High-voltage switching voltage divider protection circuit for driving switching transistor circuit

Abstract

This utility model patent relates to the field of power electronics technology and discloses a high-voltage switch divider protection circuit for driving switching transistors. The circuit includes a high-voltage divider protection circuit and a driving switching transistor circuit. A driving chip IC1 is connected to pins 1 and 2 of the driving transformer T1. The driving chip IC1 simultaneously controls the opening and closing of MOS switches TR1, TR2, and TR3, and provides electrical isolation for the MOS switches TR1, TR2, and TR3. The high-voltage switch divider protection circuit of the driving switching transistor circuit divides the input voltage of 800-1500VDC into three voltage segments using the main transformer T2 winding and Zener diodes. MOS switches TR1, TR2, and TR3 withstand one-third of the total voltage, ensuring that the voltage in each segment is stable between 300-600VDC, thereby reducing the voltage requirements of the MOS switches. This solves the technical problem of reverse voltage breakdown caused by the MOS switches being subjected to bus voltage and reflected voltage from the transformer secondary side; it also reduces the winding voltage of the main transformer T2 and increases the insulation of the transformer windings.

Description

Technical Field

[0001] This utility model belongs to the field of power electronics technology, specifically relating to a high-voltage switch voltage divider protection circuit for driving switch transistor circuits. Background Technology

[0002] In recent years, with the continuous development of power electronics technology, various application fields have placed increasingly higher demands on the safety, stability, and efficiency of transformer-driven high-voltage divider switch protection circuits. Various power electronic power supply circuits rely heavily on integrated chips and power switches, thus requiring switching power supplies to provide various levels of drive voltages, such as +5V, ±12V, and ±15V, for their control and drive circuits. Drive circuits have become a crucial component of power electronic power supply circuits. The input of the drive circuit is provided by the power electronic power supply's input bus voltage. To ensure stable operation of the power electronic power supply, the transformer and drive circuit must operate stably regardless of changes in the power electronic power supply's input bus voltage.

[0003] As the output voltage levels of power electronic power supplies continue to increase while their weight and cost continue to decrease, the high-voltage switching divider protection circuits driving the switching transistors typically operate in a critical saturation state. When multiple high-voltage MOSFETs cannot be turned off simultaneously, the MOSFETs will be subjected to the bus voltage and the reflected voltage from the transformer secondary side. A sudden voltage increase or the system operating at high temperatures can cause the MOSFETs to break down due to overvoltage. Once an MOSFET breaks down due to overvoltage, it can damage the switching transistors or even the transformer. Therefore, the design of power electronic power supplies must consider the problem of reverse voltage breakdown of the MOSFETs in the transformer-driven high-voltage divider circuit.

[0004] Most transformer-driven MOS switch high-voltage power supply circuits use single-ended flyback converters. However, the voltage across the MOS switch when it is turned off in a single-ended flyback converter is equal to the sum of the maximum DC input voltage, the secondary-side reflected voltage, and the leakage inductance spike voltage. At high input voltages, the voltage stress on the MOS switch is significant, greatly increasing its cost. Transformer-driven MOS switch high-voltage power supply circuits often use duty cycle limiting to prevent magnetic saturation and reduce the reflected voltage on the transformer secondary side; however, this is not ideal. When the input voltage fluctuates and is too high, magnetic saturation can still occur even with duty cycle limiting. Another approach is to appropriately reduce the number of turns in the transformer windings; while this reduces the reflected voltage of the MOS switch, it increases the ripple in the subsequent stages and fails to achieve a stable high-voltage output. A third approach is to add voltage-stabilizing capacitors on both sides of the MOS switch. This method is effective, but when using a combination of MOS switches driven by a circuit, the voltage-stabilizing capacitors and the MOS switch can be damaged by reverse voltage when the MOS switches are turned off at different times. Utility Model Content

[0005] (a) Technical problems to be solved The technical problem this invention aims to solve is that in DC high-voltage circuits, when the driving circuit drives the MOS switches TR1, TR2, and TR3 to work, because the MOS switches TR1, TR2, and TR3 cannot be turned off simultaneously, the first MOS switch to turn off will bear the entire bus voltage and the transformer secondary side reflected voltage. The superimposed voltage value of the entire bus voltage and the transformer secondary side reflected voltage far exceeds the withstand voltage (VDS) of 650V of the MOS switch, making the MOS switch easily prone to reverse voltage breakdown.

[0006] (II) Technical Solution To achieve the above objectives, the technical solution adopted by this utility model is as follows: This utility model provides a high-voltage switch divider protection circuit for driving a switch transistor circuit, including a high-voltage divider protection circuit and a drive switch transistor circuit. When the driver chip IC1 is powered, the main transformer T2 is in a non-working state. After the driver chip IC1 is powered, the driver switching circuit starts to work. The driver circuit provides a drive signal to the driver transformer T1, and the driver transformer T1 provides a drive signal to the MOS switches TR1, TR2, and TR3. The MOS switches TR1, TR2, and TR3 work and transfer electrical energy to the secondary output circuit of the transformer.

[0007] The high-voltage divider protection circuit includes a high-voltage input power supply, a main transformer T2, a switching transistor, a voltage regulator, and a voltage divider circuit. The main transformer T2 includes a main winding T2-1 and secondary windings T2-2, T2-3, T2-4, and T2-5; the main winding T2-1 is connected to the high-voltage input power supply. Connection; high-voltage input power supply Connect to ground (GND); Preferably, the switching transistors include MOS switches TR1, TR2, and TR3; pin 2 of MOS switch TR1 is connected to pin 2 of the primary winding T2-1 of the main transformer T2, and pin 3 of MOS switch TR1 is connected to pin 3 of the secondary winding T2-2 of the main transformer T2; pin 2 of MOS switch TR2 is connected to pin 4 of the secondary winding T2-2 of the main transformer T2, and pin 3 of MOS switch TR2 is connected to pin 5 of the secondary winding T2-3 of the main transformer T2; pin 2 of MOS switch TR3 is connected to pin 6 of the secondary winding T2-3 of the main transformer T2, and pin 3 of MOS switch TR3 is connected to a resistor. Connect it in series with ground (GND); Preferably, the Zener diodes include D1, D2, D3, D4, D5, D6, D21, D22, D23, D24, D31, and D32. Zener diodes D1, D2, D3, D4, D5, and D6 are connected to pin 2 of the primary winding T2-1 of the main transformer T2; Zener diodes D21, D22, D23, and D24 are connected to pin 3 of the secondary winding T2-2 of the main transformer T2; Zener diodes D31 and D32 are connected to pin 5 of the secondary winding T2-3 of the main transformer T2; and the other end of the Zener diodes is connected to ground GND. As a preferred option, the voltage divider circuit is connected to the high-voltage input power supply. High-voltage input power supply Parallel connection; Preferably, the driving switch circuit is connected to the MOS switches TR1, TR2, and TR3 to control the opening and closing of the MOS switches TR1, TR2, and TR3.

[0008] As a preferred embodiment, the driving switch circuit includes a main transformer T2, a driving circuit, a driving transformer T1, and an RC circuit. The driving circuit includes a driving chip IC1 connected to pins 1 and 2 of the driving transformer T1. The driving chip IC1 simultaneously controls the opening and closing of MOS switches TR1, TR2, and TR3. The driving chip IC1 electrically isolates the opening and closing of the MOS switches TR1, TR2, and TR3. Preferably, the main side T1-2 of the drive transformer T1 is connected in series with C1 and R10 and then connected to the control pin 1 of the MOS switch TR1; the secondary side T1-3 of the drive transformer T1 is connected in series with C3 and R13 and then connected to the control pin 1 of the MOS switch TR2; and the secondary side T1-4 of the drive transformer T1 is connected in series with C5 and R17 and then connected to the control pin 1 of the MOS switch TR3. Preferably, the pin 7 of the main side T1-2 of the drive transformer T1 is connected to the diode D7 via the intermediate connection between C1 and R10; the pin 5 of the secondary side T1-3 of the drive transformer T1 is connected to the diode D9 via the intermediate connection between C3 and R13; and the pin 3 of the secondary side T1-4 of the drive transformer T1 is connected to the diode D11 via the intermediate connection between C5 and R17. Preferably, pins 1 and 3 of MOS switch TR1 are connected via resistor R9, and pin 3 is connected to pin 7 of the primary side T1-2 of drive transformer T1; pins 1 and 3 of MOS switch TR2 are connected via resistor R14, and pin 3 is connected to pin 5 of the secondary side T1-3 of drive transformer T1; pins 1 and 3 of MOS switch TR3 are connected via resistor R9. The connection is made so that pin 3 is connected to pin 3 of the secondary side T1-4 of the drive transformer T1, and pin 3 of the secondary side T1-4 is connected to the ground line GND. Preferably, resistors R11 and R12 and capacitor C2 are connected in parallel to form RC1 circuit. One end of RC1 circuit is connected to pin 7 of the main side T1-2 of the drive transformer T1, and the other end of RC1 circuit is connected to the cathode of diode D8. The anode of diode D8 is connected to pin 2 of MOS switch TR2. Resistors R15 and R16 and capacitor C4 are connected in parallel to form RC2 circuit. One end of RC2 circuit is connected to pin 5 of the secondary side T1-3 of the drive transformer T1, and the other end of RC2 circuit is connected to the cathode of diode D10. The anode of diode D10 is connected to pin 2 of MOS switch TR3.

[0009] Preferably, the voltage divider circuit includes a series circuit of resistors R1-R8 and a series circuit of DC voltage divider capacitors EC1-EC4; the series circuit of resistors R1-R8 and the series circuit of DC voltage divider capacitors EC1-EC4 are connected in parallel; the positive terminal of DC voltage divider capacitor EC1 is connected to resistor R1 and to the high voltage input power supply. Connections: Connect the negative terminal of DC voltage divider capacitor EC1 to the intermediate circuit connection point of resistors R2 and R3; connect the negative terminal of DC voltage divider capacitor EC2 to the intermediate circuit connection point of resistors R4 and R5; connect the negative terminal of DC voltage divider capacitor EC3 to the intermediate circuit connection point of resistors R6 and R7; connect the negative terminal of DC voltage divider capacitor EC4 to the high-voltage input power supply. Connection, high-voltage input power supply Connect the terminal to ground (GND); connect the intermediate circuit connection points of resistors R2 and R3.

[0010] Preferably, the drive transformer T1 includes a main side T1-2 and a secondary side T1-1, T1-3, and T1-4; the drive chip IC1 simultaneously drives the switching of MOS switches TR1, TR2, and TR3, and the drive signal emitted by the drive chip IC1 drives the MOS switches TR1, TR2, and TR3 in isolation through the drive transformer T1.

[0011] Preferably, the driving circuit includes a driving chip IC1, a chip power supply VCC, a chip start-up current circuit, a current detection circuit, a PWM switching pulse output, an optocoupler voltage regulation control circuit, and the chip power supply VCC is connected to pin 6 of the driving chip IC1. Preferably, the chip startup current circuit includes a chip power supply VCC, a resistor R18, and a capacitor C7. One end of the resistor R18 is connected to the chip power supply VCC, and the other end is connected to pin 8 of the driver chip IC1. The positive terminal of the capacitor C7 is connected to pin 8 of the driver chip IC1, and the negative terminal of the capacitor C7 is connected to ground GND. The chip startup current circuit provides startup current for the driver chip IC1. Preferably, the current detection circuit includes a resistor R19 and a capacitor C6; one end of resistor R19 is connected to pin 3 of the driver chip IC1, and the other end of resistor R19 is connected to pin 3 of the driver MOS switch TR1; One end is connected to pin 3 of the driving MOS switch TR1 and resistor R19. The other end is connected to ground GND; one end of capacitor C6 is connected to pin 3 of driver chip IC1, and the other end of capacitor C6 is connected to ground GND; the current detection circuit monitors the overcurrent values ​​of drive MOS switches TR1, TR2, and TR3 when the high-voltage switch divider protection circuit of the drive switching transistor circuit is working. After the driver chip IC1 detects the return current value, the driver chip IC1 performs program judgment and adjusts the control signals of MOS switches TR1, TR2, and TR3 to turn on and off; the timing resistor R21 is externally connected to pin 1 of driver chip IC1. One end of the timing resistor R21 is connected to pin 1 of driver chip IC1, and the other end of the timing resistor R21 is connected to ground GND. The timing resistor R21 determines the oscillation frequency of MOS switches TR1, TR2, and TR3.

[0012] Preferably, the PWM switching pulse output is connected to pin 1 of the secondary side T1-1 of the drive transformer T1 after an external resistor R20 is connected to pin 5 of the drive chip IC1, and pin 4 of the drive chip IC1 is connected to pin 2 of the secondary side T1-1 of the drive transformer T1; the PWM switching pulse is used to drive the MOS switching transistors TR1, TR2, and TR3 to turn on and off.

[0013] Preferably, the optocoupler voltage regulator control circuit includes capacitor C9, capacitor C10, resistors R22, R25, R26, and optocoupler Q1. Pins 1 and 2 of optocoupler Q1 are connected in parallel with capacitor C10. Pin 2 of optocoupler Q1 is connected to ground GND. Pin 1 of optocoupler Q1 is connected to pin 2 of driver chip IC1. Pin 3 of optocoupler Q1 is connected to pin 9 of the secondary winding T2-5 of main transformer T2 after external resistor R22. Pin 10 of the secondary winding T2-5 of main transformer T2 is connected to external resistors R25 and R26 in series. One end of resistor R26 is connected to resistor R25, and the other end of resistor R26 is connected to ground GND. The connection point of resistors R25 and R26 is connected to one end of capacitor C9, and the other end of capacitor C9 is connected to pin 4 of optocoupler Q1. The optocoupler voltage regulator control circuit is used for comparator control of PWM switching pulses, realizing automatic voltage regulation control of the driver chip IC1 to turn on and off the MOS switching transistors TR1, TR2, and TR3.

[0014] (III) Beneficial Effects The above-mentioned technical solution of this utility model has at least the following advantages: The high-voltage switch divider protection circuit of the driving switch circuit is connected to the DC high-voltage circuit. The main transformer T2 winding and the Zener diode of the high-voltage switch divider protection circuit of the driving switch circuit divide the input voltage of 800-1500VDC into three voltage segments. The MOS switches TR1, TR2 and TR3 bear 1 / 3 of the total voltage, ensuring that the voltage of each voltage segment is stable between 300-600VDC, thereby reducing the voltage requirements of the MOS switches.

[0015] In a high-voltage DC circuit where MOS switches TR1, TR2, and TR3 cannot be turned off simultaneously, the first MOS switch to turn off will bear the entire bus voltage and the reflected voltage from the transformer secondary side, making it prone to reverse voltage breakdown. By adding a high-voltage divider protection circuit for the transformer-driven switches in the high-voltage DC circuit, when the MOS switches are turned off at different times, the bus voltage and the reflected voltage from the transformer secondary side that the MOS switches bear are within the withstand voltage range of the MOS switches, thus preventing the MOS switches from being broken down.

[0016] In the DC high-voltage circuit, a high-voltage switch divider protection circuit is connected to the drive switch circuit. The voltage across the windings T2-1, T2-2, and T2-3 of the main transformer T2 is 1 / 3 of the bus voltage, which reduces the voltage of the windings and increases the insulation of the transformer windings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a high-voltage divider protection circuit for MOS switching transistors provided in this embodiment of the utility model.

[0019] Figure 2 This is a transformer drive switching transistor circuit provided in an embodiment of the present invention.

[0020] Figure 3 This is the driving circuit provided in the embodiment of this utility model. Detailed Implementation

[0021] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0023] It is understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0024] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0025] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.

[0026] Example In the current DC high-voltage circuits on the market, when the drive circuit drives the MOS switches TR1, TR2, and TR3 to work, because the MOS switches TR1, TR2, and TR3 cannot be turned off simultaneously, the first MOS switch to turn off will bear the entire bus voltage and the transformer secondary reflected voltage. The superimposed voltage value of the entire bus voltage and the transformer secondary reflected voltage far exceeds the withstand voltage (VDS) of 650V of the MOS switch, making the MOS switch easily prone to reverse voltage breakdown.

[0027] In the embodiments, as shown in the appendix Figure 1 As shown, this utility model provides a high-voltage switching voltage divider protection circuit for driving the switching transistor circuit, including: High voltage divider protection circuit and drive switch circuit; When the driver chip IC1 is powered on in the high-voltage switch divider protection circuit of the drive switching transistor circuit, the main transformer T2 is in a non-working state. After the driver chip IC1 is powered on, the drive switching transistor circuit starts to work. The drive circuit provides a drive signal to the drive transformer T1, and the drive transformer T1 provides a drive signal to the MOS switches TR1, TR2, and TR3. The MOS switches TR1, TR2, and TR3 work and transfer electrical energy to the secondary output circuit of the transformer.

[0028] The high-voltage divider protection circuit includes a high-voltage input power supply, a main transformer T2, a switching transistor, a voltage regulator, and a voltage divider circuit. The main transformer T2 includes a main winding T2-1 and secondary windings T2-2, T2-3, T2-4, and T2-5; the main winding T2-1 is connected to the high-voltage input power supply. Connection; high-voltage input power supply Connect to ground (GND); The switching transistors include MOS switches TR1, TR2, and TR3. Pin 2 of MOS switch TR1 is connected to pin 2 of the primary winding T2-1 of the main transformer T2, and pin 3 of MOS switch TR1 is connected to pin 3 of the secondary winding T2-2 of the main transformer T2. Pin 2 of MOS switch TR2 is connected to pin 4 of the secondary winding T2-2 of the main transformer T2, and pin 3 of MOS switch TR2 is connected to pin 5 of the secondary winding T2-3 of the main transformer T2. Pin 2 of MOS switch TR3 is connected to pin 6 of the secondary winding T2-3 of the main transformer T2, and pin 3 of MOS switch TR3 is connected to a resistor. Connect it in series with ground (GND); The Zener diodes include D1, D2, D3, D4, D5, D6, D21, D22, D23, D24, D31, and D32. Zener diodes D1, D2, D3, D4, D5, and D6 are connected to pin 2 of the primary winding T2-1 of the main transformer T2; Zener diodes D21, D22, D23, and D24 are connected to pin 3 of the secondary winding T2-2 of the main transformer T2; Zener diodes D31 and D32 are connected to pin 5 of the secondary winding T2-3 of the main transformer T2; the other end of the Zener diodes is connected to ground (GND); Zener diodes D1-D6, D21-D24, and D31-D32 are 250VDC Zener diodes with a withstand voltage of 400V and a regulated voltage of 250V.

[0029] The voltage divider circuit and the high-voltage input power supply High-voltage input power supply Parallel connection.

[0030] The high-voltage switching voltage divider protection circuit of the driving switching transistor circuit mainly divides the DC input voltage range of 800-1500VDC into three voltage segments to ensure that the voltage of each voltage segment is stable between 300-600VDC, thereby reducing the voltage requirements of MOS switching transistors TR1, TR2, and TR3.

[0031] Preferably, the MOS switching transistors TR1, TR2, and TR3 are model 7N65 with a withstand voltage (VDS) of 650V.

[0032] The voltage divider circuit includes a series circuit of resistors R1-R8 and a series circuit of DC voltage divider capacitors EC1-EC4; the series circuit of resistors R1-R8 and the series circuit of DC voltage divider capacitors EC1-EC4 are connected in parallel; capacitors EC1-EC4 are 400V rated EC capacitors; the positive terminal of DC voltage divider capacitor EC1 is connected to resistor R1 and to the high-voltage input power supply. Connections: Connect the negative terminal of DC voltage divider capacitor EC1 to the intermediate circuit connection point of resistors R2 and R3; connect the negative terminal of DC voltage divider capacitor EC2 to the intermediate circuit connection point of resistors R4 and R5; connect the negative terminal of DC voltage divider capacitor EC3 to the intermediate circuit connection point of resistors R6 and R7; the input high voltage is 200-1500V, the capacitors are 400V each, and the resistors R1-R8 have a resistance of 1MΩ, packaged in 1206 (1 / 2W). Connect the negative terminal of DC voltage divider capacitor EC4 to the high voltage input power supply. Connection, high-voltage input power supply Connect the terminal to ground (GND); connect the intermediate circuit connection points of resistors R2 and R3.

[0033] Preferably, the main transformer T2 winding and Zener diode components of the high-voltage switch divider protection circuit driving the switching transistor circuit divide the input voltage of 800-1500VDC into three voltage segments. The MOS switching transistors TR1, TR2, and TR3 withstand 1 / 3 of the total voltage, ensuring that the voltage of each voltage segment is stable between 300-600VDC, thereby reducing the voltage requirements of the MOS switching transistors.

[0034] Preferably, in a high-voltage DC circuit where MOS switches TR1, TR2, and TR3 cannot be turned off simultaneously, the first MOS switch to turn off will bear the entire bus voltage and the reflected voltage from the transformer secondary side, making it prone to reverse voltage breakdown. By adding a high-voltage divider protection circuit for the transformer-driven switches in the high-voltage DC circuit, when the MOS switches are turned off at different times, the bus voltage and the reflected voltage from the transformer secondary side that the MOS switches bear are within the withstand voltage range of the MOS switches, thus preventing the MOS switches from being broken down.

[0035] Preferably, the high-voltage switch voltage divider protection circuit connected to the drive switch tube circuit in the DC high-voltage circuit ensures that the voltage borne by the windings T2-1, T2-2, and T2-3 of the main transformer T2 is 1 / 3 of the bus voltage, thereby reducing the voltage of the windings and increasing the insulation of the transformer windings.

[0036] Example like Figure 2 As shown, the driving switch circuit is connected to MOS switches TR1, TR2, and TR3 and is used to control the opening and closing of MOS switches TR1, TR2, and TR3.

[0037] The drive switching transistor circuit includes a main transformer T2, a drive circuit, a drive transformer T1, and an RC circuit; The driving circuit includes a driving chip IC1 connected to pins 1 and 2 of the driving transformer T1. The driving chip IC1 simultaneously controls the opening and closing of MOS switches TR1, TR2, and TR3. The driving chip IC1 electrically isolates the opening and closing of the MOS switches TR1, TR2, and TR3. The main side T1-2 of the drive transformer T1 is connected in series with C1 and R10 and then connected to the control pin 1 of the MOS switch TR1. The secondary side T1-3 of the drive transformer T1 is connected in series with C3 and R13 and then connected to the control pin 1 of the MOS switch TR2. The secondary side T1-4 of the drive transformer T1 is connected in series with C5 and R17 and then connected to the control pin 1 of the MOS switch TR3. The pin 7 of the main side T1-2 of the driving transformer T1 is connected to diode D7 via the intermediate connection between C1 and R10; the pin 5 of the secondary side T1-3 of the driving transformer T1 is connected to diode D9 via the intermediate connection between C3 and R13; and the pin 3 of the secondary side T1-4 of the driving transformer T1 is connected to diode D11 via the intermediate connection between C5 and R17. Pins 1 and 3 of the MOS switch TR1 are connected via resistor R9, and pin 3 is connected to pin 7 of the primary side T1-2 of the drive transformer T1; pins 1 and 3 of the MOS switch TR2 are connected via resistor R14, and pin 3 is connected to pin 5 of the secondary side T1-3 of the drive transformer T1; pins 1 and 3 of the MOS switch TR3 are connected via resistor R9. The connection is made so that pin 3 is connected to pin 3 of the secondary side T1-4 of the drive transformer T1, and pin 3 of the secondary side T1-4 is connected to the ground line GND. Resistors R11 and R12, along with capacitor C2, are connected in parallel to form circuit RC1. One end of circuit RC1 is connected to pin 7 of the primary winding T1-2 of the drive transformer T1, and the other end is connected to the cathode of diode D8. The anode of diode D8 is connected to pin 2 of MOS switch TR2. Resistors R15 and R16, along with capacitor C4, are connected in parallel to form circuit RC2. One end of circuit RC2 is connected to pin 5 of the secondary winding T1-3 of the drive transformer T1, and the other end is connected to the cathode of diode D10. The anode of diode D10 is connected to pin 2 of MOS switch TR3. Diodes D7, D8, D9, D10, and D11 are of type M7.

[0038] The drive transformer T1 includes a main side T1-2 and a secondary side T1-1, T1-3, and T1-4. The drive chip IC1 simultaneously drives the switching of MOS switches TR1, TR2, and TR3. The drive signal emitted by the drive chip IC1 drives the MOS switches TR1, TR2, and TR3 in isolation through the drive transformer T1.

[0039] Example As attached Figure 3 As shown, this utility model provides the driving circuit, which includes a driving chip IC1, a chip power supply VCC, a chip start-up current circuit, a current detection circuit, a PWM switching pulse output, an optocoupler voltage regulation control circuit, and the chip power supply VCC is connected to pin 6 of the driving chip IC1.

[0040] Preferably, the driver chip IC1 is model LD7575PS.

[0041] The chip startup current circuit includes a chip power supply VCC, a resistor R18, and a capacitor C7. One end of the resistor R18 is connected to the chip power supply VCC, and the other end is connected to pin 8 of the driver chip IC1. The positive terminal of the capacitor C7 is connected to pin 8 of the driver chip IC1, and the negative terminal of the capacitor C7 is connected to ground GND. The chip startup current circuit provides startup current for the driver chip IC1.

[0042] The current detection circuit includes a resistor R19 and a capacitor C6; one end of resistor R19 is connected to pin 3 of the driver chip IC1, and the other end of resistor R19 is connected to pin 3 of the driver MOS switch TR1; One end is connected to pin 3 of the driving MOS switch TR1 and resistor R19. The other end is connected to ground GND; one end of capacitor C6 is connected to pin 3 of driver chip IC1, and the other end of capacitor C6 is connected to ground GND; the current detection circuit monitors the overcurrent values ​​of drive MOS switches TR1, TR2, and TR3 when the high-voltage switch divider protection circuit of the drive switching transistor circuit is working. After the driver chip IC1 detects the return current value, the driver chip IC1 performs program judgment and adjusts the control signals of MOS switches TR1, TR2, and TR3 to turn on and off; the timing resistor R21 is externally connected to pin 1 of driver chip IC1. One end of the timing resistor R21 is connected to pin 1 of driver chip IC1, and the other end of the timing resistor R21 is connected to ground GND. The timing resistor R21 determines the oscillation frequency of MOS switches TR1, TR2, and TR3.

[0043] Preferably, the PWM switching pulse output is connected to pin 1 of the secondary side T1-1 of the drive transformer T1 after an external resistor R20 is connected to pin 5 of the drive chip IC1, and pin 4 of the drive chip IC1 is connected to pin 2 of the secondary side T1-1 of the drive transformer T1; the PWM switching pulse is used to drive the MOS switching transistors TR1, TR2, and TR3 to turn on and off.

[0044] Preferably, the optocoupler voltage regulator control circuit includes capacitor C9, capacitor C10, resistors R22, R25, and R26, and optocoupler Q1. Pins 1 and 2 of optocoupler Q1 are connected in parallel with capacitor C10. Pin 2 of optocoupler Q1 is connected to ground GND. Pin 1 of optocoupler Q1 is connected to pin 2 of driver chip IC1. Pin 3 of optocoupler Q1 is connected to pin 9 of the secondary winding T2-5 of main transformer T2 after an external resistor R22. Pin 10 of the secondary winding T2-5 of main transformer T2 is connected in series with resistors R25 and R26. One end of resistor R26 is connected to resistor R25, and the other end of resistor R26 is connected to ground GND. The connection point of resistors R25 and R26 is connected to one end of capacitor C9, and the other end of capacitor C9 is connected to pin 4 of optocoupler Q1. Optocoupler Q1 is selected as a surface-mount optocoupler, and the model can be MOS3063. The optocoupler voltage regulator control circuit is used for comparator control of PWM switching pulses, realizing automatic voltage regulation control of the driver chip IC1 to turn on and off the MOS switching transistors TR1, TR2, and TR3.

[0045] The above description is merely an embodiment of this utility model, and common knowledge regarding specific structures and characteristics is not described in detail here. It will be apparent to those skilled in the art that this utility model is not limited to the details of the above exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this utility model is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this utility model. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A high-voltage switching voltage divider protection circuit for driving a switching transistor circuit, characterized in that, include: High voltage divider protection circuit and drive switch circuit; The high-voltage divider protection circuit includes a high-voltage input power supply, a main transformer T2, a switching transistor, a voltage regulator, and a voltage divider circuit. The main transformer T2 includes a main winding T2-1 and secondary windings T2-2, T2-3, T2-4, and T2-5; the main winding T2-1 is connected to the high-voltage input power supply. Connection; high-voltage input power supply Connect to ground (GND); The switching transistors include MOS switches TR1, TR2, and TR3. Pin 2 of MOS switch TR1 is connected to pin 2 of the primary winding T2-1 of the main transformer T2, and pin 3 of MOS switch TR1 is connected to pin 3 of the secondary winding T2-2 of the main transformer T2. Pin 2 of MOS switch TR2 is connected to pin 4 of the secondary winding T2-2 of the main transformer T2, and pin 3 of MOS switch TR2 is connected to pin 5 of the secondary winding T2-3 of the main transformer T2. Pin 2 of MOS switch TR3 is connected to pin 6 of the secondary winding T2-3 of the main transformer T2, and pin 3 of MOS switch TR3 is connected to a resistor. Connect it in series with ground (GND); The Zener diodes include D1, D2, D3, D4, D5, D6, D21, D22, D23, D24, D31, and D32. Zener diodes D1, D2, D3, D4, D5, and D6 are connected to pin 2 of the primary winding T2-1 of the main transformer T2; Zener diodes D21, D22, D23, and D24 are connected to pin 3 of the secondary winding T2-2 of the main transformer T2; Zener diodes D31 and D32 are connected to pin 5 of the secondary winding T2-3 of the main transformer T2; and the other end of each Zener diode is connected to ground (GND). The voltage divider circuit and the high-voltage input power supply High-voltage input power supply Parallel connection; The driving switch circuit is connected to the MOS switches TR1, TR2, and TR3 and is used to control the opening and closing of the MOS switches TR1, TR2, and TR3.

2. The high-voltage switching voltage divider protection circuit for the driving switching transistor circuit according to claim 1, characterized in that, The drive switching transistor circuit includes a main transformer T2, a drive circuit, a drive transformer T1, and an RC circuit; The driving circuit includes a driving chip IC1 connected to pins 1 and 2 of the driving transformer T1. The driving chip IC1 simultaneously controls the opening and closing of MOS switches TR1, TR2, and TR3. The driving chip IC1 electrically isolates the opening and closing of the MOS switches TR1, TR2, and TR3. The main side T1-2 of the drive transformer T1 is connected in series with C1 and R10 and then connected to the control pin 1 of the MOS switch TR1. The secondary side T1-3 of the drive transformer T1 is connected in series with C3 and R13 and then connected to the control pin 1 of the MOS switch TR2. The secondary side T1-4 of the drive transformer T1 is connected in series with C5 and R17 and then connected to the control pin 1 of the MOS switch TR3. The pin 7 of the primary side T1-2 of the drive transformer T1 is connected to diode D7 via the intermediate connection between C1 and R10. The pin 5 of the secondary side T1-3 of the drive transformer T1 is connected to diode D9 via the intermediate connection between C3 and R13. The pin 3 of the secondary side T1-4 of the drive transformer T1 is connected to diode D11 via the intermediate connection between C5 and R17. Pins 1 and 3 of MOS switch TR1 are connected via resistor R9, and pin 3 is connected to pin 7 of the primary winding T1-2 of drive transformer T1; pins 1 and 3 of MOS switch TR2 are connected via resistor R14, and pin 3 is connected to pin 5 of the secondary winding T1-3 of drive transformer T1; pins 1 and 3 of MOS switch TR3 are connected via resistor R9. The connection is made so that pin 3 is connected to pin 3 of the secondary side T1-4 of the drive transformer T1, and pin 3 of the secondary side T1-4 is connected to the ground line GND. Resistors R11 and R12 and capacitor C2 are connected in parallel to form RC1 circuit. One end of RC1 circuit is connected to pin 7 of the main side T1-2 of the drive transformer T1, and the other end of RC1 circuit is connected to the cathode of diode D8. The anode of diode D8 is connected to pin 2 of MOS switch TR2. Resistors R15 and R16 and capacitor C4 are connected in parallel to form RC2 circuit. One end of RC2 circuit is connected to pin 5 of the secondary side T1-3 of the drive transformer T1, and the other end of RC2 circuit is connected to the cathode of diode D10. The anode of diode D10 is connected to pin 2 of MOS switch TR3.

3. The high-voltage switching voltage divider protection circuit for the driving switching transistor circuit according to claim 1, characterized in that, The voltage divider circuit includes a series circuit of resistors R1-R8 and a series circuit of DC voltage divider capacitors EC1-EC4; the series circuit of resistors R1-R8 and the series circuit of DC voltage divider capacitors EC1-EC4 are connected in parallel; the positive terminal of DC voltage divider capacitor EC1 is connected to resistor R1 and to the high-voltage input power supply. Connections: Connect the negative terminal of DC voltage divider capacitor EC1 to the intermediate circuit connection point of resistors R2 and R3; connect the negative terminal of DC voltage divider capacitor EC2 to the intermediate circuit connection point of resistors R4 and R5; connect the negative terminal of DC voltage divider capacitor EC3 to the intermediate circuit connection point of resistors R6 and R7; connect the negative terminal of DC voltage divider capacitor EC4 to the high-voltage input power supply. Connection, high-voltage input power supply Connect the terminal to ground (GND); connect the intermediate circuit connection points of resistors R2 and R3.

4. The high-voltage switching voltage divider protection circuit for the driving switching transistor circuit according to claim 2, characterized in that, The drive transformer T1 includes a main side T1-2 and a secondary side T1-1, T1-3, and T1-4. The drive chip IC1 simultaneously drives the switching of MOS switches TR1, TR2, and TR3. The drive signal emitted by the drive chip IC1 drives the MOS switches TR1, TR2, and TR3 in isolation through the drive transformer T1.

5. The high-voltage switching voltage divider protection circuit for the driving switching transistor circuit according to claim 2, characterized in that, The driving circuit includes a driving chip IC1, a chip power supply VCC, a chip start-up current circuit, a current detection circuit, a PWM switching pulse output, an optocoupler voltage regulation control circuit, and the chip power supply VCC is connected to pin 6 of the driving chip IC1. The chip startup current circuit includes a chip power supply VCC, a resistor R18, and a capacitor C7. One end of the resistor R18 is connected to the chip power supply VCC, and the other end is connected to pin 8 of the driver chip IC1. The positive terminal of the capacitor C7 is connected to pin 8 of the driver chip IC1, and the negative terminal of the capacitor C7 is connected to ground GND. The chip startup current circuit provides startup current for the driver chip IC1. The current detection circuit includes a resistor R19 and a capacitor C6; one end of resistor R19 is connected to pin 3 of the driver chip IC1, and the other end of resistor R19 is connected to pin 3 of the driver MOS switch TR1; One end is connected to pin 3 of the driving MOS switch TR1 and resistor R19. The other end is connected to ground GND; one end of capacitor C6 is connected to pin 3 of driver chip IC1, and the other end of capacitor C6 is connected to ground GND; the current detection circuit monitors the overcurrent values ​​of drive MOS switches TR1, TR2, and TR3 when the high-voltage switch divider protection circuit of the drive switching transistor circuit is working. After the driver chip IC1 detects the return current value, the driver chip IC1 performs program judgment and adjusts the control signals of MOS switches TR1, TR2, and TR3 to turn on and off; the timing resistor R21 is externally connected to pin 1 of driver chip IC1. One end of the timing resistor R21 is connected to pin 1 of driver chip IC1, and the other end of the timing resistor R21 is connected to ground GND. The timing resistor R21 determines the oscillation frequency of MOS switches TR1, TR2, and TR3; The PWM switching pulse output is connected to pin 1 of the secondary side T1-1 of the drive transformer T1 via an external resistor R20 connected to pin 5 of the drive chip IC1. Pin 4 of the drive chip IC1 is connected to pin 2 of the secondary side T1-1 of the drive transformer T1. The optocoupler voltage regulation control circuit includes capacitors C9 and C10, resistors R22, R25, and R26, and optocoupler Q1. Pins 1 and 2 of optocoupler Q1 are connected in parallel with capacitor C10, and pin 2 of optocoupler Q1 is connected to ground GND. Pin 1 of the optocoupler Q1 is connected to pin 2 of the driver chip IC1; pin 3 of the optocoupler Q1 is connected to pin 9 of the secondary winding T2-5 of the main transformer T2 after an external resistor R22 is connected to pin 10 of the secondary winding T2-5 of the main transformer T2. An external resistor R25 and a resistor R26 are connected in series to pin 10 of the secondary winding T2-5 of the main transformer T2. One end of the resistor R26 is connected to the resistor R25, and the other end of the resistor R26 is connected to the ground GND. The connection point of the resistors R25 and R26 is connected to one end of the capacitor C9, and the other end of the capacitor C9 is connected to pin 4 of the optocoupler Q1.

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