A switched capacitor converter

Abstract

A switched capacitor converter is disclosed. The switched capacitor converter includes a plurality of input switch groups connected in series between an input terminal and an output terminal, wherein each input switch group includes two power switches connected in series; a plurality of output switch groups, wherein each output switch group includes two power switches connected in series; a plurality of capacitors, whose first ends are respectively connected to a common node of each two power switches connected in series in the plurality of input switch groups, and whose second ends are respectively connected to an intermediate node of each of the output switch groups; and a plurality of inductors, wherein the first end of each output switch group is connected to the first end of a corresponding inductor, the second ends of the plurality of inductors are connected to the output terminal, and the second ends of the plurality of output switch groups are connected to a reference ground. According to the switched capacitor converter of the present invention, the power switches in the input switch group and the output switch group are controlled to control the switching of the switched capacitor converter in different working stages, so that each capacitor branch includes one of the plurality of inductors, thereby reducing the generation of peak current when the switching converter switches in the working stage.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and more particularly to a switched capacitor converter. Background Art

[0002] Figure 1 The circuit topology of a single inductor soft-charge Dickson converter is shown, and its voltage ratio is 4:1. As shown in the figure, under the original two-way 50% complementary duty cycle control mode, since the capacitive reactance is reduced after the capacitors are connected in series, the capacitor voltage charging rate is different, and the system has a state of capacitors working in parallel when the power switch performs a switching action, thereby generating a peak current. Therefore, a more complex control method is required to ensure that there is no pressure difference in the capacitor loop during the switching action, so as to reduce the current spike and improve the system working efficiency. To this end, the present invention provides a switched capacitor converter to reduce the current spike and improve the system working efficiency. Summary of the invention

[0003] In view of this, the present invention proposes a switched capacitor converter, which controls the switching of the switched capacitor converter in different working stages by controlling the switching state of the power switch of the switched capacitor converter, so that each capacitor branch includes one of the multiple inductors, thereby reducing the generation of peak current when the switching converter switches in the working stage.

[0004] According to one aspect of the present invention, a switched capacitor converter is provided. The switched capacitor converter comprises a plurality of input switch groups connected in series between an input terminal and an output terminal, wherein each input switch group comprises two power switches connected in series;

[0005] a plurality of output switch groups, wherein each output switch group includes two power switches connected in series;

[0006] a plurality of capacitors, wherein a first end of each capacitor is connected to a common node of each two power switches connected in series in the plurality of input switch groups, and a second end of each capacitor is connected to an intermediate node of each output switch group, wherein the intermediate node is a common node of two power switches connected in series in the same switch group; and

[0007] A plurality of inductors, wherein a first end of each output switch group is connected to a first end of a corresponding inductor, second ends of the plurality of inductors are connected to the output end, and second ends of the plurality of output switch groups are connected to a reference ground.

[0008] Preferably, the first end of the first inductor among the multiple inductors is connected to the first end of the first output switch group, wherein the first output switch group is directly connected in series with the multiple input switch groups, and the first ends of the other inductors are respectively connected to the first ends of corresponding two output switch groups among the multiple output switch groups.

[0009] Preferably, when the number of the input switch groups is N, the number of the output switch groups and the number of the capacitors are (2N-1) respectively, and the number of the inductors is N, wherein N≥2.

[0010] Preferably, the power switches in the input switch group and the output switch group are controlled to perform switching actions so that the switched capacitor converter switches in different working stages, wherein each capacitor branch in each working stage includes one of the multiple inductors, thereby reducing peak current when the switched capacitor converter switches working stages, wherein each of the capacitor branches includes at least one of the multiple capacitors.

[0011] Preferably, one of the two power switches in each of the input and output switch groups in the switched capacitor converter performs a switching action according to a first control signal, and the other power switch in each of the input and output switch groups operates according to a second control signal, wherein in one switching cycle, the duty cycle of the first control signal and the second control signal are the same and do not overlap with each other.

[0012] Preferably, the first control signal is complementary to the second control signal, and the duty cycle is 0.5.

[0013] Preferably, within a switching cycle, when the first control signal is valid, the switched capacitor converter operates in a first stage; and when the second control signal is valid, the switched capacitor converter operates in a second stage.

[0014] Preferably, the switching state of the first output switch group is the same as the switching state of each input switch group, and in other output switch groups, one of the two output switch groups connected to the same inductor is the same as the switching state of each input switch group, and the other is opposite to the switching state of each input switch group.

[0015] Preferably, when the switched capacitor converter operates in the first stage, N capacitor branches are formed, the first capacitor branch to the N-1th capacitor branch are connected in parallel between the output end and the reference ground, and the Nth capacitor branch is connected between the input end and the output end, wherein each of the first capacitor branch to the N-1th capacitor branch includes two capacitors, and the Nth capacitor branch includes one capacitor, wherein N is the number of the input switch groups, and N≥2.

[0016] Preferably, when the switched capacitor converter operates in the second stage, N capacitor branches are formed, and the first capacitor branch to the Nth capacitor branch are all connected in parallel between the output end and the reference ground, wherein the first capacitor branch includes one capacitor, and each of the second capacitor branch to the Nth capacitor branch includes two capacitors, wherein N is the number of the input switch groups, and N≥2.

[0017] Preferably, the inductance value of each of the inductors is the same, and the capacitance value of the capacitor connected to the common end of adjacent input switch groups is much larger than the capacitance value of the capacitor connected to the intermediate node of each input switch group; and the capacitance values ​​of the capacitors connected to the intermediate nodes of the input switch groups are all equal, so that the current of each capacitor branch is the same.

[0018] Preferably, the switched capacitor converter operates in a quasi-resonant state or a resonant state according to different inductance values ​​of the inductor.

[0019] Preferably, the ratio of the input voltage to the output voltage of the switched capacitor converter is 2N:1.

[0020] The present invention provides a switched capacitor converter. The switched capacitor converter includes a plurality of input switch groups connected in series between an input terminal and an output terminal, wherein each input switch group includes two power switches connected in series; a plurality of output switch groups, wherein each output switch group includes two power switches connected in series; a plurality of capacitors, whose first ends are respectively connected to the common node of each two power switches connected in series in the plurality of input switch groups, and whose second ends are respectively connected to the intermediate node of each of the output switch groups; and a plurality of inductors, wherein the first end of each output switch group is connected to the first end of a corresponding inductor, the second ends of the plurality of inductors are connected to the output terminal, and the second ends of the plurality of output switch groups are connected to a reference ground. According to the switched capacitor converter of the present invention, the power switches in the input switch group and the output switch group are controlled to control the switching of the switched capacitor converter in different working stages, so that each capacitor branch includes one of the plurality of inductors, thereby reducing the generation of peak current when the switching converter switches in the working stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0022] Figure 1 A Dickson switched capacitor converter according to the prior art;

[0023] Figure 2 A specific circuit diagram of a switched capacitor converter embodiment 1 of the present invention;

[0024] Figure 3 is a timing diagram of control signals of a switched capacitor converter according to a first embodiment of the present invention;

[0025] Figure 4 is an equivalent circuit diagram of a first embodiment of a switched capacitor converter of the present invention;

[0026] Figure 5a The inductor current waveform diagram of the switched capacitor converter working in the quasi-resonant state;

[0027] Figure 5b The inductor current waveform diagram of the switched capacitor converter working in the resonant state;

[0028] Figure 6 This is a specific circuit diagram of a second embodiment of a switched capacitor converter according to the present invention;

[0029] Figure 7 is a timing diagram of control signals of a second embodiment of a switched capacitor converter of the present invention;

[0030] Figure 8 is an equivalent circuit diagram of a second embodiment of a switched capacitor converter of the present invention;

[0031] Fig. 9 This is a specific circuit diagram of the third embodiment of the switched capacitor converter of the present invention;

[0032] Fig.10 A timing diagram of control signals of a switched capacitor converter according to a third embodiment of the present invention; and

[0033] Fig.11 FIG. 4 is an equivalent circuit diagram of the third embodiment of the switched capacitor converter of the present invention. DETAILED DESCRIPTION

[0034] The present invention is described below based on embodiments, but the present invention is not limited to these embodiments. In the detailed description of the present invention below, some specific details are described in detail. It is possible for a person skilled in the art to fully understand the present invention without the description of these details. In order to avoid confusing the essence of the present invention, known methods, processes, flows, components and circuits are not described in detail.

[0035] In addition, persons of ordinary skill in the art will appreciate that the drawings provided herein are for illustration purposes and are not necessarily drawn to scale.

[0036] At the same time, it should be understood that in the following description, "circuit" refers to a conductive loop composed of at least one element or subcircuit through electrical connection or electromagnetic connection. When an element or circuit is said to be "connected to" another element or an element / circuit is said to be "connected between" two nodes, it can be directly coupled or connected to another element or there can be an intermediate element, and the connection between the elements can be physical, logical, or a combination thereof. On the contrary, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there is no intermediate element between the two.

[0037] Unless the context clearly requires otherwise, throughout the specification and claims, the words "include", "comprising" and similar words should be interpreted in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to".

[0038] In the description of the present invention, it should be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0039] The switched capacitor converter of the embodiment of the present invention includes a plurality of input switch groups connected in series between an input end and an output end, wherein each input switch group includes two power switches connected in series; a plurality of output switch groups, wherein each output switch group includes two power switches connected in series; a plurality of capacitors, wherein the first ends of the capacitors are respectively connected to the common node of each two power switches connected in series in the plurality of input switch groups, and the second ends are respectively connected to the intermediate node of each output switch group, wherein the intermediate node is the common node of the two power switches connected in series in the same switch group; and a plurality of inductors, wherein the first end of each output switch group is connected to the first end of a corresponding inductor, the second ends of the plurality of inductors are all connected to the output end, and the second ends of the plurality of output switch groups are connected to a reference ground.

[0040] Figure 2 FIG. 1 is a specific circuit diagram of the first embodiment of the switched capacitor converter of the present invention. Figure 2 As shown, in the embodiment of the present invention, a switched capacitor converter with two input switch groups is taken as an example for description. The switched capacitor converter 1 includes:

[0041] A first input switch group and a second input switch group are connected in series between the input terminal i and the output terminal o, wherein the first input switch group includes two power switches Q1 and Q2 connected in series, and the second input switch group includes two power switches Q3 and Q4 connected in series;

[0042] The first output switch group, the second output switch group and the third output switch group include two power switches Q5 and Q6 connected in series, the second output switch group includes two power switches Q7 and Q8 connected in series, and the third output switch group includes power switches Q9 and Q10 connected in series. 10 ;

[0043] The first capacitor C F0 , the second capacitor C F1 And the third capacitor C F2 ., where the first capacitor C F0 The first end of the capacitor C is connected to the common node of the power switches Q3 and Q4, the second end of the capacitor C is connected to the middle node of the first output switch group (i.e., the common node of the power switches Q5 and Q6), and the second capacitor CF1 The first end of the third capacitor C is connected to the common node of the power switches Q2 and Q3, the second end of the third capacitor C is connected to the middle node of the second output switch group (i.e., the common node of the power switches Q7 and Q8), and the F2 The first end is connected to the common node of the power switches Q1 and Q2, and the second end is connected to the middle node of the third output switch group (i.e., the power switches Q9, Q 10 The public node of

[0044] A first inductor L1 and a second inductor L2, wherein a first end of the first inductor L1 is connected to a first end of the first output switch group, and a second end is connected to the output end o; a first end of the second inductor L2 is simultaneously connected to first ends of the second output switch group and the third output switch group, and a second end is connected to the output end o. In addition, second ends of the first, second and third output switch groups are all connected to a reference ground.

[0045] In the embodiment of the present invention, the power switches in the input switch group and the output switch group are controlled to perform switching actions so that the switched capacitor converter switches in different working stages, so that the first capacitor C F0 , the second capacitor C F1 And the third capacitor C F2 All capacitor branches include the first inductor L1 or the second inductor L2, so as to reduce the generation of peak current when the switched capacitor converter switches in the working phase.

[0046] Figure 3 This is a timing diagram of the control signal of the first embodiment of the switched capacitor converter of the present invention. In the embodiment of the present invention, the switching state of each input switch group is the same, and the switching state of the first output switch group is the same as the switching state of each input switch group, and the switching states of the two adjacent output switch groups are opposite. Moreover, in the two output switch groups connected to the second inductor L2, the switching state of the third output switch group is the same as the switching state of each input switch group, and the switching state of the second output switch group is opposite to the switching state of each input switch group. One of the two power switches in each input and output switch group in the switched capacitor converter performs a switching action according to the first control signal, and the other of the two power switches of each input and output switch group works according to the second control signal. The duty cycle of the first control signal is the same as that of the second control signal, and they do not overlap each other. In this embodiment, in a switching cycle, the first control signal is complementary to the second control signal and the duty cycle is 50%.

[0047] In a switching cycle, when the first control signal is valid, the switched capacitor converter operates in a first stage; when the second control signal is valid, the switched capacitor converter operates in a second stage.

[0048] Specifically, the power switches Q1, Q3, Q5, Q8 and Q9 perform synchronous switching actions according to the first control signal G1, and the power switches Q2, Q4, Q6, Q7 and Q 10 The synchronous switching action is performed according to the second control signal G2. When the first control signal G1 is valid, that is, the first control signal G1 is at a high level, switches Q1, Q3, Q5, Q8 and Q9 are turned on, and the switched capacitor converter works in the first stage. When the first control signal G2 is valid, that is, the second control signal G2 is at a high level, switches Q2, Q4, Q6, Q7 and Q 10 is turned on, and the switching converter operates in the second stage.

[0049] In the embodiment of the present invention, the ratio of the input voltage Vin to the output voltage Vout of the switched capacitor converter controlled in the above control manner is 4:1.

[0050] Figure 4 FIG. 4 is an equivalent circuit diagram of a first embodiment of a switched capacitor converter according to the present invention. Figure 4 a is an equivalent circuit diagram of the switched capacitor converter embodiment 1 of the present invention when it is operating in the first stage. Figure 4 As shown in FIG. 1 , in the first stage, the switched capacitor converter forms two capacitor branches, the first capacitor branch is connected between the output terminal and the reference ground, and the second capacitor branch is connected between the input terminal and the output terminal. The first capacitor branch includes a first capacitor C F0 , the second capacitor C F1 and a first inductor L1; the second capacitor branch includes a third capacitor C F2 In the first stage, the input voltage Vin passes through the third capacitor C in the second capacitor branch. F2 The second inductor L2 supplies power to the load. At the same time, the second capacitor C F1 Through the first capacitor C F0 and the first inductor L1 to supply power to the load. In the second stage, the switched capacitor converter forms two capacitor branches, the first capacitor branch and the second capacitor branch are connected in parallel between the output terminal and the reference ground. The first capacitor branch includes the first inductor L1 and the first capacitor C F0 The second capacitor branch includes a second inductor L2 and a second capacitor C F1 And the third capacitor C F2 In the second stage, the third capacitor C in the second capacitor branch F2 Through the second capacitor C F1 and the second inductor L2 to supply power to the load; at the same time, the first capacitor C in the first branch F0 The load is powered by the first inductor L1.

[0051] In summary, in the embodiment of the present invention, when the switched capacitor converter operates in the first stage or the second stage, each capacitor branch includes an inductor, thereby reducing current spikes when the switched capacitor converter performs switching actions and improving system efficiency.

[0052] In the embodiment of the present invention, the switched capacitor converter operates in a quasi-resonant state or a resonant state according to the different inductance values ​​of the inductor. Further, the first inductor L1 and the second inductor L2 have the same inductance value, and the second capacitor C connected to the common end of the adjacent input switch group (here, the first and second input switch groups) F1 The capacitance is much larger than the first capacitor C connected to the middle node of each input switch group. F0 With the third capacitor C F2 The capacitance of the first capacitor C F0 With the third capacitor C F2 The capacitance is equal, so in the first stage, the second capacitor C F1 With the first capacitor C F0 The capacitance of the series connection is equal to the third capacitor C F2 Basically the same; in the second stage, the second capacitor C F1 With the third capacitor C F2 The capacitance of the series capacitor is equal to the first capacitor C F0 Basically the same, therefore, in the first stage or the second stage, the capacitance and inductance of each capacitor branch are basically the same, so that the resonant center frequency remains unchanged in different working stages. It is easy to understand that in the first stage and the second stage, the inductors L1 and L2 have the same equivalent working state, each bearing a current with an average value of Iout / 2, where Iout is the output current of the switched capacitor converter.

[0053] Figure 5a This is the inductor current waveform of the switched capacitor converter operating in the quasi-resonant state. Figure 5a The horizontal axis of the waveform is the inductor current I L , the vertical axis is time t, it should be understood that the current of each inductor is the same, here we take one of the inductor currents as an example for explanation. When the circuit works in the quasi-resonant state, the inductor current ripple is small, which reduces the inductor AC loss, but the inductor value is slightly large, and there is a certain switching loss; Figure 5b is the inductor current waveform of the switched capacitor converter working in the resonant state. Figure 5b The horizontal axis of the waveform shown is the inductor current I L, the vertical axis is time t. It should be understood that the current of each inductor is the same. Here, one of the inductor currents is used as an example for explanation. When the circuit operates in a resonant state, the inductance value is small and the power tube operates in a ZCS (zero current switching) state, the switching loss is reduced, but the inductor current ripple is large, which correspondingly brings about a larger inductor AC loss. The two working states have advantages and disadvantages, and both are typical recommended working conditions. The specific mode to be adopted depends on the situation. In actual applications, when the system's requirements for efficiency indicators are higher than the requirements for power density, preferably, the system operates in the quasi-resonant state described above; when the system's requirements for efficiency indicators are lower than the requirements for power density, preferably, the system operates in the resonant state described above.

[0054] Figure 6 FIG. 2 is a specific circuit diagram of the second embodiment of the switched capacitor converter of the present invention. Figure 6 As shown, in the embodiment of the present invention, a switched capacitor converter with three input switch groups is taken as an example for description. The switched capacitor converter 2 includes:

[0055] A first input switch group, a second input switch group and a third input switch group are connected in series between the input terminal i and the output terminal o, wherein the first input switch group includes two power switches Q1 and Q2 connected in series, the second input switch group includes two power switches Q3 and Q4 connected in series, and the third input switch group includes two power switches Q5 and Q6 connected in series;

[0056] The first output switch group, the second output switch group, the third output switch group, the fourth output switch group and the fifth output switch group, wherein the first output switch group is directly connected in series with the plurality of input switch groups. Specifically, the first output switch group includes two power switches Q7 and Q8 connected in series, and the second output switch group includes two power switches Q9 and Q10 connected in series. 10 The third output switch group includes a power switch Q connected in series 11 , Q 12 The fourth output switch group includes a power switch Q connected in series 13 , Q 14 The fifth output switch group includes a power switch Q connected in series 15 , Q 16 ;

[0057] The first capacitor C F0 , the second capacitor C F1 , the third capacitor C F2 , the fourth capacitor C F3 . And the fifth capacitor C F4 , where the first capacitor C F0 The first end of the capacitor C is connected to the common node of the power switches Q5 and Q6, the second end of the capacitor C is connected to the middle node of the first output switch group (i.e., the common node of the power switches Q7 and Q8), and theF1 The first end is connected to the common node of the power switches Q4 and Q5, and the second end is connected to the middle node of the second output switch group (i.e., the power switches Q9, Q 10 The third capacitor C F2 The first end is connected to the common node of the power switches Q3 and Q4, and the second end is connected to the middle node of the third output switch group (i.e., the power switch Q 11 , Q 12 The fourth capacitor C F3 The first end is connected to the common node of the power switches Q2 and Q3, and the second end is connected to the middle node of the fourth output switch group (ie, the power switch Q 13 , Q 14 A first end of the fifth capacitor CF4 is connected to the common node of the power switches Q1 and Q2, and a second end is connected to the middle node of the fifth output switch group (ie, the power switch Q 15 , Q 16 The public nodes of the

[0058] A first inductor L1, a second inductor L2 and a third inductor L3, wherein a first end of the first inductor L1 is connected to a first end of the first output switch group, and a second end is connected to the output end; a first end of the second inductor L2 is simultaneously connected to the first ends of the second output switch group and the third output switch group, and a second end is connected to the output end; a first end of the third inductor L3 is simultaneously connected to the first ends of the fourth switch group and the fifth switch group, and a second end is connected to the output end. In addition, the second end of each output switch group is connected to a reference ground.

[0059] In the embodiment of the present invention, the power switches in the input switch group and the output switch group are controlled to perform switching actions so that the switched capacitor converter switches in different working stages, so that the first capacitor C F0 , the second capacitor C F1 , the third capacitor C F2 , the fourth capacitor C F3 . And the fifth capacitor C F4 Each capacitor branch includes an inductor, so that the switch capacitor converter can reduce the generation of peak current when switching in the working phase.

[0060] Figure 7This is a timing diagram of the control signal of the second embodiment of the switched capacitor converter of the present invention. In the embodiment of the present invention, the switching state of each input switch group is the same, and the switching state of the first output switch group is the same as the switching state of each input switch group, and the switching states of two adjacent output switch groups are opposite. In this embodiment, the switching states of the first output switch group, the third output switch group, and the fifth output switch group are the same as the switching state of each input switch group, and the switching states of the second output switch group and the fourth output switch group are opposite to the switching state of each input switch group. One of the two power switches of each input and output switch group in the switched capacitor converter performs a switching action according to the first control signal G1, and the other of the two power switches of each input and output switch group works according to the second control signal G2. In a switching cycle, the first control signal G1 is complementary to the second control signal G2 and the duty cycle is 50%.

[0061] In a switching cycle, when the first control signal G1 is valid, the switched capacitor converter operates in the first stage; when the second control signal G2 is valid, the switched capacitor converter operates in the second stage.

[0062] Specifically, switches Q1, Q3, Q5, Q7, Q 10 , Q 11 , Q 14 , Q 15 According to the first control signal G1, switches Q2, Q4, Q6, Q8, Q9, Q 12 , Q 13 , Q 16 The synchronous switching action is performed according to the second control signal G2. When the first control signal G1 is valid, that is, when the first control signal G1 is at a high level, switches Q1, Q3, Q5, Q7, Q 10 , Q 11 , Q 14 , Q 15 The switched capacitor converter works in the first stage. When the first control signal G2 is valid, that is, the second control signal G2 is at a high level, switches Q2, Q4, Q6, Q8, Q9, Q 12 , Q 13 , Q 16 is turned on, and the switching converter operates in the second stage.

[0063] In the embodiment of the present invention, the ratio of the input voltage Vin to the output voltage Vout of the switched capacitor converter controlled in the above control manner is 6:1.

[0064] Figure 8 FIG. 4 is an equivalent circuit diagram of the second embodiment of the switched capacitor converter of the present invention. Figure 8a is an equivalent circuit diagram of the switched capacitor converter of the present invention when it is operating in the first stage. Figure 8 As shown in FIG. 1 , in the first stage, the switched capacitor converter forms three capacitor branches, the first capacitor branch and the second capacitor branch are connected in parallel between the output terminal and the reference ground, and the third capacitor branch is connected between the input terminal and the output terminal. Specifically, the first capacitor branch includes a first capacitor C F0 , the second capacitor C F1 and a first inductor L1; the second capacitor branch includes a third capacitor C F2 , the fourth capacitor C F3 and a second inductor L2; the third capacitor branch includes a fifth capacitor C F4 In the first stage, the input voltage Vin passes through the fifth capacitor C in the third capacitor branch. F4 The third inductor L3 supplies power to the load, while the second capacitor C in the first capacitor branch F1 Through the first capacitor C F0 and the first inductor L1 to supply power to the load, and the fourth capacitor C in the second capacitor branch F3 Through the third capacitor C F2 In the second stage, the switched capacitor converter forms three capacitor branches, the first capacitor branch, the second capacitor branch and the third capacitor branch are connected in parallel between the output terminal and the reference ground. The first capacitor branch includes the first inductor L1 and the first capacitor C F0 The second capacitor branch includes a second inductor L2 and a second capacitor C F1 And the third capacitor C F2 The third capacitor branch includes a third inductor L3, a fourth capacitor C F3 And the fifth capacitor C F4 In the second stage, the first capacitor C in the first capacitor branch F0 The load is powered by the first inductor L1; the third capacitor C in the second capacitor branch F2 Through the second capacitor C F1 The second inductor L2 supplies power to the load, and the fifth capacitor C in the third capacitor branch F4 Through the fourth capacitor C F3 And the third inductor L3 supplies power to the load.

[0065] In summary, in the embodiment of the present invention, when the switched capacitor converter operates in the first stage or the second stage, each capacitor branch includes an inductor, thereby reducing the current spike when the switched capacitor converter performs a switching action and improving the system efficiency.

[0066] In the embodiment of the present invention, the switched capacitor converter operates in a quasi-resonant state or a resonant state according to the different inductance values ​​of the inductor. Further, the inductance values ​​of the first inductor L1, the second inductor L2, and the third inductor L3 are the same, and the capacitance value of the capacitor connected to the common end of the adjacent input switch group is much larger than the capacitance value of the capacitor connected to the middle node of each input switch group. Specifically, the second capacitor C F1 And the fourth capacitor C F3 The capacitance is much larger than the first capacitor C F0 With the third capacitor C F2 And the fifth capacitor C F4 The capacitance of the first capacitor C F0 With the third capacitor C F2 And the fifth capacitor C F4 The capacitance values ​​are equal so that the resonant center frequency remains unchanged in different working stages. It is easy to understand that in the first stage and the second stage, the inductors L1, L2, and L3 have the same equivalent working state, and each bears a current with an average value of Iout / 3.

[0067] Fig. 9 FIG. 1 is a specific circuit diagram of the third embodiment of the switched capacitor converter of the present invention. Fig. 9 As shown, in the embodiment of the present invention, a switched capacitor converter having N input switch groups is taken as an example for description, where N≥2. Specifically, the switched capacitor converter 3 includes:

[0068] N input switch groups are connected in series between the input terminal i and the output terminal o, wherein each input switch group includes two power switches connected in series. Specifically, the nth (1<=n<=N) input switch group includes two power switches Q connected in series. 2n-1 , Q 2n ;

[0069] 2N-1 output switch groups, each of which includes two power switches connected in series, and the nth (1<=n<=2N-1) output switch group includes two power switches Q connected in series. 2N+2n-1 , Q 2N+2n .

[0070] 2N-1 capacitors, the first ends of which are respectively connected to the common nodes of each two series-connected power switches in the N input switch groups, and the second ends of which are respectively connected to the middle nodes of each output switch group. Specifically, the nth (1<=n<=2N-1) capacitor is C F(n-1). When n is an odd number, the capacitor is connected between the middle node of the corresponding input switch group and the middle node of the corresponding output switch group. Specifically, the nth capacitor is connected between the middle node of the nth output switch group and the middle node of the N-(n-1) / 2th input switch group; when n is an even number, the capacitor is connected between the common end of two adjacent input switch groups (that is, the common node of two series-connected power switches of adjacent input switch groups) and the middle node of the corresponding output switch group, specifically, the nth capacitor is connected between the middle node of the nth output switch group and the common end of the N-(n-2) / 2th input switch group and the N-(n-2) / 2-1th input switch group, wherein the middle node is the common node of the two series-connected power switches in the switch group;

[0071] N inductors, wherein the first end of the first inductor L1 is connected to the first end of the first output switch group, and the first ends of the other inductors are respectively connected to the first ends of corresponding two output switch groups in the plurality of output switch groups, specifically, the first end of the nth (2<=n<=N) inductor is simultaneously connected to the first end of the (2n-2)th output switch group and the first end of the (2n-1)th output switch group, and the second end of each inductor is connected to the output end. In addition, the second end of each output switch group is connected to the reference ground.

[0072] In an embodiment of the present invention, the power switches in the input switch group and the output switch group are controlled to control the switching of the switched capacitor converter in different working stages, so that the capacitor branch where each capacitor is located includes one of N inductors, thereby reducing the generation of peak current when the switched capacitor converter switches in the working stage.

[0073] Fig.10 This is a timing diagram of the control signal of the third embodiment of the switched capacitor converter of the present invention. In the embodiment of the present invention, the switching state of the first output switch group is the same as the switching state of each input switch group, one of the two output switch groups connected to the same inductor is the same as the switching state of each input switch group, and the other is opposite to the switching state of each input switch group. The switching states of adjacent output switch groups are opposite. Specifically, the nth output switch group (n is an odd number) is the same as the switching state of each input switch group, and the nth output switch group (n is an even number) is opposite to the switching state of each input switch group. One of the two power switches of each input and output switch group in the switched capacitor converter performs a switching action according to the first control signal G1, and the other of the two power switches of each input and output switch group performs a switching action according to the second control signal G2. The first control signal and the second control signal have the same duty cycle and do not overlap each other. In this embodiment, in a switching cycle, the first control signal G1 and the second control signal G2 are complementary and the duty cycle is 50%.

[0074] During a switching period, when the first control signal G1 is valid, the switched-capacitor converter operates in the first stage; when the second control signal G2 is valid, the switched-capacitor converter operates in the second stage.

[0075] Specifically, power switches Q1, Q3... Q 2N+1 、…Q 6N-4 and Q 6N-3 perform synchronous switching actions according to the first control signal G1, and switches Q2, Q4... Q 2N 、Q 2N+2 、…Q 6N-5 and Q 6N-2 perform synchronous switching actions according to the second control signal G2.

[0076] In the embodiment of the present invention, the ratio of the input voltage Vin to the output voltage Vout of the switched-capacitor converter controlled in the above control manner is 2N:1.

[0077] Fig.11 is the equivalent circuit diagram of Embodiment 3 of the switched-capacitor converter of the present invention. Fig.11 a is the equivalent circuit diagram of the switched-capacitor converter of the present invention operating in the first stage. As Fig.11 shown in a, in the first stage, the switched-capacitor converter includes n (1 <= n <= N) capacitor branches. The nth (when n < N) capacitor branch includes the nth inductor, the 2(n - 1)th capacitor, and the 2(n - 1) + 1th capacitor. The Nth capacitor branch includes the 2N - 1th capacitor and the Nth inductor. The first capacitor branch to the N - 1th capacitor branch are connected in parallel between the output terminal and the reference ground, and the Nth capacitor branch is connected between the input terminal and the output terminal. In the second stage, the switched-capacitor converter includes n (1 <= n <= N) capacitor branches, and each capacitor branch is connected in parallel between the output terminal and the reference ground. The first capacitor branch includes the first inductor L1 and the first capacitor C F0 , and the nth (when n > 1) capacitor branch includes the nth inductor, the 2(n - 2) + 1th capacitor, and the 2(n - 2) + 2th capacitor.

[0078] In summary, in the embodiment of the present invention, when the switched-capacitor converter operates in the first stage or the second stage, each capacitor branch includes an inductor, thereby reducing current spikes during the switching operation of the switched-capacitor converter and improving system efficiency.

[0079] In an embodiment of the present invention, the switched capacitor converter operates in a quasi-resonant state or a resonant state according to the different inductance values ​​of the inductor. Furthermore, the inductance value of each of the inductors is the same; the capacitance of the capacitor connected at the first end to the common end of the adjacent input switch group is much larger than the capacitance of the capacitor connected at the first end to the middle node of the input switch group; the capacitance of the capacitor connected at the first end to the middle node of the input switch group is equal, so that the resonant center frequency remains unchanged in different working stages and the current of each inductor is the same. It is easy to understand that in the first stage and the second stage, each inductor has the same equivalent working state, and each bears a current with an average value of Iout / N.

[0080] In summary, the present invention provides a switched capacitor converter. The switched capacitor converter includes a plurality of input switch groups connected in series between the input end and the output end, wherein each input switch group includes two power switches connected in series; a plurality of output switch groups, wherein each output switch group includes two power switches connected in series; a plurality of capacitors, whose first ends are respectively connected to the common node of each two power switches connected in series in the plurality of input switch groups, and whose second ends are respectively connected to the intermediate node of each of the output switch groups; and a plurality of inductors, wherein the first end of each output switch group is connected to the first end of a corresponding inductor, the second ends of the plurality of inductors are connected to the output end, and the second ends of the plurality of output switch groups are connected to the reference ground. According to the switched capacitor converter of the present invention, the power switches in the input switch group and the output switch group are controlled to control the switching of the switched capacitor converter in different working stages, so that each capacitor branch includes one of the plurality of inductors, thereby reducing the generation of peak current when the switching converter switches in the working stage.

[0081] According to the embodiments of the present invention as described above, these embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and changes can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and the modified use based on the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A switched capacitor converter, characterized in that: include: A plurality of input switch groups are connected in series between the input terminal and the output terminal, wherein each input switch group includes two power switches connected in series; a plurality of output switch groups, wherein each output switch group comprises two power switches coupled in series at a first terminal and a second terminal of the output switch group; a plurality of capacitors, wherein the first ends of the capacitors are respectively connected to the common node of each two power switches connected in series in the plurality of input switch groups, and the second ends of the capacitors are respectively connected to the intermediate node of each of the output switch groups, wherein the intermediate node is the common node of the two power switches connected in series in the same switch group; as well as A plurality of inductors, wherein a first end of each output switch group is connected to a first end of a corresponding inductor, second ends of the plurality of inductors are connected to the output end, and second ends of the plurality of output switch groups are connected to a reference ground; A first end of a first inductor among the multiple inductors is connected to a first end of a first output switch group, wherein only the first output switch group is directly connected in series with the multiple input switch groups, and first ends of other inductors are respectively connected to first ends of corresponding two output switch groups among the multiple output switch groups.

2. The switched capacitor converter according to claim 1, characterized in that: When the number of the input switch groups is N, the number of the output switch groups and the number of the capacitors are (2N-1) respectively, and the number of the inductors is N, wherein N≥2.

3. The switched capacitor converter according to claim 1, wherein: The power switches in the input switch group and the output switch group are controlled to perform switching actions so that the switched capacitor converter switches in different working stages, wherein each capacitor branch in each working stage includes one of the multiple inductors, thereby reducing peak current when the switched capacitor converter switches working stages, wherein each of the capacitor branches includes at least one of the multiple capacitors.

4. The switched capacitor converter according to claim 3, characterized in that: One of the two power switches in each of the input and output switch groups in the switched capacitor converter performs a switching action according to a first control signal, and the other power switch in each of the input and output switch groups operates according to a second control signal, wherein in a switching cycle, the duty cycle of the first control signal and the second control signal are the same and do not overlap each other.

5. The switched capacitor converter according to claim 4, characterized in that , The first control signal is complementary to the second control signal, and the duty cycle is 0.

5.

6. The switched capacitor converter according to claim 4, characterized in that: In a switching cycle, when the first control signal is valid, the switched capacitor converter operates in a first stage; when the second control signal is valid, the switched capacitor converter operates in a second stage.

7. The switched capacitor converter according to claim 1 is characterized in that: The switching state of the first output switch group is the same as the switching state of each input switch group. In other output switch groups, one of the two output switch groups connected to the same inductor is the same as the switching state of each input switch group, and the other is opposite to the switching state of each input switch group.

8. The switched capacitor converter according to claim 3, characterized in that: When the switched capacitor converter operates in the first stage, N capacitor branches are formed, the first capacitor branch to the N-1th capacitor branch are connected in parallel between the output end and the reference ground, and the Nth capacitor branch is connected between the input end and the output end, wherein each of the first capacitor branch to the N-1th capacitor branch includes two capacitors, and the Nth capacitor branch includes one capacitor, wherein N is the number of the input switch groups, and N≥2.

9. The switched capacitor converter according to claim 3, characterized in that: When the switched capacitor converter operates in the second stage, N capacitor branches are formed, and the first capacitor branch to the Nth capacitor branch are all connected in parallel between the output end and the reference ground, wherein the first capacitor branch includes one capacitor, and each of the second capacitor branch to the Nth capacitor branch includes two capacitors, wherein N is the number of the input switch groups, and N≥2.

10. The switched capacitor converter according to claim 1, wherein: The inductance value of each inductor is the same, and the capacitance value of the capacitor connected to the common end of the adjacent input switch groups is much larger than the capacitance value of the capacitor connected to the middle node of each input switch group; and the capacitance values ​​of the capacitors connected to the middle nodes of the input switch groups are all equal, so that the current of each capacitor branch is the same.

11. The switched capacitor converter according to claim 1, characterized in that: The switched capacitor converter operates in a quasi-resonant state or a resonant state according to different inductance values ​​of the inductor.

12. The switched capacitor converter according to claim 2, characterized in that: The ratio of the input voltage to the output voltage of the switched capacitor converter is 2N:1.

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