                 Output current I out   
                 n 
               
               
                   
                 A current I 10   
                 n 
               
               
                   
                   
               
            
           
         
       
     
     The auto-converter  1040  can have a larger power gain G a10 , higher efficiency η a10 , and smaller voltage gain G v10  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases the power gain G a10  increases, the efficiency η a10  approaches unity, and the voltage gain G v10  approaches unity. The efficiency η a10  can dramatically increase for larger n values. The auto-converter  1040  can effectively be a small buck negative converter and because the output current I out  flows into the isolated DC-DC converter  1020  and the input current I in  flows out of the isolated DC-DC converter  1020 , the isolated DC-DC converter  1020  can instead be configured as a reverse converter. 
       FIG.  12    illustrates an alternative embodiment of an auto-converter  1140  that is similar to, or the same in many respects as, the auto-converter  940  of  FIG.  10   . For example, the auto-converter  1140  can include an isolated DC-DC converter  1120  that includes an input circuit  1122  and an output circuit  1124  that has a voltage ratio of 1:n. The input circuit  1122  can include a positive input terminal  1126  and a negative input terminal  1128 . The output circuit  1124  can include a positive output terminal  1132  and a negative output terminal  1134 . The auto-converter  1140  can include a positive source terminal  1142 , a negative source terminal  1144 , a positive load terminal  1146 , and a negative load terminal  1148 . 
     A DC power source  1130  can provide DC input power S in11  to the auto-converter  1140  in the form of an input current I in11  at the negative source terminal  1144  at an input voltage V in11  provided across the positive and negative source terminals  1142 ,  1144 . The input current I in11  can flow out of the negative source terminal  1144  and towards the DC power source  1130 . DC output power S a11  can be delivered to a DC load  1136  in the form of an output current T out11  at the negative load terminal  1148  at an output voltage V out11  provided across the positive and negative load terminals  1146 ,  1148 . The output current I out11  can flow out of the DC load  1136  and towards the negative load terminal  1148 . The auto-converter  1140  can have a voltage gain G v11  (defined as V out11 /V in11 ), a current gain G i11  (defined as I out11 /I in11 ), a power gain G a11  (defined as S a11 /S b ), and an efficiency rating η a11  (defined as S a11 /S in11 ) which ideally is unity but, in reality, is less than unity. 
     The negative input terminal  1128  of the isolated DC-DC converter  1120  can be galvanically connected to the negative source terminal  1144 . The negative output terminal  1134  of the isolated DC-DC converter  1120  can be galvanically connected to the negative load terminal  1148 . Different from the auto-converter  940 , however, the input circuit  1122  and the output circuit  1124  have a voltage ratio of 1:n. In addition, the positive input terminal  1126  of the isolated DC-DC converter  1120  can be galvanically connected to the negative output terminal  1134  such that the positive input terminal  1126 , the negative output terminal  1134 , and the negative load terminal  1148  are galvanically connected together at location  1154 . The positive output terminal  1132  of the isolated DC-DC converter  1120  can be galvanically connected to the main bus  1151  at location  1152 . A current I 11  can flow into the positive input terminal  1126  from the location  1154  such that the currents are added on the high voltage side of the isolated DC-DC converter  1120 . 
     By wiring the isolated DC-DC converter  1120  in this manner, the auto-converter  1140  can have the performance characteristics listed in Table 21 listed as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 21 
               
               
                   
               
             
            
               
                 Voltage Gain G v11   
                 
                   
                     
                       
                         n 
                         
                           n 
                           + 
                           1 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Current Gain G i11   
                 
                   
                     
                       
                         1 
                         + 
                         
                           
                             η 
                             b 
                           
                           n 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Power Gain G a11   
                 
                   
                     
                       
                         
                           n 
                           
                             η 
                             b 
                           
                         
                         + 
                         1 
                       
                     
                   
                 
               
               
                   
               
               
                 Efficiency Rating η a11   
                 
                   
                     
                       
                         
                           n 
                           + 
                           
                             η 
                             b 
                           
                         
                         
                           n 
                           + 
                           1 
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     When the input voltage V in  of the isolated DC-DC converter  1120  is n VDC, the output voltage V out11  across the load terminals can have a 1 VDC offset and the performance characteristics listed in Table 22 can be achieved as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 22 
               
               
                   
               
             
            
               
                 Output Voltage V out   
                 n 
               
               
                 Input Voltage V in11   
                 n + 1 
               
               
                 Output Voltage V out11   
                 n 
               
               
                   
               
               
                 Input current I in11   
                 
                   
                     
                       
                         n 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Input current I in   
                 
                   
                     
                       
                         n 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Output current I out11   
                 
                   
                     
                       
                         
                           n 
                           
                             η 
                             b 
                           
                         
                         + 
                         1 
                       
                     
                   
                 
               
               
                   
               
               
                 Output current I out   
                 1 
               
               
                   
               
               
                 A current I 11   
                 
                   
                     
                       
                         n 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     The auto-converter  1140  can have a larger power gain G a11 , higher efficiency nail, and smaller voltage gain G v11  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases the power gain G a11  increases, the efficiency nail approaches unity, and the voltage gain G v11  approaches unity. The efficiency η a11  can dramatically increase for larger n values. The auto-converter  1140  can effectively be a small buck positive converter. 
       FIG.  13    illustrates an alternative embodiment of an auto-converter  1240  that is similar to, or the same in many respects as, the auto-converter  940  of  FIG.  10   . For example, the auto-converter  1240  can include an isolated DC-DC converter  1220  that includes an input circuit  1222  and an output circuit  1224  that has a voltage ratio of 1:n. The input circuit  1222  can include a positive input terminal  1226  and a negative input terminal  1228 . The output circuit  1224  can include a positive output terminal  1232  and a negative output terminal  1234 . The auto-converter  1240  can include a positive source terminal  1242 , a negative source terminal  1244 , a positive load terminal  1246 , and a negative load terminal  1248 . 
     A DC power source  1230  can provide DC input power S in12  to the auto-converter  1240  in the form of an input current I in12  at the negative source terminal  1244  at an input voltage V in12  provided across the positive and negative source terminals  1242 ,  1244 . The input current I in12  can flow out of the negative source terminal  1244  and towards the DC power source  1230 . DC output power S a12  can be delivered to a DC load  1236  in the form of an output current I in12  at the negative load terminal  1248  at an output voltage V out12  provided across the positive and negative load terminals  1246 ,  1248 . The output current I out12  can flow out of the DC load  1236  and towards the negative load terminal  1248 . The auto-converter  1240  can have a voltage gain G v12  (defined as V out12 /V in12 ), a current gain G i12  (defined as I out12 /I in12 ), a power gain G a12  (defined as S a12 /S b ), and an efficiency rating η a12  (defined as S a12 /S in12 ) which ideally is unity but, in reality, is less than unity. 
     The negative output terminal  1234  of the isolated DC-DC converter  1220  can be galvanically connected to the negative load terminal  1248 . Different from the auto-converter  940 , however, the input circuit  1222  and the output circuit  1224  have a voltage ratio of 1:n. In addition, the positive input terminal  1226  of the isolated DC-DC converter  1220  can be galvanically connected to the negative source terminal  1244 . The negative input terminal  1228  can be galvanically connected to the negative output terminal  1234  such that the negative input terminal  1228 , the negative output terminal  1234 , and the negative load terminal  1248  are galvanically connected together at location  1254 . The positive output terminal  1232  of the isolated DC-DC converter  1220  can be galvanically connected to the main bus  1251  at location  1252 . A current I 12  can flow into the negative input terminal  1228  from the location  1254  such that the currents are added on the high voltage side of the isolated DC-DC converter  1220 . 
     By wiring the isolated DC-DC converter  1220  in this manner, the auto-converter  1240  can have the performance characteristics listed in Table 23 listed as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 23 
               
               
                   
               
             
            
               
                 Voltage Gain G v12   
                 
                   
                     
                       
                         n 
                         
                           n 
                           - 
                           1 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Current Gain G i12   
                 
                   
                     
                       
                         1 
                         - 
                         
                           1 
                           
                             n 
                             * 
                             
                               η 
                               b 
                             
                           
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Power Gain G a12   
                 n * η b  − 1 
               
               
                   
               
               
                 Efficiency Rating η a12   
                 
                   
                     
                       
                         
                           n 
                           - 
                           
                             1 
                             
                               η 
                               b 
                             
                           
                         
                         
                           n 
                           - 
                           1 
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     When the input voltage V in  of the isolated DC-DC converter  1220  is 1 VDC, the output voltage V out12  across the load terminals can have a −1 VDC offset and the performance characteristics listed in Table 24 can be achieved as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 24 
               
               
                   
                   
               
             
            
               
                   
                 Output Voltage V out   
                 n 
               
               
                   
                 Input Voltage V in12   
                 n −1 
               
               
                   
                 Output Voltage 
                 n 
               
               
                   
                 V out12   
                   
               
               
                   
                 Input current I in12   
                 n * η b   
               
               
                   
                 Input current I in   
                 n * η b   
               
               
                   
                 Output current I out12   
                 n * η b  − 1 
               
               
                   
                 Output current I out   
                 1 
               
               
                   
                 A current I 12   
                 n * η b   
               
               
                   
                   
               
            
           
         
       
     
     The auto-converter  1240  can have a larger power gain G a12 , higher efficiency η a12 , and smaller voltage gain G v12  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases the power gain G a12  increases, the efficiency η a12  approaches unity, and the voltage gain G v12  approaches unity. The efficiency η a12  can dramatically increase for larger n values. The auto-converter  1240  can effectively be a small boost negative converter and because the output current I out  flows into the isolated DC-DC converter  1220  and the input current I in  flows out of the isolated DC-DC converter  1220 , the isolated DC-DC converter  1020  can instead be configured as a reverse converter. 
       FIG.  14    illustrates an alternative embodiment of an auto-converter  1340  that is similar to, or the same in many respects as, the auto-converter  940  of  FIG.  10   . For example, the auto-converter  1340  can include an isolated DC-DC converter  1320  that includes an input circuit  1322  and an output circuit  1324 . The input circuit  1322  can include a positive input terminal  1326  and a negative input terminal  1328 . The output circuit  1324  can include a positive output terminal  1332  and a negative output terminal  1334 . An input current I in  can be present at the positive input terminal  1326  and an output current I out  can be present at the positive output terminal  1332 . The auto-converter  1340  can include a positive source terminal  1342 , a negative source terminal  1344 , a positive load terminal  1346 , and a negative load terminal  1348 . A DC power source  1330  can provide DC input power S in13  to the auto-converter  1340  in the form of an input current I in13  at the positive source terminal  1342  at an input voltage V in13  provided across the positive and negative source terminals  1342 ,  1344 . During operation, a current I 13  can be generated. 
     DC output power S a13  can be delivered to a DC load  1336  in the form of an output current T out13  at the positive load terminal  1346  at an output voltage V out13  provided across the positive and negative load terminals  1346 ,  1348 . The auto-converter  1340  can have a voltage gain G v13  (defined as V out13 /V in13 ), a current gain G i13  (defined as I out13 /I in13 ), a power gain G a13  (defined as S a13 /S b ), and an efficiency rating η a13  (S a13 /S in13 ) which ideally is unity but, in reality, is less than unity. The auto-converter  1340  can be different from the auto-converter  940  in that the input circuit  1322  and the output circuit  1324  has a voltage ratio of 1:n. 
     By wiring the isolated DC-DC converter  1320  in this manner, the auto-converter  1340  can have the performance characteristics listed in Table 25 listed as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 25 
               
               
                   
               
             
            
               
                 Voltage Gain G v13   
                 n + 1 
               
               
                   
               
               
                 Current Gain G i13   
                 
                   
                     
                       
                         1 
                         
                           
                             n 
                             
                               η 
                               b 
                             
                           
                           + 
                           1 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Power Gain G a13   
                 
                   
                     
                       
                         
                           n 
                           + 
                           1 
                         
                         n 
                       
                     
                   
                 
               
               
                   
               
               
                 Efficiency Rating η a13   
                 
                   
                     
                       
                         
                           n 
                           + 
                           1 
                         
                         
                           
                             n 
                             / 
                             
                               η 
                               b 
                             
                           
                           + 
                           1 
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     When the input voltage V in  of the isolated DC-DC converter  1320  is 1 VDC, the output voltage V out13  across the load terminals can have an offset of −n VDC and the performance characteristics listed in Table 22 can be achieved as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 26 
               
               
                   
               
             
            
               
                 Output Voltage V out   
                 n 
               
               
                 Input Voltage V in13   
                 1 
               
               
                 Output Voltage V out13   
                 n + 1 
               
               
                   
               
               
                 Input current I in13   
                 
                   
                     
                       
                         
                           n 
                           
                             η 
                             b 
                           
                         
                         + 
                         1 
                       
                     
                   
                 
               
               
                   
               
               
                 Input current I in   
                 
                   
                     
                       
                         n 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Output current I out13   
                 1 
               
               
                 Output current I out   
                 1 
               
               
                 A current I 13   
                 1 
               
               
                   
               
            
           
         
       
     
     The auto-converter  1340  can have a smaller power gain G a13  (e.g., closer to unity) and an efficiency flan that approaches the efficiency η b  of the isolated DC-DC converter  1320  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases, the power gain G a13  decreases (e.g., towards unity) and the efficiency η a13  of the auto-converter  1340  approaches the efficiency η b  of the isolated DC-DC converter  1320 . 
       FIG.  15    illustrates an alternative embodiment of an auto-converter  1440  that is similar to, or the same in many respects as, the auto-converter  1040  of  FIG.  11   . For example, the auto-converter  1440  can include an isolated DC-DC converter  1420  that includes an input circuit  1422  and an output circuit  1424 . The input circuit  1422  can include a positive input terminal  1426  and a negative input terminal  1428 . The output circuit  1424  can include a positive output terminal  1432  and a negative output terminal  1434 . An input current I in  can be present at the positive input terminal  1426  and an output current I out  can be present at the positive output terminal  1432 . The auto-converter  1440  can include a positive source terminal  1442 , a negative source terminal  1444 , a positive load terminal  1446 , and a negative load terminal  1448 . A DC power source  1430  can provide DC input power S in14  to the auto-converter  1440  in the form of an input current I in14  at the positive source terminal  1442  at an input voltage V in14  provided across the positive and negative source terminals  1442 ,  1444 . During operation, a current I 14  can be generated. 
     DC output power S a14  can be delivered to a DC load  1436  in the form of an output current I out14  at the positive load terminal  1446  at an output voltage V out14  provided across the positive and negative load terminals  1446 ,  1448 . The auto-converter  1440  can have a voltage gain G v14  (defined as V out14 /V in14 ), a current gain G i14  (defined as I out14 /I in14 ), a power gain G a14  (defined as S a14 /S b ), and an efficiency rating η a14  (S a14 /S in14 ) which ideally is unity but, in reality, is less than unity. The auto-converter  1440  can be different from the auto-converter  1140  in that the input circuit  1422  and the output circuit  1424  has a voltage ratio of n:1. 
     By wiring the isolated DC-DC converter  1420  in this manner, the auto-converter  1440  can have the performance characteristics listed in Table 27 listed as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 27 
               
               
                   
               
             
            
               
                 Voltage Gain G v14   
                 −(n − 1) 
               
               
                   
               
               
                 Current Gain G i14   
                 
                   
                     
                       
                         - 
                         
                           1 
                           
                             
                               n 
                               * 
                               
                                 η 
                                 b 
                               
                             
                             - 
                             1 
                           
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Power Gain G a14   
                 
                   
                     
                       
                         
                           - 
                           
                             ( 
                             
                               n 
                               - 
                               1 
                             
                             ) 
                           
                         
                         n 
                       
                     
                   
                 
               
               
                   
               
               
                 Efficiency Rating η a14   
                 
                   
                     
                       
                         
                           
                             n 
                             * 
                             
                               η 
                               b 
                             
                           
                           - 
                           1 
                         
                         
                           n 
                           - 
                           1 
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     When the input voltage V in  of the isolated DC-DC converter  1420  is 1 VDC, the output voltage V out14  across the load terminals can have an offset of +n VDC and the performance characteristics listed in Table 28 can be achieved as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 28 
               
               
                   
                   
               
             
            
               
                   
                 Output Voltage V out   
                 n 
               
               
                   
                 Input Voltage V in14   
                 1 
               
               
                   
                 Output Voltage 
                 —(n − 1) 
               
               
                   
                 V out14   
                   
               
               
                   
                 Input current I in14   
                 —(n * η b  − 1) 
               
               
                   
                 Input current I in   
                 n * η b   
               
               
                   
                 Output current I Out14   
                 1 
               
               
                   
                 Output current I out   
                 1 
               
               
                   
                 A current I 14   
                 1 
               
               
                   
                   
               
            
           
         
       
     
     The auto-converter  1440  can have a smaller power gain G a14  (e.g., closer to unity) and an efficiency η a14  that approaches the efficiency η b  of the isolated DC-DC converter  1420  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases, the power gain G a14  decreases (e.g., towards unity) and the efficiency η a14  of the auto-converter  1440  approaches the efficiency η b  of the isolated DC-DC converter  1420 . 
       FIG.  16    illustrates an alternative embodiment of an auto-converter  1540  that is similar to, or the same in many respects as, the auto-converter  1140  of  FIG.  12   . For example, the auto-converter  1540  can include an isolated DC-DC converter  1520  that includes an input circuit  1522  and an output circuit  1524 . The input circuit  1522  can include a positive input terminal  1526  and a negative input terminal  1528 . The output circuit  1524  can include a positive output terminal  1532  and a negative output terminal  1534 . An input current I in  can be present at the positive input terminal  1526  and an output current I out  can be present at the positive output terminal  1532 . The auto-converter  1540  can include a positive source terminal  1542 , a negative source terminal  1544 , a positive load terminal  1546 , and a negative load terminal  1548 . A DC power source  1530  can provide DC input power S in15  to the auto-converter  1540  in the form of an input current I in15  at the positive source terminal  1542  at an input voltage V in15  provided across the positive and negative source terminals  1542 ,  1544 . During operation, a current I 15  can be generated. 
     DC output power S a15  can be delivered to a DC load  1536  in the form of an output current T out15  at the positive load terminal  1546  at an output voltage V out15  provided across the positive and negative load terminals  1546 ,  1548 . The auto-converter  1540  can have a voltage gain G v15  (defined as V out15 /V in15 ), a current gain G i15  (defined as I out15 /I in15 ), a power gain G a15  (defined as S a15 /S b ), and an efficiency rating η a15  (S a15 /S in15 ) which ideally is unity but, in reality, is less than unity. The auto-converter  1540  can be different from the auto-converter  1140  in that the input circuit  1522  and the output circuit  1524  has a voltage ratio of n:1. 
     By wiring the isolated DC-DC converter  1520  in this manner, the auto-converter  1540  can have the performance characteristics listed in Table 29 listed as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 29 
               
               
                   
               
             
            
               
                 Voltage Gain G v15   
                 
                   
                     
                       
                         1 
                         
                           n 
                           + 
                           1 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Current Gain G i15   
                 n * η b  + 1 
               
               
                   
               
               
                 Power Gain G a15   
                 
                   
                     
                       
                         1 
                         + 
                         
                           1 
                           
                             n 
                             * 
                             
                               η 
                               b 
                             
                           
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Efficiency Rating η a15   
                 
                   
                     
                       
                         
                           
                             n 
                             * 
                             
                               η 
                               b 
                             
                           
                           + 
                           1 
                         
                         
                           n 
                           + 
                           1 
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     When the output voltage V out  of the isolated DC-DC converter  1520  is 1 VDC, the output voltage V out15  across the load terminals can have an offset of +n VDC and the performance characteristics listed in Table 30 can be achieved as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 30 
               
               
                   
               
             
            
               
                 Input Voltage V in   
                 n 
               
               
                 Input Voltage V in15   
                 n + 1 
               
               
                 Output Voltage V out15   
                 1 
               
               
                   
               
               
                 Input current I in15   
                 
                   
                     
                       
                         1 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Input current I in   
                 
                   
                     
                       
                         1 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Output current I out15   
                 
                   
                     
                       
                         n 
                         + 
                         
                           1 
                           
                             η 
                             b 
                           
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Output current I out   
                 n 
               
               
                   
               
               
                 A current I 15   
                 
                   
                     
                       
                         1 
                         
                           η 
                           b 
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     The auto-converter  1540  can have a smaller power gain G a15  (e.g., closer to unity) and an efficiency η a15  that approaches the efficiency η b  of the isolated DC-DC converter  1520  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases, the power gain G a15  decreases (e.g., towards unity) and the efficiency η a15  of the auto-converter  1540  approaches the efficiency η b  of the isolated DC-DC converter  1520 . 
       FIG.  17    illustrates an alternative embodiment of an auto-converter  1640  that is similar to, or the same in many respects as, the auto-converter  1240  of  FIG.  13   . For example, the auto-converter  1640  can include an isolated DC-DC converter  1620  that includes an input circuit  1622  and an output circuit  1624 . The input circuit  1622  can include a positive input terminal  1626  and a negative input terminal  1628 . The output circuit  1624  can include a positive output terminal  1632  and a negative output terminal  1634 . An input current I in  can be present at the positive input terminal  1626  and an output current I out  can be present at the positive output terminal  1632 . The auto-converter  1640  can include a positive source terminal  1642 , a negative source terminal  1644 , a positive load terminal  1646 , and a negative load terminal  1648 . A DC power source  1630  can provide DC input power S in16  to the auto-converter  1640  in the form of an input current I in16  at the positive source terminal  1642  at an input voltage V in16  provided across the positive and negative source terminals  1642 ,  1644 . During operation, a current I 16  can be generated. 
     DC output power S a16  can be delivered to a DC load  1636  in the form of an output current T out16  at the positive load terminal  1646  at an output voltage V out16  provided across the positive and negative load terminals  1646 ,  1648 . The auto-converter  1640  can have a voltage gain G v16  (defined as V out16 /V in16 ), a current gain G i16  (defined as I out16 /I in16 ), a power gain G a16  (defined as S a16 /S b ), and an efficiency rating η a16  (S a16 /S in16 ) which ideally is unity but, in reality, is less than unity. The auto-converter  1640  can be different from the auto-converter  1240  in that the input circuit  1622  and the output circuit  1624  has a voltage ratio of n:1. 
     By wiring the isolated DC-DC converter  1620  in this manner, the auto-converter  1640  can have the performance characteristics listed in Table 31 listed as a function of n. 
     
       
         
           
               
               
             
               
                 TABLE 31 
               
               
                   
               
             
            
               
                 Voltage Gain G v16   
                 
                   
                     
                       
                         
                           - 
                           1 
                         
                         
                           n 
                           - 
                           1 
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Current Gain G i16   
                 
                   
                     
                       
                         1 
                         - 
                         
                           n 
                           
                             η 
                             b 
                           
                         
                       
                     
                   
                 
               
               
                   
               
               
                 Power Gain G a16   
                 
                   
                     
                       
                         
                           
                             η 
                             b 
                           
                           n 
                         
                         - 
                         1 
                       
                     
                   
                 
               
               
                   
               
               
                 Efficiency Rating η a16   
                 
                   
                     
                       
                         
                           n 
                           - 
                           1 
                         
                         
                           
                             n 
                             / 
                             
                               η 
                               b 
                             
                           
                           - 
                           1 
                         
                       
                     
                   
                 
               
               
                   
               
            
           
         
       
     
     When the output voltage V out  of the isolated DC-DC converter  1620  is 1 VDC, the output voltage V out16  across the load terminals can have an offset of −n VDC and the performance characteristics listed in Table 32 can be achieved as a function of n. 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 32 
               
               
                   
                   
               
             
            
               
                   
                 Input Voltage V in   
                 n 
               
               
                   
                 Input Voltage V in16   
                 —(n − 1) 
               
               
                   
                 Output Voltage 
                 1 
               
               
                   
                 V out16   
                   
               
               
                   
                 Input current I in16   
                 η b   
               
               
                   
                 Input current I in   
                 η b   
               
               
                   
                 Output current I out16   
                 —(n − η b ) 
               
               
                   
                 Output current I out   
                 n 
               
               
                   
                 A current I 16   
                 η b   
               
               
                   
                   
               
            
           
         
       
     
     The auto-converter  1640  can have a smaller power gain G a16  (e.g., closer to unity) and an efficiency η a16  that approaches the efficiency η b  of the isolated DC-DC converter  1620  than the conventional isolated DC-DC converter  20  illustrated in  FIG.  1   . As the value of n increases, the power gain G a16  decreases (e.g., towards unity) and the efficiency η a16  of the auto-converter  1640  approaches the efficiency η b  of the isolated DC-DC converter  1620 . 
     The foregoing description of embodiments and examples of the disclosure has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the forms described. Numerous modifications are possible in light of the above teachings. Some of those modifications have been discussed and others will be understood by those skilled in the art. The embodiments were chosen and described in order to best illustrate the principles of the disclosure and various embodiments as are suited to the particular use contemplated. The scope of the disclosure is, of course, not limited to the examples or embodiments set forth herein, but can be employed in any number of applications and equivalent devices by those of ordinary skill in the art. Rather it is hereby intended the scope of the invention be defined by the claims appended hereto. Also, for any methods claimed and/or described, regardless of whether the method is described in conjunction with a flow diagram, it should be understood that unless otherwise specified or required by context, any explicit or implicit ordering of steps performed in the execution of a method does not imply that those steps must be performed in the order presented and may be performed in a different order or in parallel.