WO2024016997A1

WO2024016997A1 - Driving circuit and switching power supply

Info

Publication number: WO2024016997A1
Application number: PCT/CN2023/104086
Authority: WO
Inventors: 张文林; 王军科; 陈悦
Original assignee: 华为技术有限公司
Priority date: 2022-07-20
Filing date: 2023-06-29
Publication date: 2024-01-25
Also published as: CN117477912A

Abstract

The present application provides a driving circuit and a switching power supply. The driving circuit comprises a control circuit, an energy recovery circuit, a duration determination circuit, and an input power supply. The energy recovery circuit comprises a switching device and an energy storage inductor. The duration determination circuit is configured to determine a target duration. The energy recovery circuit is electrically connected to the input power supply, and is configured, under the control of the control circuit, to charge the energy storage inductor in a first current direction/second current direction according to the target duration; to turn on/off a power tube; and to control at least one switching device to be turned on for the target duration by means of a channel so as to enable energy to flow back to the input power supply. According to the present application, the target duration for which the input power supply charges the energy storage inductor is determined, and at an energy recovery stage, the switching device is turned on for the target duration by means of the channel, so that the energy stored on the energy storage inductor flows back to the input power supply by means of the channel. In this way, the energy on the energy storage inductor can directly flow back to the input power supply by means of the channel of the switching device, without causing energy loss, such that the energy recovery rate can be greatly improved.

Description

A driving circuit and switching power supply

Cross-references to related applications

This application claims priority to the Chinese patent application filed with the China Patent Office on July 20, 2022, with the application number 202210863964.3 and the application title "A driving circuit and switching power supply", the entire content of which is incorporated into this application by reference. .

Technical field

This application relates to the field of driving energy recovery, and in particular to a driving circuit and a switching power supply.

Background technique

In the context of low-voltage and high-current applications, larger-sized power tubes are needed in switching power supplies to reduce conduction losses, but larger-sized power tubes also mean larger gate capacitance, which also leads to larger power tube drive. Loss and driving loss limit the improvement of the overall efficiency of the switching power supply.

The conventional power tube driving method is that the power supply first guides the charge to the gate of the power tube to turn on the power tube, and then the power supply guides the charge from the gate to discharge the charge to the ground to turn off the power tube. Every time a switching action is performed, the driving energy (charge) will be discharged to the ground, causing energy loss.

At present, many power tube driving energy recovery schemes have been proposed. The above schemes basically use energy storage components to recover the gate discharge charge of the power tube that was originally discharged to the ground, and use it to drive the power tube in the next cycle. In order to achieve the purpose of reducing driving losses. For example, the existing technology stores the gate discharge charge by adding an inductor, and since the current on the inductor cannot suddenly change, the current can flow back to the power supply, thereby achieving energy recovery. However, in a structure that uses an inductor to store gate discharge charges, the freewheeling diode in a transistor (such as a MOS transistor or a field effect transistor, etc.) is usually used for freewheeling conduction during the energy recovery stage, so that the charge stored in the inductor is Energy can flow back into the power source. When the current in the inductor flows back through the freewheeling diode, it causes a large energy loss, resulting in a decrease in the energy recovery rate. If the current can directly pass through the channel of the transistor without freewheeling through the freewheeling diode, it can It greatly reduces the conduction loss during freewheeling and effectively improves the energy recovery rate. However, using the channel of a transistor to pass current requires extremely high timing for channel closing. If the error is too large, it may cause the channel of the transistor to close late. The consequence of late closing is that the inductor current flows back to the ground, resulting in a large energy recovery rate. decline. It is necessary to set up a zero-crossing detection circuit to determine the timing of closing the channel of the control transistor. However, the existing zero-crossing detection circuit structure is difficult to achieve nanosecond-level delay measurement, so it will also cause the channel of the transistor to turn off late, and there will also be The inductor current flows back after crossing zero, causing the recovery rate to decrease. Since the above method is difficult to implement and risky, it is difficult to apply it in practice. Therefore, freewheeling diodes in transistors are still used for freewheeling conduction to achieve energy recovery. However, this solution sacrifices the recovery rate, thus limiting the improvement of the overall efficiency of the switching power supply.

In view of this, it is necessary to propose a driving circuit to improve the current freewheeling method in the energy recovery stage and greatly increase the energy recovery rate.

Contents of the invention

This application provides a drive circuit and switching power supply to improve the current freewheeling method in the energy recovery stage and greatly increase the energy recovery rate.

In the first aspect, this application provides a driving circuit for driving a power tube, including a control circuit, an energy recovery circuit, a duration determination circuit and an input power supply. The energy recovery circuit includes: multiple switching devices and an energy storage inductor; the duration determination circuit The circuit is used to determine the target duration; the energy recovery circuit is electrically connected to the input power supply and is used under the control of the control circuit to: charge the energy storage inductor along the first current direction according to the target duration; turn on the power tube; control multiple switching devices. At least one switching device is turned on through the channel for a target duration to return the energy stored in the energy storage inductor to the input power supply; the energy storage inductor is charged along the second current direction for the target duration; the power tube is turned off; and multiple switching devices are controlled. At least one switching device is turned on through the channel for a target period of time to flow energy stored in the energy storage inductor back to the input power supply.

The recovery of driving energy can be mainly divided into three stages: the energy storage inductor charging stage (the first stage), the power tube opening/closing stage (the second stage), and the energy storage inductor energy recovery stage (the third stage). If you want to further improve the energy recovery rate, in the third stage, the switching device in the energy recovery circuit needs to be turned on through the channel to reduce energy loss. However, it is currently impossible to accurately determine the exact timing of channel closing of the switching device, so in the third stage In the third stage, the freewheeling diode freewheeling conduction method is still used to achieve energy recovery, sacrificing the energy recovery rate.

Using this application to determine the circuit length, before turning on/off the power tube, you can first determine the target length of time for the input power supply to charge the energy storage inductor (the length of the first stage), and control multiple switching devices during the energy recovery stage. At least one switching device is turned on for a target time through the channel to flow the energy stored in the energy storage inductor back to the input power supply through the channel, because the current flows back to the input power through the channel. There is no power consumption, so there is no energy consumption, thus greatly improving the energy recovery rate.

Moreover, in the first stage, the current on the energy storage inductor will rise with the first slope. In the second stage, since the direction of the current flowing on the energy storage inductor does not change, the magnitude of the current flowing on the energy storage inductor also changes. The rise will continue with a slope smaller than the first slope. In the third stage, when the energy stored in the energy storage inductor flows back to the input power supply through the channel, the current on the energy storage inductor will decrease with a second slope (the second slope and the first slope are the opposite of each other). , therefore, based on the principle that the current on the inductor does not suddenly change, after the channel is turned on and the current on the inductor decreases at the second slope for the target time, there is still energy on the energy storage inductor that has not completely returned, that is, the energy storage inductor The current on the inductor has not yet passed zero, so there will be no problem that the energy storage inductor current flows back after it crosses zero, causing the recovery rate to decrease.

As a possible implementation manner, the energy recovery circuit, under the control of the control circuit, is also used to: after turning on the power tube and conducting the channel through at least one of the plurality of switching devices for a target duration, control multiple At least one of the switching devices is turned on through the freewheeling diode to flow back the remaining energy stored in the energy storage inductor to the input power supply; when the power tube is turned off, at least one of the switching devices is passed through the channel. After being turned on for a target duration, at least one of the plurality of switching devices is controlled to be turned on through the freewheeling diode to flow back the remaining energy stored in the energy storage inductor to the input power supply.

As a possible implementation, the energy recovery circuit specifically includes a first switching device, a second switching device, a third switching device, a fourth switching device and an energy storage inductor; a first end of the first switching device and a second switching device The first end of the first switching device is connected to the input power supply, the third end of the first switching device is connected to the first end of the energy storage inductor, the third end of the second switching device is connected to the second end of the energy storage inductor, and the third end of the energy storage inductor is connected. The two ends are also connected to the gate of the power tube, the first end of the third switching device and the first end of the fourth switching device are connected to ground, the first end of the third switching device is connected to the first end of the energy storage inductor, and the fourth end of the switching device is connected to the ground. The first terminal of the switching device is connected to the second terminal of the energy storage inductor.

As a possible implementation, the control circuit is used to control the second switching device and the third switching device to turn on, so that the input power supply charges the energy storage inductor along the first current direction; keep the second switching device turned on and close the third switch device to turn on the power tube; when the gate-source voltage of the power tube is equal to the turn-on voltage of the power tube, the second switching device is turned off and the first switching device is controlled to turn on, and the fourth switching device is controlled to conduct for a target duration through the channel. The energy stored in the energy storage inductor flows back to the input power supply; the control circuit is also used to control the first switching device and the fourth switching device to turn on, so that the input power supply is controlled to charge the energy storage inductor along the second current direction; the fourth switching device is maintained Turn on and off the first switching device to turn off the power tube; when the gate-source voltage of the power tube is equal to the ground potential, turn off the fourth switching device and control the second switching device to turn on, and control the third switching device to conduct the target through the channel time, the energy stored in the energy storage inductor flows back to the input power supply.

When the gate-source voltage of the power tube is equal to or close to the turn-on voltage of the power tube, the first switching device is controlled to turn on. When the fourth switching device turns on, the fourth switching device - the energy storage inductor - the first switching device form a path to store energy. Some of the energy stored in the inductor flows back to the input supply. When the fourth switching device continues to conduct through the channel for a target length of time, the energy stored in the energy storage inductor flows back to the input power supply. Using this method can not only significantly improve the energy recovery and utilization rate, but also prevent the problem of backflow after the energy storage inductor current crosses zero.

As a possible implementation manner, the third switching device includes a first freewheeling diode, the anode of the first freewheeling diode is connected to the first end of the third switching device, and the cathode of the first freewheeling diode is connected to the third switching device. The third terminal is connected; the fourth switching device includes a second freewheeling diode, the anode of the second freewheeling diode is connected to the first terminal of the fourth switching device, and the cathode of the second freewheeling diode is connected to the third terminal of the fourth switching device. three-terminal connection;

The control circuit is also used to control the third switching device to turn off the third switching device after conducting for a target length of time through the channel, so that the input power supply, the first switching device, the energy storage inductor, the second freewheeling diode and the ground wire form a path ; The control circuit is also used to control the input power supply, the second switching device, the energy storage inductor, the first freewheeling diode and the ground wire to form a path after the fourth switching device is turned on through the channel for a target length of time.

As a possible implementation, the duration determination circuit includes a first D flip-flop, a second D flip-flop, a third D flip-flop, a comparator, a first AND gate circuit, a second AND gate circuit, and an inverter; The clock input terminal of the first D flip-flop is connected to the second terminal of the second switching device through an inverter, and the second terminal of the first switching device is connected to the second terminal of the second switching device through an inverter. The first D flip-flop is connected to the second terminal of the second switching device through an inverter. The Q non-end of the flip-flop is connected to the second end of the fourth switching device; the input positive end of the comparator is connected to the first end of the energy storage inductor, and the input negative end of the comparator is connected to the second end of the energy storage inductor. The output terminal of the device is connected to the first input terminal of the first AND gate circuit; the clock input terminal of the second D flip-flop is connected to the gate-source voltage signal. When the gate-source voltage signal of the power tube is equal to the turn-on voltage of the power tube, is a high-level signal, and the gate-source voltage signal is a low-level signal when the gate-source voltage of the power tube is equal to the ground voltage. The Q terminal of the second D flip-flop is connected to the first input terminal of the first AND gate circuit and the second The first input terminal of the AND gate circuit is connected, the Q non-terminal of the second D flip-flop is connected to the second terminal of the third switching device; the clock input terminal of the third D flip-flop is connected to the output terminal of the first AND gate circuit, The clock Q non-end of the third D flip-flop is connected to the second input end of the second AND gate circuit. The second AND gate circuit is used to output the first control signal and the second control signal; the control circuit is also used to output the first control signal according to the first According to the control signal, the fourth switching device is turned on through the channel for a target duration; according to the second control signal, the third switching device is turned on through the channel for a target duration.

In a second aspect, this application provides a switching power supply. The switching power supply includes a power tube and a drive circuit provided in the first aspect. The drive circuit is used to conduct or disconnect the loop between the input power supply and the electrical equipment to realize the switching power supply. Function; the drive circuit includes: a control circuit, an energy recovery circuit, a duration determination circuit and an input power supply. The energy recovery circuit includes: multiple switching devices and energy storage inductors; the duration determination circuit is used to determine the target duration; the energy recovery circuit, and The input power supply is electrically connected, and under the control of the control circuit, is used to: charge the energy storage inductor along the first current direction according to the target duration; turn on the power tube; control at least one of the multiple switching devices to conduct the target through the channel time to return the energy stored in the energy storage inductor to the input power supply; charge the energy storage inductor along the second current direction according to the target time; turn off the power tube; control at least one of the multiple switching devices to conduct the target through the channel time to flow the energy stored in the energy storage inductor back to the input power supply.

As a possible implementation, the energy recovery circuit specifically includes: a first switching device, a second switching device, a third switching device, a fourth switching device and an energy storage inductor; the first end of the first switching device and the second The first end of the switching device is connected to the input power supply, the third end of the first switching device is connected to the first end of the energy storage inductor, the third end of the second switching device is connected to the second end of the energy storage inductor, and the energy storage inductor The second end of the third switching device is also connected to the gate of the power tube, the first end of the third switching device is connected to the first end of the fourth switching device, and the first end of the third switching device is connected to the first end of the energy storage inductor. The first terminal of the fourth switching device is connected to the second terminal of the energy storage inductor.

As a possible implementation, the control circuit is used to control the second switching device and the third switching device to turn on, so that the input power supply charges the energy storage inductor along the first current direction; keep the second switching device turned on and turn off the third switching device. switching device to turn on the power tube; when the gate-source voltage of the power tube is equal to the turn-on voltage of the power tube, turn off the second switching device and control the first switching device to turn on, and control the fourth switching device to conduct for a target duration through the channel, Return the energy stored in the energy storage inductor to the input power supply; the control circuit is also used to control the opening of the first switching device and the fourth switching device, so as to control the input power supply to charge the energy storage inductor along the second current direction; close the first switch device to turn off the power tube; when the gate-source voltage of the power tube is equal to the ground potential, the second switching device is controlled to turn on, and the third switching device is controlled to conduct for a target length of time through the channel, and the energy stored in the energy storage inductor flows back to the input power supply.

As a possible implementation manner, the duration determination circuit includes a first D flip-flop, a second D flip-flop, a third D flip-flop, a comparator, a first AND gate circuit, a second AND gate circuit and an inverter. The clock input end of a D flip-flop is connected to the second end of the second switching device through an inverter, the second end of the first switching device is connected to the second end of the second switching device through the inverter, and the first D flip-flop The Q non-end of the comparator is connected to the second end of the fourth switching device. The input positive end of the comparator is connected to the first end of the energy storage inductor. The input negative end of the comparator is connected to the second end of the energy storage inductor. The comparator's The output terminal is connected to the first input terminal of the first AND gate circuit, and the clock input terminal of the second D flip-flop is connected to the gate-source voltage signal. The gate-source voltage signal is high when the gate-source voltage of the power tube is equal to the turn-on voltage of the power tube. The gate-source voltage signal is a low-level signal when the gate-source voltage of the power tube is equal to the ground voltage. The Q terminal of the second D flip-flop is connected to the first input terminal of the first AND gate circuit and the second AND gate circuit. The first input terminal is connected, the Q non-terminal of the second D flip-flop is connected to the second terminal of the third switching device, the clock input terminal of the third D flip-flop is connected to the output terminal of the first AND gate circuit, the third D flip-flop is connected The clock Q non-terminal of the device is connected to the second input terminal of the second AND gate circuit. The second AND gate circuit is used to output the first control signal and the second control signal; the control circuit is also used to control the signal according to the first control signal. The fourth switching device is turned on through the channel for a target duration; according to the second control signal, the third switching device is turned on through the channel for a target duration.

For the description of the technical effects that can be achieved in the second aspect above, please refer to the description of the technical effects that can be achieved by any possible design in the above-mentioned first aspect, and duplication will not be discussed.

Description of drawings

Figure 1 is a schematic diagram of the loss breakdown of each part of the switching power supply;

Figure 2A is a schematic structural diagram of a driving loss recovery circuit;

Figure 2B is a timing diagram of a driving loss recovery circuit;

Figure 2C is a structural schematic diagram 2 of a driving loss recovery circuit;

Figure 3 is a schematic structural diagram of the driving circuit provided by this application;

Figure 4 is a schematic structural diagram of an energy recovery circuit;

Figure 5 is a schematic structural diagram 2 of an energy recovery circuit;

Figure 6A is a schematic structural diagram of a duration determination circuit;

Figure 6B is a timing diagram of target duration copying based on the duration determination circuit;

Figure 6C is a timing diagram of the duration determination circuit;

Figure 6D is a simulation diagram of the gate-source voltage;

FIG. 6E is a simulation diagram illustrating the node voltage correspondence between the second switching device and the fourth switching device.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be described in further detail below in conjunction with the accompanying drawings. Example embodiments may, however, be embodied in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concepts of the example embodiments. To those skilled in the art. The same reference numerals in the drawings represent the same or similar structures, and thus their repeated description will be omitted. The words expressing position and direction described in this application are all explained by taking the accompanying drawings as examples, but they can be changed as needed, and all changes are included in the protection scope of this application. The drawings in this application are only used to illustrate relative positional relationships and do not represent true proportions.

In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be described in further detail below in conjunction with the accompanying drawings. The specific operation methods in the method embodiments can also be applied to the device embodiments or system embodiments. It should be noted that in the description of this application, "at least one" refers to one or more, and "multiple" refers to two or more. In view of this, in the embodiment of the present invention, “plurality” may also be understood as “at least two”. "And/or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and/or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/", unless otherwise specified, generally indicates that the related objects are in an "or" relationship. In addition, it should be understood that in the description of this application, words such as "first" and "second" are only used for the purpose of distinguishing the description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating. Or suggestive order.

It should be noted that “connection” in the embodiments of this application refers to electrical connection, and the connection between two electrical components may be a direct or indirect connection between two electrical components. For example, A and B can be connected directly, or A and B can be connected indirectly through one or more other electrical components. For example, A and B can be connected, or A and C can be connected directly. C and B are directly connected, and A and B are connected through C.

The embodiments of the present application are described below in conjunction with the accompanying drawings:

Refer to Figure 1, which is a schematic diagram of the loss decomposition of each part of the switching power supply. It can be seen from Figure 1 that the driving loss accounts for 2%. When other losses are difficult to reduce, the driving loss needs to be further reduced. Thereby improving the overall efficiency of the switching power supply.

As a possible implementation, by using energy storage components, the discharged charge from the gate of the power tube to the ground can be recovered, so that it can be used to drive the power tube in the next cycle, reducing driving losses. Refer to Figure 2A. Figure 2A is a structural schematic diagram 1 of a driving loss recovery circuit. Figure 2B is a timing diagram of a driving loss recovery circuit. The driving loss recovery circuit includes switching tubes Q1-Q4 and an inductor L. Each switch tube includes a freewheeling diode, which are freewheeling diodes D1-D4 respectively. The entire driving and energy recovery of the power tube mainly includes the following steps (taking the voltage of the input power supply as Vcc as an example):

The first stage of the driving tube opening phase: first turn on the switching tubes Q2 and Q3, the switching tubes Q1 and Q4 are in the closed state, and the current passes through the path: input power supply - switching tube Q2 - inductor L - switching tube Q3 - ground. Since the current on the inductor L cannot mutate suddenly, the current through the inductor L rises with a current slope of Vcc/L. After reaching the set time, it enters the second stage of the driver tube turn-on stage from the first stage of the driver tube turn-on stage.

The second stage of the driving tube opening phase: only switch tube Q2 is turned on, and switch tubes Q1, Q3 and Q4 are all in a closed state. The current passes through the path: input power supply - switching tube Q2 - inductor L - gate terminal of the power tube, thus turning the power tube Turn on, when it is detected that the voltage between the gate and source of the power tube is close to the turn-on voltage of the power tube, the stage 2 of the drive tube turn-on stage enters the stage 3 of the drive tube turn-on stage.

The third stage of the driving tube opening phase: also known as the energy recovery phase, the switching tube Q1 is turned on, and the switching tubes Q2, Q3 and Q4 are all in a closed state. Under the forward conduction of the freewheeling diode D4 in the switching tube Q4, the current passes through Path: ground wire - freewheeling diode D4 in switch tube Q4 - inductor L - switch tube Q1 - input power supply, the current through the inductor L decreases with a current slope of -Vcc/L, when the current on the inductor decreases to 0 , ends the third stage of the drive tube opening phase, and completes the energy recovery process of opening the drive tube.

Similarly, the power tube closing process is similar to the opening process, including:

The first stage of the drive tube closing phase: turn on the switching tubes Q1 and Q4, switch tubes Q2 and Q3 are in the closed state, the current passes through the path: input power supply - switching tube Q1 - inductor L - switching tube Q4 - ground wire, due to the inductor L The current cannot change suddenly. The current through the inductor L rises with the current slope of Vcc/L. After reaching the set time, it enters the second stage of the drive tube off stage from the first stage of the drive tube off stage.

The second stage of the drive tube shutdown phase: only switch tube Q4 is turned on, and switch tubes Q1, Q2, and Q3 are all in a closed state. The current passes through the path: gate end of the power tube - inductor L - switch tube Q4 - ground, thereby connecting the power tube When it is detected that the voltage between the gate and source of the power tube is close to the ground voltage, the stage 2 of the driver tube turn-off stage enters the stage 3 of the driver tube turn-off stage.

The third stage of the drive tube shutdown phase: turn on the switch tube Q2, the switch tubes Q1, Q3 and Q4 are all in the closed state. Under the forward conduction of the freewheeling diode D3 in the switch tube Q3, the current passes through the path: ground wire - switch The freewheeling diode D3 in the tube Q3 - the inductor L - the switching tube Q2 - the input power supply. The inductor L decreases with a current slope of -Vcc/L. When the current slope decreases to 0, the third stage of the drive tube opening phase ends. Complete the energy recovery process of closing the drive tube.

During the conduction process of the freewheeling diode D3 or D4, a large energy loss is generated, resulting in a decrease in the energy recovery rate. Taking the third stage of the driver tube turn-on stage as an example, the current path is specifically: ground wire - switch tube Q4 The freewheeling diode D4 - the inductor L - the switching tube Q1 - the input power supply. Therefore, a large energy loss is caused on the freewheeling diode D4. If the current can directly pass through the channel of the switching tube Q4, the freewheeling diode can be greatly reduced. time conduction loss, effectively improving the energy recovery rate.

Refer to Figure 2C, which is a structural schematic diagram 2 of a driving loss recovery circuit; the structure in Figure 2C adds a zero-crossing detection circuit for zero-crossing detection of the current flowing through the inductor. In the above energy recovery stage, switching transistor Q3 or switching transistor Q4 is turned on, so that the energy on the inductor L forms a path through the channel of switching transistor Q3 or switching transistor Q4, thereby recirculating the energy. When the zero-crossing detection circuit detects that the current flowing through the inductor crosses zero, it is determined that the energy recovery is completed, and the switch Q3 or switch Q4 is turned off. However, this solution has strict performance requirements for the zero-crossing detection circuit. If the detection accuracy of the zero-crossing detection circuit cannot meet the requirements, the switching tube Q3 or switching tube Q4 will turn off later than the zero-crossing timing of the current flowing through the inductor. This will cause the current in the inductor to flow back to the ground after the current in the inductor crosses zero, causing a significant decrease in the energy recovery rate. Moreover, the internal structure of the zero-crossing detection circuit is relatively complex, making it difficult to achieve ns-level delay. At this time, it will also cause the problem that the switching tube Q3 or the switching tube Q4 turns off later than the zero-crossing timing of the current flowing through the inductor. In addition, in high-power scenarios, the ground noise is too large, causing the zero-crossing detection to not work properly, and it is easy to cause The switch tube is accidentally opened or closed by mistake. Therefore, the method of adding a zero-crossing detection circuit is difficult to implement, risky and difficult to apply in practice. At present, in the third stage of the driving tube turning on stage and the third stage of the driving tube turning off stage, the freewheeling diode inside the switching tube is still used for forward conduction, which cannot further improve the energy recovery rate.

In view of this, it is necessary to propose a driving circuit to improve the current freewheeling method in the energy recovery stage and greatly increase the energy recovery rate. Refer to Figure 3, which is a schematic structural diagram of the driving circuit provided by the present application. The drive circuit 300 is used to drive the power tube 301. The drive circuit 300 includes: a control circuit 302, an energy recovery circuit 303, a duration determination circuit 304 and an input power supply 305. The control circuit 302 and the energy recovery circuit 303 And the duration determination circuit 304 is connected, the energy recovery circuit 303 is connected with the power tube 301; the input power supply 305 is connected with the energy recovery circuit 303.

The energy recovery circuit 303 includes: a plurality of switching devices and an energy storage inductor. The duration determination circuit 304 is used to determine a target duration. The target duration may be the time required for the input power supply 305 to charge the energy storage inductor. Charging time.

The energy recovery circuit 303, under the control of the control circuit 302, is used to: charge the energy storage inductor along the first current direction according to the target duration; turn on the power tube 301; control the multiple switches At least one switching device in the device is turned on for a target duration through a channel to flow back the energy stored in the energy storage inductor to the input power supply 305; the energy storage inductor is charged along the second current direction for the target duration. ; Turn off the power tube 301 ; Control at least one of the plurality of switching devices to conduct through the channel for a target duration to return the energy stored in the energy storage inductor to the input power supply 305 .

Among them, the plurality of switching devices and the power transistor 301 included in the energy recovery circuit 303 can be metal oxide semiconductor field effect transistor (MOSFET), bipolar junction transistor (BJT), One or more of various types of switching devices such as insulated gate bipolar transistor (IGBT), silicon carbide (SiC) power transistor, etc., which will not be listed one by one in the embodiments of this application. Each switching device may include a first terminal, a second terminal and a third terminal, where the third terminal is used to control the closing or opening of the switch. When the switch is closed, between the first terminal and the second terminal of the switch Can carry current, when the switch is open, no current can be carried between the first and second ends of the switch. Taking MOSFET as an example, the third terminal of the switch is the gate, the first terminal of the switch can be the source of the switching device, and the second terminal can be the drain of the switching device, or the first terminal can be the drain of the switch. The second terminal may be the source of the switch. It should be noted that the difference between the multiple switching devices and the power tube 301 is that the power tube 301 has a larger operating power, so the driving loss is relatively larger. Each of the multiple switching devices included in the energy recovery circuit 303 may include a flyback diode, sometimes also called a flywheel diode or a snubber diode, which is used with inductive loads. diode, when the current of the inductive load suddenly changes or decreases, a sudden voltage will be generated at both ends of the inductor, destroying other components. Therefore, after adding a freewheeling diode, the current can change smoothly, and the freewheeling diode is a reverse Provide a power consumption path to the electromotive force to avoid the occurrence of sudden voltage changes.

Among them, the energy storage inductor included in the energy recovery circuit 303 stores energy in a magnetic field. The energy it stores is proportional to its inductance and the square of the current flowing through it. The energy storage inductor is used to recover the gate charge in the power transistor 301 that was originally discharged to the ground, so as to drive the power transistor 301 again in the next cycle to achieve the purpose of reducing driving losses. A plurality of switching devices are selectively connected to both ends of the energy storage inductor, so that the control circuit 302 controls the power tube 301 to turn on and off at different stages, and stores energy through the energy storage inductor.

The duration determination circuit 304 in this application is used to determine the target duration, which is the charging duration for the input power supply 305 to charge the energy storage inductor. The duration determination circuit 304 may be a timing circuit, used to calculate the charging duration for the input power supply 305 to charge the energy storage inductor, starting from the time when the energy stored in the energy storage inductor is zero, until the input power supply 305 charges the energy storage inductor. The time it takes for the inductor to be fully charged is the charging time. Alternatively, the duration determination circuit 304 may also be connected to the switching device in the energy recovery circuit 303. Since the input power supply 305 is charged through the switching device in the energy recovery circuit 303, by detecting the The turn-on time (pulse width) of the switching device in the energy recovery circuit 303 can also determine the charging time for the input power supply 305 to charge the energy storage inductor.

It should be noted that the input power supply 305 can either charge the energy storage inductor until it cannot store energy and then stop charging. The charging time of this period is the target length, or the input power supply 305 can also store energy within a set time. For inductor charging, the set time is the target duration. However, since there is a deviation between the set time and the actual charging time, the duration determination circuit 304 is also required to obtain it. Among them, the longer the charging time of the energy storage inductor is, the more energy the energy storage inductor stores (not exceeding the upper limit), and the faster the power tube 301 is turned on/off. The specific charging time can be freely determined by those skilled in the art, and will not be described in detail here.

As a possible implementation, the energy recovery circuit 303, under the control of the control circuit, is also used to: turn on the power tube and conduct channel conduction through at least one of the plurality of switching devices. After the target duration, at least one switching device among the plurality of switching devices is controlled to be turned on through a freewheeling diode to flow back the remaining energy stored in the energy storage inductor to the input power supply; after turning off the power tube, And after at least one of the plurality of switching devices is turned on through the channel for a target duration, at least one of the plurality of switching devices is controlled to be turned on through the freewheeling diode, so that the energy storage inductor The stored residual energy flows back to the input power source.

The recovery of driving energy can be mainly divided into three stages: the energy storage inductor charging stage (the first stage), the power tube opening/closing stage (the second stage), and the energy storage inductor energy recovery stage (the third stage). If you want to further improve the energy recovery rate, in the third stage, the switching device in the energy recovery circuit needs to be turned on through the channel to reduce energy loss. However, it is currently impossible to accurately determine the exact timing of channel closing of the switching device, so in the third stage In the third stage, the freewheeling diode freewheeling conduction method is still used to achieve energy recovery, sacrificing the energy recovery rate. In the first stage, the current on the energy storage inductor will rise with the first slope. In the second stage, since the direction of the current flowing on the energy storage inductor does not change, the current flowing on the energy storage inductor will also increase with Slopes smaller than the first slope continue to rise. In the third stage, when the energy stored in the energy storage inductor flows back to the input power supply through the channel, the current on the energy storage inductor will decrease with a second slope (the second slope and the first slope are the opposite of each other). , therefore, based on the principle that the current on the inductor does not suddenly change, after the channel is turned on and the current on the inductor decreases at the second slope for a target period of time, there is still energy in the energy storage inductor that has not been fully recirculated. Therefore, at least one switching device among the plurality of switching devices can continue to conduct through the freewheeling diode to flow back the remaining energy stored in the energy storage inductor to the input power supply.

As a possible implementation, refer to Figure 4, which is a schematic structural diagram of an energy recovery circuit. The energy recovery circuit 303 specifically includes: a first switching device 401, a second switching device 402, a third switch Device 403, fourth switching device 404 and energy storage inductor 405; the first end of the first switching device 401 and the first end of the second switching device 402 are connected to the input power supply 305, and the first switch The third end of the device 401 is connected to the first end of the energy storage inductor 405. The third end of the second switching device 402 is connected to the second end of the energy storage inductor 405. The energy storage inductor 405 has The second terminal is also connected to the gate of the power tube 301 , the first terminal of the third switching device 403 and the first terminal of the fourth switching device 404 are grounded, and the first terminal of the third switching device 403 is grounded. The terminal is connected to the first terminal of the energy storage inductor 405, and the first terminal of the fourth switching device 404 is connected to the first terminal of the energy storage inductor 405. The second end of the connection.

The control circuit 302 is used to control the second switching device 402 and the third switching device 403 to turn on, so that the input power supply 305 charges the energy storage inductor 405 along the first current direction; keeping the second switching device 402 turns on and off the third switching device 403 to turn on the power tube 301; when the gate-source voltage of the power tube 301 is equal to the turn-on voltage of the power tube 301, turns off the second switching device 402 and controls all The first switching device 401 is turned on, and the fourth switching device 404 is controlled to conduct for a target duration through the channel, and the energy stored in the energy storage inductor 405 is returned to the input power supply 305;

The control circuit 302 is also used to control the first switching device 401 and the fourth switching device 404 to turn on, so as to control the input power supply 305 to charge the energy storage inductor 405 along the second current direction; maintain The fourth switching device 404 turns on and off the first switching device 401 to turn off the power tube 301; when the gate-source voltage of the power tube 301 is equal to the ground potential, the fourth switching device 404 turns off and controls the third switching device 404. The second switching device 402 is turned on, and the third switching device 403 is controlled to be turned on through the channel for a target duration to flow back the energy stored in the energy storage inductor 405 to the input power supply 305 .

Among them, the control circuit 302 in the embodiment of the present application can be a processor or a controller, for example, it can be a general central processing unit (CPU), a general processor, a digital signal processing (DSP), Application specific integrated circuits (ASIC), field programmable gate array (FPGA) or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. The above-mentioned processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of a DSP and a microprocessor, and so on. The control circuit 302 is respectively connected to the third terminals of the first switching device 401, the second switching device 402, the third switching device 403 and the fourth switching device 404, thereby controlling the opening and closing of the above switching devices.

When the driving power tube 301 is turned on, the control circuit 302 controls the third terminal of the second switching device 402 and the third terminal of the third switching device 403, so that the second switching device 402-the The energy storage inductor 405 and the third switching device 403 form a path, so that the input power supply 305 charges the energy storage inductor 405 .

After the energy storage inductor 405 is charged, the third terminal of the third switching device 403 is controlled to close the third switching device 403, so that the second switching device - the energy storage inductor 405 - the power The tube 301 forms a passage, and the input power supply 305 is used to turn on the power tube 301 . It should be noted that at this time, the energy storage inductor 405 is still being charged.

When the gate-source voltage of the power tube 301 is equal to or close to the turn-on voltage of the power tube 301, the first switching device 401 is controlled to be turned on, and the fourth switching device 404 is turned on through the channel. The channel 404 - the energy storage inductor 405 - the first switching device 401 forms a path, and part of the energy stored in the energy storage inductor 405 flows back to the input power supply 305. After the fourth switching device 404 continues to be turned on for the target duration, the channel of the fourth switching device 404 is closed, and the freewheeling diode-energy storage inductor 405-the first switching device 401 in the fourth switching device 404 forms a path. Another part of the energy stored in the energy storage inductor 405 flows back to the input power supply 305 . At this time, since the freewheeling current becomes smaller and the time is very short, the freewheeling diode's freewheeling loss can be ignored. The target duration is the charging duration for the input power supply 305 to charge the energy storage inductor when it is not connected to the power tube 301. Since the current of the energy storage inductor 405 cannot change suddenly, the energy storage inductor 405 is charged. The target time period when the energy in the energy inductor 405 is completely recovered must be greater than the target time period. This method can not only significantly improve the energy recovery utilization rate, but also prevent the problem of backflow after the inductor current crosses zero.

When the driving power transistor 301 is turned off, the control circuit 302 controls the third terminal of the first switching device 401 and the third terminal of the fourth switching device 404 so that the first switching device 401 - the The energy storage inductor 405 and the fourth switching device 404 form a path, so that the input power supply 305 charges the energy storage inductor 405 .

After the energy storage inductor 405 is charged, the third terminal of the first switching device 401 is controlled to close the first switching device 401, so that the power tube 301 - the energy storage inductor 405 - the fourth The switching device 404 forms a path, and the input power supply 305 is used to turn off the power tube 301 . It should be noted that at this time, the energy storage inductor 405 is still being charged.

When the gate-source voltage of the power tube 301 is equal to or close to the ground (zero voltage) voltage, the second switching device 402 is controlled to turn on. When the third switching device 403 is turned on through the channel, the third switching device 403 is turned on. The channel of 403 - the energy storage inductor 405 - the second switching device 402 forms a path, and part of the energy stored in the energy storage inductor 405 flows back to the input power supply 305. After the third switching device 403 continues to be turned on for the target duration, the channel of the third switching device 403 is closed, and the freewheeling diode-energy storage inductor 405-the second switching device 402 in the third switching device 403 forms a path. Another part of the energy stored in the energy storage inductor 405 flows back to the input power supply 305 . In the same way, since the freewheeling current becomes smaller and the time is very short, the freewheeling loss of the freewheeling diode can be ignored. Since the current of the energy storage inductor 405 cannot change suddenly, the target time period to completely recover the energy in the energy storage inductor 405 must be longer than the target time period.

Based on the above embodiment, as a possible implementation, refer to Figure 5, which is a schematic structural diagram 2 of an energy recovery circuit. The third switching device 403 includes a first freewheeling diode 501. The anode of the first freewheeling diode 501 is connected to the third The first end of the switching device 403 is connected, and the cathode of the first freewheeling diode 501 is connected to the third end of the third switching device 403; the fourth switching device 404 includes a second freewheeling diode 502, so The anode of the second freewheeling diode 502 is connected to the first end of the fourth switching device 404, and the cathode of the second freewheeling diode 502 is connected to the third end of the fourth switching device 404; controlling the After the third switching device 403 is turned on for the target duration, the input power supply 305, the energy storage inductor 405, the first freewheeling diode 501 and the ground wire form a path; the fourth switching device 404 is controlled to turn on After the target time, the input power supply 305, the energy storage inductor 405, the second freewheeling diode 502 and the ground wire form a path.

The duration determination circuit 304 may also be connected to the switching device in the energy recovery circuit 303. Since the input power supply 305 is charged through the switching device in the energy recovery circuit 303, the duration determination circuit 304 What is copied is the pulse width of the switching device in the energy recovery circuit 303, which can also be equal to determining the charging time (target time) for the input power supply 305 to charge the energy storage inductor, as shown in Figure 6A. Figure 6A is A schematic structural diagram of a duration determination circuit. As a possible implementation, the duration determination circuit includes a first D flip-flop 601, a second D flip-flop 602, a third D flip-flop 603, a comparator 604, An AND gate circuit 605, a second AND gate circuit 606 and an inverter 607.

The clock input terminal (Clk) of the first D flip-flop 601 is connected to the second terminal of the second switching device 402 through the inverter 607, and the second terminal of the first switching device 401 is connected through the inverter 607. The Q non-terminal of the first D flip-flop 601 is connected to the second terminal of the fourth switching device 404 . The positive input terminal of the comparator 604 is connected to the first terminal of the energy storage inductor 405, and the negative input terminal of the comparator 604 is connected to the second terminal of the energy storage inductor 405. The output terminal is connected to the first input terminal of the first AND gate circuit 605 .

The clock input terminal (Clk) of the second D flip-flop 602 is connected to a gate-source voltage signal. The gate-source voltage signal is high level when the gate-source voltage of the power tube 301 is equal to the voltage of the input power supply 305 signal, the gate-source voltage signal is a low-level signal when the gate-source voltage of the power transistor 301 is equal to the ground voltage, the Q terminal of the second D flip-flop 602 and the first AND gate circuit 605 The first input terminal is connected to the first input terminal of the second AND gate circuit 606, and the Q NOT terminal of the second D flip-flop 602 is connected to the second terminal of the third switching device 403; the third The clock input terminal of the D flip-flop 603 is connected to the output terminal of the first AND gate circuit 605, and the clock Q NOT terminal of the third D flip-flop 603 is connected to the second input terminal of the second AND gate circuit 606. , the second AND gate circuit 606 is used to output the first control signal and the second control signal.

The control circuit 302 is configured to turn on the fourth switching device 404 for the target duration according to the first control signal; to turn on the third switching device 403 for the target according to the second control signal. duration.

As shown in FIG. 6B , FIG. 6B is a timing diagram of copying the target duration based on the duration determination circuit. Among them, the control pulse width of the first switching device 401 and the second switching device 402 determines the charging time of the energy storage inductor 405. The time length determination circuit 304 is copied to obtain the turn-on time of the first switching device 401. The corresponding first control signal corresponds to the second control signal corresponding to the turn-on time of the second switching device 402 . Since the current of the energy storage inductor 405 cannot change suddenly, the target time period to completely recover the energy in the energy storage inductor 405 must be longer than the target time period. The remaining energy on the energy storage inductor 405 can flow through the freewheeling diode for freewheeling. Since the freewheeling current becomes smaller and the time is very short, the freewheeling loss of the freewheeling diode can be ignored, which can significantly improve the energy recovery and utilization rate. , and can also prevent the problem of backflow after the inductor current crosses zero.

Refer to FIG. 6C , which is a timing diagram of the duration determination circuit. In FIG. 6C, the pulse input (PULSE_IN) signal is a copied pulse signal that turns on the second switching device 402. When the gate-source voltage of the power tube 301 is equal to the voltage of the input power supply 305, the gate-source voltage is equal to the voltage of the input power supply 305. The voltage signal is a high-level signal, which triggers the copying action. When the gate-source voltage of the power transistor 301 is equal to the ground voltage, the gate-source voltage signal is a low-level signal, and the copying action ends. RSTN is a reset signal, used to reset the triggering states of the first D flip-flop 601, the second D flip-flop 602, and the third D flip-flop 603. V ₁ is the input negative terminal signal of the comparator 604 , V ₂ is the input positive terminal signal of the comparator 604 , and V _out is the output terminal signal of the comparator 604 . q ₁ is the first input signal of the second AND gate circuit 606 , q ₂ is the second input signal of the second AND gate circuit 606 , and the pulse output (PULSE_OUT) is corresponding to the turn-on time of the second switching device 402 the second control signal. The above circuit has a simple structure. There is only a comparator in the delay link, which enables ns-level delay settings. It replaces the existing zero-crossing detection circuit to directly control the turn-off of the switching device. Noise has little impact on the above circuit. , it can still work normally even when the ground noise is very serious.

Refer to Figure 6D, which is a simulation diagram of the gate-source voltage. It can be seen from Figure 6D that when the power tube 301 is turned on in this application, the gate-source voltage of the power tube 301 is smaller than the gate-source voltage of the power tube 301 in the prior art. This is equivalent to that when the power tube 301 is turned on in this application, The gate-source voltage of the power tube 301 is closer to the voltage of the input power supply 305. When the power tube 301 is turned off, the gate-source voltage of the power tube 301 is greater than the gate-source voltage of the power tube 301 in the prior art, which is equivalent to In this application, when the power transistor 301 is turned off, the gate-source voltage of the power transistor 301 is closer to the ground voltage (zero voltage). Refer to Figure 6E. Figure 6E shows the second switching device and the fourth switching device. Simulation diagram corresponding to the node voltage between components. It can be seen from Figure 6E that after the power transistor 301 is turned on, the node voltage between the second switching device and the fourth switching device in the present application is higher than that between the second switching device and the fourth switching device in the prior art. After the power transistor 301 is turned off, the node voltage between the second switching device and the fourth switching device is lower than the node voltage between the second switching device and the fourth switching device in the prior art. Therefore, the freewheeling loss in the energy recovery stage is significantly improved. Compared with the existing technology, it has extremely strong anti-interference ability under the premise of low power consumption and low complexity.

Based on the same concept, this application also provides a switching power supply. The switching power supply includes a power tube and a driving circuit as shown in Figure 3 to Figure 6A. The driving circuit enables the loop between the input power supply and the electrical equipment to be connected or Disconnected to realize the function of switching power supply; the drive circuit includes: a control circuit, an energy recovery circuit, a duration determination circuit and an input power supply; the energy recovery circuit includes: a plurality of switching devices and an energy storage inductor; the duration The determination circuit is used to determine the target duration; the energy recovery circuit is electrically connected to the input power supply, and under the control of the control circuit, is used to: store energy along the first current direction according to the target duration. Charging the inductor; turning on the power tube; controlling at least one of the plurality of switching devices to conduct through a channel for a target duration to return the energy stored in the energy storage inductor to the input power supply; as described The target duration charges the energy storage inductor along the second current direction; turns off the power tube; and controls at least one of the plurality of switching devices to conduct through the channel for the target duration to store the energy storage inductor. The energy flows back to the input power source.

As a possible implementation, the energy recovery circuit, under the control of the control circuit, is also used to: turn on the power tube and pass the channel through at least one switching device among the plurality of switching devices. After the channel is turned on for a target duration, at least one of the plurality of switching devices is controlled to be turned on through a freewheeling diode to flow back the remaining energy stored in the energy storage inductor to the input power supply; after turning off the power tube, and after at least one of the plurality of switching devices is turned on through the channel for a target length of time, at least one of the plurality of switching devices is controlled to be turned on through a freewheeling diode to turn on the storage device. The remaining energy stored in the inductor flows back to the input power supply.

As a possible implementation, the energy recovery circuit specifically includes: a first switching device, a second switching device, a third switching device, a fourth switching device and an energy storage inductor; the third switching device of the first switching device One end and the first end of the second switching device are connected to the input power supply, the third end of the first switching device is connected to the first end of the energy storage inductor, and the third end of the second switching device is connected to the input power supply. Three terminals are connected to the second terminal of the energy storage inductor, the second terminal of the energy storage inductor is also connected to the gate of the power tube, and the first terminal of the third switching device is connected to the fourth switch. The first end of the device is connected to ground, the first end of the third switching device is connected to the first end of the energy storage inductor, and the first end of the fourth switching device is connected to the second end of the energy storage inductor. .

As a possible implementation, the control circuit is used to control the second switching device and the third switching device to turn on, so that the input power supply charges the energy storage inductor along the first current direction. ; Keep the second switching device turned on and turn off the third switching device to turn on the power tube; when the gate-source voltage of the power tube is equal to the turn-on voltage of the power tube, turn off the second switching device and control all The first switching device is turned on, and the fourth switching device is controlled to conduct for a target duration through the channel, and the energy stored in the energy storage inductor is returned to the input power supply; the control circuit is also used to control the The first switching device and the fourth switching device are turned on to control the input power supply to charge the energy storage inductor along the second current direction; the first switching device is turned off to turn off the power tube; When the gate-source voltage of the power tube is equal to the ground potential, the second switching device is controlled to turn on, and the third switching device is controlled to conduct for a target duration through the channel, so that the energy stored in the energy storage inductor flows back to the Enter power.

As a possible implementation manner, the third switching device includes a first freewheeling diode, the anode of the first freewheeling diode is connected to the first end of the third switching device, and the first freewheeling diode The cathode of the current diode is connected to the third terminal of the third switching device; the fourth switching device includes a second freewheeling diode, and the anode of the second freewheeling diode is connected to the first terminal of the fourth switching device. terminal is connected, and the cathode of the second freewheeling diode is connected to the third terminal of the fourth switching device;

The control circuit is also used to control the third switching device to turn off the third switching device through the channel for a target duration, so that the input power supply, the first switching device, and the energy storage device The inductor, the second freewheeling diode and the ground wire form a path; the control circuit is also used to control the input power supply, the second switching device after the fourth switching device conducts through the channel for a target length of time. , the energy storage inductor, the first freewheeling diode and the ground wire form a path.

As a possible implementation manner, the duration determination circuit includes a first D flip-flop, a second D flip-flop, a third D flip-flop, a comparator, a first AND gate circuit, a second AND gate circuit, and an inverter. phase inverter; the clock input terminal of the first D flip-flop is connected to the second terminal of the second switching device through the inverter, and the second terminal of the first switching device is connected to the second terminal through the inverter. The second end of the second switching device is connected, the Q non-end of the first D flip-flop is connected to the second end of the fourth switching device; the input positive end of the comparator is connected to the energy storage inductor. The first end of the comparator is connected to the first end of the comparator, the negative input end of the comparator is connected to the second end of the energy storage inductor, and the output end of the comparator is connected to the first input end of the first AND gate circuit; The clock input terminal and gate-source voltage signal of the second D flip-flop connection, the gate-source voltage signal is a high-level signal when the gate-source voltage of the power tube is equal to the turn-on voltage of the power tube, and the gate-source voltage signal is a high-level signal when the gate-source voltage of the power tube is equal to the ground voltage. is a low level signal, the Q terminal of the second D flip-flop is connected to the first input terminal of the first AND gate circuit and the first input terminal of the second AND gate circuit, and the second D flip-flop The Q non-end of the flip-flop is connected to the second end of the third switching device; the clock input end of the third D flip-flop is connected to the output end of the first AND gate circuit, and the third D flip-flop The non-end of the clock Q is connected to the second input end of the second AND gate circuit. The second AND gate circuit is used to output the first control signal and the second control signal; the control circuit is also used to output the first control signal and the second control signal according to the second AND gate circuit. According to the first control signal, the fourth switching device is turned on through the channel for a target duration; according to the second control signal, the third switching device is turned on through the channel for a target duration.

Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the scope of the present application. In this way, if these modifications and variations of the present application fall within the scope of the claims of this application and its equivalent technology, then this application is also intended to include these modifications and variations.

Claims

A driving circuit for driving a power tube, characterized in that the driving circuit includes: a control circuit, an energy recovery circuit, a duration determination circuit and an input power supply;

The energy recovery circuit includes: multiple switching devices and energy storage inductors;

The duration determination circuit is used to determine the target duration;

The energy recovery circuit is electrically connected to the input power supply, and under the control of the control circuit, is used for:

Charge the energy storage inductor along the first current direction according to the target duration;

Turn on the power tube;

Controlling at least one of the plurality of switching devices to be turned on through a channel for a target duration to flow back the energy stored in the energy storage inductor to the input power supply;

Charge the energy storage inductor along the second current direction according to the target duration;

Turn off the power tube;

At least one switching device among the plurality of switching devices is controlled to be turned on through a channel for a target duration to flow back energy stored in the energy storage inductor to the input power supply.
The circuit according to claim 1, characterized in that the energy recovery circuit, under the control of the control circuit, is also used to:

After turning on the power tube and conducting at least one of the plurality of switching devices through the channel for a target duration, controlling at least one of the plurality of switching devices to conduct through the freewheeling diode, To flow back the remaining energy stored in the energy storage inductor to the input power supply;

After turning off the power tube and conducting at least one of the plurality of switching devices through the channel for a target duration, controlling at least one of the plurality of switching devices to conduct through a freewheeling diode, to flow back the remaining energy stored in the energy storage inductor to the input power supply.
The circuit according to claim 1 or 2, characterized in that the energy recovery circuit specifically includes: a first switching device, a second switching device, a third switching device, a fourth switching device and an energy storage inductor; The first end of the first switching device and the first end of the second switching device are connected to the input power supply, and the third end of the first switching device is connected to the first end of the energy storage inductor. The third end of the second switching device is connected to the second end of the energy storage inductor. The second end of the energy storage inductor is also connected to the gate of the power tube. The first end of the third switching device The first end of the fourth switching device is connected to ground, the first end of the third switching device is connected to the first end of the energy storage inductor, and the first end of the fourth switching device is connected to the energy storage inductor. The second end of the inductor is connected.
The circuit according to claim 3, characterized in that the control circuit is used to control the second switching device and the third switching device to turn on, so that the input power supply supplies power to the first current direction along the first current direction. Charging the energy storage inductor; keeping the second switching device turned on and turning off the third switching device to turn on the power tube; when the gate-source voltage of the power tube is equal to the turn-on voltage of the power tube, turn off the second switch device and controls the first switching device to be turned on, and controls the fourth switching device to conduct for a target duration through the channel, so that the energy stored in the energy storage inductor flows back to the input power supply;

The control circuit is also used to control the first switching device and the fourth switching device to turn on, so as to control the input power supply to charge the energy storage inductor along the second current direction; keep the fourth switching device turned on. And turn off the first switching device to turn off the power tube; when the gate-source voltage of the power tube is equal to the ground potential, turn off the fourth switching device and control the second switching device to turn on, and control the third switching device to turn on. The three-switch device is turned on for a target duration through the channel, and the energy stored in the energy storage inductor flows back to the input power supply.
The circuit according to claim 3 or 4, characterized in that the third switching device includes a first freewheeling diode, and the anode of the first freewheeling diode is connected to the first end of the third switching device. , the cathode of the first freewheeling diode is connected to the third terminal of the third switching device; the fourth switching device includes a second freewheeling diode, and the anode of the second freewheeling diode is connected to the third terminal of the third switching device. The first terminals of the four switching devices are connected, and the cathode of the second freewheeling diode is connected to the third terminal of the fourth switching device;

The control circuit is also used to control the third switching device to turn off the third switching device through the channel for a target duration, so that the input power supply, the first switching device, and the energy storage device The inductor, the second freewheeling diode and the ground wire form a path; the control circuit is also used to control the input power supply, the second switching device after the fourth switching device conducts through the channel for a target length of time. , The energy storage inductor, the first freewheeling diode and the ground wire form a path.
The circuit according to any one of claims 3 to 5, characterized in that the duration determination circuit includes a first D flip-flop, a second D flip-flop, a third D flip-flop, a comparator, and a first AND gate circuit , the second AND gate circuit and inverter;

The clock input terminal of the first D flip-flop is connected to the second terminal of the second switching device through the inverter, and the second terminal of the first switching device is connected to the third terminal through the inverter. The second terminals of the two switching devices are connected, and the Q non-terminal of the first D flip-flop is connected to the second terminal of the fourth switching device;

The positive input terminal of the comparator is connected to the first terminal of the energy storage inductor, the negative input terminal of the comparator is connected to the second terminal of the energy storage inductor, and the output terminal of the comparator is connected to the first terminal of the energy storage inductor. The first input terminal of the first AND gate circuit is connected;

The clock input end of the second D flip-flop is connected to a gate-source voltage signal. The gate-source voltage signal is a high-level signal when the gate-source voltage of the power tube is equal to the turn-on voltage of the power tube. The source voltage signal is a low-level signal when the gate-source voltage of the power tube is equal to the ground voltage. The Q terminal of the second D flip-flop and the first input terminal of the first AND gate circuit and the third The first input terminal of the two AND gate circuits is connected, and the Q inverter terminal of the second D flip-flop is connected to the second terminal of the third switching device;

The clock input terminal of the third D flip-flop is connected to the output terminal of the first AND gate circuit, and the clock Q non-terminal of the third D flip-flop is connected to the second input terminal of the second AND gate circuit. , the second AND gate circuit is used to output the first control signal and the second control signal;

The control circuit is further configured to conduct the fourth switching device through the channel for a target duration according to the first control signal; and conduct the third switching device through the channel according to the second control signal. Pass target duration.
A switching power supply, characterized in that the switching power supply includes a power tube and a drive circuit as claimed in any one of claims 1 to 6, through which the circuit between the input power supply and the electrical equipment is connected or disconnected. Turn on to realize the function of switching power supply;

The drive circuit includes: a control circuit, an energy recovery circuit, a duration determination circuit and an input power supply. The energy recovery circuit includes: a plurality of switching devices and an energy storage inductor; the duration determination circuit is used to determine the target duration;

The energy recovery circuit is electrically connected to the input power supply, and under the control of the control circuit, is used for:

Charge the energy storage inductor along the first current direction according to the target duration;

Turn on the power tube;

Controlling at least one switching device among the plurality of switching devices to conduct for a target duration through a channel to flow back the energy stored in the energy storage inductor to the input power supply;

Charge the energy storage inductor along the second current direction according to the target duration;

Turn off the power tube;

At least one switching device among the plurality of switching devices is controlled to be turned on through a channel for a target duration to flow back energy stored in the energy storage inductor to the input power supply.
The switching power supply according to claim 7, characterized in that the energy recovery circuit, under the control of the control circuit, is also used to:

After turning on the power tube and conducting at least one of the plurality of switching devices through the channel for a target duration, controlling at least one of the plurality of switching devices to conduct through the freewheeling diode, To flow back the remaining energy stored in the energy storage inductor to the input power supply;

After turning off the power tube and conducting at least one of the plurality of switching devices through the channel for a target duration, controlling at least one of the plurality of switching devices to conduct through a freewheeling diode, to flow back the remaining energy stored in the energy storage inductor to the input power supply.
The switching power supply according to claim 7 or 8, characterized in that the energy recovery circuit specifically includes: a first switching device, a second switching device, a third switching device, a fourth switching device and an energy storage inductor; The first end of the first switching device and the first end of the second switching device are connected to the input power supply, and the third end of the first switching device is connected to the first end of the energy storage inductor, so The third end of the second switching device is connected to the second end of the energy storage inductor. The second end of the energy storage inductor is also connected to the gate of the power tube. The first end of the third switching device The first terminal of the fourth switching device is connected to the ground, the first terminal of the third switching device is connected to the first terminal of the energy storage inductor, and the first terminal of the fourth switching device is connected to the storage inductor. can be connected to the second end of the inductor.
The switching power supply according to claim 9, characterized in that the control circuit is used to control the second switching device and the third switching device to turn on, so that the input power supply supplies power to the switching device along the first current direction. The energy storage inductor is charged; keep the second switching device turned on and turn off the third switching device to turn on the power tube; when the gate-source voltage of the power tube is equal to the turn-on voltage of the power tube, turn off the second switching device and controlling the first switching device to turn on, and controlling the fourth switching device to conduct for a target duration through the channel, and return the energy stored in the energy storage inductor to the input power supply;

The control circuit is also used to control the first switching device and the fourth switching device to turn on, so as to control the input power supply to charge the energy storage inductor along the second current direction; close the first switch device to turn off the power tube; when the gate-source voltage of the power tube is equal to the ground potential, the second switching device is controlled to turn on, and the third switching device is controlled to conduct for a target duration through the channel, so that the The energy stored in the energy storage inductor flows back to the input power supply.
The switching power supply according to claim 9 or 10, characterized in that the third switching device includes a first freewheeling diode, and the anode of the first freewheeling diode is connected to the first terminal of the third switching device. connection, the cathode of the first freewheeling diode is connected to the third terminal of the third switching device; the fourth switching device includes a second freewheeling diode, and the anode of the second freewheeling diode is connected to the third terminal of the third switching device. The first end of the fourth switching device is connected, and the cathode of the second freewheeling diode is connected to the third end of the fourth switching device;

The control circuit is also used to control the third switching device to turn off the third switching device through the channel for a target duration, so that the input power supply, the first switching device, and the energy storage device The inductor, the second freewheeling diode and the ground wire form a path; the control circuit is also used to control the input power supply, the second switching device after the fourth switching device conducts through the channel for a target length of time. , the energy storage inductor, the first freewheeling diode and the ground wire form a path.
The switching power supply according to any one of claims 9-11, characterized in that the duration determination circuit includes a first D flip-flop, a second D flip-flop, a third D flip-flop, a comparator, a first AND gate circuit, second AND gate circuit, and inverter;

The clock input terminal of the first D flip-flop is connected to the second terminal of the second switching device through the inverter, and the second terminal of the first switching device is connected to the third terminal through the inverter. The second terminals of the two switching devices are connected, and the Q non-terminal of the first D flip-flop is connected to the second terminal of the fourth switching device;

The positive input terminal of the comparator is connected to the first terminal of the energy storage inductor, the negative input terminal of the comparator is connected to the second terminal of the energy storage inductor, and the output terminal of the comparator is connected to the first terminal of the energy storage inductor. The first input terminal of the first AND gate circuit is connected;

The clock input end of the second D flip-flop is connected to a gate-source voltage signal. The gate-source voltage signal is a high-level signal when the gate-source voltage of the power tube is equal to the turn-on voltage of the power tube. The source voltage signal is a low-level signal when the gate-source voltage of the power tube is equal to the ground voltage. The Q terminal of the second D flip-flop and the first input terminal of the first AND gate circuit and the third The first input end of the two AND gate circuits is connected, and the Q inverter end of the second D flip-flop is connected to the second end of the third switching device;

The clock input terminal of the third D flip-flop is connected to the output terminal of the first AND gate circuit, and the clock Q non-terminal of the third D flip-flop is connected to the second input terminal of the second AND gate circuit. , the second AND gate circuit is used to output the first control signal and the second control signal;

The control circuit is further configured to conduct the fourth switching device through the channel for a target duration according to the first control signal; and conduct the third switching device through the channel according to the second control signal. Pass target duration.