CN113206595B - Switching type power supply conversion circuit and switching circuit - Google Patents

Abstract

The invention relates to a switching power conversion circuit and a switching circuit. The switching power conversion circuit includes a conversion capacitor, a capacitive power conversion circuit, an inductor, an inductive power conversion circuit and a switching control circuit. The capacitive power conversion circuit includes a plurality of switching elements to convert the input voltage into a relay voltage, so that the relay voltage and the input voltage have a preset proportional relationship; the inductive power conversion circuit includes a plurality of switching elements to convert the intermediate voltage. The subsequent voltage is converted into an output voltage; the switching control circuit is used to generate a switching control signal; a plurality of switching elements of the capacitive power conversion circuit and the inductive power conversion circuit periodically switch the conversion capacitor and the inductive power conversion circuit according to the duty ratio of the switching control signal. inductor. The capacitive power conversion circuit and the inductive power conversion circuit share one of the switching elements.

Description

Switching power conversion circuit and switching circuit

technical field

The invention relates to a switching power conversion circuit, in particular to a switching power conversion circuit which has both capacitive and inductive power conversion functions and has high conversion efficiency. The present invention also relates to a switching circuit, which can be used to form the above-mentioned switching power conversion circuit.

Background technique

FIG. 1A shows a prior art switching power conversion circuit (switching power conversion circuit 1 ), which includes a switching control circuit 10 , a charge pump circuit 11 and a buck switching power conversion circuit 12. The switching control circuit 10 is used for generating the switching control signals dDUTY, dDUTYB and dPWMB. The pumping circuit 11 includes switches SW1 , SW3 , SW4 and SW5 , and capacitors C1 ′ and C2 ′. The switches SW1 , SW3 , SW4 and SW5 switch the capacitors C1 ′ and C2 ′ according to the switching control signal dDUTY or dDUTYB to switch the input voltage. Vin is converted into a relay voltage VCP, and the level of the relay voltage VCP is approximately twice the input voltage Vin. The step-down switching power conversion circuit 12 includes switches SW2, SWH, an inductor L' and an output capacitor Co'. The switches SW2 and SWH switch the inductor L' according to the switching control signal dPWMB to convert the relay voltage VCP into the output voltage Vout , wherein the level of the output voltage Vout is approximately a preset step-down multiple less than 1 of the relay voltage VCP, and the ratio of the output voltage Vout to the input voltage Vin is related to the duty cycle of the switching control signal dPWMB. FIG. 1B shows an operation waveform diagram corresponding to FIG. 1A . Since the pumping circuit 11 and the step-down switching power conversion circuit 12 can be regarded as independent two-stage power conversion circuits, the switching control signal dDUTY can have and switch The duty cycle of the control signal dPWMB is different. From another perspective, the duty cycle of the switching control signal dDUTY and the switching control signal dPWMB are not related. In addition, the switching frequencies of the two may be different or irrelevant.

It is worth noting that, in the prior art of FIG. 1A , the relay voltage VCP is generally a stable, non-pulse voltage, while the switching voltage VLX′ is a pulsed voltage. The voltage VLX' switches between the relay voltage VCP and the ground potential.

Compared with the prior art shown in FIG. 1A , the present invention has the advantage that the present invention can achieve better effects than the prior art with fewer components, thereby improving efficiency and reducing costs.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a switching power conversion circuit, comprising: a conversion capacitor; a capacitive power conversion circuit, including a plurality of switching elements, wherein the plurality of switching elements of the capacitive power conversion circuit for switching the conversion capacitor according to a switching control signal to convert an input voltage into a relay voltage, wherein the plurality of switching elements of the capacitive power conversion circuit include a first switching element, the relay voltage and the relay voltage The input voltage has a preset proportional relationship; an inductor; an inductive power conversion circuit, comprising a plurality of switching elements, wherein the plurality of switching elements of the inductive power conversion circuit are used to switch the switching control signal according to the switching control signal an inductor for converting the relay voltage into an output voltage, wherein the plurality of switching elements of the inductive power conversion circuit include the first switching element; and a switching control circuit for generating the switching control signal, wherein The plurality of switching elements of the capacitive power conversion circuit periodically switch the coupling relationship between a proportional voltage node, the input voltage, and a ground potential of the conversion capacitor according to a duty ratio of the switching control signal , so as to generate the relay voltage on the first end of the conversion capacitor, wherein the relay voltage is in the form of a pulse wave; wherein the plurality of switching elements of the inductive power conversion circuit are periodically switched according to the duty cycle The coupling relationship between the relay voltage, the output voltage and the ground potential of the inductor generates the output voltage, wherein the first end of the inductor is coupled to the proportional voltage node; wherein the output voltage and The proportional relationship between a high level of the relay voltage is related to the duty cycle.

In a preferred embodiment, the inductive power conversion circuit is configured as a step-down (buck) switching power conversion circuit, wherein the plurality of switching elements of the inductive power conversion circuit further includes a second switching element, wherein The first switching element is coupled between the first terminal of the conversion capacitor and the proportional voltage node, the second terminal of the inductor is coupled to the output voltage, and the second switching element is coupled to the proportional voltage node and the ground potential; the capacitive power conversion circuit is configured as a charge pump circuit, wherein the high level of the relay voltage is higher than the input voltage; wherein during a duty cycle, the first The switching element conducts the connection path between the first end of the conversion capacitor and the proportional voltage node, and simultaneously conducts the connection path between the first end of the inductor and the relay voltage, wherein the duty cycle period It refers to the period during which the first switching element is controlled to be turned on according to the duty cycle.

In a preferred embodiment, the level of the input voltage is optionally greater or less than the level of the output voltage.

In a preferred embodiment, the first switching element is a switch, the second switching element is a diode or a switch, wherein the first and second switching elements correspond to the duty cycle of the switching control signal Operation, so that the first end of the inductor is periodically correspondingly coupled to the relay voltage or the ground potential, so that the level of the output voltage is approximately a predetermined drop of the high level of the relay voltage voltage scale-down factor, wherein the preset voltage-down factor is less than 1.

In a preferred embodiment, the plurality of switching elements of the capacitive power conversion circuit further include: a third switching element coupled between the input voltage and the first end of the conversion capacitor; a fourth switching element , coupled between the input voltage and the second end of the conversion capacitor; and a fifth switching element, coupled between the second end of the conversion capacitor and the ground potential; wherein the first, third, The fourth and fifth switching elements operate correspondingly according to the duty cycle of the switching control signal, so that the switching capacitor is periodically correspondingly coupled between the input voltage and the ground potential, or the proportional voltage node and the input between the voltages, so that the high level of the relay voltage is approximately a predetermined voltage scale-up factor of the level of the input voltage, wherein the predetermined voltage scale-up factor is greater than 1.

In a preferred embodiment, the preset boost multiplier is 2.

In a preferred embodiment, a low level of the relay voltage is substantially equal to the level of the input voltage.

In a preferred embodiment, during the duty cycle, the relay voltage has the high level; wherein during a non-duty cycle period, the relay voltage has a low level, wherein the non-duty cycle period is Refers to the period during which the first switching element is controlled to be non-conductive according to the duty cycle.

In a preferred embodiment, the third, fourth and fifth switching elements are switches; wherein during the duty cycle, the first and fourth switching elements are controlled to be turned on, and the second and third switching elements are and the fifth switching element are controlled to be non-conductive at the same time, so that the connection path between the input voltage and the second end of the conversion capacitor, and the connection path between the first end of the conversion capacitor and the proportional voltage node are controlled In order to conduct, so that the relay voltage has the high level, and the first end of the inductor has the high level; wherein during the non-duty period, the second, third and fifth switching elements control In order to conduct, the first and fourth switching elements are simultaneously controlled to be non-conductive, so that the connection path between the input voltage and the first end of the conversion capacitor, the second end of the conversion capacitor and the ground potential The connection path of the inductor, and the connection path between the first end of the inductor and the ground potential are controlled to be turned on, so that the relay voltage has the low level, and the first end of the inductor has the ground potential potential.

In a preferred embodiment, the first, third and fourth switching elements are PMOS transistors, and the second and fifth switching elements are NMOS transistors.

In a preferred embodiment, there is one and only switch between the first end of the inductor and the first end of the conversion capacitor, and the first switching element corresponds to the one and only switch.

From another point of view, the present invention also provides a switching circuit, comprising: a capacitive power conversion circuit including a plurality of switching elements, wherein the plurality of switching elements of the capacitive power conversion circuit are used to control a switching according to a The signal switches a conversion capacitor to convert an input voltage into a relay voltage, wherein the plurality of switching elements of the capacitive power conversion circuit include a first switching element, and the relay voltage and the input voltage have a preset A proportional relationship of; an inductive power conversion circuit, comprising a plurality of switching elements, wherein the plurality of switching elements of the inductive power conversion circuit are used to switch an inductor according to the switching control signal to convert the relay voltage is an output voltage, wherein the plurality of switching elements of the inductive power conversion circuit include the first switching element; and a switching control circuit for generating the switching control signal, wherein the plurality of the capacitive power conversion circuit The switching element periodically switches the coupling relationship between a proportional voltage node, the input voltage, and a ground potential of the switching capacitor according to a duty ratio of the switching control signal, so that the first end of the switching capacitor is The relay voltage is generated on the relay voltage, wherein the relay voltage is in the form of a pulse wave; wherein the plurality of switching elements of the inductive power conversion circuit periodically switch the inductor between the relay voltage, the The coupling relationship between the output voltage and the ground potential generates the output voltage, wherein the first end of the inductor is coupled to the proportional voltage node; wherein the output voltage is between a high level of the relay voltage is proportional to the duty cycle.

The following describes in detail through specific embodiments, and it should be easier to understand the purpose, technical content, characteristics and effects of the present invention.

Description of drawings

FIG. 1A shows a prior art switching power conversion circuit.

FIG. 1B shows an operation waveform diagram corresponding to FIG. 1A.

FIG. 2 shows a block diagram of an embodiment of the switching power conversion circuit of the present invention.

FIG. 3 shows a schematic diagram of an embodiment of the switching power conversion circuit of the present invention.

FIG. 4A shows a schematic diagram of a specific embodiment of the switching power conversion circuit of the present invention.

FIG. 4B shows an operation waveform diagram corresponding to FIG. 4A.

FIG. 5A shows a schematic diagram of a specific embodiment of the switching power conversion circuit of the present invention.

5B shows schematic diagrams of two specific embodiments of the second switching element in the switching power conversion circuit of the present invention.

FIG. 6A shows a schematic diagram of a specific embodiment of the switching power conversion circuit according to the present invention.

FIG. 6B shows an operation waveform diagram corresponding to FIG. 6A.

FIG. 7 shows a block diagram of an embodiment of the switching circuit of the present invention.

FIG. 8 is a diagram showing the power conversion efficiency of the prior art and the present invention corresponding to different loads.

Description of symbols in the figure

1,2,3,4,5,6 switching power conversion circuit

10 Switching control circuit

11 Pumping circuit

12 Step-down switching power conversion circuit

200 switching circuits

21,31,41,51,61 Capacitive power conversion circuit

22,32,42,52,62 Inductive power conversion circuit

C1 Conversion Capacitor

C1’, C2’ Capacitors

Cep1 Converts the first terminal of capacitor C1

Cep2 Converts the second end of capacitor C1

Co,Co’ output capacitance

CTRL toggle control signal

dDUTY,dDUTYB switch control signal

dPWM, dPWMB switch control signal

L Inductor

L’ inductance

Lep1 The first end of the inductor L

Lep2 The second end of the inductor L

Np proportional voltage node

SC1-SCn switching element

SC1-SCm switching element

SC2, SC21, SC22 switching element

SC3,SC4,SC5 switching element

SW1, SW2, SW3 switches

SW4,SW5,SWH switch

T1,T3 duty cycle period

T2 non-duty period

VCP relay voltage

Vin input voltage

VLX proportional voltage

VLX’ switching voltage

Vm relay voltage

Vout output voltage

Detailed ways

The drawings in the present invention are schematic diagrams, mainly intended to show the coupling relationship between the circuits and the relationship between the signal waveforms, and the circuits, signal waveforms and frequencies are not drawn to scale.

Please refer to FIG. 2 . FIG. 2 shows a block diagram of an embodiment of the switching power conversion circuit of the present invention (switching power conversion circuit 2 ). In one embodiment, as shown in FIG. 2 , the switching power conversion circuit 2 includes a conversion capacitor C1 , a capacitive power conversion circuit 21 , an inductor L, an inductive power conversion circuit 22 and a switching control circuit 10 .

In one embodiment, as shown in FIG. 2 , the capacitive power conversion circuit 21 includes a plurality of switching elements, wherein the plurality of switching elements include a first switching element SC1 to an n-th switching element SCn, wherein n is an integer greater than 1. . A plurality of switching elements (switching elements SC1-SCn) of the capacitive power conversion circuit 21 are used to switch the conversion capacitor C1 according to the switching control signal CTRL generated by the switching control circuit 10, so as to convert the input voltage Vin into the relay voltage Vm, The relay voltage Vm and the input voltage Vin have a predetermined proportional relationship.

In one embodiment, as shown in FIG. 2 , the inductive power conversion circuit 22 includes a plurality of switching elements, wherein the plurality of switching elements include a first switching element SC1 to an m-th switching element SCm, wherein m is an integer greater than 1 . Specifically, the first switching element SC1 is a switching element of the capacitive power conversion circuit 21 and is also a switching element of the inductive power conversion circuit 22 . The multiple switching elements (switching elements SC1 ˜ SCm ) of the inductive power conversion circuit 22 are used to switch the inductor L according to the switching control signal CTRL, so as to convert the relay voltage Vm into the output voltage Vout.

Please continue to refer to FIG. 2 , in one embodiment, the switching control circuit 10 is used to generate the switching control signal CTRL. In one embodiment, a plurality of switching elements (switching elements SC1 ˜ SCn ) of the capacitive power conversion circuit 21 periodically switch the conversion capacitor C1 between the proportional voltage node Np and the input voltage Vin according to the duty cycle of the switching control signal CTRL , and the coupling relationship between the ground potential, so as to generate the relay voltage Vm on the first end Cep1 of the conversion capacitor C1, wherein the relay voltage Vm is in the form of a pulse wave. During the switching operation of SCn), the relay voltage Vm has at least two levels. In one embodiment, the multiple switching elements (switching elements SC1 ˜ SCm ) of the inductive power conversion circuit 22 periodically switch the inductor L between the relay voltage Vm and the output voltage Vout according to the duty ratio of the switching control signal CTRL and the coupling relationship between the ground potentials to generate the output voltage Vout, wherein the proportional relationship between the output voltage Vout and the high level of the relay voltage Vm is related to the duty cycle. In one embodiment, the first terminal Lep1 of the inductor L is coupled to the proportional voltage node Np.

Please refer to FIG. 3 . FIG. 3 shows a schematic diagram of an embodiment of the switching power conversion circuit of the present invention (switching power conversion circuit 3 ). In one embodiment, as shown in FIG. 3 , the inductive power conversion circuit 32 is configured as a buck switching power conversion circuit. In this embodiment, the plurality of switching elements of the inductive power conversion circuit 32 are also A second switching element SC2 is included.

In one embodiment, as shown in FIG. 3 , the first switching element SC1 is coupled between the first terminal Cep1 of the conversion capacitor C1 and the proportional voltage node Np, and the second terminal Lep2 of the inductor L is coupled to the output voltage Vout , the output capacitor Co is coupled between the second end Lep2 of the inductor L and the ground potential, and the second switching element SC2 is coupled between the proportional voltage node Np and the ground potential.

Please continue to refer to FIG. 3 , in one embodiment, the capacitive power conversion circuit 31 is configured as a charge pump circuit. In this embodiment, the high level of the relay voltage Vm is higher than the level of the input voltage Vin. From an angle, the capacitive power conversion circuit 31 and the inductive power conversion circuit 32 share at least the first switching element SC1. In one embodiment, the sharing method is as follows: during the duty cycle period, that is, the period during which the first switching element SC1 is controlled to be turned on according to the duty cycle, for the capacitive power conversion circuit 31, the first switching element SC1 conducts the connection path between the first end Cep1 of the conversion capacitor C1 and the proportional voltage node Np. On the other hand, for the inductive power conversion circuit 32, the first switching element SC1 also conducts the first switching element of the inductor L at the same time. A connection path between the terminal Lep1 and the relay voltage Vm.

Please refer to FIG. 4A . FIG. 4A shows a schematic diagram of a specific embodiment of the switching power conversion circuit of the present invention (switching power conversion circuit 4 ). In one embodiment, as shown in FIG. 4A , the plurality of switching elements of the capacitive power conversion circuit 41 further include: a third switching element SC3 , a fourth switching element SC4 and a fifth switching element SC5 .

In a specific embodiment, as shown in FIG. 4A , the third switching element SC3 is coupled between the input voltage Vin and the first end Cep1 of the conversion capacitor C1, and the fourth switching element SC4 is coupled between the input voltage Vin and the conversion capacitor Between the second end Cep2 of C1, the fifth switching element SC5 is coupled between the second end Cep2 of the conversion capacitor C1 and the ground potential.

Please refer to FIG. 4A and FIG. 4B at the same time. FIG. 4B shows an operation waveform diagram corresponding to FIG. 4A . In one embodiment, the first switching element SC1, the third switching element SC3, the fourth switching element SC4 and the fifth switching element SC5 operate correspondingly according to the duty cycle of the switching control signal CTRL generated by the switching control circuit 10, so that The conversion capacitor C1 is periodically correspondingly coupled between the input voltage Vin and the ground potential, or between the proportional voltage node Np and the input voltage Vin, so that the high level of the relay voltage Vm is approximately a predetermined level of the input voltage Vin. The preset voltage scale-upfactor, wherein the preset voltage scale-upfactor is greater than 1 (in this embodiment, the voltage scale-upfactor may be 2).

In one embodiment, the inductive power conversion circuit 42 of FIG. 4A may correspond to, for example, the inductive power conversion circuit 32 of FIG. 3 , and the first switching element SC1 and the second switching element SC2 are switched according to the duty cycle of the switching control signal CTRL. Corresponding operation, the first end Lep1 of the inductor L is periodically correspondingly coupled to the relay voltage Vm or the ground potential, so that the level of the output voltage Vout is approximately a predetermined step-down of the high level of the relay voltage Vm multiple (voltage scale-downfactor), wherein the preset voltage reduction multiple is less than 1. It should be noted that the high level of the proportional voltage VLX on the proportional voltage node Np is approximately the same as the high level of the relay voltage Vm, the low level is approximately the level of the ground potential, and the level of the output voltage Vout is approximately is the average value of the level of the proportional voltage VLX, which is related to the duty cycle of the switching control signal CTRL. In this embodiment, the relationship between the level of the output voltage Vout and the level of the proportional voltage VLX is, for example: Vout=2*Vin*D, where D is the duty cycle of the switching control signal CTRL. In this embodiment, the switching control signal The duty ratio of CTRL is, for example, T1/(T1+T2).

Specifically, for the capacitive power conversion circuit 41 , during the non-duty period (period T2 shown in FIG. 4B ), the third switching element SC3 and the fifth switching element SC5 are controlled to be turned on, and the first switching element is switched on. The element SC1 and the fourth switching element SC4 are controlled to be non-conductive at the same time. At this time, the conversion capacitor C1 is correspondingly coupled between the input voltage Vin and the ground potential, so that the connection path between the input voltage Vin and the first end Cep1 of the conversion capacitor C1 . The connection path between the second end Cep2 of the conversion capacitor C1 and the ground potential is controlled to be turned on, that is, the conversion capacitor C1 is charged to the same level as the input voltage Vin through the third switching element SC3 and the fifth switching element SC5 , so that the relay voltage Vm has a low level (in this embodiment, as shown in period T2 in FIG. 4B , the low level of the relay voltage Vm is substantially equal to the level of the input voltage Vin). On the other hand, for the inductive power conversion circuit 42, the first switching element SC1 is controlled to be non-conductive and the second switching element SC2 is controlled to be conductive, so that the proportional voltage VLX on the proportional voltage node Np has the ground potential, in other words , during the non-duty period, the first end Lep1 of the inductor L is correspondingly coupled to the ground potential and has a ground potential.

Then, during the duty cycle period (period T3 or T1 shown in FIG. 4B ), for the capacitive power conversion circuit 41 , the first switching element SC1 and the fourth switching element SC4 are controlled to be turned on, and the third switching element is switched on. The element SC3 and the fifth switching element SC5 are controlled to be non-conductive at the same time. At this time, the conversion capacitor C1 is correspondingly coupled between the proportional voltage node Np and the input voltage Vin, so that the input voltage Vin and the second end Cep2 of the conversion capacitor C1 are connected. The connection path and the connection path between the first end Cep1 of the conversion capacitor C1 and the proportional voltage node Np are controlled to be turned on, at this time, the input voltage Vin and the cross voltage stored on the conversion capacitor C1 (also in this embodiment is Vin) is superimposed to pump the relay voltage Vm to a high level. In this embodiment, as shown in the figure, during the duty cycle period (eg, T3 period), the relay voltage Vm will be pumped to 2Vin. On the other hand, for the inductive power conversion circuit 42, the first switching element SC1 is controlled to be turned on and the second switching element SC2 is controlled to be turned off, so that the proportional voltage VLX on the proportional voltage node Np has a high level (2Vin ), in other words, during the duty cycle, the first end Lep1 of the inductor L is correspondingly coupled to the relay voltage Vm, so the first end Lep1 of the inductor L also has a high level.

Please continue to refer to FIG. 4A , in one embodiment, the high level of the relay voltage Vm is approximately a predetermined boost multiple of the level of the input voltage Vin, and the level of the output voltage Vout is approximately equal to the relay voltage Vm A predetermined step-down multiple of the high level, so the level of the input voltage Vin is optionally larger or smaller than the level of the output voltage Vout. To sum up, the switching power conversion circuit of the present invention can realize the effect of a buck-boost switching power conversion circuit through a capacitive power conversion circuit and an inductive power conversion circuit, but does not need to use More complex inductive buck-boost switching power conversion circuit.

Please refer to FIGS. 5A and 5B , FIG. 5A shows a schematic diagram of a specific embodiment of the switching power conversion circuit of the present invention (switching power conversion circuit 5 ), and FIG. 5B shows that in the switching power conversion circuit of the present invention, the second Schematic diagrams of two specific embodiments of switching elements (second switching elements SC21 and SC22 ). In one embodiment, as shown in FIG. 5A , the first switching element SC1 is a switch. In one embodiment, the third switching element SC3 , the fourth switching element SC4 and the fifth switching element SC5 of the capacitive power conversion circuit 51 are switches. The operation of this embodiment is similar to that of the aforementioned embodiment of FIG. 4A , and details are not described here. As shown in FIG. 5B , in one embodiment, the second switching element (eg, corresponding to the second switching element SC2 of FIG. 5A ) may be configured as a diode ( SC22 ) or a switch ( SC21 ). It should be noted that when the second switching element is configured as a diode ( SC22 ), the switching control signal CTRL does not directly control whether the second switching element SC22 is turned on or not, but is determined by the direction of the current.

Please refer to FIG. 6A . FIG. 6A shows a schematic diagram of a specific embodiment of a switching power conversion circuit according to the present invention (switching power conversion circuit 6 ). In one embodiment, as shown in FIG. 6A , the first switching element SC1 , the third switching element SC3 and the fourth switching element SC4 in the capacitive power conversion circuit 61 are PMOS transistors, and the fifth switching element SC5 is an NMOS transistor, The second switching element SC2 in the inductive power conversion circuit 62 is an NMOS transistor.

Please refer to FIG. 6A and FIG. 6B at the same time. FIG. 6B shows an operation waveform diagram corresponding to FIG. 6A . In this embodiment, the switching control signal CTRL generated by the switching control circuit 10 includes a switching control signal dPWM and a switching control signal dPWMB. The switching control signal dPWM is, for example, in phase with the waveform of the switching control signal CTRL in FIG. The waveforms of the control signal dPWMB and the switching control signal CTRL are opposite to each other. In this embodiment, the first switching element SC1 , the second switching element SC2 , the fourth switching element SC4 and the fifth switching element SC5 operate correspondingly according to the switching control signal dPWMB, and the third switching element SC3 corresponds to the switching control signal dPWM operation, so that the conversion capacitor C1 is periodically correspondingly coupled between the input voltage Vin and the ground potential, or between the proportional voltage node Np and the input voltage Vin, and the first end Lep1 of the inductor L is periodically correspondingly coupled Regarding the relay voltage Vm or the ground potential, the details and effects of its operation are as described in the embodiment of FIG. 4A , and will not be repeated here.

From another perspective, the present invention also discloses a switching circuit, as shown in FIG. 7 , which shows a block diagram (switching circuit 200 ) of an embodiment of the switching circuit of the present invention. In one embodiment, the switching circuit 200 includes a capacitive power conversion circuit 21 , an inductive power conversion circuit 22 and a switching control circuit 10 , wherein the switching control circuit 10 is used to generate a switching control signal CTRL to control the capacitive power conversion circuit 21 . The switching elements SC1 to SCn in the inductive power conversion circuit 22 are also used to control the switching elements SC1 to SCm of the inductive power conversion circuit 22 . In one embodiment, the switching circuit 200 is used to switch the switching capacitor C1 and the inductor L. The details of the operation are described in the embodiments of FIGS. 2 to 6A , and are not repeated here.

It is worth noting that, compared with the prior art in the aforementioned FIG. 1A , the switching power conversion circuit of the present invention (such as the switching power conversion circuit 3 - 6 ) can save energy by sharing the first switching element SC1 . At least one capacitor (ie, no need for C2' in the prior art as shown in FIG. 1A ) and at least one switch (ie, the switches SW1 and SWH in the prior art as shown in FIG. 1A are combined into the first switching element SC1 in the present invention), which can effectively Cost saving, and since the number of switches on the power path is reduced, the on-resistance value of the switch is also reduced, which can improve the power conversion efficiency. Please refer to FIG. 8 , which shows the power supply corresponding to different loads in the prior art and the present invention. The conversion efficiency diagram, as shown in FIG. 8 , the power conversion efficiency of the switching power conversion circuit of the present invention is better than that of the prior art. In addition, due to the switching power conversion circuit of the present invention, all the switching elements in the capacitive power conversion circuit 21 and the inductive power conversion circuit 22 can be operated according to the switching control signals (CTRL, dPWM, dPWMB) related to each other, so , can also greatly simplify the complexity of the control.

The present invention has been described above with respect to the preferred embodiments, but the above description is only for those skilled in the art to easily understand the content of the present invention, and is not intended to limit the scope of rights of the present invention. The described embodiments are not limited to be applied individually, but can also be applied in combination. For example, two or more embodiments can be applied in combination, and some components in one embodiment can also be used to replace those in another embodiment. corresponding components. In addition, under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations. It is limited to the signal itself, but also includes, when necessary, performing voltage-to-current conversion, current-to-voltage conversion, and/or ratio conversion, etc. on the signal, and then processing or calculating according to the converted signal to generate a certain output result. It can be seen from this that under the same spirit of the present invention, those skilled in the art can think of various equivalent changes and various combinations, and there are many combinations, which are not listed and described here. Accordingly, the scope of the present invention should cover the above and all other equivalent changes.

Claims (12)

1. A switching power conversion circuit, characterized in that, comprising: a conversion capacitor; A capacitive power conversion circuit includes a plurality of switching elements, wherein the plurality of switching elements of the capacitive power conversion circuit are used to switch the conversion capacitor according to a switching control signal to convert an input voltage into a relay voltage , wherein the plurality of switching elements of the capacitive power conversion circuit include a first switching element, and the relay voltage and the input voltage have a preset proportional relationship; an inductor; An inductive power conversion circuit includes a plurality of switching elements, wherein the plurality of switching elements of the inductive power conversion circuit are used to switch the inductor according to the switching control signal, so as to convert the relay voltage into an output voltage , wherein the plurality of switching elements of the inductive power conversion circuit include the first switching element; and a switching control circuit for generating the switching control signal, wherein the switching elements of the capacitive power conversion circuit periodically switch the switching capacitor to a proportional voltage node, according to a duty cycle of the switching control signal The coupling relationship between the input voltage and a ground potential generates the relay voltage on the first end of the conversion capacitor, wherein the relay voltage is in the form of a pulse wave; wherein the inductive power conversion circuit A plurality of switching elements periodically switch the coupling relationship between the relay voltage, the output voltage and the ground potential according to the duty ratio to generate the output voltage, wherein the first of the inductors The terminal is coupled to the proportional voltage node; Wherein, the proportional relationship between the output voltage and a high level of the relay voltage is related to the duty cycle; Wherein, the inductive power conversion circuit is configured as a step-down switching power conversion circuit, wherein the plurality of switching elements of the inductive power conversion circuit further includes a second switching element, wherein the first switching element is coupled to the between the first end of the conversion capacitor and the proportional voltage node, the second end of the inductor is coupled to the output voltage, the second switching element is coupled between the proportional voltage node and the ground potential; The capacitive power conversion circuit is configured as a pumping circuit, wherein the high level of the relay voltage is higher than the input voltage; Wherein, during a duty cycle, the first switching element conducts the connection path between the first end of the conversion capacitor and the proportional voltage node, and simultaneously conducts the first end of the inductor and the relay a connection path between voltages, wherein the duty cycle period refers to a period during which the first switching element is controlled to be turned on according to the duty cycle; Wherein, the first switching element is a switch, the second switching element is a diode or a switch, wherein the first and second switching elements operate correspondingly according to the duty ratio of the switching control signal, so that the inductor The first end of the relay is periodically coupled to the relay voltage or the ground potential, so that the level of the output voltage is approximately a predetermined step-down multiple of the high level of the relay voltage, wherein the pre- The set step-down multiple is less than 1; Wherein, the plurality of switching elements of the capacitive power conversion circuit further include: a third switching element, coupled between the input voltage and the first end of the conversion capacitor; a fourth switching element, coupled between the input voltage and the second end of the conversion capacitor; and a fifth switching element, coupled between the second end of the conversion capacitor and the ground potential; Wherein, the first, third, fourth and fifth switching elements operate correspondingly according to the duty ratio of the switching control signal, so that the switching capacitor is periodically and correspondingly coupled between the input voltage and the ground potential , or between the proportional voltage node and the input voltage, so that the high level of the relay voltage is approximately a preset boosting multiple of the level of the input voltage, wherein the preset boosting multiple is greater than 1; Wherein, during the duty cycle, the relay voltage has the high level; wherein, in a non-duty cycle period, the relay voltage has a low level, wherein the non-duty cycle period refers to a period during which the first switching element is controlled to be non-conductive according to the duty cycle; Wherein, the third, fourth and fifth switching elements are switches; Wherein, during the duty cycle, the first and fourth switching elements are controlled to be turned on, and the second, third and fifth switching elements are simultaneously controlled to be non-conductive, so that the input voltage and the conversion capacitor are The connection path between the second terminals and the connection path between the first terminal of the conversion capacitor and the proportional voltage node are controlled to be turned on, so that the relay voltage has the high level, and the inductor has the high level. the first end has the high level; Wherein, during the non-duty period, the second, third and fifth switching elements are controlled to be turned on, and the first and fourth switching elements are controlled to be non-conductive at the same time, so that the input voltage and the conversion capacitor are The connection path between the first ends, the connection path between the second end of the conversion capacitor and the ground potential, and the connection path between the first end of the inductor and the ground potential are controlled to be turned on, and then The relay voltage has the low level, and the first end of the inductor has the ground potential. 2 . The switching power conversion circuit of claim 1 , wherein the level of the input voltage is optionally larger or smaller than the level of the output voltage. 3 . 3 . The switching power conversion circuit of claim 1 , wherein the preset boosting multiple is 2. 4 . 4. The switching power conversion circuit of claim 1, wherein a low level of the relay voltage is substantially equal to a level of the input voltage. 5 . The switching power conversion circuit of claim 1 , wherein the first, third and fourth switching elements are PMOS transistors, and the second and fifth switching elements are NMOS transistors. 6 . 6 . The switching power conversion circuit of claim 1 , wherein there is one and only switch between the first end of the inductor and the first end of the conversion capacitor, and the first switching element corresponds to The one and only switch. 7. A switching circuit, characterized in that, comprising: A capacitive power conversion circuit includes a plurality of switching elements, wherein the plurality of switching elements of the capacitive power conversion circuit are used to switch a conversion capacitor according to a switching control signal to convert an input voltage into a relay voltage , wherein the plurality of switching elements of the capacitive power conversion circuit include a first switching element, and the relay voltage and the input voltage have a preset proportional relationship; An inductive power conversion circuit includes a plurality of switching elements, wherein the plurality of switching elements of the inductive power conversion circuit are used to switch an inductor according to the switching control signal, so as to convert the relay voltage into an output voltage , wherein the plurality of switching elements of the inductive power conversion circuit include the first switching element; and a switching control circuit for generating the switching control signal, wherein the switching elements of the capacitive power conversion circuit periodically switch the switching capacitor to a proportional voltage node, according to a duty cycle of the switching control signal The coupling relationship between the input voltage and a ground potential generates the relay voltage on the first end of the conversion capacitor, wherein the relay voltage is in the form of a pulse wave; wherein the inductive power conversion circuit A plurality of switching elements periodically switch the coupling relationship between the relay voltage, the output voltage and the ground potential according to the duty ratio to generate the output voltage, wherein the first of the inductors The terminal is coupled to the proportional voltage node; Wherein, the proportional relationship between the output voltage and a high level of the relay voltage is related to the duty cycle; Wherein, the inductive power conversion circuit is configured as a step-down switching power conversion circuit, wherein the plurality of switching elements of the inductive power conversion circuit further includes a second switching element, wherein the first switching element is coupled to the between the first end of the conversion capacitor and the proportional voltage node, the second end of the inductor is coupled to the output voltage, the second switching element is coupled between the proportional voltage node and the ground potential; The capacitive power conversion circuit is configured as a pumping circuit, wherein the high level of the relay voltage is higher than the input voltage; Wherein, during a duty cycle, the first switching element conducts the connection path between the first end of the conversion capacitor and the proportional voltage node, and simultaneously conducts the first end of the inductor and the relay a connection path between voltages, wherein the duty cycle period refers to a period during which the first switching element is controlled to be turned on according to the duty cycle; Wherein, the first switching element is a switch, the second switching element is a diode or a switch, wherein the first and second switching elements operate correspondingly according to the duty ratio of the switching control signal, so that the inductor The first end of the relay is periodically coupled to the relay voltage or the ground potential, so that the level of the output voltage is approximately a predetermined step-down multiple of the high level of the relay voltage, wherein the pre- The set step-down multiple is less than 1; Wherein, the plurality of switching elements of the capacitive power conversion circuit further include: a third switching element, coupled between the input voltage and the first end of the conversion capacitor; a fourth switching element, coupled between the input voltage and the second end of the conversion capacitor; and a fifth switching element, coupled between the second end of the conversion capacitor and the ground potential; Wherein, the first, third, fourth and fifth switching elements operate correspondingly according to the duty ratio of the switching control signal, so that the switching capacitor is periodically and correspondingly coupled between the input voltage and the ground potential , or between the proportional voltage node and the input voltage, so that the high level of the relay voltage is approximately a preset boost multiple of the input voltage level, wherein the preset boost multiple is greater than 1; Wherein, during the duty cycle, the relay voltage has the high level; wherein, in a non-duty cycle period, the relay voltage has a low level, wherein the non-duty cycle period refers to a period during which the first switching element is controlled to be non-conductive according to the duty cycle; Wherein, the third, fourth and fifth switching elements are switches; Wherein, during the duty cycle period, the first and fourth switching elements are controlled to be turned on, and the second, third and fifth switching elements are simultaneously controlled to be non-conductive, so that the input voltage and the conversion capacitor are The connection path between the second terminals and the connection path between the first terminal of the conversion capacitor and the proportional voltage node are controlled to be turned on, so that the relay voltage has the high level, and the inductor has the high level. the first end has the high level; Wherein, during the non-duty period, the second, third and fifth switching elements are controlled to be turned on, and the first and fourth switching elements are controlled to be non-conductive at the same time, so that the input voltage and the conversion capacitor are The connection path between the first ends, the connection path between the second end of the conversion capacitor and the ground potential, and the connection path between the first end of the inductor and the ground potential are controlled to be turned on, thereby The relay voltage has the low level, and the first end of the inductor has the ground potential. 8. The switching circuit of claim 7, wherein the level of the input voltage is optionally larger or smaller than the level of the output voltage. 9 . The switching circuit of claim 7 , wherein the preset boosting multiplier is 2. 10 . 10. The switching circuit of claim 7, wherein a low level of the relay voltage is substantially equal to a level of the input voltage. 11. The switching circuit of claim 7, wherein the first, third and fourth switching elements are PMOS transistors, and the second and fifth switching elements are NMOS transistors. 12. The switching circuit of claim 7, wherein there is one and only switch between the first end of the inductor and the first end of the conversion capacitor, and the first switching element corresponds to the one and the only switch.

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