Patent Publication Number: US-6700807-B1

Title: Flexible converter

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present invention claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 60/294,529, filed May 30, 2001, which is herein incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to the field of converters, and particularly to a flexible converter. 
     BACKGROUND OF THE INVENTION 
     The use of electronic devices in society has become more and more pervasive as these devices become a part of everyday life. Because of the wide variety of uses, electronic devices are typically configured and optimized for operation in the contemplated environments. For example, electronic devices configured for mobile applications typically have power requirements based on conservation of power for extended operational ability while electronic devices having a readily accessible external power supply are configured for speed of operation and performance, with power efficiency being a lower consideration. However, with recent advances in electronics and power supply, users of devices in mobile operations are desirous of the full range of functionality achieved in office settings, especially as devices are configured for interoperability between mobile and office applications. 
     For example, preferred uses of electrical and electronic type equipment that was previously configured only for an office environment have evolved into those same uses in a “mobile” or “portable” environment. Such uses typically require a portable power source, such as a battery, solar power cell, and the like. The most conventional type of portable power sources for most mobile electric and electronic devices include a battery. Batteries may be classified broadly into rechargeable and expendable types, with a variety of electrical and physical characteristic subclasses. 
     In addition, batteries may not have a completely constant output over the span of a discharge cycle, which may vary greatly depending on the type of battery involved. Therefore, with the use of a battery, a variety of considerations must be addressed for efficient utilization. For example, electronic devices configured to use the power of a battery over a battery&#39;s intended discharge cycle may require a minimum supply voltage which exceeds the supply voltage requirements of the device. To determine this minimum supply voltage, a battery is typically rated at a minimum voltage level so during the life cycle of the battery, the output voltage exceeds the nominal, rated voltage level. 
     Some electronic circuits of electronic devices may accept excess voltage output without a problem. However, circuits of other devices may need to be protected from voltages that exceed a certain design voltage by a percentage of the nominal voltage, such as, for example, some percent or more of the rated voltage. A voltage regulating circuit may be interposed between the power terminals of an electronic device and a particular circuit element. 
     However, such a method may require modifying external components based on the desired power output. This obligates a manufacturer of the device to know the required and contemplated loads of devices utilizing the converter. Thus, such devices are inflexible and are designed only to provide a contemplated load. 
     Another method involved running at lower levels of efficiency (when the power output is not well-matched to the operating mode) such as by utilizing a fixed frequency and/or duty cycle. Low levels of efficiency are not desirable during battery operation. For example, with a portable device, such as a wireless phone, portable computer, personal digital assistant, and the like, efficient use promotes user satisfaction. Therefore, users of these devices may experience decreased operational time, may be limited in accessible features due to limited available power resources, and the like. 
     For example, electronic devices which include a voltage protection circuit may cause higher power batteries to perform less efficiently. If, for instance, a protection circuit is a dissipative power regulating circuit, a substantial part of the excess power may be dissipated or slowly drained by the protection circuit in effecting regulation of the supply voltage. This power drainage may significantly diminish the life cycle or discharge cycle of the respective battery, making the battery appear to be less efficient than a comparable battery requiring less regulation over its discharge cycle. 
     A further method involved increasing the amount of output voltage ripple depending on the load. Although voltage ripple may be acceptable in certain applications, some devices may not tolerate the voltage ripple, and may be thus susceptible to operational problems and malfunctions. 
     Therefore, it would be desirable to provide a flexible converter. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention is directed to a flexible converter. A flexible converter of the present invention may provide a desired output utilizing a variety of methods, systems and apparatus without departing from the spirit and scope of the present invention. In a first aspect of the present invention, a system for converting an input power supply into a desired output supply includes a converter, at least one comparator coupled to an output supply of the converter, and a controller coupled to the comparator. The converter is capable of providing an output supply from an input supply coupled to the converter. The comparator is capable of measuring the output supply in relation to a target output supply. The controller is capable of implementing a process within the converter such that the output supply is approximately equal to the target output supply, wherein the target output supply is retrievable by the controller. 
     In a second aspect of the present invention, a method includes loading an initial configuration including at least one power characteristic into a converter. The converter is suitable for providing power to an electrical device. A power output is generated having the at least one power characteristic. The power output is monitored with a comparator, the comparator suitable for measuring the power characteristic. 
     In a third aspect of the present invention, an apparatus for controlling a voltage includes a converter, at least one comparator, and a controller coupled to the comparator. The converter is capable of providing an output voltage from a received input voltage. The comparator is capable of measuring the output voltage in relation to a target output voltage. The controller is capable of implementing a process within the converter for at least one of increasing and decreasing the output voltage. The output voltage is approximately equal to the target output voltage and is retrievable by the controller. 
     In a fourth aspect of the present invention, a system for converting an input power supply into a desired output supply includes a means for converting an output supply from an input supply coupled to the converting means, the output supply including at least one power characteristic. Means for comparing is coupled to the output supply of the converting means, the comparing means being capable of measuring the output supply in relation to a target output supply having the at least one power characteristic. Means for controlling is coupled to the comparing means, the controlling means is capable of implementing a process within the converting means such that the output supply is approximately equal to the target output supply including the characteristic. 
    
    
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention and together with the general description, serve to explain the principles of the invention. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The numerous advantages of the present invention may be better understood by those skilled in the art by reference to the accompanying figures in which: 
     FIG. 1 is a block diagram of an exemplary embodiment of the present invention wherein a system for automatically converting a power output to a target level from an input voltage or current is shown; 
     FIG. 2 is a diagram of an embodiment of the present invention wherein of a power conversion circuit in accordance with the present invention is shown; 
     FIG. 3A is a diagram of an embodiment of the present invention employing an inductor-based converter; 
     FIG. 3B is a diagram of an embodiment of the present invention employing a charge pump-based converter; 
     FIG. 4 is a block diagram of an embodiment of the present invention illustrating an alternate embodiment of the exemplary embodiment depicted in FIG. 3A; 
     FIG. 5 is a flow diagram depicting an exemplary method of the present invention in which a voltage converter including control logic is monitored and output adjusted based on monitored performance; 
     FIG. 6 is a flow diagram illustrating an exemplary method of the present invention wherein logic of a converter finds connected devices, determines corresponding power characteristics, monitors for changes based on addition/subtraction of devices, and adjusts accordingly; 
     FIG. 7 is a flow diagram illustrating an embodiment of the present invention wherein logic of a converter adjusts output to a minimum level for connected devices; 
     FIG. 8 is a flow diagram of an exemplary method of the present invention in which a single comparator is utilized to determine a target output duty cycle and drive strength; 
     FIG. 9 is a flow diagram depicting an embodiment of the present invention wherein a voltage converter configured as a boost converter monitors output for operation of extended periods of time to maximize efficiency; 
     FIG. 10 is a flow diagram illustrating an exemplary method of the present invention wherein an information handling system including a converter of the present invention configures output of a converter based on data received from devices coupled to the voltage converter; 
     FIG. 11 is a flow diagram depicting an exemplary method of the present invention in which an initial output of a voltage conversion circuit is determined based on identified devices and is monitored for further optimization of power efficiency; 
     FIG. 12 is a flow diagram of an exemplary embodiment of the present invention wherein a voltage converter, after reaching a regulated state based on data received from connected devices, recalibrates due to devices entering a power conservation state; 
     FIG. 13 is a flow diagram of an exemplary method of the present invention in which a voltage converter included in a USB interface utilizes protocol data to determine power needs of connected devices; 
     FIG. 14 is a flow diagram illustrating an exemplary method of the present invention wherein a comparator output of a voltage converter is utilized to trigger an interrupt; 
     FIG. 15 is a flow diagram of an exemplary method of the present invention wherein a comparator is utilized to indicate power level operation outside of a performance level for a specified period of time; 
     FIG. 16 is a flow diagram of an exemplary embodiment of the present invention wherein a converter included in a USB interface is suitable for supporting a first current output corresponding to a standard USB current output and a second current output suitable for supporting mobile applications; 
     FIG. 17 is a flow diagram illustrating an exemplary method of the present invention wherein power utilization of a device connected to a converter of the present invention is used to detect error conditions; and 
     FIG. 18 is a flow diagram depicting an exemplary method of the present invention wherein power utilization by a device connected to a converter of the present invention may be utilized to determine whether a condition which may damage a host and/or converter will occur. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to the presently preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. 
     Referring generally now to FIGS. 1 through 4 block diagrams depicting embodiments of the present invention are shown. 
     Referring to FIG. 1, an exemplary embodiment of a system  100  for automatically converting a power output to a target level from an input voltage or current is shown. An input supply  105  may include a input voltage supply or input current supply. The conversion circuitry  110  may increase or decrease the input supply  105  to obtain a desired output supply  120 . This may be accomplished via a processor  125  utilizing firmware  135  which may direct the operation of the components within the system  100 . 
     A comparator  130  may be coupled to the output supply in order to compare the output supply  120  with a target output supply. The comparator  130  may be coupled with the processor  125  and firmware  135  to alert the processor of the current output supply. The processor  125  and firmware  135  of the present invention may implement processes to ensure the output supply closely resembles the target output supply. For example, the processor may be coupled with a clock generator  140 . The clock generator  140  of the present invention may be capable of generating a clock with a desired frequency and a desired duty cycle. The duty cycle and frequency of the clock may control the desired effects of the conversion circuitry to manipulate the input supply into the target output supply. 
     A target output level may also be simply entered within the firmware  130  of the present invention. In an alternative embodiment of the present invention, the system  100  may be capable of determining a target output supply by connecting itself with a desired load. For example, a device could be connected to the output supply of the system. The system may be capable of determining the optimal power requirements for the device and providing those requirements. 
     Referring now to FIG. 2, an exemplary embodiment of a power conversion circuit  200  in accordance with the present invention is shown. A controller  210  may include a processor with firmware. Firmware utilized in conjunction with a processor may be capable of directing the operation of components within the power conversion circuit of the present invention in order to provide a desired power output. Clock generator logic  215  may be connected to the controller  210 . Clock generator logic may be used in conjunction with the controller to provide a low or high output according to a desired frequency and rate. An AND gate  220  may be coupled with the clock generator logic  215 , the controller  210 , and at least one or more voltage comparators  230 - 235 . If all of the inputs is “high”, the output of the AND gate may be high. A “high” output from the AND gate may turn transistor  240  on. 
     As shown in FIG. 2 in an embodiment of the invention, transistor  240  may be a metal-oxide-semiconductor field-effect transistor (MOSFET), however one of ordinary skill in the art may substitute other types of transistors including bipolar junction transistors without departing from the scope and spirit of the present invention. When transistor  240  is on, current may increase in the inductor  245  as the inductor  245  is pulled to ground. When transistor  240  is off, current may be dumped via a diode  250  to an output load  255 . The duty cycle of the clock generated by clock generator logic  215  may determine the amount of time transistor  240  is on, thus may determine the amount of current dumped to the output load  255 . By varying the duty cycle of the clock, the amount of current dumped to the output load  255  may be adjusted in order to provide a desirable output current and output voltage. 
     Referring to FIGS. 3A and 3B, exemplary embodiments of a power conversion circuit  300  of the present invention are shown. Power conversion circuit  300  may include alternative embodiments of implementing a system  100  for automatically converting a power output to a target level from an input voltage or current as shown in FIG.  1 . FIG. 3A may depict an inductor-based converter in accordance with the present invention where FIG. 3B may depict a charge pump converter in accordance with the present invention. It should be recognized by one of ordinary skill in the art that various methods of converting a power supply exist and may be utilized in accordance with the present invention without departing from the scope and spirit of the invention. FIGS. 3A and 3B merely depict embodiments of the present invention wherein two examples of converters have been shown. 
     The power conversion circuit  300  as shown in FIGS. 3A and 3B of the present invention may utilize an input voltage  310  source which may provide an initial amount of current and voltage to the circuit. Through a process performed in accordance with the present invention, a desired amount of current, a desired voltage, or both may be supplied to an output device. A configurator  320  may provide an initial configuration into the power conversion circuit of the present invention. Configurator  320  may be in the form of a processor with firmware. A processor may include a variety of processors and contemplated by a person of ordinary skill in the art. A clock source  330  connected to configurator  320  may generate a clock. The clock source  330  may be capable of producing a clock operating at a specified frequency and duty cycles. Further, clock source  330  may be adjustable to allow generation of a clock with a wide frequency range and duty cycle. Variation of the frequency and duty cycle of the clock generated by clock source  330  may provide the ability to adjust a current and voltage output from the power conversion circuit of the present invention. A drive and power control cell  340  may respond to output supply level, the clock generated by clock source  330 , and the power configuration settings. 
     In FIG. 3A, an inductor-based conversion embodiment, an output drive  350  coupled to the drive and power control cell  340  may receive input from drive and power control cell  340  to determine whether to output a low or zero voltage or output a high voltage. Output drive  350  may be implemented in one of several ways by one of ordinary skill in the art including TTL logic and transistor logic. If a high voltage is output from output drive  350 , transistor  360  may be on. As shown in FIG. 3A in an embodiment of the invention, transistor  360  may be a metal-oxide-semiconductor field-effect transistor (MOSFET), however, one of ordinary skill in the art may substitute other types of transistors including bipolar junction transistors without departing from the scope and spirit of the present invention. When transistor  360  is on, current may increase in the inductor  370  as the inductor is pulled to ground. When transistor  360  is off, current may be dumped via a diode  374  to an output load  378 . In a preferred embodiment, diode  374  may be a Shottky diode, however, other types of diodes may be utilized in accordance with the present invention without departing from the scope and spirit of the present invention. The duty cycle of the clock generated by clock source  330  may determine the amount of time transistor  360  is on, thus may determine the amount of current dumped to the output load  378 . By varying the duty cycle of the clock, the amount of current dumped to the output load may be adjusted in order to provide a desirable output current and output voltage. 
     Referring to FIG. 3B, a charge pump-based conversion embodiment, switch drivers  365  coupled to the drive and power control cell  340  may receive input from drive and power control cell  340  to drive switches  366 - 369 . Switches  366 - 369  may operate in combination to add or remove charge from charge pump  373  depending upon whether an output supply may need to be decreased or increased. Further, drive and power control  340  may control switch drivers  365 , which in turn, may control switches  366 - 369 , to produce a desired output supply. Other ways of implementing a charge pump-based converter may be utilized by one of ordinary skill in the art without departing from the scope and spirit of the present invention. 
     An advantageous aspect of the power conversion circuit  300  of the present invention as shown in both FIGS. 3A and 3B is the ability to monitor the output voltage of the power conversion circuit. One or more comparators  386 - 390  may be utilized to compare the output voltage with a reference voltage  392 . Upon a comparison with a reference voltage, signals may be delivered to the configurator  320  and drive and power control cell  340  of the present invention. A first comparator  386  may be set at a target output voltage level with additional comparators being set at various levels above and below a target output voltage level that may indicate that the output is above or below a target output voltage level by various amounts. A resistor divider  394  may be placed between the output voltage and each of the comparators  386 - 390  in order to more precisely determine the value of the output voltage. 
     The outputs of one or more comparators  386 - 390  may be monitored by firmware of configurator  320 . Firmware, based upon the outputs from one or more comparators  386 - 390  may adjust the output accordingly. For example, if the target output voltage level is too low, firmware may adjust the circuit to boost the output level. Adjustment of the operation of the circuit may be achieved by altering the duty cycle of the clock, altering the strength and size of output driver devices, or by altering the frequency of the clock. 
     Referring now to FIG. 4, an alternative embodiment of the power conversion circuit  400  of the present invention is shown. The power conversion circuit of FIG. 4 is substantially similar to the power conversion circuit as shown in FIG. 3A, however, an alternative embodiment of a reference voltage  406  is shown. FIG. 4 includes reference voltage  406  which may be provided utilizing a voltage divider. Utilizing a voltage divider may be advantageous as it may allow for easier adjustment of the reference voltage. For example, if the target output voltage has been changed during the course of operation, it may be beneficial to adjust the reference voltage supplied to one or more comparators to provide a more accurate determination of the value of the output voltage. However, it should be understood by one of ordinary skill in the art that other ways of providing an adjustable reference voltage exist which would not depart from the scope and spirit of the present invention. 
     Referring generally now to FIG. 5 through 18, exemplary methods of the present invention are shown. A flexible converter of the present invention may provide a desired output utilizing a variety of methods without departing from the spirit and scope of the present invention. The following exemplary methods should not be taken as limiting, and it should be realized elements and steps of the methods may be recombined and removed as contemplated by a person of ordinary skill in the art. Further, methods are discussed which include voltage, current, noise, signal clarity, duty cycle, frequency, and the like. It should be realized methods discussed and claimed contemplate additional power characteristics, and further methods discussed contemplating a single power characteristic are to be taken to include other power characteristics as stated and as contemplated by a person of ordinary skill in the art without departing from the spirit and scope of the present invention. 
     Referring now to FIG. 5, an exemplary method  500  of the present invention is shown wherein a voltage converter including control logic is monitored and output adjusted based on monitored performance. An initial configuration is loaded into a control circuit  502  of a voltage converter, such as the voltage converters shown in FIGS. 1 through 4. For example, a clock source generates a clock with a specified frequency and duty cycle  504 , and supplies the signal to control circuitry. The control logic feeds an output drive circuit controlling flow of current through an inductor  506 , such as an external inductor. The voltage signal is monitored with comparators to measure the outputted voltage  508 . Thus, firmware operating a processor of the voltage converter may monitor comparator outputs and adjust control accordingly  510 . For example, a change in clock duty cycle  512  may be performed, change in strength/size of output driver devices  514 , clock frequency changes  516 , and other  518  changes as contemplated by a person of ordinary skill in the art, such as a combination of the previous changes, additional changes, and the like. 
     Referring now to FIG. 6, an exemplary method  600  of the present invention is shown wherein logic of a converter finds connected devices, determines corresponding power characteristics, monitors for changes based on addition/subtraction of devices, and adjusts accordingly. For example, device logic finds connected devices and corresponding power characteristics  602 . Consequently, logic may communicate through a connected bus and bus protocols to determine the characteristics of a connected device, may identify a connected device and query a database of device characteristics, and the like. An initial configuration is loaded  604  based on the found characteristics. For instance, a clock source may generate a clock signal with specified characteristics  606 . The control logic then feeds the output drive circuit  608  to provide a corresponding power characteristic for the found connected devices. Firmware, as implemented through a processor, controller, and the like, monitors comparator outputs and adjusts control accordingly  610 . For instance, if the current needs of devices change, the output of the converter may be adjusted. 
     Additionally, if a device is added or subtracted to a system utilizing the converter, additional adjustments may be needed. For example, if a device is added and/or subtracted  612  to an output of a converter circuit of the present invention, logic may determine the required power characteristics for the remaining devices  614  and adjust characteristics based on the determination  616 . For example, a current conversion circuit may identify the type of device added utilizing bus protocols, such as universal serial bus (USB), and the like, and determine the desired current based on a corresponding entry in a look-up table. Further, a current conversion circuit may identify through a bus protocol the action of adding and/or deleting a device from the circuit, and thus reinitiate monitoring of the circuit for desired changes. 
     Referring now to FIG. 7, an exemplary method  700  of the present invention is shown wherein logic of a converter adjusts output to a minimum level for connected devices. Logic of a converter, such as a voltage converter, finds connected devices  702 . A minimum operational voltage of the connected devices is determined  704 . Determining a minimum operational voltage may include utilizing a previously stored value for operational voltage encountered, a preprogrammed initial voltage, and the like. 
     An initial configuration is then loaded  706  based on the determined minimum operational voltage. Control logic then feeds the output drive circuit  708 . Firmware monitors comparator outputs and adjusts control accordingly  710 . For example, even though a minimum operational voltage was determined, due to operational characteristics that may be encountered by the connected devices, such as a power-saving mode, high-power performance mode, and the like, it may be desirable to reconfigure output of the voltage converter to correspond to the changing conditions. 
     Additionally, if a device is added and/or subtracted  712 , such as the replacement of an existing connected device with another device, it may be necessary to reconfigure the output. Thus, the logic may determine a new minimum voltage  714  and adjust characteristics due to the determination  716 . For example, a device may be replaced on an interface with a device having different power requirements, such as a powered connection to a first device as opposed to a connection which is un-powered, such as a pure data transfer connection. Therefore, the voltage output may be reconfigured for the change. 
     Referring now to FIG. 8, an exemplary method  800  of the present invention is shown wherein a single comparator is utilized to determine a target output duty cycle and drive strength. A converter, configured as a boost converter, is configured for minimum drive operation  802 , such as by employing a minimum duty cycle, minimum drive output, and the like. The converter begins operation  804 , and reaches a regulated state  806 . A first comparator reads an output regulated state  808 . If the regulated state is acceptable  810 , such as within normal operating range for connected devices, no changes are made, and monitoring continues. However, if the regulated state is not within normal operating range for a connected device, a determination is made as to whether the drive settings are at the maximum level  812 . If the drive settings are at maximum, the converter may be shut down  814  for failure to regulate. However, if the drive settings are not at the maximum level  812 , and if duty cycle is lower than the maximum duty cycle, the duty cycle may be increased, the drive strength may be increased  816 , and the like. Thus, power efficient operation of a converter may be achieved, such as by increasing efficiency by configuring a boost cell to supply the smallest (or weakest) drive setting that properly supplies the desired load. 
     Referring now to FIG. 9, an embodiment  900  of the present invention is shown wherein a voltage converter configured as a boost converter monitors output for operation of extended periods of time to maximize efficiency. A boost converter is configured for minimum drive operation  902 , such as by setting the duty cycle and output drive to minimum operational values, and operation of the converter is begun  904 . After the boost converter has regulated  906 , the output regulated state is read at a first comparator  908 . In this example, the first comparator is configured to “trip” at a target output voltage. 
     If the first comparator is within range of the target output voltage  910 , a determination is made if the output is acceptable for an extended period of time. For example, periodic sampling may be made to determine if the device and/or output of the voltage converter is within a specified range, what trends in output are occurring which are undesirable, and the like. If device operation and/or output voltage is not within range of the target output voltage for an extended period of time  912 , monitoring may continue. However, if a determination is made that operation may continue for an extended period of time  912 , drive settings are reduced by one increment  914  (which contemplates an infinite range of movement). For instance, a duty cycle, drive strength, a combination of duty cycle and drive strength, and the like may be reduced as contemplated by a person of ordinary skill in the art. 
     If the first comparator is not within range of the target output voltage  910  as indicated by the first comparator, a determination is made as to whether the drive settings are at maximum  916 . If the drive settings are at maximum, the voltage converter may shut down  918  for failure to regulate, thereby preventing damage to connected devices, the circuit itself, a host system, and the like. If the drive settings are not at maximum (or optimum), a second drive strength may be selected from a matrix based on current settings and additional comparator indications. For example, a second comparator may be configured to “trip” at a voltage which is 95 percent of the target voltage and a third comparator may be configured to “trip” at a voltage which corresponds to 90 percent of the target voltage  920 . The output from the first comparator, second comparator and third comparator may thus be utilized in conjunction with a look up table of configuration settings  922  to determine a new configuration, such as converter settings, for the voltage converter. Thus, efficiency may be optimized by continuously turning drive levels down, i.e. reducing power requirements, if possible. 
     Referring now to FIG. 10, an exemplary method  1000  of the present invention is shown wherein an information handling system including a converter of the present invention configures output of a converter based on data received from devices coupled to the voltage converter, the devices utilizing the converter output. An information handling system is initiated  1002 , such as by performing a “warm” or “cold” boot. Electronic devices connected to the converter are queried  1004 . The converter then receives information regarding voltage needs  1006 . For example, a device may receive the query, and transmit data regarding power needs  1008 , such as voltage, current, duty cycle, and the like. Additionally, a device may return a device identifier, which is referenced in a look-up table for corresponding requirements. Such referencing may be performed by a converter of the present invention, information handling system, and the like  1010 . Further, a desired power characteristic may be based on calculations and other methods as contemplated by a person of ordinary skill in the art. 
     The configuration is then loaded  1012  and operation commences. Therefore, if a device is added and/or subtracted  1014 , a new determination of power requirements may be made. For example, logic may determine a new minimum voltage  1016  based on, for example, a referenced look-up table indexed by device type, so that the logic may adjust the output characteristics based on the determination  1018 . In this way, a determination of optimum power characteristics may be made based on device identifiers as referenced in a look-up table; actual transmittal of device requirements by the device itself; made based on device identifiers as referenced in a look-up table by an information handling system, the table either located locally on the information handling system or accessible over a network; and the like as contemplated by a person of ordinary skill in the art. Additionally, it is contemplated the power supply of the present invention may monitor load and adjust supply accordingly. 
     Referring now to FIG. 11, an exemplary method  1100  of the present invention is shown wherein an initial output of a voltage conversion circuit is determined based on identified devices and is monitored for further optimization of power efficiency. An information handling system, such as a desktop computer, server, internet appliance, personal digital assistant, convergence system, and the like, is initiated  1102 . Devices connected to a voltage converter are queried  1104 . The devices receive the query, and return data regarding device voltage needs  1106 , such as device identifiers, voltage requirement values, and the like. The voltage converter then receives data regarding device voltage needs  1108 , such as receipt of a corresponding entry from a look-up table, and loads the configuration  1110  such that the output drive circuit may be implemented  1112  at an initial level. 
     The voltage converter then monitors output and adjusts boost control accordingly  1114 , such as through the use of comparators, receipt of an interrupt, and the like. If a device is added and/or subtracted  1116 , a new minimum voltage may be determined  1118  based upon the identified devices. Further, if a device is subtracted, i.e. disconnected from the voltage converter, the voltage converter may adjust the output  1120  based upon the derivation of the initial value. For example, a voltage converter may determine each device has certain voltage requirements, and then utilize those requirements to determine a target voltage. If the voltage converter stored those values, then if a device is disconnected from the voltage converter, the voltage converter may utilize the preexisting information without requiring the access of a look-up table. Thus, if the look-up table was implemented as a database over a network connection; stored in local memory in an information handling system, such as in memory accessible over a bus and located “off-chip”; and the like, the device may efficiently determine an optimal voltage. 
     Referring now to FIG. 12, an exemplary method  1200  of the present invention is shown wherein a voltage converter, after reaching a regulated state based on data received from connected devices, recalibrates due to devices entering a power conservation state. A request is made for data regarding device voltage needs  1202 . 
     The device transmits data  1204 , and a voltage conversion circuit  1206  loads a configuration corresponding to the device voltage needs. The output drive circuit of the voltage converter is then fed in a manner corresponding to transmitted data  1208 . The voltage conversion circuit then monitors outputs and adjusts the controls accordingly  1210 . 
     For example, a device may enter into a low power state to conserve power, such as in a mobile application, sleep mode, due to inactivity of the device for a specified period of time, and the like. The device, when entering the low power mode, may transmit an identifier indicating entry into a low power state  1212 . Logic may then be utilized to determine a new minimum voltage  1214 , preferable a voltage which will supply the voltage required to operate the devices in an efficient manner. The characteristics of the voltage conversion circuit may then be adjusted due to the determination  1216 , such as by adjusting the duty cycle, clock cycle, and the like. 
     Referring now to FIG. 13, an exemplary method  1300  of the present invention is shown wherein a voltage converter included in a USB interface (or the like interface, such as IEEE 1394, SCSI, and others) utilizes protocol data to determine power needs of connected devices. Devices connected to a converter over a universal serial bus (USB) interface are queried  1302 . Data is received from the devices over the USB interface, the data including USB protocols  1304 . For example, a desired power characteristic may be determined based on USB protocol data  1306  or the like. The USB protocol data may indicate the identity of a device, which may then be utilized in conjunction with a look-up table, database, and the like to determine the desired power level and/or range of the device, such as a voltage and/or amplifier level, may receive an identifier which indicates the desired power characteristics directly without requiring use of a look-up table, and the like as contemplated by a person of ordinary skill in the art. The determined configuration is then loaded  1308  and utilized to feed the output drive circuit  1310 . 
     If a device enters a second power state  1312 , the device may send data over the USB indicating state change  1314 . For example, the device may enter a low power state, may enter a higher performance state in which greater power demands are encountered, and the like. Thus, the present invention may determine a new voltage based on the data  1316 , and adjust characteristics based on the determination  1318 . In this way, the present invention may react to different power needs without waiting to encounter the actual state change through monitoring the outputs, thereby permitting greater reaction time and improved efficiency. 
     Referring now to FIG. 14, an exemplary embodiment  1400  of the present invention is shown wherein a comparator output of a voltage converter is utilized to trigger an interrupt. Logic finds a number of connected devices  1402  and loads an initial configuration based on the found number  1404 . For example, logic may determine that an “N” number of devices are connected to a circuit of the present invention, and may thus utilize this number to configure the power characteristics. For example, a clock source may generate a clock with a specified characteristic  1406 . The control logic may then feed an output circuit  1408 . After the circuit and the device have regulated  1410 , operation of a comparator may be initiated. The comparator is configured to trigger an interrupt at an output power level  1412 . 
     For example, a plurality of comparators may be included, each of which is triggered at a differing power characteristic, such as current, voltage, noise level, signal clarity, and the like. The differing levels may be utilized by the logic to determine the output power characteristics, and may therefore change the characteristics as desired. For instance, a determination may be made if the drive settings are at optimal performance  1414 , such as if a duty cycle is above or below a threshold above optimum. If the duty cycle is above a threshold above optimum performance, the drive settings may be recalibrated for power savings  1416 . However, if the duty cycle is below optimum, the duty cycle may be increased  1418  to correspond to the optimum performance characteristics. Thus, interrupts may be utilized by logic of the present invention to optimize performance of the converter. 
     Referring now to FIG. 15, an exemplary method  1500  of the present invention is shown wherein a comparator is utilized to indicate power level operation outside of a performance level for a specified period of time. In some instances it may be desirable to reconfigure power output, such as current, voltage, noise, signal clarity, duty cycle, frequency, and the like, after a specified period of time rather that being triggered when a certain power condition is encountered, such as operation outside of a threshold, and the like. For example, an initial current configuration of a current converter of the present invention may be loaded  1502 . Control logic of the current converter may feed an output drive circuit  1504  so as to correspond with the initial configuration. Once the cell has regulated  1506 , a comparator output may be monitored  1508 , such as through constant monitoring, the use of interrupts, and the like. 
     If comparator output indicated performance outside of a specified level for a specified period of time  1510 , actions may be taken by the logic to restore performance to desired levels. For example, if the performance level is greater than a threshold indicated optimum performance, the current converter may be recalibrated for power savings  1512 . Likewise, if output performance is indicated which is below a threshold, such as a threshold indicating minimum operational power, the current converter may be recalibrated for increased output  1514  within a threshold range. In this way, anomalies encountered by a converter, and subsequent undesirable actions taken, may be diminished through the verification an encountered state is outside of a threshold. 
     Referring now to FIG. 16, an exemplary method  1600  of the present invention is shown wherein a converter included in a USB interface is suitable for supporting a first current output corresponding to a standard USB current output and a second current output suitable for supporting mobile applications. A USB interface may support a variety of devices in a variety of environments. One such contemplated environment includes devices configured for mobile applications and devices configured for standard power configurations. In mobile applications, for instance, a 5 mA, 4 mA and even lower power output may be desired, but in standard applications, 100 mA power output for powering legacy (such as traditional) devices may be desired. 
     For example, logic determines utilization of a device including a converter  1602  of the present invention. If the device is being utilized in a mobile application, such as being operated on battery power, an initial configuration may be set for mobile use  1604 , such as for 4 mA power output. If the device is being utilized in an externally powered application, the initial configuration may be set as a conventional configuration  1606 , such as 100 mA power output. The output is fed based on the determined configuration  1608 . The logic may then monitor comparator outputs and adjusts control accordingly  1610 , such as if the device switches from battery operation to externally powered operation, switches power modes, and the like. For example, a device may be added and/or disconnected  1612  to an interface. If a device is added, logic may determine required current for the remaining devices  1614  and adjust power characteristics based on the determination  1616 . 
     Referring now to FIG. 17, an exemplary method  1700  of the present invention is shown wherein power utilization of a device connected to a converter of the present invention is used to detect error conditions. Logic finds connected devices and corresponding power characteristics  1702 . An initial configuration is loaded  1704  and utilized to supply corresponding power characteristics. For example, a clock source may generate a clock signal with specified characteristics  1706 , such as to generate a corresponding duty cycle and the like. Thus, control logic may feed the output circuit  1708 . 
     For example, firmware, as employed in a processor of a converter of the present invention, monitors comparator outputs  1710 . The comparator outputs are then compared with stored values for device utilization  1712 . If device utilization matches a profile of the stored values, such as a profile indicating normal operating range, the device may be functioning properly and the firmware may continue to monitor the outputs  1710 . However, if device utilization does not match the stored values  1712 , logic may trigger an error indication  1714  to indicate the device is not functioning properly, such as by implementing an interrupt and the like as contemplated by a person of ordinary skill in the art. In this way, utilization of power by a device may be used to determine if a device is functioning properly. Additionally, power utilization by a device connected to a converter of the present invention may be utilized to determine possible damaging conditions which may occur to a host and/or converter of the present invention. 
     For example, as shown in the exemplary method  1800  depicted in FIG. 18, power utilization by a device connected to a converter of the present invention may be utilized to determine whether a condition which may damage a host and/or converter will occur. Logic finds connected devices and corresponding power characteristics  1802 . An initial configuration is loaded  1804 , and control logic is used to feed an output circuit  1806 . For example, firmware monitors comparator outputs  1808 . A determination is then made as to whether power utilization is within a safe range for connected devices  1810 . For instance, power utilization of a device may indicate a possible harmful condition that may affect the rest of a host system. Additionally, power utilization of a device may occur at levels that are harmful to a converter and/or host system. Thus, logic identifying the possible harmful condition may trigger an interrupt to notify a host system and stop a power supply  1812 . 
     Although the invention has been described with a certain degree of particularity, it should be recognized that elements thereof may be altered by persons skilled in the art without departing from the spirit and scope of the invention. One of the embodiments of the invention can be implemented as sets of instructions resident in the memory of one or more host systems. Until required by a host system, the set of instructions may be stored in another readable memory device, for example in a hard disk drive or in a removable memory such as an optical disc for utilization in a CD-ROM drive, a floppy disk for utilization in a floppy disk drive, a floppy/optical disc for utilization in a floppy/optical drive, or a personal computer memory card for utilization in a personal computer card slot. Further, the set of instructions may be stored in the memory of an information handling system and transmitted over a local area network or a wide area network, such as the Internet, when desired by the user. Additionally, the instructions may be transmitted over a network in the form of an applet that is interpreted or compiled after transmission to the computer system rather than prior to transmission. One skilled in the art would appreciate that the physical storage of the sets of instructions or applets physically changes the medium upon which it is stored electrically, magnetically, chemically, physically, optically or holographically so that the medium carries computer readable information. 
     In exemplary embodiments, the methods disclosed may be implemented as sets of instructions or software readable by a device. Further, it is understood that the specific order or hierarchy of steps in the methods disclosed are examples of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the method can be rearranged while remaining within the scope of the present invention. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented. 
     It is believed that the flexible converter of the present invention and many of its attendant advantages will be understood by the foregoing description. It is also believed that it will be apparent that various changes may be made in the form, construction and arrangement of the components thereof without departing from the scope and spirit of the invention or without sacrificing all of its material advantages. The form herein before described being merely an explanatory embodiment thereof. It is the intention of the following claims to encompass and include such changes.