Patent Publication Number: US-2013241296-A1

Title: Switching voltage regulator with multiple power input terminals and related power converter

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority to Patent Application No. 101204935, filed in Taiwan on Mar. 19, 2012; the entirety of which is incorporated herein by reference for all purposes. 
     BACKGROUND 
     The disclosure generally relates to a switching voltage regulator and, more particularly, to a switching voltage regulator with multiple power input terminals and related power converter. 
     A switching voltage regulator usually comprises an upper switch and a lower switch to receive corresponding control signals from a regulator controller. In a conventional power converter with multiple power input terminals, upper switches corresponding to different power sources should be arranged in different power input paths of the switching voltage regulator, such as that illustrated in U.S. Pat. No. 7,777,455. 
     Therefore, if the number of power input terminals of the power converter increases, the number of required upper switches of the switching voltage regulator should be increased as well, thereby occupying more circuit areas and increasing circuit cost. 
     SUMMARY 
     In view of the foregoing, it can be appreciated that a substantial need exists for a switching voltage regulator that can support multiple power input terminals and reduce required circuit area. 
     An example embodiment of a switching voltage regulator with multiple power input terminals for a power converter is disclosed. The power converter comprises a power source selector, a regulator controller, and an inductor. The switching voltage regulator comprises: a first power input terminal; a second power input terminal; a first switch having a first terminal coupled with the first power input terminal; a second switch having a first terminal coupled with the second power input terminal; a third switch having a first terminal coupled with a second terminal of the first switch and a second terminal of the second switch; and a fourth switch having a first terminal coupled with a second terminal of the third switch and for coupling with the inductor; wherein a control terminal of the first switch and a control terminal of the second switch are utilized for coupling with the power source selector, and a control terminal of the third switch and a control terminal of the fourth switch are utilized for coupling with the regulator controller. 
     Another example embodiment of a switching voltage regulator with multiple power input terminals for a power converter is disclosed. The power converter comprises a regulator controller and an inductor. The switching voltage regulator comprises: a first power input terminal; a second power input terminal; a first switch having a first terminal coupled with the first power input terminal; a second switch having a first terminal coupled with the second power input terminal; a third switch having a first terminal coupled with a second terminal of the first switch and a second terminal of the second switch; a fourth switch having a first terminal coupled with a second terminal of the third switch and for coupling with the inductor; and a power source selector coupled with a control terminal of the first switch and a control terminal of the second switch to control operations of the first switch and the second switch; wherein a control terminal of the third switch and a control terminal of the fourth switch are utilized for coupling with the regulator controller. 
     Another example embodiment of a switching voltage regulator with multiple power input terminals for a power converter is disclosed. The power converter comprises a power source selector and a regulator controller. The switching voltage regulator comprises: a first power input terminal; a second power input terminal; a first switch having a first terminal coupled with the first power input terminal; a second switch having a first terminal coupled with the second power input terminal; a third switch having a first terminal coupled with a second terminal of the first switch and a second terminal of the second switch; a fourth switch having a first terminal coupled with a second terminal of the third switch; and an inductor having a first terminal coupled between the third switch and the fourth switch, and a second terminal of the inductor being utilized for providing an output voltage; wherein a control terminal of the third switch and a control terminal of the fourth switch are utilized for coupling with the regulator controller. 
     Another example embodiment of a power converter is disclosed, comprising: a first power input terminal; a second power input terminal; a first switch having a first terminal coupled with the first power input terminal; a second switch having a first terminal coupled with the second power input terminal; a third switch having a first terminal coupled with a second terminal of the first switch and a second terminal of the second switch; a fourth switch having a first terminal coupled with a second terminal of the third switch; a power source selector coupled with a control terminal of the first switch and a control terminal of the second switch to control operations of the first switch and the second switch; a regulator controller coupled with a control terminal of the third switch and a control terminal of the fourth switch to control operations of the third switch and the fourth switch; and an inductor having a first terminal coupled between the third switch and the fourth switch, and a second terminal of the inductor being utilized for providing an output voltage; wherein when the third switch turns on, the fourth switch turns off, and when the fourth switch turns on, the third switch turns off. 
     One of the advantages of the above mentioned switching voltage regulator is that the required circuit area for supporting multiple power input terminals can be effectively reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1˜3  show simplified functional block diagrams of a power converter according to several embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference is made in detail to embodiments of the invention, which are illustrated in the accompanying drawings. The same reference numbers may be used throughout the drawings to refer to the same or like parts, components, or operations. Throughout the description and claims, the term “element” contains the concept of component, layer, or region. 
     Certain terms are used throughout the description and the claims to refer to particular components. One skilled in the art appreciates that a component may be referred to as different names. This disclosure does not intend to distinguish between components that differ in name but not in function. In the description and in the claims, the term “comprise” is used in an open-ended fashion, and thus should be interpreted to mean “include, but not limited to . . . .” Also, the phrase “coupled” with is intended to compass any indirect or direct connection. Accordingly, if this disclosure mentioned that a first device is coupled with a second device, it means that the first device may be directly or indirectly connected to the second device through electrical connections, wireless communications, optical communications, or other signal connections with/without other intermediate devices or connection means. 
     The term “and/or” may comprise any and all combinations of one or more of the associated listed items. In addition, the singular forms “a”, “an”, and “the” herein are intended to comprise the plural forms as well, unless the context clearly indicates otherwise. 
       FIG. 1  shows a simplified functional block diagram of a power converter  100  with two power input terminals according to an embodiment of the present disclosure. The power converter  100  comprises a switching voltage regulator  110 , a power source selector  120 , a regulator controller  130 , and an inductor  140 . In operations, the power converter  100  may receive electricity from one of two different power sources VS 1  and VS 2  and convert the received electricity into an appropriate voltage Vout to supply to an external battery  150  and a system device  160 . 
     In the embodiment shown in  FIG. 1 , the switching voltage regulator  110  comprises a first switch  111 , a second switch  112 , a third switch  113 , a fourth switch  114 , a first power input terminal  115 , and a second power input terminal  116 . A first terminal of the switch  111  is coupled with the power input terminal  115 . A first terminal of the switch  112  is coupled with the power input terminal  116 . The switch  113  is utilized as an upper switch, and a first terminal of the switch  113  is coupled with a second terminal of the switch  111  and a second terminal of the switch  112 . The switch  114  is utilized as a lower switch. A first terminal of the switch  114  is coupled with a second terminal of the switch  113  and a second terminal of the switch  114  is coupled with a fixed-voltage terminal (such as a grounded terminal). The power input terminal  115  is utilized for coupling with the first power source VS 1 , and the power input terminal  116  is utilized for coupling with the second power source VS 2 . In implementations, each of the switches  111 ˜ 114  may be implemented by a P-type field effect transistor or an N-type field effect transistor. The power source VS 1  and the power source VS 2  may be two different DC power sources (e.g., USB power sources, batteries, or rectifiers with DC output). 
     In the power converter  100 , the power source selector  120  is coupled with a control terminal of the switch  111  and a control terminal of the switch  112  to control operations of the switch  111  and the switch  112  so as to select a source of voltage to be processed by the switching voltage regulator  110 . The regulator controller  130  is coupled with control terminals of the switch  113  and the switch  114  to control operations of the switch  113  and the switch  114 . A first terminal of the inductor  140  is coupled between the switch  113  and the switch  114 , and a second terminal of the inductor  140  is utilized for coupling with the external battery  150  and for providing an output voltage Vout. 
     In operations, the power source selector  120  detects power reception statuses of the power input terminals  115  and  116  and accordingly controls the operations of the switches  111  and  112  to select the source of voltage to be processed by the switching voltage regulator  110 . For example, when the power source selector  120  has detected a presence of input power at the power input terminal  115  and an absence of input power at the power input terminal  116 , the power source selector  120  turns on the switch  111  and turns off the switch  112 . On the contrary, when the power source selec- tor  120  has detected a presence of input power at the power input terminal  116  and an absence of input power at the power input terminal  115 , the power source selector  120  turns on the switch  112  and turns off the switch  111 . When the power source selector  120  has detected a presence of input power at the power input terminal  115  and a presence of input power at the power input terminal  116 , the power source selector  120  may select one of the two power sources VS 1  and VS 2  as the source of voltage to be processed by the switching voltage regulator  110  according to a default priority configuration of the power sources VS 1  and VS 2  or according to a users&#39; configuration. 
     The regulator controller  130  performs a feedback control on the output voltage Vout of the power converter  100  to generate control signals UG and LG for controlling the switch  113  and the switch  114 . In this embodiment, when the regulator controller  130  turns on the switch  113 , the regulator controller  130  turns the switch  114  off; and when the regulator controller  130  turns on the switch  114 , the regulator controller  130  turns the switch  113  off. 
     When the power source selector  120  turns on the switch  111 , the switch  113  and the switch  114  of the switching voltage regulator  110  are alternately switched under the control of the control signals UG and LG to cooperate with the inductor  140  to convert the voltage received by the power input terminal  115  into the output voltage Vout. When the power source selector  120  turns on the switch  112 , the switching voltage regulator  110  cooperates with the inductor  140  to convert the voltage received by the power input terminal  116  into the output voltage Vout under the control of the regulator controller  130 . 
     In the embodiment shown in  FIG. 1 , the power converter  100  may charge the external battery  150  with the output voltage Vout and simultaneously supply power to the subsequent system device  160 . 
     In implementations, any one, any two, or all of the power source selector  120 , the regulator controller  130 , and the inductor  140  may be integrated into the switching voltage regulator  110 . 
       FIG. 2  shows a simplified functional block diagram of a power converter  200  with two power input terminals according to another embodiment of the present disclosure. The power converter  200  comprises a switching voltage regulator  210 , the power source selector  120 , the regulator controller  130 , and the inductor  140 . The power converter  200  may receive electricity from one of the two different power sources VS 1  and VS 2  and convert the received electricity into an appropriate voltage Vout to supply to the external battery  150  and the system device  160 . 
     As shown in  FIG. 2 , the switching voltage regulator  210  of the power converter  200  is similar to the switching voltage regulator  110  shown in  FIG. 1 . The difference between the two embodiments is that the switching voltage regulator  210  further comprises a fifth switch  217  and a current path controller  218 . A first terminal of the switch  217  is coupled with the second terminal of the inductor  140  and a second terminal of the switch  217  is utilized for coupling with the external battery  150 . The current path controller  218  is coupled with a control terminal of the switch  217  to control an operation of the switch  217 . In implementations, the switch  217  may be realized by a P-type field effect transistor, an N-type field effect transistor, or any other kind of transistor architectures. 
     In the embodiment shown in  FIG. 2 , the switch  217  is coupled between the inductor  140  and the external battery  150 . Accordingly, when the power converter  200  supplies power to the system device  160 , the current path controller  218  may decide whether to control the power converter  200  to simultaneously charge the external battery  150  by switching the switch  217 . For example, when the current path controller  218  turns on the switch  217 , the power converter  200  is allowed to charge the external battery  150  and simultaneously supply power to the system device  160 . When the current path controller  218  turns off the switch  217 , the power converter  200  would not charge the external battery  150  while supplying power to the system device  160 . 
     In implementations, any one, any two, or all of the power source selector  120 , the regulator controller  130 , and the inductor  140  may be integrated into the switching voltage regulator  210 . 
     The descriptions regarding the implementations and operations of the other function blocks of the power converter  100  in the embodiment shown in  FIG. 1  are also applicable to the power converter  200  shown in  FIG. 2 . For simplicity, the descriptions will not be repeated here. 
       FIG. 3  shows a simplified functional block diagram of a power converter  300  with two power input terminals according to another embodiment of the present disclosure. The power converter  300  comprises a switching voltage regulator  310 , the power source selector  120 , the regulator controller  130 , and the inductor  140 . The power converter  300  may receive electricity from one of the two different power sources VS 1  and VS 2  and convert the received electricity into an appropriate voltage Vout to supply to the external battery  150  and the system device  160 . 
     As shown in  FIG. 3 , the switching voltage regulator  310  of the power converter  300  is similar to the switching voltage regulator  110  shown in  FIG. 1 . The difference between the two embodiments is that the switching voltage regulator  310  further comprises a sixth switch  317 , the current path controller  218 , and a body diode controller  319 . A first terminal of the switch  317  is coupled with the second terminal of the inductor  140  and a second terminal of the switch  317  is coupled with the external battery  150 . The switch  317  comprises a first body diode  321  and a second body diode  322 . The body diode  321  is coupled between the first terminal of the switch  317  and a first node  323 , and the body diode  322  is coupled between the second terminal of the switch  317  and the first node  323 . The current path controller  218  is coupled with a control terminal of the switch  317  to control operations of the switch  317 . In implementations, the switch  317  may be realized by a P-type field effect transistor, an N-type field effect transistor, or any other kind of transistor architectures. 
     The switch  317  is coupled between the inductor  140  and the external battery  150 . Accordingly, when the power converter  300  supplies power to the system device  160 , the current path controller  218  may decide whether to control the power converter  300  to simultaneously charge the external battery  150  by switching the switch  317 . For example, when the current path controller  218  turns on the switch  317 , the power converter  300  is allowed to charge the external battery  150  and simultaneously supply power to the system device  160 . When the current path controller  218  turns off the switch  317 , the power converter  300  would not charge the external battery  150  while supplying power to the system device  160 . 
     The body diode controller  319  is coupled with the switch  317  and utilized for selectively coupling the node  323  with the first terminal of the switch  317  or the second terminal of the switch  317 . The body diode  321  is configured as active and the body diode  322  is configured as inactive when the body diode controller  319  couples the node  323  with the second terminal of the switch  317 . In this status, an equivalent diode characteristic of the switch  317  is determined by the body diode  321 . 
     On the contrary, the body diode  322  is configured as active and the body diode  321  is configured as inactive when the body diode controller  319  couples the node  323  with the first terminal of the switch  317 . In this status, the equivalent diode characteristic of the switch  317  is determined by the body diode  322 . 
     Accordingly, when the current path controller  218  turns on the switch  317  and the body diode controller  319  couples the node  323  with the second terminal of the switch  317 , a reverse bias voltage characteristic of the body diode  321  prevents a leakage current of the charging external battery  150  from flowing to the inductor  140  through the switch  317 . In this way, it is allowed to avoid reduction of charging efficiency of the external battery  150  incurred by the leakage current. 
     On the other hand, when the current path controller  218  turns off the switch  317  and the body diode controller  319  couples the node  323  with the second terminal of the switch  317 , the reverse bias voltage characteristic of the body diode  321  prevents a leakage current of the idle external battery  150  from flowing to the inductor  140  through the switch  317 . In this way, it is allowed to prevent reduction of charges which are stored in the idle external battery  150  incurred by the leakage current. 
     In implementations, any one, any two, or all of the power source selector  120 , the regulator controller  130 , and the inductor  140  may be integrated into the switching voltage regulator  310 . 
     The descriptions regarding the implementations and operations of the other function blocks of the power converter  100  in the embodiment shown in  FIG. 1  are also applicable to the power converter  300  shown in  FIG. 3 . For simplicity, the descriptions will not be repeated here. 
     It can be appreciated from the foregoing descriptions that each of the switching voltage regulators disclosed in the previous embodiments is capable of supporting two power input terminals by employing only one upper switch  113 . Thus, the required circuit area of the switching voltage regulator for supporting multiple power input terminals can be effectively reduced. In addition, the functionality of the aforementioned structure where a single upper switch  113  is shared by two power input paths can be extended by utilizing the power source selector  120  to cooperate with a sufficient number of power selection switches in order to support the applications with more power input terminals. In this situation, the required circuit area can be further reduced. 
     Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention indicated by the following claims.