Switched capacitor voltage converter and method of operating the same

Abstract

Embodiments of a switched capacitor voltage converter and a method for operating the switched capacitor voltage converter are disclosed. In the embodiment, the switched capacitor voltage converter includes: switching devices connected in series; a voltage generator connected to the series-connected switching devices and configured to generate a driver voltage in response to a first voltage at a first terminal connected to the series-connected switching devices; and a voltage driver configured to drive the series-connected switching devices based on the driver voltage.

Description

Technical Field

[0001] The present application relates to switched capacitor voltage converters. Background Art

[0002] A voltage converter can be used to convert an input voltage into a desired output voltage. For example, a direct current (DC)-DC converter can be used to convert an input DC voltage into a desired output DC voltage. A switched capacitor voltage converter can use a combination of one or more switching devices and one or more capacitors to convert an input voltage into a desired output voltage. However, additional capacitors take up additional substrate area, may increase component cost, and may require more electrical terminals (e.g., pins) in the packaged semiconductor chip. Summary of the Invention

[0003] Embodiments of a switched capacitor voltage converter and a method for operating the switched capacitor voltage converter are disclosed. In one embodiment, the switched capacitor voltage converter includes: series-connected switching devices; a voltage generator connected to the series-connected switching devices and configured to generate a driver voltage in response to a first voltage at a first terminal connected to the series-connected switching devices; and a voltage driver configured to drive the series-connected switching devices based on the driver voltage. Other embodiments are also described.

[0004] In an embodiment, the voltage driver includes: a first voltage driver configured to drive a first switching device in the series-connected switching devices based on a first driver voltage; second and third voltage drivers configured to drive the second and third switching devices in the series-connected switching devices based on the second driver voltage; and a fourth voltage driver configured to drive the fourth switching device in the series-connected switching devices based on the third driver voltage.

[0005] In an embodiment, the voltage generator includes switches connected to a plurality of terminals of the first and second driver voltages, the input voltage, and the output voltage of a switched capacitor voltage converter.

[0006] In an embodiment, the switched capacitor voltage converter further includes a capacitor electrically connectable to the terminal.

[0007] In an embodiment, the switches include a first switch connected to a first terminal having a first driver voltage and connected to a second terminal, a second switch connected to a third terminal having a second driver voltage and connected to the second terminal, a third switch connected to the second terminal and the third driver voltage, a fourth switch connected to a fourth terminal and a reference voltage, a fifth switch connected to the fourth terminal and a fifth terminal having an input voltage, and a sixth switch connected to the fourth terminal and a sixth terminal having an output voltage.

[0008] In an embodiment, the switched capacitor voltage converter further includes a first capacitor electrically connectable to the first terminal, a second capacitor electrically connectable to the third terminal, and a third capacitor electrically connectable to the second terminal and the fourth terminal.

[0009] In an embodiment, the voltage generator includes switches connected to a plurality of terminals of a first driver voltage and an input voltage with a switched capacitor voltage converter.

[0010] In an embodiment, the switched capacitor voltage converter further includes a capacitor electrically connectable to the terminal.

[0011] In an embodiment, the switches include a first switch connected to a first terminal having a first driver voltage and connected to a second terminal, a second switch connected to the second terminal and a third driver voltage, a third switch connected to a third terminal and a reference voltage, and a fourth switch connected to the third terminal and a fourth terminal having an input voltage.

[0012] In an embodiment, the switched capacitor voltage converter further includes a first capacitor electrically connectable to the first terminal, a second capacitor electrically connectable to the second terminal and the third terminal, and a third capacitor electrically connectable to the fourth terminal.

[0013] In an embodiment, the first, second, third and fourth voltage drivers are connected to the gate terminals of the first, second, third and fourth switching devices, respectively.

[0014] In an embodiment, a switched capacitor voltage converter includes: N-type transistors connected in series; a voltage generator connected to the N-type transistors connected in series and configured to generate a plurality of driver voltages in response to an input voltage at an input terminal connected to the N-type transistors connected in series; and a voltage driver configured to drive the N-type transistors connected in series based on the driver voltages.

[0015] In an embodiment, the voltage drivers are respectively connected to the gate terminals of the N-type transistors connected in series.

[0016] In an embodiment, the voltage driver includes: a first voltage driver configured to drive a first N-type transistor based on a first driver voltage; second and third voltage drivers configured to drive second and third N-type transistors based on a second driver voltage; and a fourth voltage driver configured to drive a fourth N-type transistor based on a third driver voltage.

[0017] In an embodiment, the voltage generator includes switches connected to a plurality of terminals of a first driver voltage and an input voltage with a switched capacitor voltage converter.

[0018] In an embodiment, the switched capacitor voltage converter further includes a capacitor electrically connectable to the terminal.

[0019] In an embodiment, the switches include a first switch connected to a first terminal having a first driver voltage and connected to a second terminal, a second switch connected to the second terminal and a third driver voltage, a third switch connected to a third terminal and a reference voltage, and a fourth switch connected to the third terminal and a fourth terminal having an input voltage.

[0020] In an embodiment, the switched capacitor voltage converter further includes a first capacitor electrically connectable to the first terminal, a second capacitor electrically connectable to the second terminal and the third terminal, and a third capacitor electrically connectable to the fourth terminal.

[0021] In an embodiment, a method for operating a switched capacitor voltage converter involves generating a driver voltage in response to an input voltage at an input terminal connected to series-connected switching devices of the switched capacitor voltage converter; and driving the series-connected switching devices based on the driver voltage.

[0022] In an embodiment, generating the driver voltage in response to the input voltage involves generating the driver voltage in response to the input voltage using a plurality of capacitors that are not directly connected to the series-connected switching devices.

[0023] Other aspects of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic block diagram of a switched capacitor voltage converter according to a first embodiment of the present invention.

[0025] Figure 2 Depicts Figure 1 An embodiment of a voltage generator for a switched capacitor voltage converter is depicted.

[0026] Figures 3A-3D Shown Figure 2 The switching stages / phases of a voltage generator are depicted.

[0027] Figure 4 Depicts Figure 1 An embodiment of a voltage driver for a switched capacitor voltage converter is depicted.

[0028] Figure 5 Depicts Figure 1 Another embodiment of a voltage driver for a switched capacitor voltage converter is depicted.

[0029] Figure 6Depicts the terminal / pin configuration of a dual-phase voltage conversion circuit.

[0030] Figure 7 is a schematic block diagram of a switched capacitor voltage converter according to a second embodiment of the present invention.

[0031] Figure 8 is a schematic block diagram of a switched capacitor voltage converter according to a third embodiment of the present invention.

[0032] Figure 9 Depicts Figure 8 An embodiment of a voltage generator for a switched capacitor voltage converter is depicted.

[0033] Figure 10A and Figure 10B Shown Figure 9 Switching stages / phases of a voltage generator are depicted.

[0034] Figure 11 Depicts the terminal / pin configuration of a dual-phase voltage conversion circuit.

[0035] Figure 12 is a schematic block diagram of a switched capacitor voltage converter according to a fourth embodiment of the present invention.

[0036] Figure 13 is a process flow diagram of a method for operating a switched capacitor voltage converter according to an embodiment of the present invention.

[0037] Like reference numerals may be used to identify like elements throughout the specification. DETAILED DESCRIPTION

[0038] It will be readily understood that the components of the embodiments generally described herein and illustrated in the accompanying drawings may be arranged and designed in a variety of different configurations. Therefore, the following more detailed description of various embodiments, as illustrated in the figures, is not intended to limit the scope of the present disclosure, but is merely illustrative of various embodiments. Although various aspects of the embodiments are presented in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0039] The present invention may be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. The described embodiments are to be considered in all respects as illustrative only and not restrictive. Therefore, the scope of the present invention is indicated by the appended claims rather than by this detailed description. All variations within the meaning and scope of equivalents of the claims are intended to be included within their scope.

[0040] Reference throughout this specification to features, advantages, or similar language does not imply that all features and advantages that can be achieved with the present invention should be or are included in any single embodiment of the present invention. Rather, language referring to features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of features and advantages and similar language throughout this specification may, but do not necessarily, refer to the same embodiment.

[0041] Furthermore, the described features, advantages, and characteristics of the present invention may be combined in any suitable manner in one or more embodiments. Based on the description herein, one skilled in the relevant art will recognize that the present invention may be practiced without one or more of the specific features or advantages of a particular embodiment. In other cases, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the present invention.

[0042] Reference throughout this specification to "one embodiment," "an embodiment," or similar language means that a particular feature, structure, or characteristic described in connection with the indicated embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment," "in an embodiment," and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0043] Figure 1 FIG. 1 is a schematic block diagram of a switched capacitor voltage converter 100 according to a first embodiment of the present invention. The switched capacitor voltage converter converts an input voltage V IN Converts to the desired output voltage V OUT Switched capacitor voltage converters can be used in a variety of applications, such as automotive applications, communications applications, industrial applications, medical applications, computer applications, and / or consumer or appliance applications. Figure 1 In the depicted embodiment, the switched capacitor voltage converter includes a voltage conversion circuit 102, an input capacitor "C IN "、Flying capacitor "C FLY ”、output capacitor “C OUT ”, and the driver capacitor “C D1 ”, “C D2 ” and “C DR The voltage conversion circuit 102 includes switching devices 104-1, 104-2, 104-3, and 104-4 connected in series, a voltage generator 106 connected to the switching devices connected in series, and voltage drivers 108-1, 108-2, 108-3, and 108-4. The flying capacitor C FLY , input capacitor C IN and output capacitor C OUTIt can be an external capacitor of the voltage conversion circuit. In some embodiments, the flying capacitor C FLY has a capacitance value between 1μF and 100μF, and the output capacitor C OUT Having a capacitance value between 1 μF and 100 μF. In some embodiments, the switched capacitor voltage converter is included in a computing device, such as a smart phone, tablet computer, laptop computer, etc. In some embodiments, at least some components of the switched capacitor voltage converter are implemented in a substrate, such as a semiconductor wafer or a printed circuit board (PCB). In an embodiment, at least some components of the switched capacitor voltage converter are packaged as a separate semiconductor IC chip. Although the switched capacitor voltage converter is Figure 1 Although shown as including certain circuit elements, in other embodiments, the switched capacitor voltage converter may include one or more additional circuit elements. For example, in other embodiments, the switched capacitor voltage converter may include more than four switching devices or fewer than four switching devices. In another example, in other embodiments, the switched capacitor voltage converter may include more than four voltage drivers or fewer than four voltage drivers.

[0044] In some embodiments, the voltage conversion circuit 102 is implemented in a substrate and packaged as a standalone semiconductor IC device or chip. In these embodiments, the driver capacitor C D1 、C D2 and C DR It is an external capacitor of the voltage conversion circuit. For example, N-type high voltage transistors, such as N-channel laterally diffused MOS (NLDMOS) transistors, can be used in the voltage conversion circuit to achieve better power efficiency. However, due to the size of N-type transistors, driver capacitors are typically not integrated with these transistors (i.e., integrated onto the same substrate as the transistors). In a conventional switched capacitor voltage converter, each switching device of the voltage conversion circuit is electrically connected to a separate bootstrap capacitor. Therefore, multiple external bootstrap capacitors are used in a conventional switched capacitor voltage converter. However, the additional capacitors occupy additional substrate area, may increase component cost, and may require more electrical terminals (e.g., pins) in the packaged voltage conversion circuit, which may increase the size of the packaged voltage conversion circuit as well as the component cost. For example, for a two-phase switched capacitor voltage converter in which each switching device of the voltage conversion circuit is electrically connected to an external bootstrap capacitor, five external capacitors and five additional terminals (e.g., pins) may be required, even assuming that the intermediate bootstrap capacitors are reused. In contrast, Figure 1The voltage conversion circuit 102 of the depicted switched capacitor voltage converter 100 does not use an external bootstrap capacitor. Therefore, compared to the voltage conversion circuit of a switched capacitor voltage converter in which each switching device of the voltage conversion circuit is electrically connected to an external bootstrap capacitor, Figure 1 The depicted voltage conversion circuit 102 does not require terminals (eg, pins) to connect to external bootstrap capacitors.

[0045] exist Figure 1 In the depicted embodiment, the packaged IC device of the voltage conversion circuit 102 includes nine terminals / pins: V IN (power supply voltage) terminal / pin 110; reference terminal / pin (eg, GND (ground) terminal / pin) 112; can be electrically connected to the driver capacitor C D1 Terminal / pin 114; can be electrically connected to the flying capacitor C FLY The terminal / pin 116 between transistors M1 and M2 can be electrically connected to the driver capacitor C D2 The terminal / pin 118 can be electrically connected to the output capacitor C OUT The terminal / pin 120 between transistors M2 and M3 can be electrically connected to the flying capacitor C FLY The terminal / pin 122 between the transistors M3 and M4; and the terminal / pin 122 electrically connected to the driver capacitor C DR Terminals / pins 124, 126.

[0046] exist Figure 1 In the depicted embodiment, the series-connected switching devices 104-1, 104-2, 104-3, 104-4 are electrically connected to a circuit having an input voltage V IN The terminal 110 has a voltage lower than the input voltage V IN In some embodiments, the reference voltage is ground (0 volts). Figure 1 In the depicted embodiment, for better power efficiency, the series-connected switching devices are implemented as N-type transistors M1, M2, M3, M4, such as NLDMOS transistors. However, in other embodiments, the switching devices may be implemented by other semiconductor devices. Figure 1 In the depicted embodiment, the drain terminal D of transistor M1 is connected to the input voltage V IN , the source terminal S of the transistor M1 is connected to the drain terminal D of the transistor M2, the source terminal S of the transistor M2 is connected to the drain terminal D of the transistor M3, the source terminal S of the transistor M3 is connected to the drain terminal D of the transistor M4, and the source terminal S of the transistor M4 is connected to a reference voltage (e.g., ground). Figure 1 In the depicted embodiment, the driver capacitor C D1 、C D2 and C DRIt is not directly connected to the N-type transistors M1, M2, M3, and M4, and is not a bootstrap capacitor for the N-type transistors M1, M2, M3, and M4.

[0047] exist Figure 1 In the depicted embodiment, the voltage generator 106 is electrically connected to the series-connected switching devices 104-1, 104-2, 104-3, 104-4 and is configured to respond to an input voltage V at a terminal 110. IN To generate the driver voltage "V D1 ”, “V D2 ”, “V DR ”.

[0048] Figure 2 Depicted is a voltage generator 206, which is Figure 1 An embodiment of the voltage generator 106 is depicted. Figure 2 The voltage generator 206 is depicted as Figure 1 One possible embodiment of the voltage generator 106 is depicted. However, Figure 1 The depicted voltage generator 106 is not limited to Figure 2 The voltage generator may use a floating capacitor C DR In a time-division multiplexing manner, two driver voltages V D1 、V D2 Charging. Figure 2 In the depicted embodiment, the voltage generator 206 includes switches 232, 234, 236, 238, 240, 242 connected to the driver voltage V with a switched capacitor voltage converter. D1 、V D2 、Input voltage V IN and the output voltage V OUT Terminals / pins 110, 120, 114, 118, 124, 126 of the driver capacitor C D1 、C D2 and C DR , input capacitor C IN and output capacitor C OUT The switch 236 is electrically connected to the terminals / pins 110, 120, 114, 118, 124, 126. The switch 236 is connected to the terminal with the driver voltage V D1 The switch 232 is connected to the terminal 114 and connected to the terminal 124. D2 The switch 234 is connected to the terminal 124 and the driver voltage V DR The switch 238 is connected to the terminal 126 and a reference voltage (eg, ground). The switch 240 is connected to the terminal 126 and a reference voltage (eg, ground). INThe switch 242 is connected to the terminal 126 and has an output voltage V OUT The terminal 120. Capacitor C D1 Can be electrically connected to terminal 114, capacitor C D2 can be electrically connected to terminal 118, and capacitor C DR Can be electrically connected to terminals 124, 126. Input capacitor C IN The output capacitor C can be electrically connected to terminal 110 and a reference voltage (eg, ground). OUT The switches 232, 234, 236, 238, 240, 242 can be controlled to connect the driver capacitor C D1 、C D2 and C DR In some embodiments, the voltage generator 206 includes one or more processors, such as a microcontroller or a central processing unit (CPU) configured to control the switches 232 , 234 , 236 , 238 , 240 , 242 .

[0049] In an example operation of the voltage generator 206 , the voltage generator operates with four stages / phases. Figures 3A-3D Shown Figure 2 The depicted switching stages / phases of the voltage generator. Specifically, Figure 3A The first stage of the voltage generator is shown. In the first stage, the driver capacitor C DR Be refreshed. Figure 3A As shown, switches 234 , 238 are closed (ie, conducting), and switches 232 , 236 , 240 , 242 are open (ie, non-conducting).

[0050] Figure 3B The second stage of the voltage generator 206 is shown. In the second stage, the driver capacitor C D1 is charged. Figure 3B As shown, switches 236 and 240 are closed (ie, conducting), and switches 232 , 234 , 238 , and 242 are open (ie, non-conducting).

[0051] Figure 3C The third stage of the voltage generator 206 is shown. In the third stage, the driver capacitor C DR Be refreshed. Figure 3C As shown, switches 234 , 238 are closed (ie, conducting), and switches 232 , 236 , 240 , 242 are open (ie, non-conducting).

[0052] Figure 3D The fourth stage of the voltage generator 206 is shown. In the fourth stage, the driver capacitor C D2 is charged. Figure 3D As shown, switches 232 and 242 are closed (ie, conducting), and switches 234, 236, 238, and 242 are open (ie, non-conducting).

[0053] Back to Figure 1 The voltage drivers 108-1, 108-2, 108-3, 108-4 are configured to drive the switching devices 104-1, 104-2, 104-3, 104-4 using the driver signals 180-1, 180-2, 180-3, 180-4 in response to the control signals 182-1, 182-2, 182-3, 182-4. The voltage driver 108-1 is configured to drive the switching devices 104-1, 104-2, 104-3, 104-4 based on the output voltage V generated by the voltage generator 106. D1 The voltage drivers 108 - 2 and 108 - 3 are configured to drive the transistor M1 based on the output voltage V generated by the voltage generator. D2 To drive transistors M2 and M3. The voltage driver 108-4 is configured to generate a driver voltage V based on the driver voltage V generated by the voltage generator. DR To drive transistor M4. When the series-connected switching devices are implemented as N-type transistors M1, M2, M3, and M4, voltage drivers 108-1, 108-2, 108-3, and 108-4 are electrically connected to gate terminals G of transistors M1, M2, M3, and M4, respectively. Voltage drivers 108-1, 108-2, 108-3, and 108-4 can be implemented using known driver circuits.

[0054] Figure 4 Depicted is a voltage driver 408, which is Figure 1 Embodiments of voltage drivers 108 - 1 , 108 - 3 are depicted. Figure 4 The voltage driver 408 is depicted as Figure 1 One possible embodiment of the voltage drivers 108-1, 108-3 is depicted. However, Figure 1 The depicted voltage drivers 108-1, 108-3 are not limited to Figure 4 The embodiment shown. Figure 4 In the depicted embodiment, the voltage driver 408 includes an inverter 452, voltage level shifters 454, 456, transistors 458, 460, 462, a resistor 464, and a diode 466. The voltage driver is configured to generate a voltage signal V HIGH 484 (which may be the output voltage V generated by the voltage generator 106) D1 or V D2 ) in response to control signal 482 to generate a voltage for transistor 404 (which may be Figure 1 Transistor M1 in or Figure 1 The driver signal 480 of the transistor M3 in FIG.

[0055] Figure 5 A voltage driver 508 is depicted, which is Figure 1 Embodiments of voltage drivers 108 - 2 , 108 - 4 are depicted. Figure 5 The voltage driver 508 is depicted as Figure 1 One possible embodiment of the voltage drivers 108-2, 108-4 is depicted. However, Figure 1 The depicted voltage drivers 108-2, 108-4 are not limited to Figure 5 The embodiment shown. Figure 5 In the depicted embodiment, the voltage driver 508 includes a voltage level shifter 552 and transistors 554, 556. The voltage driver is configured to generate a voltage level shifter based on the voltage signal V HIGH 584 (which may be the output voltage V generated by the voltage generator 106) D2 or V DR ) in response to control signal 582 to generate a transistor 504 (which may be Figure 1 The transistor M2 or Figure 1 The driver signal 580 of the transistor M4 in FIG.

[0056] For an N-phase (N is a positive integer) switched capacitor voltage converter according to an embodiment of the present invention, no bootstrap capacitor is used. Therefore, there are no terminals / pins for electrical connection between the bootstrap capacitor and the packaged IC device of the N-phase voltage conversion circuit. For an N-phase voltage conversion circuit in which each switching device is electrically connected to an external bootstrap capacitor, even if the intermediate bootstrap capacitor is reused, there are a total of 2N+1 terminals / pins for electrical connection to the bootstrap capacitor. Therefore, compared to an N-phase voltage conversion circuit in which each switching device is electrically connected to a separate bootstrap capacitor, the N-phase (N is a positive integer) switched capacitor voltage converter according to an embodiment of the present invention uses three external capacitors and four terminals / pins for electrical connection to the three external capacitors. Figure 6 The terminal / pin configuration of the dual-phase voltage conversion circuit 602 implemented as a packaged IC device is depicted. Figure 6 As shown, the packaged IC device of the dual-phase voltage conversion circuit includes twelve terminals / pins, which are two V IN(Power supply voltage) terminals / pins 610-1, 610-2; two GND (ground) terminals / pins 612-1, 612-2; a terminal / pin 616-1 between transistors M1 and M2 that can be electrically connected to the corresponding flying capacitor; a terminal / pin 620-1 between transistors M2 and M3 that can be electrically connected to the corresponding output capacitor; a terminal / pin 622-1 between transistors M3 and M4 that can be electrically connected to the corresponding flying capacitor; a terminal / pin 616-2 between transistors M5 and M6 that can be electrically connected to the corresponding flying capacitor; a terminal / pin 620-2 between transistors M6 and M7 that can be electrically connected to the corresponding output capacitor and can be connected to the terminal / pin 620-1; a terminal / pin 622-2 between transistors M7 and M8 that can be electrically connected to the corresponding flying capacitor; a terminal / pin 622-1 between transistors M7 and M8 that can be electrically connected to the driver capacitor C D1 Terminal / pin 614; can be electrically connected to the driver capacitor C D2 and electrically connected to the driver capacitor C DR For a two-phase voltage conversion circuit in which each switching device is electrically connected to a separate bootstrap capacitor, a total of fifteen terminals / pins and five external bootstrap capacitors are used, even if the intermediate bootstrap capacitors are reused. In contrast, Figure 6 The depicted two-phase voltage conversion circuit uses fourteen terminals / pins and three external driver capacitors. Thus, compared to a two-phase voltage conversion circuit in which each switching device is electrically connected to a separate bootstrap capacitor, Figure 6 The depicted dual-phase voltage conversion circuit uses one less terminal / pin and two less external capacitors. Thus, compared to a dual-phase voltage conversion circuit in which each switching device is electrically connected to a separate bootstrap capacitor, Figure 6 The depicted dual-phase voltage conversion circuit can have a smaller size and lower component cost.

[0057] Figure 7 FIG. 1 is a schematic block diagram of a switched capacitor voltage converter 700 according to a second embodiment of the present invention. Figure 7 In the depicted embodiment, the switched capacitor voltage converter includes a voltage conversion circuit 702 including series-connected switching devices 704-1, 704-2, 704-3, 704-4 implemented by transistors M1, M2, M3, M4, a voltage generator 706 connected to the series-connected switching devices, and voltage drivers 708-1, 708-2, 708-3, 708-4; an input capacitor C IN , flying capacitor C FLY , output capacitor C OUT , and the driver capacitor C D1 、C D2and C DR . Figure 7 The voltage conversion circuit 702, switching devices 704-1, 704-2, 704-3, 704-4, voltage generator 706, and voltage drivers 708-1, 708-2, 708-3, 708-4 in the depicted embodiment are similar to the embodiment of FIG. Figure 1 The voltage conversion circuit 102 , switching devices 104 - 1 , 104 - 2 , 104 - 3 , 104 - 4 , voltage generator 106 , and voltage drivers 108 - 1 , 108 - 2 , 108 - 3 , 108 - 4 in the depicted embodiment are similar or identical. Figure 7 The depicted switched capacitor voltage converter 700 is Figure 1 The difference between the depicted switched capacitor voltage converters 100 is that the driver capacitor C D1 The bottom plate is connected to the input voltage V IN instead of ground, and the driver capacitor C D2 The bottom plate is connected to the output voltage V OUT Instead of grounding.

[0058] Figure 8 FIG is a schematic block diagram of a switched capacitor voltage converter 800 according to a third embodiment of the present invention. Figure 8 In the depicted embodiment, the switched capacitor voltage converter includes a voltage conversion circuit 702 including series-connected switching devices 804-1, 804-2, 804-3, 804-4 implemented by transistors M1, M2, M3, M4, a voltage generator 806 connected to the series-connected switching devices, and voltage drivers 808-1, 808-2, 808-3, 808-4; an input capacitor C IN , flying capacitor C FLY , output capacitor C OUT , and the driver capacitor C D1 、C DR .exist Figure 8 In the depicted embodiment, the drain terminal D of transistor M1 is connected to the input voltage V IN The source terminal S of the transistor M1 is connected to the drain terminal D of the transistor M2, the source terminal S of the transistor M2 is connected to the drain terminal D of the transistor M3, the source terminal S of the transistor M3 is connected to the drain terminal D of the transistor M4, the source terminal S of the transistor M4 is connected to a reference voltage (e.g., ground), and the gate terminals G of the transistors M1, M2, M3, and M4 are connected to voltage drivers 808-1, 808-2, 808-3, and 808-4. Figure 8The voltage conversion circuit 802, switching devices 804-1, 804-2, 804-3, 804-4, voltage generator 806, and voltage drivers 808-1, 808-2, 808-3, 808-4 in the depicted embodiment are similar to the embodiment of FIG. Figure 1 The voltage conversion circuit 102, switching devices 104-1, 104-2, 104-3, 104-4, voltage generator 106, and voltage drivers 108-1, 108-2, 108-3, 108-4 in the depicted embodiment are similar or identical. Figure 8 In the depicted embodiment, the packaged IC device of the voltage conversion circuit 802 includes eight terminals / pins: V IN (power supply voltage) terminal / pin 810; reference terminal / pin (e.g., GND (ground) terminal / pin) 812; can be electrically connected to the driver capacitor C D1 Terminal / pin 814; can be electrically connected to the flying capacitor C FLY The terminal / pin 816 between transistors M1 and M2 can be electrically connected to the output capacitor C OUT The terminal / pin 820 between transistors M2 and M3 can be electrically connected to the flying capacitor C FLY The terminal / pin 822 between the transistors M3 and M4; and the terminal / pin 822 electrically connected to the driver capacitor C DR The terminals / pins 824, 826. Figure 8 In the depicted embodiment, the driver capacitor C D1 、C D2 and C DR Not directly connected to the N-type transistors M1, M2, M3, M4, and not for the bootstrap capacitors of the N-type transistors M1, M2, M3, M4. In a single-phase switched capacitor voltage converter in which each switching device of the voltage conversion circuit is electrically connected to a separate bootstrap capacitor, three external capacitors and three additional terminals (e.g., pins) are used for the voltage conversion circuit. Instead, Figure 8 The voltage conversion circuit 802 of the depicted switched capacitor voltage converter 800 uses two external driver capacitors C D1 、C DR and for electrically connecting to these external driver capacitors C D1 、C DR Therefore, compared with a switched capacitor voltage converter in which each switching device of the voltage conversion circuit is electrically connected to a separate bootstrap capacitor, Figure 8 The depicted switched capacitor voltage converter 800 uses fewer external capacitors. Thus, compared to a switched capacitor voltage converter in which each switching device of the voltage conversion circuit is electrically connected to a separate bootstrap capacitor, Figure 8The depicted switched capacitor voltage converter 800 can have a smaller size and lower component cost. Figure 1 Compared to the depicted switched capacitor voltage converter 100, Figure 8 The depicted switched capacitor voltage converter 800 uses one less external driver capacitor and thus one less terminal / pin to electrically connect to the driver capacitor.

[0059] Figure 9 Depicted is a voltage generator 906 which is Figure 8 An embodiment of a voltage generator 806 is depicted. Figure 9 The voltage generator 906 depicted is Figure 8 One possible embodiment of the voltage generator 806 is depicted. However, Figure 8 The depicted voltage generator 806 is not limited to Figure 8 The embodiment shown. Figure 9 In the depicted embodiment, the voltage generator 906 includes switches 932, 934, 936, 938 connected to terminals / pins 810, 814, 824, 826 having a driver voltage V D1 and input voltage V IN . Driver capacitor C D1 and C DR and the input capacitor C IN Can be electrically connected to terminals / pins 810, 814, 824, 826. Switch 934 is connected to a drive voltage V D1 The switch 932 is connected to the terminal 824 and the driver voltage V DR The switch 936 is connected to the terminal 826 and a reference voltage (eg, ground). The switch 938 is connected to the terminal 826 and a reference voltage (eg, ground). IN Terminal 810. Capacitor C D1 can be electrically connected to terminal 814, and capacitor C DR Can be electrically connected to terminals 824, 826. Input capacitor C IN The switches 932, 934, 936, 938 can be controlled to connect the driver capacitor C D1 and C DR At least one of the switches 932, 934, 936, and 938 is refreshed and / or charged by the internal voltage converter 940. In some embodiments, the voltage generator 906 includes some digital logic configured to control switches 932, 934, 936, and 938. In some embodiments, the internal voltage converter is implemented using a clamped voltage generator, a linear regulator, or other suitable voltage conversion circuit.

[0060] In an example operation of the voltage generator 906 , the voltage generator operates in two stages / phases. Figure 10A and Figure 10B Shown Figure 9 The switching stages / phases of the voltage generator are depicted. Specifically, Figure 10A The first stage of the voltage generator is shown. In the first stage, the driver capacitor C DR Be refreshed. Figure 10A As shown, switches 932 , 936 are closed (ie, conducting) and switches 934 , 938 are open (ie, non-conducting).

[0061] Figure 10B The second stage of the voltage generator 906 is shown. In the second stage, the driver capacitor C D1 is charged, and the driver voltage V D2 Generated by internal voltage converter 940. Figure 10B As shown, switches 934 , 938 are closed (ie, conducting) and switches 932 , 936 are open (ie, non-conducting).

[0062] For an N-phase (N is a positive integer) switched capacitor voltage converter according to an embodiment of the present invention, no bootstrap capacitor is used. Therefore, there are no terminals / pins for electrical connection between the bootstrap capacitor and the packaged IC device of the N-phase voltage conversion circuit. For an N-phase voltage conversion circuit in which each switching device is electrically connected to an external bootstrap capacitor, even if the intermediate bootstrap capacitor is reused, there are a total of 2N+1 terminals / pins for electrical connection to the bootstrap capacitor. Therefore, compared to an N-phase voltage conversion circuit in which each switching device is electrically connected to a separate bootstrap capacitor, the N-phase (N is a positive integer) switched capacitor voltage converter according to an embodiment of the present invention uses two external capacitors and three terminals / pins for electrical connection to the two external capacitors. Figure 11 The terminal / pin configuration of the dual-phase voltage conversion circuit 1102 implemented as a packaged IC device is depicted. Figure 11 As shown, the packaged IC device of the dual-phase voltage conversion circuit includes twelve terminals / pins, which are two V IN(Power supply voltage) terminals / pins 1110-1, 1110-2; two GND (ground) terminals / pins 1112-1, 1112-2; a terminal / pin 1116-1 between transistors M1 and M2 that can be electrically connected to the corresponding flying capacitor; a terminal / pin 1120-1 between transistors M2 and M3 that can be electrically connected to the corresponding output capacitor; a terminal / pin 1122-1 between transistors M3 and M4 that can be electrically connected to the corresponding flying capacitor; a terminal / pin 1116-2 between transistors M5 and M6 that can be electrically connected to the corresponding flying capacitor; a terminal / pin 1120-2 between transistors M6 and M7 that can be electrically connected to the corresponding output capacitor and can be connected to terminal / pin 1120-1; a terminal / pin 1122-2 between transistors M7 and M8 that can be electrically connected to the corresponding flying capacitor; a terminal / pin 1122-2 between transistors M7 and M8 that can be electrically connected to the driver capacitor C D1 and electrically connected to the driver capacitor C DR For a two-phase voltage conversion circuit in which each switching device is electrically connected to a separate bootstrap capacitor, a total of fifteen terminals / pins and five external bootstrap capacitors are used, even if the intermediate bootstrap capacitors are reused. In contrast, Figure 11 The depicted two-phase voltage conversion circuit uses thirteen terminals / pins and two external driver capacitors. Thus, compared to a two-phase voltage conversion circuit in which each switching device is electrically connected to a separate bootstrap capacitor, Figure 11 The depicted dual-phase voltage conversion circuit uses two fewer terminals / pins and three fewer external capacitors. Thus, compared to a dual-phase voltage conversion circuit in which each switching device is electrically connected to a separate bootstrap capacitor, Figure 11 The depicted dual-phase voltage conversion circuit can have a smaller size and lower component cost.

[0063] Figure 12 FIG. 1 is a schematic block diagram of a switched capacitor voltage converter 1200 according to a fourth embodiment of the present invention. Figure 12 In the depicted embodiment, the switched capacitor voltage converter includes a voltage conversion circuit 1202 including series-connected switching devices 1204-1, 1204-2, 1204-3, 1204-4 implemented by transistors M1, M2, M3, M4, a voltage generator 1206 connected to the series-connected switching devices, and voltage drivers 1208-1, 1208-2, 1208-3, 1208-4; an input capacitor C IN , flying capacitor C FLY , output capacitor C OUT , and the driver capacitor C D1 and C DR . Figure 12 The voltage conversion circuit 1202, switching devices 1204-1, 1204-2, 1204-3, 1204-4, voltage generator 1206, and voltage drivers 1208-1, 1208-2, 1208-3, 1208-4 in the depicted embodiment are similar to the embodiment of FIG. Figure 8 The voltage conversion circuit 802 , switching devices 804 - 1 , 804 - 2 , 804 - 3 , 804 - 4 , voltage generator 806 , and voltage drivers 808 - 1 , 808 - 2 , 808 - 3 , 808 - 4 in the depicted embodiment are similar or identical. Figure 12 The depicted switched capacitor voltage converter 1200 is Figure 8 The difference between the depicted switched capacitor voltage converter 800 is that the driver capacitor C D1 The bottom plate is connected to the input voltage V IN Instead of grounding.

[0064] Figure 13 is a process flow diagram of a method for operating a switched capacitor voltage converter according to an embodiment of the present invention. At block 1302, a driver voltage is generated in response to an input voltage at an input terminal connected to a series-connected switching device of the switched capacitor voltage converter. At block 1304, the series-connected switching device is driven based on the driver voltage. The switched capacitor voltage converter may be connected to a Figures 1-12 The depicted switched capacitor voltage converters are the same or similar.

[0065] In the above description, specific details of various embodiments are provided. However, some embodiments may be practiced with less than all of these specific details. In other cases, for the sake of brevity and clarity, certain methods, processes, components, structures and / or functions are described in no more detail than is necessary to implement the various embodiments of the present invention.

[0066] Although the operations of the methods herein are shown and described in a particular order, the order of the operations of each method may be changed so that certain operations may be performed in a reverse order, or so that certain operations may be performed at least partially simultaneously with other operations. In another embodiment, instructions or sub-operations of different operations may be implemented in an intermittent and / or alternating manner.

[0067] It should also be noted that at least some of the operations of the methods described herein can be implemented using software instructions stored on a computer-usable storage medium to be executed by a computer. As an example, an embodiment of a computer program product includes a computer-usable storage medium that stores a computer-readable program. Computer-usable or computer-readable storage media can be an electrical, magnetic, optical, electromagnetic, infrared or semiconductor system (or device or apparatus). Examples of non-transient computer-usable and computer-readable storage media include semiconductor or solid-state memory, magnetic tape, removable computer disk, random access memory (RAM), read-only memory (ROM), hard disk and optical disk. Current examples of optical disks include compact disks (CD-ROM) with read-only memory, compact disks (CD-R / W) with read / write, and digital video disks (DVD).

[0068] Alternatively, embodiments of the present invention may be implemented entirely in hardware, or in an embodiment comprising both hardware and software elements. In embodiments using software, the software may include but is not limited to firmware, resident software, microcode, etc.

[0069] Although specific embodiments of the invention have been described and illustrated, the invention is not to be limited to the specific forms or arrangements of parts so described and illustrated.The scope of the invention is defined by the following claims and their equivalents.

Claims

1. A switched capacitor voltage converter, characterized in that: The switched capacitor voltage converter comprises: The switch device is connected in series, comprising a first switch, a second switch, a third switch, and a fourth switch, with a seventh terminal, an eighth terminal, and a ninth terminal therebetween, respectively; a voltage generator connected to the series-connected switching devices and configured to generate a first driver voltage, a second driver voltage, and a third driver voltage in response to an input voltage at an input terminal connected to the series-connected switching devices; a first voltage driver configured to drive the first switching device based on a first driver voltage; a second voltage driver and a third voltage driver configured to drive the second switch and the third switch, respectively, based on a second driver voltage; and a fourth voltage driver configured to drive a fourth switching device based on the third driver voltage; The voltage generator includes: a first switch connected between a first terminal having a first driver voltage and a second terminal; a second switch connected between the third terminal having the second driver voltage and the second terminal; a third switch connected between the second terminal and a third driver voltage; a fourth switch connected between the fourth terminal and the reference voltage; a fifth switch connected between the fourth terminal and a fifth terminal having an input voltage; and a sixth switch connected between the fourth terminal and a sixth terminal having an output voltage; A third capacitor may be electrically connected to the second end and the fourth end.

2. The switched capacitor voltage converter according to claim 1, wherein: The voltage driver comprises: a first voltage driver configured to drive a first switching device of the series-connected switching devices based on a first driver voltage; a second voltage driver and a third voltage driver configured to drive a second switching device and a third switching device of the series-connected switching devices based on a second driver voltage; and A fourth voltage driver is configured to drive a fourth switching device of the series-connected switching devices based on a third driver voltage.

3. The switched capacitor voltage converter according to claim 2, wherein: The voltage generator includes a plurality of switches connected to a plurality of terminals having the first and second driver voltages of the switched capacitor voltage converter, the input voltage, and an output voltage.

4. The switched capacitor voltage converter according to claim 3, wherein: The switched capacitor voltage converter further includes a plurality of capacitors electrically connectable to the terminals.

5. The switched capacitor voltage converter according to claim 1, wherein: The switched capacitor voltage converter further comprises: a first capacitor electrically connectable to the first end; A second capacitor may be electrically connected to the third terminal.

6. The switched capacitor voltage converter according to claim 2, wherein: The voltage generator includes a plurality of switches connected to a plurality of terminals having the first driver voltage and the input voltage of the switched capacitor voltage converter.

7. The switched capacitor voltage converter according to claim 6, wherein: The switched capacitor voltage converter further includes a plurality of capacitors electrically connectable to the terminals.

8. A switched capacitor voltage converter, characterized in that: The switched capacitor voltage converter comprises: a plurality of N-type transistors connected in series; a voltage generator connected to the series-connected N-type transistors and configured to generate a plurality of driver voltages in response to an input voltage at an input terminal connected to the series-connected N-type transistors; and a plurality of voltage drivers configured to drive the series-connected N-type transistors based on the driver voltage; a voltage generator connected to the series-connected switching devices and configured to generate a first driver voltage, a second driver voltage, and a third driver voltage in response to an input voltage at an input terminal connected to the series-connected switching devices; a first voltage driver configured to drive the first switching device based on a first driver voltage; a second voltage driver and a third voltage driver configured to drive the second switch and the third switch, respectively, based on a second driver voltage; and a fourth voltage driver configured to drive a fourth switching device based on the third driver voltage; The voltage generator includes: a first switch connected between a first terminal having a first driver voltage and a second terminal; a second switch connected between the third terminal having the second driver voltage and the second terminal; a third switch connected between the second terminal and a third driver voltage; a fourth switch connected between the fourth terminal and the reference voltage; a fifth switch connected between the fourth terminal and a fifth terminal having an input voltage; and a sixth switch connected between the fourth terminal and a sixth terminal having an output voltage; A third capacitor may be electrically connected to the second end and the fourth end.

9. A method for operating a switched capacitor voltage converter, characterized in that The method comprises: generating a plurality of driver voltages in response to an input voltage at an input terminal connected to a plurality of series-connected switching devices of the switched capacitor voltage converter; and driving the series-connected switching devices based on the driver voltage; a voltage generator connected to the series-connected switching devices and configured to generate a first driver voltage, a second driver voltage, and a third driver voltage in response to an input voltage connected to an input terminal of the series-connected switching devices; driving the first switching device based on a first driver voltage by a first voltage driver; driving the second switch and the third switch based on the second driver voltage by the second voltage driver and the third voltage driver, respectively; driving a fourth switching device by a fourth voltage driver based on the third driver voltage; The voltage generator includes: a first switch connected between a first terminal having a first driver voltage and a second terminal; a second switch connected between the third terminal having the second driver voltage and the second terminal; a third switch connected between the second terminal and a third driver voltage; a fourth switch connected between the fourth terminal and the reference voltage; a fifth switch connected between the fourth terminal and a fifth terminal having an input voltage; and a sixth switch connected between the fourth terminal and a sixth terminal having an output voltage; A third capacitor may be electrically connected to the second end and the fourth end.

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