An IGBT gate driver based on a single power supply circuit

Abstract

The invention discloses an IGBT gate driver based on a single power supply circuit, comprising: a power supply circuit, an isolation drive and a fault feedback circuit; the power supply circuit converts the input alternating current into direct current, and provides DC+22V and DC+6V voltages to the isolation drive and fault feedback circuits respectively; the isolation drive and fault feedback circuits receive the DC±15V drive signal sent by the host computer, convert it into an IGBT drive signal and output it to the IGBT, and generate a fault feedback signal to the host computer. The controlled IGBT state is detected in real time, and a fault latch signal is generated to the isolation drive and fault feedback circuits. The invention realizes the control and state monitoring of the IGBT through a single power supply circuit. The output waveform is controlled by a push-pull circuit, and has the characteristics of simple structure, high reliability, fast action speed, and continuously adjustable waveform.

Description

Technical Field

[0001] The invention belongs to the technical field of control of power electronics and power automation equipment, and in particular relates to an IGBT gate driver based on a single power supply circuit. Background Art

[0002] At present, the application of IGBT driver technology in the field of small and medium power at home and abroad is relatively mature. It mainly adopts digital control to achieve driving, and its functions are relatively simple. IGBT concentrates the advantages of MOSFET and GTR, and has the characteristics of high input impedance, fast switching speed, good thermal stability, low on-state voltage, high withstand voltage, and large current. In recent years, it has been widely used in various fields. The use of a set of good-performance drive circuits can shorten the switching time, reduce switching losses, and make the IGBT work in a more ideal switching state. At the same time, it is of great significance to the operating efficiency, reliability and safety of the product. IGBT is a voltage-controlled device. When a DC voltage of more than ten volts is applied between its gate and emitter, only micro-ampere current flows. The IGBT driver is an interface circuit between the IGBT and the controller DSP chip. Its function is to convert the control signal from the digital signal processor into a drive signal with sufficient power to realize the safe opening and closing of the IGBT and provide electrical isolation between the processor and the IGBT. In order to correctly and effectively protect the IGBT when a system failure occurs, the IGBT driver also needs to provide corresponding overcurrent, overvoltage, short circuit and other fault protection functions.

[0003] In the related art, most of the dual power supply methods are used to limit the pulse width of the input IGBT control signal, which has a complex structure and many components, resulting in high driver cost and large size. Summary of the invention

[0004] In view of the deficiencies of the above-mentioned prior art, the object of the present invention is to provide an IGBT gate driver based on a single power supply circuit to meet the requirements of the current trend of miniaturization of high-power inverters; the driver of the present invention adopts a single power supply circuit to control the IGBT gate, the output waveform is continuous and smooth, and can flexibly adjust the output waveform curve according to specific control requirements, which can meet different application cases and has a wide range of applications.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] An IGBT gate driver based on a single power supply circuit of the present invention comprises: a power supply circuit, an isolation drive and a fault feedback circuit; wherein,

[0007] The power supply circuit is used to convert the input AC power into DC power and provide DC+22V and DC+6V voltages for the isolation drive and fault feedback circuits;

[0008] The power supply circuit comprises: a rectifier circuit, a first RC filter circuit, a voltage stabilizing circuit and an output filter circuit;

[0009] The rectifier circuit converts high-frequency AC power into DC+22V DC power, and the first RC filter circuit filters out the interference harmonics in the DC power; the voltage stabilization circuit converts the DC+22V DC power into DC+6V DC power, which is supplied to the isolation drive and fault feedback circuits; the output filter circuit further filters the DC+6V DC power to improve the ripple characteristics of the DC+6V power supply;

[0010] The isolation drive and fault feedback circuit receives the DC±15V drive signal from the host computer, converts it into an IGBT drive signal and outputs it to the IGBT, and generates a fault feedback signal to the host computer; it includes: an isolation drive circuit and a fault feedback circuit;

[0011] The isolation driving circuit comprises: a photoelectric coupler U1, a first-stage amplifying transistor V10, transistors V9 and V17, a load circuit and a driving signal transmission circuit;

[0012] The photocoupler U1 converts the DC±15V driving signal sent by the host computer into a control signal. The control signal is amplified by the transistor V10 of the first-stage amplifier circuit and input to the base of the transistors V9 and V17. The transistors V9 and V17 form a push-pull circuit and output DC+15V and DC-6V IGBT gate driving signals respectively.

[0013] The load circuit is used to improve the waveform of the IGBT gate drive signal and make the waveform smooth;

[0014] The driving signal transmission circuit is used to adjust the signal level.

[0015] The fault feedback circuit comprises: a photoelectric coupler U2, a feedback signal driving circuit, a feedback signal self-locking circuit, a second RC filter circuit, a level conversion circuit and a state detection circuit;

[0016] The photoelectric coupler U2 realizes the photoelectric isolation between the driver and the host computer, and feeds back the fault feedback signal to the host computer through the photocoupler;

[0017] The feedback signal driving circuit is used to drive the optocoupler to work;

[0018] The feedback signal self-locking circuit realizes the self-locking retention of the fault signal. When a fault occurs, the feedback signal self-locking circuit is reset (such as the driver board is powered off) and the IGBT gate drive signal is output again; otherwise, the driver always outputs the DC-6V IGBT shutdown signal;

[0019] The second RC filter circuit is used to prevent interference from causing malfunction of the fault feedback signal, so as to improve the stability and reliability of the driver;

[0020] The level conversion circuit realizes the level conversion of the trigger signal;

[0021] The status detection circuit realizes the driver output status detection and IGBT status detection, and then determines whether the IGBT fails.

[0022] Beneficial effects of the present invention:

[0023] The driver of the present invention has the characteristics of simple structure, high integration, strong anti-interference ability, fast response speed and low energy consumption, and can meet the needs of high-frequency and high-speed IGBT control; in addition, the driver also has overvoltage, overcurrent and abnormal protection functions; the state of the IGBT is monitored and delayed triggered through an analog circuit; the output waveform is controlled through a push-pull circuit, and has the characteristics of fast action speed and continuously adjustable waveform.

[0024] The present invention greatly meets the requirements of the current trend of miniaturization of high-power inverters and is an inevitable trend in the development of IGBT gate drivers in the future.

[0025] The present invention is mainly implemented using an analog circuit composed of discrete components, and has the characteristics of high flexibility and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The figure is a working principle diagram of the driver of the present invention.

[0027] Figure 2 It is the structural principle diagram of the driver of the present invention.

[0028] Figure 3 This is the power supply circuit schematic.

[0029] Figure 4 This is the schematic diagram of the isolation drive circuit.

[0030] Figure 5 This is the schematic diagram of the fault feedback circuit.

[0031] Figure 6 This is the schematic diagram of the floating ground circuit.

[0032] Figure 7 This is the schematic diagram of the driving waveform adjustment circuit. DETAILED DESCRIPTION

[0033] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments and drawings. The contents mentioned in the implementation modes are not intended to limit the present invention.

[0034] Reference Figure 1 , Figure 2As shown, an IGBT gate driver based on a single power supply circuit of the present invention comprises: a power supply circuit, an isolation drive and a fault feedback circuit; wherein,

[0035] The power supply circuit converts the input AC power into DC voltage and provides DC+22V and DC+6V voltages for the isolation drive and fault feedback circuits;

[0036] The isolation drive and fault feedback circuit receives the DC±15V drive signal from the host computer, converts it into an IGBT drive signal and outputs it to the IGBT, and generates a fault feedback signal to the host computer; it includes: an isolation drive circuit and a fault feedback circuit.

[0037] The fault feedback circuit detects the state of the controlled IGBT in real time according to the driving signal sent by the host computer, and generates a fault self-locking signal to the isolation drive and the host computer.

[0038] Reference Figure 3 As shown, the power supply circuit includes: a rectifier circuit, a first RC filter circuit, a voltage stabilizing circuit, and an output filter circuit;

[0039] Diodes V1 to V4 form a bridge rectifier circuit to convert high-frequency AC into DC; the K pin of V1 is connected to the K pin of V2 and then to the 2 pin of R1, the A pin of V1 is connected to the K pin of V3, the A pin of V2 is connected to the K pin of V4, the A pins of V3 and V4 are connected and connected to the 2 pin of capacitor C3;

[0040] The first RC filter circuit is composed of a resistor R1 and a capacitor C3, and pin 1 of R1 is connected to pin 1 of C3;

[0041] The voltage stabilizing circuit is composed of resistors R2, R3, R4 and voltage stabilizing tube V5. Pin 1 of R2 is connected to pin 1 of R3 and then to pin 1 of R1; pin 2 of R2 is connected to pin 2 of R3 and then to pin 2 of V5; pin 1 of V5 is connected to pin 1 of R4 and pin 2 of R4 is connected to pin 2 of C3.

[0042] The output filter circuit is composed of capacitor C1, capacitor C2, capacitor C4, and capacitor C5; pin 1 of C1 is connected to pin 1 of C2 and to pin 1 of R1, which is named as the power network VCC+22V; pin 2 of C1 is connected to pin 2 of C2 and to pin 2 of R3, which is named as the power network VCC+6V; pin 1 of C4 is connected to pin 1 of C5 and to pin 2 of C2; pin 2 of C4 is connected to pin 2 of C5 and to pin 2 of R4, which is named as the power network GND.

[0043] Reference Figure 4As shown, the isolation driving circuit includes: a photocoupler U1, a first-stage amplifying transistor V10, second-stage amplifying transistors V9 and V17, a load circuit and a driving signal transmission circuit; which controls the IGBT to be turned on or off.

[0044] The photocoupler U1 realizes the photoelectric isolation function between the driver and the upper bit; the PWM+ signal is connected to pin 2 of C8 and then to pin 2 of U1, the PWM- is connected to pin 2 of R8, pin 1 of C8 is connected to pin 1 of R8 and then to pin 3 of U1, pin 8 of U1 is connected to the power network VCC+22V, pin 6 of U1 is connected to pin 1 of resistor R6, and pin 5 of U1 is connected to the power network GND.

[0045] The driving signal transmission circuit includes: a resistor R6, a resistor R9, a diode V6, a voltage regulator tube V7, and a diode V8; the resistors R6 and R9 are connected in parallel, the pin 1 of the resistor R6 is connected to the pin 1 of the resistor R9, and the pin 2 of the resistor R6 is connected to the pin 2 of the resistor R9; the pin 2 of the resistor R9 is connected to the pin 1 of the voltage regulator tube V7; the pin 2 of the voltage regulator tube V7 is connected to the pin 2 of the diode V6, and the pin 2 of the diode V6 is connected to the pin 2 of the diode V8; the pin 1 of the diode V6 is connected to the pin 2 of the resistor R5, the pin 1 of the resistor R5 is connected to the power supply network VCC+22V, the pin 1 of the diode V6 is connected to the pin 1 of the capacitor C6, and the pin 2 of the capacitor C6 is connected to the power supply network VCC+22V, and the diode V8 is connected to the pin 2 of the diode V6. Pin 1 of capacitor C6 is connected to pin 2 of the first-stage amplifying transistor V10, and network node FB1 is defined here; pin 3 of the first-stage amplifying transistor V10 is connected to the power supply network VCC+22V, pin 1 of the first-stage amplifying transistor V10 is connected to pin 1 of resistor R12, and network node FB2 is defined here, pin 2 of resistor R12 is connected to pin 1 of resistor R15, and pin 2 of R15 is connected to the power supply network GND; pin 1 of diode V8 is connected to pin 1 of diode V13, and is connected to pin 1 of the first-stage amplifying transistor V10; pin 2 of diode V13 is connected to pin 1 of resistor R16, and network node FB3 is defined here, and pin 2 of resistor R16 is connected to the power supply network GND;

[0046] Secondary amplifier transistor V9, V17 circuit, pin 1 of transistor V9 is connected to pin 1 of resistors R10 and R11; pin 2 of resistor R10 is connected to pin 2 of resistor R11, and connected to pin 1 of diode V8; pin 2 of transistor V9 is connected to power supply network VCC+22V, pin 3 of transistor V9 is connected to pin 3 of transistor V17, pin 1 of transistor V17 is connected to pin 1 of transistor V9, and pin 3 of transistor V17 is connected to power supply network GND; pin 1 of diode V12 is connected to pin 3 of transistor V9. Pin 2 of the diode V12 is connected to pin 2 of the resistor R14, and pin 1 of the resistor R14 is connected to pin 3 of the output terminal X1, where network node FB4 is defined; pin 2 of the resistor R13 is connected to pin 1 of the diode V12, and pin 1 of the resistor R13 is connected to pin 2 of the diode V12; pin 1 of the diode V15 is connected to pin 3 of the output terminal X1, and pin 2 of the diode V16 is connected, pin 2 of the diode V15 is connected to pin 1 of the capacitor C9, and pin 1 of the diode V16 is connected to the power supply network GND.

[0047] The load circuit is composed of a resistor R7, a diode V11, a diode V14, a resistor R17, and a capacitor C9; pin 1 of the resistor R7 is connected to the power supply network VCC+22V, and pin 2 of the resistor R7 is connected to pin 1 of the diode V11; pin 2 of the diode V11 is connected to pin 1 of the diode V14, and pin 2 of the diode V14 is connected to pin 1 of the resistor R17, and pin 2 of the resistor R17 is connected to the power supply network VCC+6V; pin 1 of the capacitor C9 is connected to pin 1 of the resistor R17, and pin 2 of the capacitor C9 is connected to pin 2 of the resistor R17.

[0048] Reference Figure 5 As shown, the fault feedback circuit includes: a photocoupler U2, a feedback signal driving circuit, a feedback signal self-locking circuit, a second RC filter circuit, a level conversion circuit, and a state detection circuit;

[0049] The photoelectric coupler U2 realizes the photoelectric isolation function between the driver and the host computer. The 8th pin of the photoelectric coupler U2 is connected to the VCC+15V power supply of the host computer; the 6th pin of the photoelectric coupler U2 is connected to the feedback signal of the host computer, and the 5th pin of the photoelectric coupler U2 is connected to the GND of the host computer; the 2nd pin of the capacitor C11 is connected to the 8th pin of the photoelectric coupler U2, and the 1st pin of the capacitor C11 is connected to the 5th pin of the photoelectric coupler U2; the 2nd pin of the capacitor C12 is connected to the 6th pin of the photoelectric coupler U2, and the 1st pin of the capacitor C12 is connected to the 5th pin of the photoelectric coupler U2, the 2nd pin of the photoelectric coupler U2 is connected to the 2nd pin of the resistor R20, and the 3rd pin of the photoelectric coupler U2 is connected to the 1st pin of the diode V24;

[0050] The feedback signal driving circuit realizes the driving function of the optocoupler U2 and enhances the driving ability of the feedback signal to drive the optocoupler U2 to work normally. The feedback signal driving circuit is composed of resistor R20, resistor R21, resistor R22, diode V24, and diode V32; the pins 1 of resistors R20, R21, and R22 are connected together and connected to the power supply network VCC+22V, and the pins 2 of resistors R20, R21, and R22 are connected together and connected to the pin 2 of the optocoupler U2; the pin 2 of diode V24 is connected to the pin 1 of diode V32, and the pin 2 of diode V32 is connected to the power supply network GND; the pin 1 of transistor V28 is connected to the pin 2 of resistor R20, the pin 3 of transistor V28 is connected to the power supply network GND, the pin 2 of transistor V28 is connected to the pin 1 of resistor R30, and the pin 2 of resistor R30 is connected to the pin 2 of resistor R25;

[0051] The feedback signal self-locking circuit is composed of a resistor R19, a resistor R23, a capacitor C10, a transistor V25, a transistor V19, and a resistor R25; the resistor R19 and the capacitor C10 are connected in parallel, the pin 1 of the resistor R19 is connected to the pin 2 of the capacitor C10, and is connected to the power supply network VCC+22V, the pin 2 of the resistor R19 is connected to the pin 1 of the capacitor C10, and is connected to the pin 2 of the transistor V19 and the pin 1 of the resistor R23; the pin 2 of the resistor R23 is connected to the pin 1 of the capacitor C10, and is connected to the pin 2 of the transistor V19 and the pin 1 of the resistor R23; Pin 2 is connected to pin 1 of transistor V25, pin 3 of transistor V25 is connected to GND, and transistor V25 is connected to pin 2 of resistor R29; pin 3 of transistor V19 is connected to power supply network VCC+22V, and pin 1 of transistor V19 is connected to pin 1 of resistor R25; pin 2 of resistor R25 is connected to pin 1 of resistor R29, pin 1 of resistor R29 is connected to pin 1 of resistor R31, and pin 2 of resistor R31 is connected to GND;

[0052] The second RC filter circuit is used to prevent interference from causing malfunction of the fault feedback circuit, so as to improve the stability and reliability of the driver; the RC filter circuit is composed of a resistor R31 and a capacitor C13, the capacitor C13 is connected in parallel with the resistor R31, the pin 2 of the capacitor C13 is connected to the pin 1 of the resistor R31, and the pin 1 of the capacitor C13 is connected to the pin 2 of the resistor R31;

[0053] The level conversion circuit is used to achieve signal level conversion so that the circuit can receive 22V signals. The level conversion circuit is composed of a voltage regulator tube V29, a diode V30, a resistor R28, and a diode V33; the 2nd pin of the voltage regulator tube V29 is connected to the 2nd pin of the diode V30, the 1st pin of the diode V30 is connected to the 1st pin of the diode V33, and the 2nd pin of the diode V33 is connected to FB3; the resistor R28 is connected in parallel with the diode V33, the 2nd pin of the resistor R28 is connected to the 1st pin of the diode V33, and the 1st pin of R28 is connected to the 2nd pin of V33;

[0054] The state detection circuit is used to detect the state of the IGBT and the state of the driving signal. The state detection circuit is composed of a diode V20, a diode V23, a resistor R26, a resistor R24, a resistor R27, a diode V26, a resistor R18, a diode V18, a TVS tube V21, a TVS tube V22, a TVS tube V27, and a diode V31;

[0055] Pin 2 of resistor R24 ​​is connected to pin 2 of resistor R23, and pin 1 of resistor R24 ​​is connected to FB1; pin 2 of resistor R27 is connected to pin 2 of resistor R24, and pin 1 of resistor R27 is connected to pin 2 of V26, and pin 1 of V26 is connected to FB2;

[0056] Pin 2 of resistor R26 is connected to the GND network, pin 1 of resistor R26 is connected to pin 2 of diode V23, pin 1 of diode V23 is connected to pin 1 of capacitor C14, and pin 2 of capacitor C14 is connected to the GND network; pin 2 of diode V23 is connected to pin 1 of diode V20, and pin 2 of diode V20 is connected to the power supply network VCC+22V;

[0057] Pin 1 of resistor R18 is connected to pin 1 of resistor R26, pin 2 of resistor R18 is connected to pin 1 of diode V18; pin 2 of diode V18 is connected to pin 2 of TVS tube V21 and to pin 1 of X1, pin 1 of TVS tube V21 is connected to pin 2 of TVS tube V22, pin 1 of TVS tube V22 is connected to pin 2 of TVS tube V27, pin 1 of TVS tube V27 is connected to pin 1 of diode V31; pin 2 of diode V31 is connected to pin 3 of X1 and to FB4.

[0058] The driver of the present invention can receive the ±15V drive signal of the host computer. After modifying the current limiting resistor, it can adapt to the drive signal of the host computer with different voltage levels, so it has wide applicability. And the drive model is adjusted to the +15V / -6V drive signal required to drive the IGBT gate; using a +22V single power supply and +6V floating ground technology, it can not only realize the effective drive of the IGBT, but also ensure that the IGBT gate is not damaged in the event of a fault, so it can improve the reliability and stability of the inverter. Figure 6 shown.

[0059] At the same time, the driver of the present invention has an output waveform adjustment circuit, which can adapt to IGBTs of various signals, so it has wide applicability, such as Figure 7 shown.

[0060] The present invention adopts a single power supply to drive the IGBT. Compared with the previous dual power supply driver, it has the characteristics of simple structure, fewer components, high reliability and low cost. The specific implementation method is to adopt the design concept of floating ground, connect the E pole of the IGBT to the VCC+6V network as the IGBT gate floating ground. The power supply voltage of the entire circuit is 22V. Even if the driver outputs 22V, it is not easy to cause the IGBT gate to break down due to overvoltage, which can effectively prevent the expansion of faults. The IGBT shutdown drive voltage is set to -6V, which can not only ensure the reliable shutdown of the IGBT, but also improve the IGBT opening action speed compared to the -10V or -15V shutdown drive voltage.

[0061] In addition, the present invention designs an IGBT gate drive waveform adjustment circuit so that the driver can adapt to various types of IGBTs, so the design has wide practicality.

[0062] The present invention has many specific application paths. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principle of the present invention. These improvements should also be regarded as the protection scope of the present invention.

Claims

1. An IGBT gate driver based on a single power supply circuit, characterized in that: include: Power supply circuit, isolation drive and fault feedback circuit; among which, The power supply circuit is used to convert the input AC power into DC power and provide DC+22V and DC+6V voltages for the isolation drive and fault feedback circuits; The power supply circuit comprises: a rectifier circuit, a first RC filter circuit, a voltage stabilizing circuit and an output filter circuit; Diodes V1 to V4 form a bridge rectifier circuit to convert high-frequency AC into DC; the K pin of V1 is connected to the K pin of V2 and then to the 2 pin of R1, the A pin of V1 is connected to the K pin of V3, the A pin of V2 is connected to the K pin of V4, the A pins of V3 and V4 are connected and connected to the 2 pin of capacitor C3; The first RC filter circuit is composed of a resistor R1 and a capacitor C3, and pin 1 of R1 is connected to pin 1 of C3; The voltage stabilizing circuit is composed of resistors R2, R3, R4 and voltage stabilizing tube V5. Pin 1 of R2 is connected to pin 1 of R3 and then to pin 1 of R1; pin 2 of R2 is connected to pin 2 of R3 and then to pin 2 of V5; pin 1 of V5 is connected to pin 1 of R4 and pin 2 of R4 is connected to pin 2 of C3. The output filter circuit is composed of capacitors C1, C2, C4 and C5; Pin 1 of C1 is connected to Pin 1 of C2 and to Pin 1 of R1, named as power network VCC+22V; Pin 2 of C1 is connected to Pin 2 of C2 and to Pin 2 of R3, named as power network VCC+6V; Pin 1 of C4 is connected to Pin 1 of C5 and to Pin 2 of C2; Pin 2 of C4 is connected to Pin 2 of C5 and to Pin 2 of R4, named as power network GND; The rectifier circuit converts high-frequency AC power into DC+22V DC power, and the first RC filter circuit filters out the interference harmonics in the DC power; the voltage stabilization circuit converts the DC+22V DC power into DC+6V DC power, which is supplied to the isolation drive and fault feedback circuits; the output filter circuit further filters the DC+6V DC power to improve the ripple characteristics of the DC+6V power supply; The isolation drive and fault feedback circuit receives the DC±15V drive signal from the host computer, converts it into an IGBT drive signal and outputs it to the IGBT, and generates a fault feedback signal to the host computer; it includes: an isolation drive circuit and a fault feedback circuit; The isolation driving circuit comprises: a photoelectric coupler U1, a first-stage amplifying transistor V10, transistors V9 and V17, a load circuit and a driving signal transmission circuit; The photocoupler U1 converts the DC±15V driving signal sent by the host computer into a control signal. The control signal is amplified by the transistor V10 of the first-stage amplifier circuit and input to the base of the transistors V9 and V17. The transistors V9 and V17 form a push-pull circuit and output DC+15V and DC-6V IGBT gate driving signals respectively. The load circuit is used to improve the waveform of the IGBT gate drive signal and make the waveform smooth; The driving signal transmission circuit is used for adjusting the signal level; The fault feedback circuit comprises: a photoelectric coupler U2, a feedback signal driving circuit, a feedback signal self-locking circuit, a second RC filter circuit, a level conversion circuit and a state detection circuit; The photoelectric coupler U2 realizes the photoelectric isolation between the driver and the host computer, and feeds back the fault feedback signal to the host computer through the photocoupler; The feedback signal driving circuit is used to drive the optocoupler to work; The feedback signal self-locking circuit realizes the self-locking retention of the fault signal; The second RC filter circuit is used to prevent interference from causing malfunction of the fault feedback signal; The level conversion circuit realizes the level conversion of the trigger signal; The status detection circuit realizes the driver output status detection and IGBT status detection, and then determines whether the IGBT fails; The driving signal transmission circuit includes: a resistor R6, a resistor R9, a diode V6, a voltage regulator tube V7, and a diode V8; the resistors R6 and R9 are connected in parallel, the pin 1 of the resistor R6 is connected to the pin 1 of the resistor R9, and the pin 2 of the resistor R6 is connected to the pin 2 of the resistor R9; the pin 2 of the resistor R9 is connected to the pin 1 of the voltage regulator tube V7; the pin 2 of the voltage regulator tube V7 is connected to the pin 2 of the diode V6, and the pin 2 of the diode V6 is connected to the pin 2 of the diode V8; the pin 1 of the diode V6 is connected to the pin 2 of the resistor R5, the pin 1 of the resistor R5 is connected to the power supply network VCC+22V, the pin 1 of the diode V6 is connected to the pin 1 of the capacitor C6, and the pin 2 of the capacitor C6 is connected to the power supply network VCC+22V, and the diode V8 is connected to the pin 2 of the diode V6. Pin 1 of capacitor C6 is connected to pin 2 of the first-stage amplifying transistor V10, and network node FB1 is defined here; pin 3 of the first-stage amplifying transistor V10 is connected to the power supply network VCC+22V, pin 1 of the first-stage amplifying transistor V10 is connected to pin 1 of resistor R12, and network node FB2 is defined here, pin 2 of resistor R12 is connected to pin 1 of resistor R15, and pin 2 of R15 is connected to the power supply network GND; pin 1 of diode V8 is connected to pin 1 of diode V13, and is connected to pin 1 of the first-stage amplifying transistor V10; pin 2 of diode V13 is connected to pin 1 of resistor R16, and network node FB3 is defined here, and pin 2 of resistor R16 is connected to the power supply network GND; Secondary amplifier transistor V9, V17 circuit, pin 1 of transistor V9 is connected to pin 1 of resistors R10 and R11; pin 2 of resistor R10 is connected to pin 2 of resistor R11, and connected to pin 1 of diode V8; pin 2 of transistor V9 is connected to power supply network VCC+22V, pin 3 of transistor V9 is connected to pin 3 of transistor V17, pin 1 of transistor V17 is connected to pin 1 of transistor V9, and pin 3 of transistor V17 is connected to power supply network GND; pin 1 of diode V12 is connected to pin 3 of transistor V9. Pin 2 of the diode V12 is connected to pin 2 of the resistor R14, and pin 1 of the resistor R14 is connected to pin 3 of the output terminal X1, where network node FB4 is defined; pin 2 of the resistor R13 is connected to pin 1 of the diode V12, and pin 1 of the resistor R13 is connected to pin 2 of the diode V12; pin 1 of the diode V15 is connected to pin 3 of the output terminal X1, and pin 2 of the diode V16 is connected, pin 2 of the diode V15 is connected to pin 1 of the capacitor C9, and pin 1 of the diode V16 is connected to the power supply network GND; The load circuit is composed of a resistor R7, a diode V11, a diode V14, a resistor R17, and a capacitor C9; a pin 1 of the resistor R7 is connected to a power supply network VCC+22V, and a pin 2 of the resistor R7 is connected to a pin 1 of the diode V11; a pin 2 of the diode V11 is connected to a pin 1 of the diode V14, a pin 2 of the diode V14 is connected to a pin 1 of the resistor R17, and a pin 2 of the resistor R17 is connected to a power supply network VCC+6V; a pin 1 of the capacitor C9 is connected to a pin 1 of the resistor R17, and a pin 2 of the capacitor C9 is connected to a pin 2 of the resistor R17; The state detection circuit is composed of a diode V20, a diode V23, a resistor R26, a resistor R24, a resistor R27, a diode V26, a resistor R18, a diode V18, a TVS tube V21, a TVS tube V22, a TVS tube V27, and a diode V31; Pin 2 of resistor R24 ​​is connected to pin 2 of resistor R23, and pin 1 of resistor R24 ​​is connected to FB1; pin 2 of resistor R27 is connected to pin 2 of resistor R24, and pin 1 of resistor R27 is connected to pin 2 of V26, and pin 1 of V26 is connected to FB2; Pin 2 of resistor R26 is connected to the GND network, pin 1 of resistor R26 is connected to pin 2 of diode V23, pin 1 of diode V23 is connected to pin 1 of capacitor C14, and pin 2 of capacitor C14 is connected to the GND network; pin 2 of diode V23 is connected to pin 1 of diode V20, and pin 2 of diode V20 is connected to the power supply network VCC+22V; Pin 1 of resistor R18 is connected to pin 1 of resistor R26, pin 2 of resistor R18 is connected to pin 1 of diode V18; pin 2 of diode V18 is connected to pin 2 of TVS tube V21 and to pin 1 of X1, pin 1 of TVS tube V21 is connected to pin 2 of TVS tube V22, pin 1 of TVS tube V22 is connected to pin 2 of TVS tube V27, pin 1 of TVS tube V27 is connected to pin 1 of diode V31; pin 2 of diode V31 is connected to pin 3 of X1 and to FB4.

Images