阅读说明：本技术 一种谐振驱动电路及其控制方法 (Resonance driving circuit and control method thereof ) 是由 牛宇杰 李广 朱春辉 于 2021-09-02 设计创作，主要内容包括：本发明提供了一种谐振驱动电路及其控制方法,其中谐振驱动电路主要由驱动信号生成及控制电路、驱动变压器和分压阻抗网络三部分组成；驱动变压器实现原副边隔离的同时,利用其原边励磁电感与副边负载的谐振,通过控制驱动变压器上电平的正负及导通时刻以达到减小功耗和简化电路结构的目的；且通过副边阻抗分压网络实现正负非对称双极性电压输出,从而适用于多种开关器件的驱动,扩大了驱动电路的适用范围；本发明的优点在于以尽量简单的电路结构实现了适用于多种功率开关器件的非对称双极性谐振驱动,并且具有较高的效率、抗扰性和稳定性。(The invention provides a resonance driving circuit and a control method thereof, wherein the resonance driving circuit mainly comprises a driving signal generating and controlling circuit, a driving transformer and a voltage-dividing impedance network; the driving transformer realizes the isolation of the primary side and the secondary side, and simultaneously achieves the purposes of reducing power consumption and simplifying a circuit structure by controlling the positive and negative of the level on the driving transformer and the conduction time by utilizing the resonance of the primary side excitation inductance and the secondary side load; the output of positive and negative asymmetric bipolar voltage is realized through a secondary impedance voltage-dividing network, so that the circuit is suitable for driving various switching devices, and the application range of a driving circuit is expanded; the invention has the advantages that the asymmetrical bipolar resonance driving suitable for various power switching devices is realized by using the circuit structure as simple as possible, and the asymmetrical bipolar resonance driving has higher efficiency, higher noise immunity and higher stability.)

1. A resonant drive circuit, comprising: sequentially carrying out a drive signal generation and control circuit, a drive transformer and a voltage division impedance network which are connected by a circuit;

the driving signal generating and controlling circuit is used for converting a control signal of the resonance driving circuit into a driving pulse signal and transmitting the driving pulse signal to the driving transformer;

the driving transformer is used for executing corresponding actions according to the input driving pulse signal, outputting a symmetrical bipolar driving signal to the voltage-dividing impedance network and providing a resonant inductor for the resonant driving circuit;

the voltage division impedance network is used for carrying out bias processing on the symmetrical bipolar driving signal to obtain a positive and negative asymmetrical bipolar driving signal and transmitting the positive and negative asymmetrical bipolar driving signal to a main switching tube, wherein the positive and negative asymmetrical bipolar driving signal is used for controlling the main switching tube to be switched on or switched off.

2. The resonant driving circuit according to claim 1, wherein the driving signal generating and controlling circuit comprises a driving power source, a level shifting circuit and a driving pulse generating circuit, the driving power source supplies power to the level shifting circuit and the driving pulse generating circuit simultaneously, and an output terminal of the level shifting circuit is connected to the driving pulse generating circuit.

3. The resonant driving circuit according to claim 2, wherein the level converting circuit is constructed by a driving chip or by an analog circuit.

4. The resonant driving circuit of claim 3, wherein the driving pulse generating circuit is a half-bridge circuit, and comprises a switching transistor PMOS, an NMOS, a first capacitor C1, and a second capacitor C2; the gates of the PMOS and the NMOS are connected to the output end of the level shift circuit, the source of the PMOS is connected to the positive electrode of the driving power supply, the drain of the PMOS is connected to the drain of the NMOS, the source of the NMOS is grounded, the first capacitor C1 is connected in parallel to the source and the drain of the PMOS, the second capacitor C2 is connected in parallel to the source and the drain of the NMOS, the drain of the PMOS and the drain of the NMOS are connected to one end of the primary winding of the driving transformer, and the first capacitor C1 and the second capacitor C2 are connected to the other end of the primary winding of the driving transformer.

5. The resonant drive circuit of claim 3, wherein the drive pulse generation circuit further comprises a full bridge circuit or other circuit topology.

6. The resonant drive circuit of claim 1, wherein the drive transformer comprises a primary winding and at least one secondary winding.

7. The resonant driving circuit of claim 6, wherein the driving transformer comprises a primary winding and two secondary windings, and the two secondary windings are in anti-phase, or the driving transformer comprises a primary winding and a plurality of in-phase or anti-phase secondary windings for driving the plurality of switching tubes.

8. The resonant driving circuit of claim 1, wherein the voltage-dividing impedance network comprises a third capacitor C3, a fourth capacitor C4, a first resistor R1, a second resistor R2, and a diode D, the first resistor R1 is connected in parallel with a third capacitor C3, the second resistor R2 is connected in parallel with the fourth capacitor C4, one end of the first resistor R1 connected in parallel with the third capacitor C3 is connected with one end of the secondary winding of the driving transformer, one end of the second resistor R2, which is connected in parallel with the fourth capacitor C4, is connected with the other end of the secondary winding of the driving transformer, the two parallel resistor-capacitor networks are not connected with the secondary winding end of the transformer and are connected through the diode D, wherein the anode of the diode D is connected with the parallel side of the first resistor R1 and the third capacitor C3, the cathode of the diode D is connected with the parallel side of the second resistor R2 and the fourth capacitor C4.

9. The resonant driving circuit of claim 8, wherein the diode D is a schottky diode or a fast recovery diode.

10. A control method of a resonance drive circuit is applied to the resonance drive circuit, and the resonance drive circuit comprises the following steps: sequentially carrying out a drive signal generation and control circuit, a drive transformer and a voltage division impedance network which are connected by a circuit; the control method comprises the following steps:

controlling the main switching tube to be switched off:

initial state: the gate level of the main switching tube is a positive driving level, and the main switching tube is in a switching-on state;

and (3) a turn-off process: t is t₀The input control signal is changed at any time, the drive power supply in the drive signal generation and control circuit is controlled to be disconnected with the drive transformer, and the gate level of the main switching tube resonates from the positive drive level to the negative peak valueTime (note time as time t)₁) The shutdown process is completed;

keeping turning off: t is t₁Changing an input control signal at any moment, controlling the voltage input into the driving transformer to be negative voltage, keeping the gate level of the main switching tube at a negative driving level, and keeping the main switching tube in a turn-off state;

controlling a main switching tube to be switched on:

initial state: the gate level of the main switching tube is a negative driving level, and the main switching tube is in a turn-off state;

the opening process: t is t₂Changing input control signal at any time, controlling the drive power supply in the drive signal generation and control circuit to be disconnected with the drive transformer, and making the gate level of the main switching tube resonate from the negative drive level to the positive peak value (at the time, time t is recorded)₃) The opening process is completed;

keeping on: t is t₃Changing an input control signal at any moment, controlling the level input into the driving transformer to be positive voltage, keeping the gate level of the main switching tube at a positive driving level, and keeping the main switching tube in a turn-on state;

and the switching speed of the main switching tube is controlled by controlling the size of the resonant inductor of the driving transformer.

Technical Field

The invention belongs to the technical field of switching power supplies, relates to a resonance driving circuit and a control method thereof, and particularly relates to an isolated asymmetric bipolar resonance driving circuit and a control method thereof.

Background

The current isolation type driving circuit of the commonly used switch tube (including a metal-oxide semiconductor field effect transistor (MOSFET) and an Insulated Gate Bipolar Transistor (IGBT)) adopts a scheme of a driving resistor, the driving loss of the isolation type driving circuit is rapidly increased along with the increase of the switching frequency, and the driving loss is large at high frequency.

With the development of power electronic technology, SiC devices have gradually become mainstream switching devices, which are generally applied to occasions with high switching frequency and have high requirements on driving circuits. The existing isolation type resonance driving scheme not only has complex primary side control, but also generally needs full-bridge or half-bridge topology and other topologies, and the low-power switching tubes still need complex driving circuits; in addition, the resonance scheme requires adding inductance in the circuit or adopting a scheme of transformer leakage inductance, the added inductance can increase the complexity and cost of the circuit, and the transformer leakage inductance is generally difficult to accurately design; finally, the existing method for generating the asymmetric bipolar voltage is complex, two power supplies or a complex secondary circuit design is needed, positive and negative asymmetric bipolar output is difficult to realize, and although some circuits can realize positive and negative asymmetric bipolar output, no clamping circuit exists, and the device cannot be guaranteed to work at the optimal working point.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the invention provides a resonance driving circuit and a control method thereof, and aims to solve the problems that a switching tube (especially a SiC-MOSFET) driving circuit in the prior art is large in loss at high frequency, difficult to realize asymmetric bipolar driving, and complex in structure and control.

In order to solve the technical problems, the invention adopts the technical scheme that:

a first aspect of the present invention provides a resonant drive circuit, comprising: sequentially carrying out a drive signal generation and control circuit, a drive transformer and a voltage division impedance network which are connected by a circuit;

the driving signal generating and controlling circuit is used for converting a control signal of the resonance driving circuit into a driving pulse signal and transmitting the driving pulse signal to the driving transformer;

the driving transformer is used for executing corresponding actions according to an input driving pulse signal, outputting a symmetrical bipolar driving signal to the voltage-dividing impedance network and providing a resonant inductor for the resonant driving circuit;

the voltage division impedance network is used for carrying out bias processing on the symmetrical bipolar driving signal output by the driving transformer to obtain a positive and negative asymmetrical bipolar driving signal and outputting the positive and negative asymmetrical bipolar driving signal to the main switching tube, wherein the positive and negative asymmetrical bipolar driving signal is used for controlling the main switching tube to be switched on or switched off.

A second aspect of the present invention provides a method for controlling a resonant driving circuit, which is applied to a resonant driving circuit, the resonant driving circuit including: sequentially carrying out a drive signal generation and control circuit, a drive transformer and a voltage division impedance network which are connected by a circuit; the control method comprises the following steps:

controlling the main switching tube to be switched off:

initial state: the gate level of the main switching tube is a positive driving level, and the main switching tube is in a switching-on state;

and (3) a turn-off process: t is t₀Changing input control signal at any moment, controlling the drive power supply in the drive signal generation and control circuit to be disconnected with the drive transformer, and making the gate level of the main switching tube resonate from positive drive level to negative peak value (at the moment, the moment is denoted as time t)₁) The shutdown process is completed;

keeping turning off: t is t₁And changing the input control signal at any time, controlling the level input into the driving transformer to be negative voltage, keeping the gate level of the main switching tube at a negative driving level, and keeping the main switching tube in a turn-off state.

Controlling a main switching tube to be switched on:

initial state: the gate level of the main switching tube is a negative driving level, and the main switching tube is in a turn-off state;

the opening process: t is t₂Constantly changing input control signals, controlling the drive power supply in the drive signal generation and control circuit to be disconnected with the drive transformer, and enabling the gate level of the main switching tube to resonate from a negative drive level to a positive drive levelPeak time (time t)₃) The opening process is completed;

keeping on: t is t₃Changing an input control signal at any moment, controlling the level input into the driving transformer to be positive voltage, keeping the gate level of the main switching tube at a positive driving level, and keeping the main switching tube in a turn-on state;

and the switching speed of the main switching tube is controlled by controlling the size of the resonant inductor of the driving transformer.

Compared with the prior art, the invention has the beneficial effects that:

1. the primary side and the secondary side of the driving transformer are isolated, and the primary side excitation inductance and the secondary side load of the transformer are resonated, so that the purpose of reducing the power consumption of the driving circuit is achieved, additional resonant inductance is not needed, and the design and the circuit structure are simplified while the driving loss is reduced.

2. The secondary impedance network realizes the output of positive and negative asymmetric bipolar voltage, and the size of the positive and negative voltage values can be adjusted by adjusting the parameters of the impedance network, so that the secondary impedance network is suitable for the driving of various switching devices, and the application range of the driving circuit is expanded.

3. The input driving transformer is controlled to be conducted to drive a pulse signal, so that the inductance of the driving transformer and the secondary load resonate in the switching process of the switching tube, the power consumption of a circuit is reduced, and after the switching tube completes switching action, the gate voltage of the switching tube is clamped, and the device is ensured to work at the optimal working point.

Drawings

The detailed structure of the invention is described in detail below with reference to the accompanying drawings

FIG. 1 is a block diagram of the circuit architecture of the present invention;

FIG. 2 is a schematic diagram of a circuit topology according to an embodiment of the present invention;

FIG. 3 is a logic timing diagram of a key signal in the circuit of FIG. 2;

FIG. 4 is a schematic circuit topology according to another embodiment of the present invention;

FIG. 5 is a circuit topology diagram according to another embodiment of the present invention;

FIG. 6 is a circuit topology diagram according to another embodiment of the present invention;

FIG. 7 is a flow chart of a control method according to the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

The invention provides a resonance driving circuit for driving the on and off of a main switch tube, wherein the main switch tube to be driven can be an IGBT (insulated gate bipolar transistor), an MOSFET (metal-oxide semiconductor field effect transistor) and comprises Si base, SiC, GaN and the like.

As shown in the circuit composition architecture diagram of fig. 1, the present invention provides a resonant driving circuit mainly composed of three parts, including: the driving circuit comprises a driving signal generating and controlling circuit 10, a driving transformer 20 and a voltage-dividing impedance network 30, wherein the driving signal generating and controlling circuit 10 is arranged on the primary side of the driving transformer 20; the voltage dividing impedance network 30 is disposed on the secondary side of the driving transformer 20, wherein:

the primary side driving signal generating and controlling circuit 10 generates a driving pulse signal, which is mainly used for converting a control signal of the resonance driving circuit into a driving pulse signal and transmitting the driving pulse signal to the driving transformer 20; the driving transformer 20 is configured to act according to an input driving pulse signal, output a symmetric bipolar driving signal to the voltage-dividing impedance network, and provide a resonant inductor for the resonant driving circuit; the voltage dividing impedance network 30 is used for performing bias processing on the symmetric bipolar driving signal output by the driving transformer 20 to obtain a positive and negative asymmetric bipolar driving signal and transmitting the positive and negative asymmetric bipolar driving signal to the main switching tube.

Specifically, the driving signal generating and controlling circuit 10 includes a driving power source 101, a level converting circuit 102 and a driving pulse generating circuit 103, where the level converting circuit 102 may be directly composed of a dual-channel driving chip, such as a chip PM8834 and peripheral circuits thereof, or may be implemented by building an analog circuit or other level converting circuits, such as building a push-pull circuit by using a power tube. The level shift circuit 102 and the driving power supply of the main switching tube use the same power supply VCC, and isolation is not needed, and VCC generally selects a voltage lower than 20V, and simultaneously can directly use the power supply to drive the primary side driving pulse generation circuit 103.

The driving pulse generating circuit 103 can be composed of a half-bridge circuit, a full-bridge circuit or other deformed topologies, the output end of the level conversion circuit 102 is connected to the driving pulse generating circuit 103, when the main switching tube needs to be switched, the driving pulse generating circuit 103 controls the input of the driving transformer 20 to be zero, and at the moment, the primary side excitation inductance and the secondary side load of the transformer resonate to recycle energy; after the resonance reaches the design value, the primary side clamps the input of the driving transformer 20 at the power supply voltage, and at the moment, the output voltage is also clamped, so that the output voltage is ensured to be stabilized at the optimal working point of the device, and the interference resistance and the stability of the circuit are improved.

The driving transformer 20 can be a transformer manufactured by a traditional magnetic core and coil mode, preferably, the magnetic core is an EE-type magnetic core, and can also be a planar transformer, the transformer T can also be designed with a primary winding and a secondary winding to control the switch of a main switching tube or can be designed with a plurality of secondary windings to control the switches of a plurality of main switching tubes simultaneously, and simultaneously, the purpose of reducing the power consumption of the driving circuit is achieved by utilizing the scheme that the primary side excitation inductance of the transformer and the secondary side load (mainly gate capacitance of the main switching tube) resonate, no additional resonant inductance is needed to be added, the design of the primary side circuit and the secondary side circuit is simplified, the whole circuit can be ensured to output voltages with asymmetric positive and negative polarities and double polarities, and the driving circuit has the simplest structure.

The voltage-dividing impedance network 30 adjusts the voltage value of each point of the impedance network when each point is stable by designing different charging and discharging loops, so that the voltage with symmetrical positive and negative is shifted to adapt to the application of positive and negative asymmetrical bipolar driving occasions.

Example 1

Referring to fig. 2, fig. 2 is a circuit topology diagram of the resonant driving circuit according to the present invention.

In the present embodiment, the driving signal generating and controlling circuit 10 includes a driving power VCC, a level shift circuit 102, and a driving pulse generating circuit 103, and the level shift circuit 102 is directly formed by a two-way driving chip and its peripheral circuits. The driving pulse generating circuit 103 adopts a low-power PMOS plus a low-power NMOS, and combines a first capacitor C1 and a second capacitor C2 to form a half-bridge circuit, wherein the gates of the PMOS and the NMOS are connected to the output terminal of the level shift circuit, the source of the PMOS is connected to the positive electrode of the driving power supply, the drain of the PMOS is connected to the drain of the NMOS, the source of the NMOS is grounded, the first capacitor C1 is connected in parallel to the source and the drain of the PMOS, the second capacitor C2 is connected in parallel to the source and the drain of the NMOS, the drain of the PMOS and the drain of the NMOS are connected to one end of the primary winding of the driving transformer, the first capacitor C1 and the second capacitor C2 are connected to the other end of the primary winding of the driving transformer, and the first capacitor C1 and the second capacitor C2 have the same capacitance value. The circuit structure enables all signals on the primary side to be grounded (including control signals, a level conversion circuit and a low-power MOS tube driving circuit), a complex isolation or bootstrap circuit is not needed, the circuit structure is simplified, and it is to be noted that a switching tube in a half-bridge circuit can also be composed of other devices (such as a triode) or two MOS tubes of the same type.

The driving transformer 20 comprises a primary side and a secondary side, and one secondary side is connected with a voltage dividing impedance network 30 for controlling the switching of a main switching tube 40.

The voltage divider impedance network 30 is composed of a third capacitor C3, a fourth capacitor C4, a first resistor R1, a second resistor R2, and a diode D, preferably a schottky diode or a fast recovery diode, wherein the first resistor R1 is connected in parallel with the third capacitor C3, the second resistor R2 is connected in parallel with the fourth capacitor C4, one end of the first resistor R1, which is connected in parallel with the third capacitor C3, is connected with one end of the secondary winding of the driving transformer (the end is defined as the positive end of the input of the voltage-dividing impedance network), one end of the second resistor R2, which is connected in parallel with the fourth capacitor C4, is connected with the other end of the secondary winding of the driving transformer (the end is defined as the negative end of the input of the voltage-dividing impedance network), the two parallel resistor-capacitor networks are not connected with the secondary winding end of the driving transformer through the diode D, the anode of the diode D is connected with the side, connected in parallel, of the first resistor R1 and the third capacitor C3, and the cathode of the diode D is connected with the side, connected in parallel, of the second resistor R2 and the fourth capacitor C4; the voltage value of each point of the impedance network is adjusted when the points are stable by designing different charging and discharging loops, so that the positive and negative symmetrical voltage is shifted to realize the positive and negative asymmetrical bipolar voltage output, and the circuit is suitable for driving various switching devices and expanding the application range of a driving circuit.

The basic principle of the circuit is as follows:

the control signal 1 and the control signal 2 can be obtained from any digital control chip or analog signal, and are converted into signals capable of directly driving a low-power MOS through the level conversion circuit 102, and the level conversion circuit 102 realizes a level conversion function and converts the control signals into driving signals with large driving capability. The on-off of the primary side small-power PMOS and the primary side small-power NMOS can be controlled by controlling the duty ratio and the phase relationship of the control signal 1 and the control signal 2, so as to control the primary side voltage waveform of the driving transformer 20, and a typical waveform is shown in fig. 3.

When the circuit works in a steady state, the voltage at two ends of the second capacitor C2 should be VCC/2, the primary side small power PMOS and the primary side small power NMOS are conducted complementarily, and a dead zone with a certain time needs to be added, so that two switching tubes are prevented from being conducted simultaneously, and the dead zone time needs to be designed according to the resonance parameters of the circuit. When the primary side small-power PMOS is switched on and the primary side small-power NMOS is switched off, the voltage at two ends of the primary side of the driving transformer 20 is clamped at VCC/2; when the primary side low-power NMOS is switched on and the primary side low-power PMOS is switched off, the voltage at the two ends of the primary side of the driving transformer 20 is clamped at-VCC/2; when the primary side low-power NMOS and the primary side low-power PMOS are both turned off, the primary side excitation inductor of the transformer and the secondary side load generate resonance, so that the period of time needs to be designed according to the resonance parameters of an actual circuit, and the gate driving voltage of the main switching tube is ensured to be resonant to a required value when the dead time is over, thereby achieving the purpose of reducing the driving loss.

In addition, the primary and secondary turn ratio of the driving transformer 20 needs to be determined according to the driving voltage and the driving power supply required by the main switching tube, for example, the driving power supply is 18V, the driving voltage required by the main switching tube is +15V (on)/-3V (off), and then the turn ratio of the transformer can be designed to be 1: in addition, because the primary side excitation inductance of the transformer directly participates in resonance, the resonance frequency and the peak value are determined, and therefore in actual design, the proper excitation inductance is selected according to the gate capacitance of an actual switching tube. The secondary side of the driving transformer is provided with different current loops when the voltage of the secondary side winding is positive and the voltage of the secondary side winding is negative through the diode D, so that the purpose of different positive and negative output voltages in a steady state is achieved, parameters of an impedance network need to be designed in the actual design process, the magnitude of the positive and negative values of the output voltage is adjusted, and finally a third resistor R3 is arranged between the voltage-dividing impedance network and the main switching tube to provide a discharging loop for a gate electrode capacitor of the main switching tube.

Example 2

Referring to fig. 4, fig. 4 is a schematic diagram of a resonant driving pulse circuit according to another embodiment of the present invention, and the circuit topology provided in this embodiment is different from that of embodiment 1 in terms of circuit structure: the driving pulse generating circuit 103 adopts a full-bridge circuit, and the control signal is converted into a driving signal through the level converting circuit 102 to control the on-off of a triode or an MOS (metal oxide semiconductor) transistor in the full-bridge circuit, so as to control the voltage waveform of the primary side of the driving transformer 20. Other structures and connections such as the driving transformer 20, the voltage-dividing impedance network 30 and the main switching tube 40 are not different from the scheme in embodiment 1, and are not described herein again; it should be understood that the circuit topology structure diagram provided in this embodiment is an alternative to the implementation of the driving pulse generating circuit in embodiment 1, and the effects of the circuit topology structure diagram can also achieve the effects of embodiment 1.

Example 3

Referring to fig. 5, fig. 5 is a schematic diagram of another embodiment of the resonant driving pulse circuit of the present invention, and the circuit topology provided in this embodiment is different from that of embodiment 1 in terms of circuit structure: in this embodiment, the driving transformer 20 has a primary winding and two secondary windings, and correspondingly, the two secondary windings are respectively connected to two voltage-dividing impedance networks 301 and 302 to simultaneously control the two main switching tubes 401 and 402, wherein the two secondary windings are distinguished in that the dotted end of one secondary winding is connected to the positive end of the input of the voltage-dividing impedance network 301, and the dotted end of the other secondary winding is connected to the negative end of the input of the voltage-dividing impedance network 302, that is, the two secondary windings are in opposite phases. A plurality of in-phase or anti-phase secondary windings can be designed to control a plurality of main switching tubes, and the structure and connection of other circuits such as the driving signal generation and control circuit are not different from those in embodiment 1, and are not described herein again.

Example 4

Referring to fig. 6, fig. 6 is a schematic diagram of another embodiment of the resonant driving pulse circuit of the present invention, and the circuit topology provided in this embodiment is different from that of embodiment 1 in terms of circuit structure: if the main switch tube 40 does not need a driving signal (e.g. Si-based MOSFET or IGBT) with asymmetric positive and negative polarities, the voltage divider impedance network 30 can be omitted, so as to output a driving signal with symmetric positive and negative polarities, thereby further reducing the complexity and cost of the circuit. The rest of the circuit structures and the control method are not different from those in embodiment 1, and are not described herein again.

The second aspect of the present invention provides a method for controlling a resonant driving circuit, which is applied to the above-mentioned driving signal generating and controlling circuit, driving transformer and voltage-dividing impedance network, which are sequentially connected by a circuit; as shown in the control flowchart of fig. 7, the control method includes:

controlling the main switching tube to be switched off:

initial state: the initial moment control signal controls the voltage output by the driving signal generating and controlling circuit to the primary side of the driving transformer to be positive voltage, the gate level of the main switching tube is kept at a positive driving level, and the main switching tube is kept in a turn-on state;

and (3) a turn-off process: t is t₀The input control signal is changed at any time, and the input control signal is characterized in that the input control signal can control the generation of the drive signal and the disconnection of a drive power supply and a drive transformer in a control circuit, the resonant inductance of the transformer and the rear-end load freely resonate in the process, and the gate level of a main switching tube resonates from a positive drive level to a negative drive level; when the level of the main switching tube gate resonates to the negative peak (note this moment as t)₁Moment), the turn-off process is completed;

keeping turning off: t is t₂The input control signal is changed at any time, and the control circuit can control the generation of the drive signal and the output of the control circuit to the primary side of the drive transformerThe voltage is negative voltage, the gate level of the main switching tube is kept at a negative driving level in the process, and the main switching tube is kept in a turn-off state.

Controlling a main switching tube to be switched on:

initial state: the initial time control signal controls the voltage output by the driving signal generating and controlling circuit to the primary side of the driving transformer to be negative voltage, the gate level of the main switching tube is kept at a negative driving level, and the main switching tube is kept in a turn-off state;

the opening process: t is t₂The input control signal is changed at any time, and the input control signal is characterized in that the input control signal can control the generation of the drive signal and the disconnection of a drive power supply and a drive transformer in a control circuit, the resonant inductance of the transformer and the rear-end load freely resonate in the process, and the gate level of a main switching tube resonates from a negative drive level to a positive drive level; when the main switching tube gate level resonates to the positive peak (note this moment as t)₃Moment), the opening process is completed;

keeping on: t is t₃The input control signal is changed at any time, and the control circuit is characterized in that the voltage output to the primary side of the driving transformer by the control signal generation and control circuit can be controlled to be positive voltage, the gate level of the main switching tube is kept at a positive driving level in the process, and the main switching tube is kept in an on state.

The switching speed of the main switching tube is controlled by controlling the size of the resonant inductor of the driving transformer, and the smaller the resonant inductor is, the shorter the resonant period is, and the faster the switching speed is. The time required by the switching-on and switching-off processes can be obtained by calculating parameters such as a resonant inductor of the driving transformer, a gate electrode capacitor of the main switching tube and the like, but the actual calculation is complex, and the time required by the switching-on and switching-off processes can be obtained by an offline test mode in engineering so as to determine the phase of an input control signal.

In summary, the resonant driving circuit and the control method thereof provided by the invention utilize the driving transformer to realize the isolation of the primary side and the secondary side, and utilize the resonance of the primary side excitation inductor and the secondary side load to achieve the purposes of reducing the power consumption and simplifying the circuit structure; when the switching tube needs to be switched on and switched off, the primary side driving pulse generating circuit controls the driving transformer to be disconnected with a driving power supply in the driving signal generating and controlling circuit, and at the moment, the primary side excitation inductor and the secondary side load of the transformer resonate to recycle energy; after the resonance reaches a design value, the primary side clamps the input of the driving transformer at the power supply voltage, and the output voltage is clamped at the moment, so that the output voltage is ensured to be stabilized at the optimal working point of the device; the noise immunity and the stability of the circuit are improved; meanwhile, the primary side generates the driving pulse by using the control and level conversion circuit and the driving pulse generating circuit, the primary side circuit can be greatly simplified by design, and a complex bootstrap circuit or an isolation circuit is not needed. And finally, the secondary side realizes the output of positive and negative asymmetric bipolar voltage through an impedance voltage division network, thereby being suitable for the driving of various switching devices and expanding the application range of a driving circuit.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.