ZVS type BUCK circuit

Abstract

The utility model discloses a ZVS type BUCK circuit, comprising a power supply module, a ZVS module and a BUCK circuit, the power supply module is electrically connected with the ZVS module, the ZVS module is electrically connected with the BUCK circuit, the ZVS module comprises a first energy storage module, a second energy storage module, a first protection follow current module and a first switch module, the first energy storage module is electrically connected with the second energy storage module, the first switch module and the BUCK circuit, and the BUCK circuit is electrically connected with the first protection follow current module. The second energy storage module is electrically connected with the first protection follow current module, the first switch module and the BUCK circuit, and the first protection follow current module is electrically connected with the first switch module. By adopting the ZVS module, the ZVS module is connected into the BUCK circuit, and the charging and discharging processes of the first energy storage module and the second energy storage module are controlled by the first switch module. Through the energy storage effect of the first energy storage module, when the voltage value of the first energy storage module is the same as the voltage value of the power supply module, due to the fact that the two ends of the first energy storage module are equal in potential and the potential difference is 0, the BUCK circuit can be started to achieve zero-voltage opening, and the opening loss is reduced.

Description

Technical Field

[0001] The utility model relates to the field of circuits, and in particular to a ZVS type BUCK circuit. Background Art

[0002] When the charger is charging the electrical equipment, since the mains power is AC, it cannot directly charge the electrical equipment. For this, rectification is required first. The AC current is converted into DC current through rectification, and the voltage is also converted from AC voltage to DC voltage. Since rectification converts AC current and AC voltage into DC current and DC voltage, it changes the characteristics of current and voltage, and does not change the size of the voltage and current source. The converted DC voltage value is still the same as the voltage value of the mains. Because the converted DC voltage value is still high and cannot be directly connected to the electrical equipment, the DC voltage needs to be stepped down before it can be connected to the electrical equipment.

[0003] Generally speaking, a DC step-down circuit is generally called a Buck circuit, which is a conversion circuit that can reduce the DC voltage. The basic working principle of the Buck circuit is to reduce the voltage through the conduction and disconnection of the MOS tube, as well as the action of components such as inductors and capacitors. Specifically, when the MOS tube is turned on, the inductor stores electrical energy and the capacitor charges; when the MOS tube is turned off, the energy between the inductor and the capacitor is transferred to the electrical equipment. Therefore, the voltage is reduced by controlling the conduction and shutdown of the MOS tube. However, since the conduction of the MOS tube requires the consumption of electrical energy, the consumption of electrical energy will generate turn-on loss and cause the temperature of the MOS tube to rise, which will cause changes in the electrical performance parameters of the MOS tube, such as increased leakage current and slower switching speed, which will cause damage to the MOS tube components. Utility Model Content

[0004] In view of the deficiencies in the prior art, the utility model provides a ZVS type BUCK circuit. ZVS is a zero voltage switching technology, which can start the MOS tube when there is no voltage at both ends of the MOS tube, so as to reduce the turn-on loss generated by the MOS tube.

[0005] The purpose of the utility model is achieved through the following solutions:

[0006] A ZVS type BUCK circuit comprises: a power module 10, a ZVS module 20 and a BUCK circuit 30, wherein the power module 10 is electrically connected to the BUCK circuit 30, the ZVS module 20 is electrically connected to the BUCK circuit 30, and the ZVS module 20 comprises a first energy storage module 21, a second energy storage module 22, a first protection freewheeling module 23 and a first switch module 24; the power module 10 is electrically connected to the first energy storage module 21 and the first switch module 24 respectively; the first energy storage module 21 is electrically connected to the second energy storage module 22, the first switch module 24 and the BUCK circuit 30 respectively, the second energy storage module 22 is electrically connected to the first protection freewheeling module 23, the first switch module 24 and the BUCK circuit 30 respectively; the first protection freewheeling module 23 is electrically connected to the first switch module 24.

[0007] In one embodiment, the first energy storage module 21 includes a capacitor C1, the capacitor C1 has a terminal 1 and a terminal 2, the terminal 1 of the capacitor C1 is electrically connected to the second energy storage module 22, the terminal 2 of the capacitor C1 is electrically connected to the first switch module 24 and the positive electrode of the power module 10, and the terminal 1 and the terminal 2 of the capacitor C1 are connected in parallel to the BUCK circuit 30.

[0008] In one embodiment, the second energy storage module 22 includes an inductor L1, the inductor L1 has a terminal 1 and a terminal 2, the terminal 1 of the inductor L1 is electrically connected to the first energy storage module 21, the terminal 2 of the inductor L1 is electrically connected to the first switch module 24, and the terminal 1 of the inductor L1 is electrically connected to the BUCK circuit 30.

[0009] In one embodiment, the first protection freewheeling module 23 includes a diode D100, the diode D100 has a terminal 1 and a terminal 2, the terminal 1 of the diode D100 is electrically connected to the ground GND, and the terminal 2 of the diode D100 is electrically connected to the second energy storage module 22 and the first switch module 24.

[0010] In one embodiment, the first switch module 24 includes a MOS tube Q1, which has a drain D1, a gate G1 and a source S1. The drain D1 of the MOS tube Q1 is electrically connected to the first energy storage module 21 and the positive electrode of the power module 10, the source S1 of the MOS tube Q1 is electrically connected to the second energy storage module 22 and the first protection freewheeling module 23, and the gate G1 of the MOS tube Q1 is connected to the driving pulse P1.

[0011] In one embodiment, the BUCK circuit 30 includes a second switch module 31, a chopping module 32, a filtering module 33 and a second protection freewheeling module 34;

[0012] The second switch module 31 is electrically connected to the positive electrode of the power module 10, the chopper module 32 and the second protection freewheeling module 34; the second switch module 31 is connected in parallel with the first energy storage module 21; the second energy storage module 22 and the first switch module 24 are connected in series and then in parallel with the second switch module 31;

[0013] The chopping module 32 is electrically connected to the second switch module 31, the filter module 33, the second protection freewheeling module 34, the first energy storage module 21 and the second energy storage module 22;

[0014] The filter module 33 is connected in parallel with the second protection and freewheeling module 34 and the power module 10, and the filter module 33 is electrically connected with the first protection and freewheeling module 23 and the second switch module 31;

[0015] The second protection and freewheeling module 34 is electrically connected to the second switch module 31 , the first protection and freewheeling module 23 and the power module 10 .

[0016] In one embodiment, the second switch module 31 includes a MOS tube Q2, which has a drain D2, a gate G2 and a source S2. A series circuit of a second energy storage module 22 and a first switch module 24 is connected in parallel at both ends of the drain D2 and the source S2 of the MOS tube Q2. The first energy storage module 21 is also connected in parallel at both ends of the drain D2 and the source S2 of the MOS tube Q2. The drain D2 of the MOS tube Q2 is electrically connected to the positive electrode of the power module 10, and the source S2 of the MOS tube Q2 is connected to the driving pulse P2.

[0017] In one embodiment, the chopping module 32 includes an inductor L2, the inductor L2 has a terminal 1 and a terminal 2, the terminal 1 of the inductor L2 is electrically connected to the first switch module 31, the second protection freewheeling module 34, the first energy storage module 21 and the second energy storage module 22, and the terminal 2 of the inductor L2 is electrically connected to the filter module 33.

[0018] In one embodiment, the filter module 33 includes a capacitor C2 and a capacitor C3, the capacitor C2 and the capacitor C3 have a terminal 1 and a terminal 2 respectively, the terminal 1 and the terminal 2 of the capacitor C2 are connected in parallel with the power module 10, the terminal 1 of the capacitor C2 is electrically connected to the first switch module 24, the first energy storage module 21 and the second switch module 31, the terminal 2 of the capacitor C2 is electrically connected to the first protection and freewheeling module 22; the terminal 1 of the capacitor C3 is electrically connected to the chopping module 32. The terminal 2 of the capacitor C3 is electrically connected to the first protection and freewheeling module 23, and the terminal 1 and the terminal 2 of the capacitor C3 are connected in parallel with the second protection and freewheeling module 34.

[0019] In one embodiment, the second protection freewheeling module 34 includes a diode D200, the diode D200 has a terminal 1 and a terminal 2, the terminal 1 of the diode D200 is electrically connected to the first freewheeling protection module 23; the terminal 2 of the diode D200 is electrically connected to the first energy storage module 21, the second energy storage module 22, the second switch module 31 and the chopper module 32. Compared with the prior art, the utility model has at least the following advantages:

[0020] The utility model adopts a ZVS type BUCK circuit, which is connected to the BUCK circuit by using a ZVS module, and the first switch module controls the charging and discharging process of the first energy storage module and the second energy storage module. Through the energy storage function of the first energy storage module, when the voltage value of the first energy storage module is the same as the voltage value of the power module, since the two ends of the first energy storage module are equal in potential, the potential difference is 0, and at this time, starting the BUCK circuit can achieve zero voltage opening, thereby reducing opening loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0022] Figure 1 This is the circuit structure diagram of the utility model;

[0023] Among them, the figure markings are, 1. a ZVS type BUCK circuit; 10. a power supply; 20. a ZVS module; 21. a first energy storage module; 22. a second energy storage module; 23. a first protection and freewheeling module; 24. a first switch module; 30. a BUCK circuit; 31. a second switch module; 32. a chopping module; 33. a filtering module; 34. a second protection and freewheeling module; 40. a load R. DETAILED DESCRIPTION

[0024] The following will disclose multiple embodiments of the present invention with drawings. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. In other words, in some embodiments of the present invention, these practical details are not necessary. In addition, in order to simplify the drawings, some conventional structures and components will be depicted in a simple schematic manner in the drawings.

[0025] It should be noted that all directional indications such as up, down, left, right, front, back... in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture as shown in the accompanying drawings. If the specific posture changes, the directional indication will also change accordingly.

[0026] In addition, in the present utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes, and do not specifically refer to the order or sequence, nor are they used to limit the present utility model. They are only used to distinguish components or operations described with the same technical terms, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present utility model.

[0027] In order to further understand the content, features and effects of the utility model, the following embodiments are given as examples and described in detail with reference to the accompanying drawings:

[0028] like Figure 1 As shown, a ZVS type BUCK circuit 1 includes: a power module 10, a ZVS module 20, and a BUCK circuit 30. The power module 10 is electrically connected to the ZVS module 20, and the ZVS module 20 is electrically connected to the BUCK circuit 30. When the ZVS type BUCK circuit 1 is used, the load R 40 is electrically connected to the BUCK circuit 30. The power module 10 provides power to the ZVS module 20, the BUCK circuit 30, and the load R40. The ZVS module 20 is used to start the BUCK circuit 30 at zero voltage. The BUCK circuit 30 is used to step down the voltage output by the power module 20, and then output the reduced voltage to the load R40 to ensure that the working voltage of the load R40 is not too high, so as to prevent the load R40 from being damaged.

[0029] Furthermore, if Figure 1 As shown, the ZVS module 20 includes a first energy storage module 21, a second energy storage module 22, a first protection and continuous flow module 23 and a first switch module 24, the power module 10 is electrically connected to the first energy storage module 21 and the first switch module 24, the first energy storage module 21 is electrically connected to the second energy storage module 22, the first switch module 23 and the BUCK circuit 30, the second energy storage module 22 is electrically connected to the first protection and continuous flow module 23, the first switch module 23 and the BUCK circuit 30, and the first protection and continuous flow module 22 is electrically connected to the first switch module 23. Among them, the first energy storage module 21 and the second energy storage module 22 can store electric energy, the first protection and continuous flow module 23 prevents the current of the second energy storage module from flowing backwards, and is used to protect the power module 10, and the first switch module 24 controls the conduction and shutdown of the ZVS module 20.

[0030] Specifically, Figure 1As shown, the first energy storage module 21 includes a capacitor C1, the capacitor C1 has a terminal 1 and a terminal 2, the terminal 1 of the capacitor C1 is electrically connected to the second energy storage module 22, the terminal 2 of the capacitor C1 is electrically connected to the first switch module 24 and the positive electrode of the power module 10, and the terminal 1 and the terminal 2 of the capacitor C1 are connected in parallel with the BUCK circuit 30;

[0031] The second energy storage module 22 includes an inductor L1, the inductor L1 has a terminal 1 and a terminal 2, the terminal 1 of the inductor L1 is electrically connected to the first energy storage module 21, the terminal 2 of the inductor L1 is electrically connected to the first switch module 24, and the terminal 1 of the inductor L1 is electrically connected to the BUCK circuit 30;

[0032] The first protection freewheeling module 23 includes a diode D100, the diode D100 has a terminal 1 and a terminal 2, the terminal 1 of the diode D100 is electrically connected to the ground GND, and the terminal 2 of the diode D100 is electrically connected to the second energy storage module 22 and the first switch module 24;

[0033] The first switch module 24 includes a MOS transistor Q1, which has a drain D1, a gate G1 and a source S1. The drain D1 of the MOS transistor Q1 is electrically connected to the first energy storage module 21 and the positive electrode of the power module 10, the source S1 of the MOS transistor Q1 is electrically connected to the second energy storage module 22 and the first protection freewheeling module 23, and the gate G1 of the MOS transistor Q1 is connected to the driving pulse P1.

[0034] Among them, the terminal 1 of the capacitor C1 is electrically connected to the terminal 1 of the inductor L1, the terminal 2 of the capacitor C1 is electrically connected to the drain D1 of the MOS tube Q1 and the positive electrode of the power module 10; the terminal 2 of the inductor L1 is electrically connected to the source S1 of the MOS tube Q1 and the terminal 2 of the diode D100; the terminal 1 of the diode D100 is connected to the ground GND; the drain D1 of the MOS tube Q1 is electrically connected to the terminal 2 of the capacitor C1, the source S1 of the MOS tube Q1 is electrically connected to the terminal 2 of the inductor L1 and the terminal 2 of the diode D100, and the gate G1 of the MOS tube Q1 is connected to the driving pulse P1. In this embodiment, the driving pulse P1 is a driving signal provided by the MCU.

[0035] It should be noted that the inductor L1 has the function of storing electric energy, and can charge the capacitor C1. At the same time, being connected in series with the MOS tube Q1 can prevent the current flowing through the MOS tube Q1 from suddenly changing, so as to protect the MOS tube Q1. The capacitor C1 can store the electric energy charged by the inductor L1. The diode D100 is connected in series with the inductor L1 when the MOS tube Q1 is turned off, and can prevent the current on the inductor L1 from being output from the No. 2 terminal of the inductor L1, and prevent the current from impacting the power module 10 in reverse, so as to ensure that the current of the inductor L1 flows from the No. 1 terminal of the inductor L1 to the load R40, and at the same time release the current on the inductor L1 to prevent the inductor L1 from being saturated. The MOS tube Q1 is also used to control the charging degree of the capacitor C1 and the inductor L1, so as to prevent the capacitor C1 and the inductor L1 from being overcharged and saturated and damaging the component.

[0036] Furthermore, if Figure 1 As shown, the BUCK circuit 30 includes a second switch module 31, a chopping module 32, a filtering module 33 and a second protection freewheeling module 34;

[0037] The second switch module 31 is electrically connected to the positive electrode of the power module 10, the chopper module 32, the filter module 33, and the second protection freewheeling module 34, respectively, and is also connected in parallel with the first energy storage module 21; the second energy storage module 22 and the first switch module 24 are connected in series and then connected in parallel with the second switch module 31;

[0038] The chopping module 32 is electrically connected to the second switch module 31, the filter module 33, the second protection freewheeling module 34, the first energy storage module 21 and the second energy storage module;

[0039] The filter module 33 is connected in parallel with the second protection and freewheeling module 34 and the power module 10. The filter module 33 is electrically connected with the first protection and freewheeling module 23 and the second switch module 31. When the ZVS type BUCK circuit is working, the filter module 33 is also connected in parallel with the load 40.

[0040] The second protection and freewheeling module 34 is electrically connected to the second switch module 31, the first protection and freewheeling module 23 and the power module 10. When the ZVS type BUCK circuit is working, the second protection and freewheeling module 34 is also electrically connected to the load 40.

[0041] Among them, the second switch module 31 controls the on and off of the BUCK circuit 30; the chopper module 32 is used to adjust the voltage of the circuit, reduce the voltage and output it to the load R 40, the filter module 33 is used to smooth the output voltage, reduce the ripple of the output voltage, and prevent damage to the load R 40; the second protection freewheeling module 34 can prevent the current of the chopper module 32 from flowing back, and is used to control the direction of the current to ensure that the current always flows through the load R 40.

[0042] Specifically, the second switch module 31 comprises a MOS tube Q2, the MOS tube Q2 having a drain electrode D1, a gate electrode G1 and a source electrode S1; a series circuit of a second energy storage module 22 and a first switch module 24 is connected in parallel at both ends of the drain electrode D2 and the source electrode S2 of the MOS tube Q2, and a first energy storage module 21 is also connected in parallel at both ends of the drain electrode D2 and the source electrode S2 of the MOS tube Q2; the drain electrode D2 of the MOS tube Q2 is electrically connected to the positive electrode of the power module (10), and the source electrode S2 of the MOS tube Q2 is connected to a driving pulse P2;

[0043] The chopper module 32 includes an inductor L2 having a terminal 1 and a terminal 2; the terminal 1 of the inductor L2 is electrically connected to the first switch module 31, the second protection freewheeling module 34, the first energy storage module 21 and the second energy storage module 22, and the terminal 2 of the inductor L2 is electrically connected to the filter module 33;

[0044] The filter module 33 includes a capacitor C2 and a capacitor C3, and the capacitor C2 and the capacitor C3 have a terminal 1 and a terminal 2, respectively. The terminal 1 and the terminal 2 of the capacitor C2 are connected in parallel with the power module 10, the terminal 1 of the capacitor C2 is electrically connected to the first switch module 24, the first energy storage module 21 and the second switch module 31, and the terminal 2 of the capacitor C2 is electrically connected to the first protection freewheeling module 22; the terminal 1 of the capacitor C3 is electrically connected to the chopping module 32. The terminal 2 of the capacitor C3 is electrically connected to the first protection freewheeling module 23, and the terminals 1 and 2 of the capacitor C3 are connected in parallel with the second protection freewheeling module 34. When the ZVS type BUCK circuit is working, the terminals 1 and 2 of the capacitor C3 are also connected in parallel with the load 40.

[0045] The second protection freewheeling module 34 includes a diode D200, which has a terminal 1 and a terminal 2. The diode D200 has a terminal 1 and a terminal 2. The terminal 1 of the diode D200 is electrically connected to the first freewheeling protection module 23; the terminal 2 of the diode D200 is electrically connected to the first energy storage module 21, the second energy storage module 22, the second switch module 31 and the chopper module 32.

[0046] Among them, the drain D2 and source S2 of MOS tube Q2 are connected in parallel with the No. 2 terminal and the No. 1 terminal of capacitor C2 respectively, the source S2 is electrically connected with the No. 2 terminal of diode D200 and the No. 1 terminal of inductor L2, and the gate G2 is connected with the driving pulse P2. After the source S1 of MOS tube Q1 is connected in series with the No. 2 terminal of inductor L1, the No. 1 terminal of inductor L1 and the drain D1 of MOS tube Q1 are connected in parallel with the source S2 and drain D2 of MOS tube Q2 respectively. In this embodiment, the driving pulse P2 is a driving signal provided by the MCU;

[0047] The terminal 1 of the inductor L2 is electrically connected to the terminal 2 of the diode D200, the source S2 of the MOS tube Q2, the terminal 1 of the capacitor C1 and the terminal 1 of the inductor L1 respectively, and the terminal 2 of the inductor L2 is electrically connected to the terminal 1 of the capacitor C3 and the load R40;

[0048] Terminal 1 of capacitor C2 is electrically connected to terminal 2 of capacitor C1, drain D1 of MOS tube Q1, and drain D2 of MOS tube Q2. Terminal 2 of capacitor C2 and terminal 1 of diode D200 are electrically connected. Capacitor C2 is also connected in parallel with power module 10. Terminal 1 of capacitor C3 is electrically connected to terminal 2 of inductor L1. Capacitor C3 is connected in parallel with diode D200. When the ZVS type BUCK circuit is working, capacitor C3 is also connected in parallel with load R40.

[0049] Terminal 1 of diode D200 is electrically connected to terminal 1 of diode D100 and terminal 2 of capacitor C3, and terminal 2 of diode D200 is electrically connected to terminal 1 of inductor L1, source S2 of MOS tube Q2, terminal 1 of capacitor C1 and terminal 1 of inductor L2.

[0050] It should be noted that the MOS tube Q2 controls the on-off of the BUCK circuit 30; the inductor L2 adjusts the current of the BUCK circuit 30 by charging and discharging itself, thereby adjusting the output voltage; the capacitor C2 is used to smooth the input voltage of the power module and reduce the input voltage ripple; the capacitor C3 is used to smooth the output voltage and reduce the output voltage ripple to prevent damage to the load R 40; the diode D200 is used as a freewheeling diode to prevent the current of the inductor L2 from flowing back from the terminal 1 to the power module 10, thereby preventing the impact on the power module 10, and is used to control the current to flow from the terminal 2 of the inductor L2 to the load R 40.

[0051] In summary, in the specific implementation, in the initial state, the MOS tube Q1 and the MOS tube Q2 are in the off state, and the positive output current of the power module 10 flows through the drain D1 of the MOS tube Q1. At this time, the MCU sends a driving pulse P1 to the MOS tube Q1, and controls the conduction of the MOS tube Q1 by inputting the driving pulse P1 into the gate G1, so that the current flows from the source S1 of the MOS tube Q1 into the No. 2 terminal of the inductor L1. Therefore, when the current continues to flow into the No. 2 terminal of the inductor L1 and flows out from the No. 1 terminal, the capacitor C1 is continuously charged. At this time, the current of the inductor L1 gradually increases, the current change rate of the inductor L1 itself decreases, and the induced voltage of the inductor L1 itself also decreases with the decrease in the current change rate, that is, the voltage of the No. 1 terminal and the No. 2 terminal of the inductor L1 will gradually decrease. Therefore, the capacitor C1 is continuously charged by the inductor L1, and the voltage of the No. 1 terminal and the No. 2 terminal of the capacitor C1 increases, so that the voltage at point A continues to rise.

[0052] Next, when the voltages at the terminals 1 and 2 of the capacitor C1 rise to be equal to the voltage of the power module 10, that is, the voltage at point A is equal to the voltage of the power supply 10, the voltage at the source S2 of the MOS tube Q1 is also equal to the voltage at point A. At this time, the gate G2 of the MOS tube Q2 is input by the driving pulse P2 to control the opening of the MOS tube Q2. The voltage between the gates G2 and S2 of the MOS tube Q2 is greater than the threshold voltage of the MOS tube Q2 itself for the MOS tube Q2 to be turned on, and no current flows between the drain D2 and the source S2 of the MOS tube Q2. The potential difference between the drain D2 and the source S2 of the MOS tube Q2 is 0, so that the MOS tube Q2 can be turned on at zero voltage, thereby reducing the turn-on loss of the MOS tube Q2.

[0053] Further, when the MOS transistor Q2 is turned on, the MOS transistor Q1 is turned off by the driving pulse P1, and the current on the inductor L1 flows through the inductor L2 and is output to the load R40. At the same time, the current at the positive electrode of the power module 10 flows into the inductor L2 through the MOS transistor Q2 and stores energy. When the voltage value at the two ends of the No. 1 and No. 2 of the inductor L2 is equal to the voltage value of the power module 10, the MOS transistor Q2 is turned off by the driving pulse P2, and the capacitor C1 storing electric energy releases the internal electric energy. At this time, in order to suppress the loss of current, the inductor L1 generates a reverse induced electromotive force. At this time, the No. 2 end of the inductor L2 is the positive pole and the No. 1 end is the negative pole. The current of the inductor L2 flows from the No. 2 end to the load R40, and then flows from the load R40 back through the No. 1 end of the diode D100 to form a loop. When the electric energy of the inductor L2 is released, the current gradually decreases, and the current in the series circuit remains unchanged. According to Ohm's law, U=IR, the current in the circuit decreases, and the voltage across the load R40 also decreases accordingly, that is, the voltage output to the load R40 decreases, thereby finally achieving the voltage value across the load R40.

[0054] Finally, due to the discharge of capacitor C1, the voltages at both ends of terminal 1 and terminal 2 of capacitor C1 decrease, causing the voltage at point A to decrease, and then repeating the above-mentioned opening step of MOS tube Q1, turning on MOS tube Q1, continuing to charge capacitor C1, and then turning on MOS tube Q2, and looping the above-mentioned steps to continue to step down the output to load R40.

[0055] The above is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A ZVS type BUCK circuit, characterized in that: include: A power module (10), a ZVS module (20) and a BUCK circuit (30), wherein the power module (10) is electrically connected to the BUCK circuit (30), the ZVS module (20) is electrically connected to the BUCK circuit (30), and the ZVS module (20) comprises a first energy storage module (21), a second energy storage module (22), a first protection freewheeling module (23) and a first switch module (24); the power module (10) is electrically connected to the first energy storage module (21) and the first switch module (24) respectively; the first energy storage module (21) is electrically connected to the second energy storage module (22), the first switch module (24) and the BUCK circuit (30) respectively; the second energy storage module (22) is electrically connected to the first protection freewheeling module (23), the first switch module (24) and the BUCK circuit (30) respectively; and the first protection freewheeling module (23) is electrically connected to the first switch module (24).

2. A ZVS type BUCK circuit according to claim 1, characterized in that: The first energy storage module (21) comprises a capacitor C1, the capacitor C1 having a terminal 1 and a terminal 2, the terminal 1 of the capacitor C1 being electrically connected to the second energy storage module (22), the terminal 2 of the capacitor C1 being electrically connected to the first switch module (24) and the positive electrode of the power module (10), and the terminal 1 and the terminal 2 of the capacitor C1 being connected in parallel to the BUCK circuit (30).

3. A ZVS type BUCK circuit according to claim 1, characterized in that: The second energy storage module (22) comprises an inductor L1, the inductor L1 having a terminal 1 and a terminal 2, the terminal 1 of the inductor L1 being electrically connected to the first energy storage module (21), the terminal 2 of the inductor L1 being electrically connected to the first switch module (24), and the terminal 1 of the inductor L1 being electrically connected to the BUCK circuit (30).

4. A ZVS type BUCK circuit according to claim 1, characterized in that: The first protection freewheeling module (23) comprises a diode D100, the diode D100 having a terminal 1 and a terminal 2, the terminal 1 of the diode D100 being electrically connected to the ground GND, and the terminal 2 of the diode D100 being electrically connected to the second energy storage module (22) and the first switch module (24).

5. A ZVS type BUCK circuit according to claim 1, characterized in that: The first switch module (24) comprises a MOS tube Q1, the MOS tube Q1 having a drain D1, a gate G1 and a source S1, the drain D1 of the MOS tube Q1 being electrically connected to the first energy storage module (21) and the positive electrode of the power module (10), the source S1 of the MOS tube Q1 being electrically connected to the second energy storage module (22) and the first protection freewheeling module (23), and the gate G1 of the MOS tube Q1 being connected to a drive pulse P1.

6. A ZVS type BUCK circuit according to claim 1, characterized in that: The BUCK circuit (30) comprises a second switch module (31), a chopping module (32), a filtering module (33) and a second protection freewheeling module (34); The second switch module (31) is electrically connected to the positive electrode of the power module (10), the chopper module (32) and the second protection freewheeling module (34); the second switch module (31) is connected in parallel with the first energy storage module (21); the second energy storage module (22) and the first switch module (24) are connected in series and then connected in parallel with the second switch module (31); The chopping module (32) is electrically connected to the second switch module (31), the filter module (33), the second protection freewheeling module (34), the first energy storage module (21) and the second energy storage module (22); The filter module (33) is connected in parallel with the second protection and freewheeling module (34) and the power module (10); the filter module (33) is electrically connected with the first protection and freewheeling module (23) and the second switch module (31); The second protection freewheeling module (34) is electrically connected to the second switch module (31), the first protection freewheeling module (23) and the power module (10).

7. A ZVS type BUCK circuit according to claim 6, characterized in that: The second switch module (31) comprises a MOS tube Q2, the MOS tube Q2 having a drain electrode D2, a gate electrode G2 and a source electrode S2, a series circuit of a second energy storage module (22) and a first switch module (24) is connected in parallel at both ends of the drain electrode D2 and the source electrode S2 of the MOS tube Q2, the first energy storage module (21) is also connected in parallel at both ends of the drain electrode D2 and the source electrode S2 of the MOS tube Q2, the drain electrode D2 of the MOS tube Q2 is electrically connected to the positive electrode of the power module (10), and the source electrode S2 of the MOS tube Q2 is connected to a driving pulse P2.

8. A ZVS type BUCK circuit according to claim 6, characterized in that: The chopping module (32) comprises an inductor L2, the inductor L2 having a terminal 1 and a terminal 2, the terminal 1 of the inductor L2 being electrically connected to the second switch module (31), the second protection freewheeling module (34), the first energy storage module (21) and the second energy storage module (22), and the terminal 2 of the inductor L2 being electrically connected to the filter module (33).

9. A ZVS type BUCK circuit according to claim 6, characterized in that: The filter module (33) comprises a capacitor C2 and a capacitor C3, the capacitor C2 and the capacitor C3 respectively having a terminal 1 and a terminal 2, the terminal 1 and the terminal 2 of the capacitor C2 being connected in parallel with the power module (10), the terminal 1 of the capacitor C2 being electrically connected with the first switch module (24), the first energy storage module (21) and the second switch module (31), the terminal 2 of the capacitor C2 being electrically connected with the first protection freewheeling module (23); the terminal 1 of the capacitor C3 being electrically connected with the chopping module (32); the terminal 2 of the capacitor C3 being electrically connected with the first protection freewheeling module (23), and the terminal 1 and the terminal 2 of the capacitor C3 being connected in parallel with the second protection freewheeling module (34).

10. A ZVS type BUCK circuit according to claim 6, characterized in that: The second protection freewheeling module (34) comprises a diode D200, the diode D200 having a terminal 1 and a terminal 2, the terminal 1 of the diode D200 being electrically connected to the first protection freewheeling module (23); and the terminal 2 of the diode D200 being electrically connected to the first energy storage module (21), the second energy storage module (22), the second switch module (31) and the chopper module (32).

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