阅读说明：本技术 一种基于自举方式的igbt单电源驱动电路 (IGBT single power supply driving circuit based on bootstrap mode ) 是由 季金虎 赵晓宇 胡永峰 于 2019-09-30 设计创作，主要内容包括：本发明涉及一种基于自举方式的IGBT单电源驱动电路,属于电子电路技术领域,解决密勒效应引起的误导通的问题；电路包括将输入的PWM信号进行驱动放大输出PWM驱动信号的驱动芯片N1,提供自举浮动电源的自举电路,和用于将PWM驱动信号输出到开关电路,控制开关管开通或关断的全桥驱动电路,全桥驱动电路在开关管出现密勒效应时,将开关管的驱动电压箝位到零电压,防止开关管误导通。本发明电路形式新颖,结构简单,成本低,可以满足一般开关管单电源驱动的需求,可以运用到各类电力电子设备中。(The invention relates to an IGBT single power supply driving circuit based on a bootstrap mode, which belongs to the technical field of electronic circuits and solves the problem of misconduction caused by the Miller effect; the circuit includes that the PWM signal that will input drives drive chip N1 of enlargiing output PWM drive signal, provides the bootstrap circuit of bootstrap floating power supply and is used for exporting the PWM drive signal to switch circuit, the full-bridge drive circuit that the control switch tube opened or shut off, and when the miller effect appears in the switch tube, the full-bridge drive circuit clamps the drive voltage of switch tube to zero voltage, prevents that the switch tube from switching on by mistake. The circuit of the invention has novel form, simple structure and low cost, can meet the requirement of single power supply driving of a common switch tube, and can be applied to various power electronic equipment.)

1. A bootstrap mode-based IGBT single power supply driving circuit is characterized by comprising a driving chip N1, a full-bridge driving circuit, a switching circuit and a bootstrap suspension circuit;

the driving chip N1 adopts a single power supply to supply power, and drives and amplifies the input PWM signal to output a PWM driving signal;

the full-bridge driving circuit is connected between the driving signal output end of the driving chip N1 and the control end of the switching circuit and is used for outputting a PWM driving signal to the switching circuit and controlling the switching-on or switching-off of the switching tube; independently setting the turn-on time and the turn-off time of the switching tube, and clamping the driving voltage of the switching tube to zero voltage when the Miller effect occurs to the switching tube to prevent the switching tube from being conducted by mistake;

the bootstrap suspension circuit is electrically connected with the driving chip N1 and is used for providing a bootstrap floating power supply, so that the driving chip N1 realizes isolated driving of the full-bridge driving circuit under the condition of single power supply.

2. The IGBT single power supply driving circuit according to claim 1, wherein the bootstrap suspension circuit comprises a resistor R1, a diode V1 and a capacitor C1;

one end of the resistor R1 is connected with a power supply, and the other end of the resistor R1 is connected with the anode of the diode V1; the cathode of the diode V1 is respectively connected with one end of the capacitor C1 and a pin VB of the driving chip N1; the other end of the capacitor C1 is connected to a pin VS of the driver chip N1.

3. The IGBT single power supply driving circuit according to claim 1 or 2, characterized in that the full bridge driving circuit comprises an upper bridge arm driving circuit and a lower bridge arm driving circuit; the switching circuit comprises an upper bridge arm switching tube V5 and a lower bridge arm switching tube V9;

the upper bridge arm driving circuit connects a pin VS of the driving chip N1 with an emitting electrode of an upper bridge arm switch tube V5; the driving input end of the upper bridge arm driving circuit is connected with a pin HO of a driving chip N1, and the driving output end of the upper bridge arm driving circuit is connected with a gate pole of an upper bridge arm switching tube V5;

the driving input end of the lower bridge arm driving circuit is connected with a pin LO of a driving chip N1; the driving output end is connected with a gate pole of a lower bridge arm switching tube V9;

the collector electrode of the upper bridge arm switching tube V5 is connected with a high-voltage direct-current power supply; the emitting electrode of the upper bridge arm switch tube V5 is connected with the collector electrode of the lower bridge arm switch tube V9; the emitter of the lower bridge arm switching tube V9 is connected with the ground.

4. The IGBT single power supply driving circuit as claimed in claim 3, wherein the upper bridge arm driving circuit comprises a switching tube turn-on circuit for outputting a driving high level output by a pin HO of a driving chip N1 to a gate of an upper bridge arm switching tube V5, and turning on the upper bridge arm switching tube V5 at a set turn-on time;

the switching tube opening circuit comprises a resistor R3 and a diode V2, one end of the resistor R3 is connected with a pin HO of a driving chip N1, the other end of the resistor R3 is connected with the anode of a diode V2, and the cathode of the diode V2 is connected with the gate of an upper bridge arm switching tube V5; by setting the resistance value of resistor R3, the on time of upper arm switching tube V5 is set.

5. The IGBT single power supply driving circuit as claimed in claim 3, wherein the upper bridge arm driving circuit comprises a switching tube turn-off circuit for outputting a low level output from pin HO of the driving chip N1 to the gate of the upper bridge arm switching tube V5, and turning off the upper bridge arm switching tube V5 at a set turn-off time;

the switching tube turn-on circuit comprises a resistor R2 and a diode V3, one end of the resistor R2 is connected with a gate of the upper bridge arm switching tube V5, the other end of the resistor R2 is connected with an anode of the diode V3, a cathode of the diode V3 is connected with a pin HO of the N1 of the driving chip, and the turn-off time of the upper bridge arm switching tube V5 is set by setting the resistance value of the resistor R2.

6. The IGBT single-power-supply driving circuit as claimed in claim 3, wherein the upper bridge arm driving circuit comprises a Miller effect compensation circuit for clamping the driving voltage of the switching tube V5 to zero voltage to prevent the switching tube from being conducted by mistake when the Miller effect occurs in the upper bridge arm switching tube V5;

the Miller effect compensation circuit comprises a diode V2, a resistor R4 and a triode V4; the triode V4 is a PNP type triode, and an emitting electrode of the triode V4 is respectively connected with a cathode of the diode V2 and a gate electrode of the upper bridge arm switching tube V5; the collector of the triode V4 is connected with the emitter of the upper bridge arm switch tube V5; the gate of the transistor V4 is connected to one end of a resistor R4, and the other end of the resistor R4 is connected to the anode of a diode V2.

7. The IGBT single-power-supply driving circuit as claimed in claim 3, wherein the upper bridge arm driving circuit further comprises a TVS tube V6, the cathode of the TVS tube V6 is connected with the gate of the upper bridge arm switching tube V5, and the anode of the TVS tube V6 is connected with the emitter of the upper bridge arm switching tube V5 for absorbing the pulse interference signal on the driving signal of the switching tube V5.

8. The IGBT single-power-supply driving circuit as claimed in claim 3, wherein the upper bridge arm driving circuit further comprises a resistor R5, one end of the resistor R5 is connected with the gate electrode of the upper bridge arm switching tube V5, and the other end of the resistor R5 is connected with the emitter electrode of the upper bridge arm switching tube V5, and is used for discharging the parasitic capacitance of the gate electrode and the emitter electrode of the switching tube V5.

9. The IGBT single power supply driving circuit as claimed in any one of claims 3-8, wherein the lower bridge arm driving circuit is the same in principle as the upper bridge arm driving circuit, and comprises a switching tube on circuit, a switching tube off circuit, a Miller effect compensation circuit, and a pulse interference signal absorbing TVS tube V11 and a parasitic capacitance discharge resistor R9 which are connected between the gate electrode and the emitter electrode of the lower bridge arm switching tube V9;

the switching tube switching-on circuit comprises a resistor R7 and a diode V7, one end of the resistor R7 is connected with a pin LO of a driving chip N1, the other end of the resistor R7 is connected with an anode of a diode V7, and a cathode of a diode V7 is connected with a gate of a lower bridge arm switching tube V9;

the switching tube switching-on circuit comprises a resistor R6 and a diode V8, one end of the resistor R6 is connected with a gate pole of the upper bridge arm switching tube V8, the other end of the resistor R6 is connected with an anode of a diode V8, and a cathode of a diode V8 is connected with a pin LO of the driving chip N1;

the Miller effect compensation circuit comprises a diode V7, a resistor R8 and a triode V10; the triode V10 is a PNP type triode, and an emitting electrode of the triode V10 is respectively connected with a cathode of the diode V7 and a gate electrode of the lower bridge arm switching tube V9; the collector of the triode V10 is connected with the emitter of the lower bridge arm switch tube V9; the gate of the transistor V10 is connected to one end of a resistor R8, and the other end of the resistor R8 is connected to the anode of a diode V7.

10. The IGBT single-power-supply driving circuit according to claim 9, wherein the power parameter P of the resistors R2, R3, R6 and R7 satisfies the formula P ═ fQ Δ U; in the formula, f is a switching frequency, Q is a gate electric charge of the switching tube, and Δ U is a driving voltage.

Technical Field

The invention relates to the technical field of electronic circuits, in particular to an IGBT single power supply driving circuit based on a bootstrap mode.

Background

At present, in a conventional driving circuit of a switching tube such as an IGBT (insulated gate bipolar transistor), a PWM (pulse width modulation) signal is converted into a level suitable for driving the switching tube through a driving chip, and a driving signal is provided to an upper tube and a lower tube of the same bridge arm through a driving resistor.

The traditional drive circuit can meet the requirements of most occasions. But the disadvantages are: if the output of the switching tube runs under an inductive load, the switching tube in the off state bears higher dv/dt due to the recovery process of the anti-parallel diode, and due to the miller effect, the parasitic capacitance of the collector and the gate of the switching tube discharges to the driving circuit, which may exceed the switching-on threshold voltage of the switching tube to cause misconduction, thereby burning the switching tube.

Disclosure of Invention

In view of the above analysis, the present invention is directed to providing a bootstrap IGBT single-power-supply driving circuit, which solves the problem of mis-conduction due to the miller effect.

The purpose of the invention is mainly realized by the following technical scheme:

the invention discloses an IGBT single power supply driving circuit based on a bootstrap mode, which comprises a driving chip N1, a full-bridge driving circuit, a switching circuit and a bootstrap suspension circuit;

the driving chip N1 adopts a single power supply to supply power, and drives and amplifies the input PWM signal to output a PWM driving signal;

the full-bridge driving circuit is connected between the driving signal output end of the driving chip N1 and the control end of the switching circuit and is used for outputting a PWM driving signal to the switching circuit and controlling the switching-on or switching-off of the switching tube; independently setting the turn-on time and the turn-off time of the switching tube, and clamping the driving voltage of the switching tube to zero voltage when the Miller effect occurs to the switching tube to prevent the switching tube from being conducted by mistake;

the bootstrap suspension circuit is electrically connected with the driving chip N1 and is used for providing a bootstrap floating power supply, so that the driving chip N1 realizes isolated driving of the full-bridge driving circuit under the condition of single power supply.

Further, the bootstrap suspension circuit comprises a resistor R1, a diode V1 and a capacitor C1;

one end of the resistor R1 is connected with a power supply, and the other end of the resistor R1 is connected with the anode of the diode V1; the cathode of the diode V1 is respectively connected with one end of the capacitor C1 and a pin VB of the driving chip N1; the other end of the capacitor C1 is connected to a pin VS of the driver chip N1.

Further, the full-bridge driving circuit comprises an upper bridge arm driving circuit and a lower bridge arm driving circuit; the switching circuit comprises an upper bridge arm switching tube V5 and a lower bridge arm switching tube V9;

the upper bridge arm driving circuit connects a pin VS of the driving chip N1 with an emitting electrode of an upper bridge arm switch tube V5; the driving input end of the upper bridge arm driving circuit is connected with a pin HO of a driving chip N1, and the driving output end of the upper bridge arm driving circuit is connected with a gate pole of an upper bridge arm switching tube V5;

the driving input end of the lower bridge arm driving circuit is connected with a pin LO of a driving chip N1; the driving output end is connected with a gate pole of a lower bridge arm switching tube V9;

the collector electrode of the upper bridge arm switching tube V5 is connected with a high-voltage direct-current power supply; the emitting electrode of the upper bridge arm switch tube V5 is connected with the collector electrode of the lower bridge arm switch tube V9; the emitter of the lower bridge arm switching tube V9 is connected with the ground.

Further, the upper bridge arm driving circuit comprises a switching tube turn-on circuit, and is used for outputting a driving high level output by a pin HO of a driving chip N1 to a gate of an upper bridge arm switching tube V5, and enabling the upper bridge arm switching tube V5 to be conducted at a set turn-on time;

the switching tube opening circuit comprises a resistor R3 and a diode V2, one end of the resistor R3 is connected with a pin HO of a driving chip N1, the other end of the resistor R3 is connected with the anode of a diode V2, and the cathode of the diode V2 is connected with the gate of an upper bridge arm switching tube V5; by setting the resistance value of resistor R3, the on time of upper arm switching tube V5 is set.

Further, the upper bridge arm driving circuit comprises a switching tube turn-off circuit, and the switching tube turn-off circuit is used for outputting the low level output by the pin HO of the driving chip N1 to the gate of the upper bridge arm switching tube V5, and turning off the upper bridge arm switching tube V5 at the set turn-off time;

the switching tube turn-on circuit comprises a resistor R2 and a diode V3, one end of the resistor R2 is connected with a gate of the upper bridge arm switching tube V5, the other end of the resistor R2 is connected with an anode of the diode V3, a cathode of the diode V3 is connected with a pin HO of the N1 of the driving chip, and the turn-off time of the upper bridge arm switching tube V5 is set by setting the resistance value of the resistor R2.

Further, the upper bridge arm driving circuit comprises a miller effect compensation circuit, and is used for clamping the driving voltage of the switching tube V5 to zero voltage when the miller effect occurs in the upper bridge arm switching tube V5, so as to prevent the switching tube from being conducted by mistake;

the Miller effect compensation circuit comprises a diode V2, a resistor R4 and a triode V4; the triode V4 is a PNP type triode, and an emitting electrode of the triode V4 is respectively connected with a cathode of the diode V2 and a gate electrode of the upper bridge arm switching tube V5; the collector of the triode V4 is connected with the emitter of the upper bridge arm switch tube V5; the gate of the transistor V4 is connected to one end of a resistor R4, and the other end of the resistor R4 is connected to the anode of a diode V2.

Further, the upper bridge arm driving circuit further comprises a TVS tube V6, a cathode of the TVS tube V6 is connected to a gate of the upper bridge arm switching tube V5, and an anode of the TVS tube V6 is connected to an emitter of the upper bridge arm switching tube V5, and is configured to absorb a pulse interference signal on a driving signal of the switching tube V5.

Further, the upper bridge arm driving circuit further comprises a resistor R5, one end of the resistor R5 is connected with the gate of the upper bridge arm switching tube V5, and the other end of the resistor R5 is connected with the emitter of the upper bridge arm switching tube V5, and is used for discharging parasitic capacitances of the gate and the emitter of the switching tube V5.

The circuit is characterized in that the lower bridge arm driving circuit and the upper bridge arm driving circuit have the same principle, and comprise a switching tube on circuit, a switching tube off circuit, a miller effect compensation circuit, and a pulse interference signal absorption TVS tube V11 and a parasitic capacitance discharging resistor R9, wherein the pulse interference signal absorption TVS tube V3578 is connected between a gate pole and an emitter of the lower bridge arm switching tube V9;

the switching tube switching-on circuit comprises a resistor R7 and a diode V7, one end of the resistor R7 is connected with a pin LO of a driving chip N1, the other end of the resistor R7 is connected with an anode of a diode V7, and a cathode of a diode V7 is connected with a gate of a lower bridge arm switching tube V9;

the switching tube switching-on circuit comprises a resistor R6 and a diode V8, one end of the resistor R6 is connected with a gate pole of the upper bridge arm switching tube V8, the other end of the resistor R6 is connected with an anode of a diode V8, and a cathode of a diode V8 is connected with a pin LO of the driving chip N1;

the Miller effect compensation circuit comprises a diode V7, a resistor R8 and a triode V10; the triode V10 is a PNP type triode, and an emitting electrode of the triode V10 is respectively connected with a cathode of the diode V7 and a gate electrode of the lower bridge arm switching tube V9; the collector of the triode V10 is connected with the emitter of the lower bridge arm switch tube V9; the gate of the transistor V10 is connected to one end of a resistor R8, and the other end of the resistor R8 is connected to the anode of a diode V7.

Further, the power parameter P of the resistors R2, R3, R6 and R7 satisfies the formula P ═ fQ Δ U; in the formula, f is a switching frequency, Q is a gate electric charge of the switching tube, and Δ U is a driving voltage.

The invention has the following beneficial effects:

1. according to the invention, the Miller effect compensation circuit is arranged, when the Miller effect occurs to the switching tube, the driving voltage of the switching tube is clamped to zero voltage, and the switching tube is prevented from being conducted by mistake;

2. isolating the on-circuit and the off-circuit of the switch tube, so that the on-time and the off-time of the switch tube can be respectively set for complementary interference;

3. the bootstrap circuit is adopted, so that the drive chip N1 realizes the isolated drive of the full-bridge drive circuit under the condition of single power supply;

4. the absorption of interference signals in the driving pulse and the parasitic capacitance discharge are realized;

5. the circuit of the invention has novel form, simple structure and low cost, can meet the requirement of single power supply driving of a common switch tube, and can be applied to various power electronic equipment.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout.

Fig. 1 is a schematic diagram of an IGBT single power supply driving circuit in an embodiment of the present invention.

Detailed Description

The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which together with the embodiments of the invention serve to explain the principles of the invention.

The embodiment discloses an IGBT single-power-supply driving circuit based on a bootstrap mode, as shown in fig. 1, including a driving chip N1, a bootstrap suspension circuit, a full-bridge driving circuit, and a switching circuit;

the driver chip N1 of the present embodiment drives and amplifies the input PWM signal and outputs a PWM drive signal.

The driving chip N1 may be an IR2110S chip or the like. The PWM signal input end of the driving chip N1 is a pin HIN and a pin LIN; the pin HIN and the pin LIN are respectively connected to PWMH and PWML signals, the PWMH and PWML signals are complementary and have certain dead time, and are output after being generated by chips such as a singlechip and the like;

a pin SD of the driving chip N1 is connected with a driving chip turn-off signal for turning off the output of the driving chip under abnormal conditions;

the driving chip N1 is powered by a single power supply, a pin VDD and a pin VCC are connected with a +15V direct current power supply, and a pin VSS and a pin COM are grounded;

a capacitor C2 is connected between a pin VDD and a pin VSS, a capacitor C3 is connected between a pin VCC and a pin COM, and the decoupling capacitor is a decoupling capacitor of a power supply port of the driving chip and is used for filtering high-frequency stray interference of a +15V power supply branch circuit.

After the PWMH and PWML signals are amplified by a driving chip N1, the PWMH and PWML driving signals are respectively output through a pin HO and a pin LO of the driving chip;

in the embodiment, full-bridge isolated driving under the condition of single power supply is realized through a bootstrap circuit;

the bootstrap circuit is electrically connected with the driving chip N1 and is used for providing a bootstrap floating power supply, so that the driving chip N1 realizes the isolated driving of the full-bridge driving circuit under the condition of single power supply;

specifically, the bootstrap suspension circuit comprises a resistor R1, a diode V1 and a capacitor C1;

one end of the resistor R1 is connected with a power supply, and the other end of the resistor R1 is connected with the anode of the diode V1; the cathode of the diode V1 is respectively connected with one end of the capacitor C1 and a pin VB of the driving chip N1; the other end of the capacitor C1 is connected with a pin VS of a driving chip N1;

the capacitor C1 in the bootstrap circuit is a bootstrap suspension drive power supply holding capacitor and is used for providing enough energy and voltage for driving the bridge arm switching tubes on the full-bridge drive circuit, the drive resistor R1 is a charging current-limiting resistor of the capacitor C1, and the diode V1 is an isolation diode between the upper bridge arm drive power supply and the lower bridge arm drive power supply. The bootstrap suspension driving power supply can simultaneously drive the upper and lower switching devices of the full-bridge driving circuit, thereby simplifying the design of the driving power supply.

The full-bridge driving circuit of the embodiment is connected between the driving signal output end of the driving chip N1 and the control end of the switching circuit, and is used for outputting a PWM driving signal to the switching circuit to control the on or off of the switching tube; independently setting the turn-on time and the turn-off time of the switching tube, and clamping the driving voltage of the switching tube to zero voltage when the Miller effect occurs to the switching tube to prevent the switching tube from being conducted by mistake;

specifically, the full-bridge driving circuit comprises an upper bridge arm driving circuit and a lower bridge arm driving circuit; the switching circuit comprises an upper bridge arm switching tube V5 and a lower bridge arm switching tube V9;

the upper bridge arm driving circuit connects a pin VS of the driving chip N1 with an emitting electrode of an upper bridge arm switch tube V5; the driving input end of the upper bridge arm driving circuit is connected with a pin HO of a driving chip N1, and the driving output end of the upper bridge arm driving circuit is connected with a gate pole of an upper bridge arm switching tube V5;

the driving input end of the lower bridge arm driving circuit is connected with a pin LO of a driving chip N1; the driving output end is connected with a gate pole of a lower bridge arm switching tube V9;

the collector electrode of the upper bridge arm switching tube V5 is connected with a high-voltage direct-current power supply; the emitting electrode of the upper bridge arm switch tube V5 is connected with the collector electrode of the lower bridge arm switch tube V9; the emitter of the lower bridge arm switching tube V9 is connected with the ground.

Specifically, the upper bridge arm driving circuit comprises a switching tube on circuit, a switching tube off circuit and a miller effect compensation circuit;

the switching tube turn-on circuit is used for outputting a driving high level output by a pin HO of the driving chip N1 to a gate pole of the upper bridge arm switching tube V5, and enabling the upper bridge arm switching tube V5 to be conducted at a set turn-on time;

specifically, the switching tube turn-on circuit comprises a resistor R3 and a diode V2, one end of the resistor R3 is connected with a pin HO of a driving chip N1, the other end of the resistor R3 is connected with an anode of a diode V2, and a cathode of the diode V2 is connected with a gate of an upper bridge arm switching tube V5; by setting the resistance value of resistor R3, the on time of upper arm switching tube V5 is set.

The switching tube turn-off circuit is used for outputting the low level output by the pin HO of the driving chip N1 to the gate of the upper bridge arm switching tube V5, and turning off the upper bridge arm switching tube V5 at the set turn-off time;

specifically, the switching tube turn-on circuit comprises a resistor R2 and a diode V3, one end of the resistor R2 is connected with a gate of the upper arm switching tube V5, the other end of the resistor R2 is connected with an anode of the diode V3, a cathode of the diode V3 is connected with a pin HO of the N1 of the driving chip, and the turn-off time of the upper arm switching tube V5 is set by setting the resistance value of the resistor R2.

Because the diode V2 in the switch tube on circuit bears negative pressure when the switch tube is turned off, and is in a cut-off state, the switch tube off control current can not reach the pin HO of the driving chip N1 through the on resistor R3; when the switching tube is switched on, a diode V3 in the switching tube turn-off circuit bears negative pressure and is in a cut-off state, and the switching tube conduction control current cannot reach a gate pole of an upper bridge arm switching tube V5 through a turn-off resistor R2; therefore, the switching-on and switching-off time of the upper bridge arm switching tube V5 is independent and adjustable.

The miller effect compensation circuit is used for clamping the driving voltage of the switching tube V5 to zero voltage when the miller effect occurs in the upper bridge arm switching tube V5, so as to prevent the switching tube from being conducted by mistake;

because the driving chip N1 can not generate negative bias under the condition of single power supply, if the output of the switching tube runs under the inductive load, the switching tube in the off state can bear higher dv/dt due to the recovery process of the anti-parallel diode, the miller effect can occur, the parasitic capacitance of the collector electrode and the gate electrode of the switching tube discharges to the driving circuit, and the parasitic capacitance may exceed the on-threshold voltage of the switching tube to cause misconduction and burn the circuit; in the embodiment, the miller effect compensation circuit is added, so that the problem of the miller effect is solved, and the switch tube is prevented from being conducted by mistake.

Specifically, the miller effect compensation circuit comprises a diode V2, a resistor R4 and a triode V4; the triode V4 is a PNP type triode, and an emitting electrode of the triode V4 is respectively connected with a cathode of the diode V2 and a gate electrode of the upper bridge arm switching tube V5; the collector of the triode V4 is connected with the emitter of the upper bridge arm switch tube V5; the gate of the transistor V4 is connected to one end of a resistor R4, and the other end of the resistor R4 is connected to the anode of a diode V2.

When an upper bridge arm switching tube V5 is controlled to be turned off, a pin HO of a driving chip N1 outputs a low level, a grid electrode of a triode V4 is grounded through resistors R4 and R3, no voltage exists between an emitter electrode and a collector electrode of a triode V4, the triode V4 is in a cut-off state, when the Miller effect occurs, the grid electrode of a triode V4 is grounded, forward voltage is provided between the emitter electrode and the collector electrode of a triode V4 through emitter electrode and gate electrode parasitic capacitance voltage of the switching tube, V4 is conducted, the driving voltage of the switching tube V5 is clamped to be about zero, and misconduction is prevented; v2 is used to provide a loop for normally turning on the switch tube, and R4 is the driving resistor of transistor V4, which is used to limit the driving current of V4.

Preferably, the upper arm driving circuit of this embodiment further includes a TVS tube V6, a cathode of the TVS tube V6 is connected to a gate of the upper arm switching tube V5, and an anode of the TVS tube V6 is connected to an emitter of the upper arm switching tube V5, and is configured to absorb a pulse interference signal in a driving signal of the switching tube V5.

Preferably, the upper arm driving circuit of this embodiment further includes a resistor R5, one end of the resistor R5 is connected to the gate of the upper arm switching tube V5, and the other end of the resistor R5 is connected to the emitter of the upper arm switching tube V5, and is configured to discharge parasitic capacitances of the gate and the emitter of the switching tube V5.

The lower bridge arm driving circuit of the embodiment has the same principle as the upper bridge arm driving circuit, and comprises a switching tube on circuit, a switching tube off circuit, a miller effect compensation circuit, and a pulse interference signal absorption TVS tube V11 and a parasitic capacitance discharge resistor R9 which are connected between a gate electrode and an emitter electrode of a lower bridge arm switching tube V9;

the switching tube switching-on circuit comprises a resistor R7 and a diode V7, one end of the resistor R7 is connected with a pin LO of a driving chip N1, the other end of the resistor R7 is connected with an anode of a diode V7, and a cathode of a diode V7 is connected with a gate of a lower bridge arm switching tube V9;

the switching tube switching-on circuit comprises a resistor R6 and a diode V8, one end of the resistor R6 is connected with a gate pole of the upper bridge arm switching tube V8, the other end of the resistor R6 is connected with an anode of a diode V8, and a cathode of a diode V8 is connected with a pin LO of the driving chip N1;

the Miller effect compensation circuit comprises a diode V7, a resistor R8 and a triode V10; the triode V10 is a PNP type triode, and an emitting electrode of the triode V10 is respectively connected with a cathode of the diode V7 and a gate electrode of the lower bridge arm switching tube V9; the collector of the triode V10 is connected with the emitter of the lower bridge arm switch tube V9; the gate of the transistor V10 is connected to one end of a resistor R8, and the other end of the resistor R8 is connected to the anode of a diode V7.

The resistors R2, R3, R6 and R7 in the embodiment are the on-resistance or off-resistance of the circuit, and bear high power when the switch tube is switched on or off, so the power parameter requirements of the resistors meet the requirements of the circuit parameters,

specifically, the power parameter P of the resistors R2, R3, R6 and R7 satisfies the formula P ═ fC_INΔU²fQ Δ U; where f is the switching frequency, Q is the amount of gate charge of the switching tube, as given in the switching tube handbook, Δ U is the drive voltage, 15V in this circuit, and C_INTo take into account the input capacitance of the switching tube under the miller effect.

The embodiment also limits the maximum driving current of the driving chip N1 pin HO and pin LO which respectively output PWMH and PWML driving signals; the maximum drive current must be equal to or greater than the actual required gate drive current.

Normally, the gate drive current

Wherein R is_gintFor internal gate electrodeR is_gminA minimum on resistance;

because the rising slope of the actual gate maximum drive current is slowed down by the presence of the drive line inductance, the gate maximum drive current can be calculated as follows:

in summary, in the present embodiment, by providing the miller effect compensation circuit, when the miller effect occurs in the switching tube, the driving voltage of the switching tube is clamped to the zero voltage, so as to prevent the switching tube from being turned on by mistake; isolating the on-circuit and the off-circuit of the switch tube, so that the on-time and the off-time of the switch tube can be respectively set for complementary interference; the bootstrap circuit is adopted, so that the drive chip N1 realizes the isolated drive of the full-bridge drive circuit under the condition of single power supply; the absorption of interference signals in the driving pulse and the parasitic capacitance discharge are realized; the circuit can be used for single power supply driving of switching tubes such as IGBT, MOSFET and the like below 600V. The switch tube has the advantages of novel form, simple structure and low cost, can meet the requirement of single power supply driving of a common switch tube, and can be applied to various power electronic equipment.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.