A composite overvoltage protection circuit for a high-voltage power supply control system

Abstract

This utility model discloses a composite overvoltage protection circuit for a high-voltage power supply control system, comprising a load voltage detection and judgment circuit, a power supply voltage detection circuit, a microcontroller circuit, a hardware judgment and protection circuit, and an auxiliary power supply circuit. The hardware judgment and protection circuit is connected to the load voltage detection and judgment circuit, the power supply voltage detection circuit, and the microcontroller circuit, respectively. The microcontroller circuit is connected to the load voltage detection and judgment circuit. The auxiliary power supply circuit supplies power to the load voltage detection and judgment circuit, the power supply voltage detection circuit, the microcontroller circuit, and the hardware judgment and protection circuit. This utility model can effectively prevent overvoltage problems in the load.

Description

Technical Field

[0001] This utility model relates to the field of high-voltage power supply control systems, and in particular to a composite overvoltage protection circuit for a high-voltage power supply control system. Background Technology

[0002] Existing high-voltage power supply control systems generally use software overvoltage protection circuits or hardware overvoltage protection circuits for overvoltage protection.

[0003] The principle of the software overvoltage protection circuit is as follows: the microcontroller detects whether the load is overvoltage through a voltage detection circuit. If the load is overvoltage, the microcontroller controls the entire system to stop output, thereby achieving overvoltage protection. However, if the microcontroller malfunctions or the auxiliary power supply to the microcontroller is abnormal, the overvoltage protection function will fail.

[0004] The principle of a hardware overvoltage protection circuit is as follows: a comparator circuit compares the load voltage with a reference voltage. If the load is overvoltaged, the comparator circuit controls the entire system to stop outputting, thus achieving overvoltage protection. However, if the reference voltage deviates, the overvoltage protection function will fail.

[0005] In view of the above problems, it is necessary to study a composite overvoltage protection circuit for a high-voltage power supply control system, which can effectively prevent overvoltage problems from occurring in the load. Utility Model Content

[0006] The purpose of this invention is to provide a composite overvoltage protection circuit for a high-voltage power supply control system, which can effectively prevent overvoltage problems from occurring in the load.

[0007] To achieve the above objectives, the solution of this utility model is: A composite overvoltage protection circuit for a high-voltage power supply control system includes a load voltage detection and judgment circuit, a power supply voltage detection circuit, a microcontroller circuit, a hardware judgment and protection circuit, and an auxiliary power supply circuit. The auxiliary power supply circuit provides an analog power supply A+12V, a digital power supply +12V, and a digital power supply +3.3V. The load voltage detection and judgment circuit includes a load voltage comparison circuit, a reference voltage circuit, a first optocoupler isolation circuit, and a second optocoupler isolation circuit. The load voltage comparison circuit and the reference voltage circuit are powered by the analog power supply A+12V. The non-inverting input of the load voltage comparison circuit is connected to the output of the reference voltage circuit, and the inverting input of the load voltage comparison circuit is used to input the load voltage signal V-CH. The output of the load voltage comparison circuit is connected to the inputs of the first and second optocoupler isolation circuits. The output of the first optocoupler isolation circuit is connected to the hardware judgment and protection circuit, and its output is used to output a first hardware detection signal Test1-H to the hardware judgment and protection circuit. The output of the second optocoupler isolation circuit is connected to the microcontroller circuit. Furthermore, the output of the second optocoupler isolation circuit is used to output an isolation detection signal Test-S' to the microcontroller circuit. The microcontroller circuit is powered by a digital power supply of +3.3V and is connected to the hardware judgment and protection circuit. The microcontroller circuit outputs a software detection signal Test-S to the hardware judgment and protection circuit based on the isolation detection signal Test-S'. The input of the power supply voltage detection circuit is connected to the analog power supply A+12V, and the output of the power supply voltage detection circuit is connected to the hardware judgment and protection circuit. The power supply voltage detection circuit outputs a second hardware detection signal Test2-H to the hardware judgment and protection circuit based on whether the analog power supply A+12V is normal. The hardware judgment and protection circuit is powered by a digital power supply of +12V. The hardware judgment and protection circuit only outputs a valid enable signal EN-SW when the digital power supply +12V is normal and the first hardware detection signal Test1-H, the second hardware detection signal Test2-H, and the software detection signal Test-S are all valid. When the enable signal EN-SW is valid, the high-voltage power supply control system supplies power to the load.

[0008] The hardware judgment and protection circuit includes resistors R64, R65, R66, and R67, transistor Q8, and logic gate chip U12. Logic gate chip U12 integrates four AND gates. Pin 1A of logic gate chip U12 is connected to the first input terminal of the hardware judgment and protection circuit through resistor R64. Pin 1B of logic gate chip U12 is connected to the third input terminal of the hardware judgment and protection circuit through resistor R65. Pin 1Y of logic gate chip U12 is connected to pin 4B of logic gate chip U12. Pins 2A and 2B of logic gate chip U12 are connected to the second input terminal of the hardware judgment and protection circuit. Pin 2Y of logic gate chip U12 is connected to pin 4A of logic gate chip U12. Pin 4Y of logic gate chip U12 is connected to pin 3B of logic gate chip U12. Pin 3A of logic gate chip U12 is connected to the first terminal of resistor R66 and the collector of transistor Q8. The second terminal of resistor R66 and the VDD pin of logic gate chip U12 are connected to the digital power supply. +12V; The emitter of transistor Q8 and the VSS pin of logic gate chip U12 are connected to ground GND. The base of transistor Q8 is connected to the fourth input terminal of the hardware judgment and protection circuit through resistor R67. The 3Y pin of logic gate chip U12 is connected to the output terminal of the hardware judgment and protection circuit. The first input terminal of the hardware judgment and protection circuit is used to input the first hardware detection signal Test1-H, which is active high. The second input terminal of the hardware judgment and protection circuit is used to input the second hardware detection signal Test2-H, which is active high. The third input terminal of the hardware judgment and protection circuit is used to input the digital power supply +12V. The fourth input terminal of the hardware judgment and protection circuit is used to input the software detection signal Test-S, which is active low. The output terminal of the hardware judgment and protection circuit is used to output the enable signal EN-SW, which is active high.

[0009] The power supply voltage detection circuit includes resistors R2 and R3 and optocoupler U1. The first end of resistor R2 is connected to the input terminal of the power supply voltage detection circuit, the second end of resistor R2 is connected to the positive terminal of the input side of optocoupler U1, the negative terminal of the input side of optocoupler U1 is connected to ground AGND, the positive terminal of the output side of optocoupler U1 is connected to the digital power supply +12V, the negative terminal of the output side of optocoupler U1 and the first end of resistor R3 are connected to the output terminal of the power supply voltage detection circuit, and the second end of resistor R3 is connected to ground GND.

[0010] The first optocoupler isolation circuit includes resistors R5 and R7 and optocoupler U2. The first end of resistor R7 is connected to the analog power supply A+12V, the second end of resistor R7 is connected to the positive input terminal of optocoupler U2, the negative input terminal of optocoupler U2 is connected to the input terminal of the first optocoupler isolation circuit, the positive output terminal of optocoupler U2 and the first end of resistor R5 are connected to the output terminal of the first optocoupler isolation circuit, the second end of resistor R5 is connected to the digital power supply +12V, and the negative output terminal of optocoupler U2 is connected to ground GND.

[0011] The second optocoupler isolation circuit includes resistors R8 and R9 and optocoupler U5. The first end of resistor R9 is connected to the analog power supply A+12V, the second end of resistor R9 is connected to the positive input terminal of optocoupler U5, the negative input terminal of optocoupler U5 is connected to the input terminal of the second optocoupler isolation circuit, the positive output terminal of optocoupler U5 and the second end of resistor R8 are connected to the output terminal of the second optocoupler isolation circuit, the second end of resistor R8 is connected to the digital power supply +3.3V, and the negative output terminal of optocoupler U5 is connected to ground GND.

[0012] The load voltage comparison circuit includes a comparator U38. The non-inverting input, inverting input, and output of the comparator U38 are respectively connected to the non-inverting input, inverting input, and output of the load voltage comparison circuit. The power supply terminal of the comparator U38 is connected to the analog power supply A+12V, and the ground terminal of the comparator U38 is connected to the ground terminal AGND.

[0013] The reference voltage circuit includes a resistor R4, a capacitor C2, a capacitor C3, and a three-terminal regulator U4. The first end of the resistor R4 is connected to the analog power supply A+12V. The second end of the resistor R4, the first end of the capacitor C2, the positive terminal of the capacitor C3, and the reference terminal and cathode of the three-terminal regulator U4 are connected to the output terminal of the reference voltage circuit. The second end of the capacitor C2, the negative terminal of the capacitor C3, and the anode of the three-terminal regulator U4 are connected to the ground terminal AGND.

[0014] The load voltage detection and judgment circuit also includes an indicator circuit connected to the output terminal of the load voltage comparison circuit.

[0015] The indicator circuit includes a resistor R1 and an indicator LED1. The first end of the resistor R1 is connected to the analog power supply A+12V, the second end of the resistor R1 is connected to the positive terminal of the indicator LED1, and the negative terminal of the indicator LED1 is connected to the output terminal of the load voltage comparison circuit.

[0016] The output of the load voltage comparison circuit is connected to ground AGND through capacitor C4.

[0017] After adopting the above scheme, the composite overvoltage protection circuit of the high-voltage power supply control system of this utility model is effective only when the analog power supply A+12V and the microcontroller circuit are normal and the load voltage signal V-CH is lower than the voltage output by the reference voltage circuit (i.e., the load is not overvoltage). At this time, the first hardware detection signal Test1-H, the second hardware detection signal Test2-H, and the software detection signal Test-S are all effective. The hardware judgment protection circuit is powered by the digital power supply +12V, and the hardware judgment protection circuit only outputs an effective signal when the digital power supply +12V is normal and the first hardware detection signal Test1-H, the second hardware detection signal Test2-H, and the software detection signal Test-S are all effective. The enable signal EN-SW is active; when the enable signal EN-SW is active, the high-voltage power supply control system supplies power to the load. This configuration ensures that the high-voltage power supply control system only supplies power to the load when the circuit is normal (i.e., the analog power supply A+12V, the digital power supply +12V are normal, and the microcontroller circuit is normal) and the load is not overvoltaged. However, if the circuit is abnormal (i.e., the analog power supply A+12V, the digital power supply +12V are normal, and at least one of the microcontroller circuits is abnormal) and / or the load is overvoltaged, the hardware determines that the enable signal EN-SW is invalid, thus preventing the high-voltage power supply control system from supplying power to the load. This ensures stable overvoltage protection and avoids the problem of overvoltage protection failure due to circuit abnormalities. Attached Figure Description

[0018] Figure 1 This is a circuit diagram of the load voltage detection and judgment circuit and the power supply voltage detection circuit of this utility model.

[0019] Figure 2 This is a circuit diagram of the hardware judgment and protection circuit of this utility model.

[0020] Figure 3 This is the circuit schematic diagram of the microcontroller circuit of this utility model.

[0021] Figure 4 This is a circuit diagram of the auxiliary power supply circuit of this utility model. Detailed Implementation

[0022] To further explain the technical solution of this utility model, the following detailed description is provided through specific embodiments.

[0023] like Figures 1 to 4As shown, this utility model discloses a composite overvoltage protection circuit for a high-voltage power supply control system, which includes a load voltage detection and judgment circuit, a power supply voltage detection circuit, a microcontroller circuit, a hardware judgment and protection circuit, and an auxiliary power supply circuit. The auxiliary power supply circuit provides analog power supply A+12V, analog power supply A+5V, digital power supply +12V, digital power supply -12V, digital power supply +5V, digital power supply -5V, and digital power supply +3.3V. The load voltage detection and judgment circuit includes a load voltage comparison circuit, a reference voltage circuit, a first optocoupler isolation circuit, and a second optocoupler isolation circuit. The load voltage comparison circuit and the reference voltage circuit are powered by the analog power supply A+12V. The non-inverting input of the load voltage comparison circuit is connected to the output of the reference voltage circuit, and the inverting input of the load voltage comparison circuit is used to input the load voltage signal V-CH. The output of the load voltage comparison circuit is connected to the inputs of the first and second optocoupler isolation circuits. The output of the first optocoupler isolation circuit is connected to the hardware judgment and protection circuit, and the output of the first optocoupler isolation circuit is used to output a first hardware detection signal Test1-H to the hardware judgment circuit. The protection circuit includes a second optocoupler isolation circuit whose output is connected to a microcontroller circuit. The output of the second optocoupler isolation circuit is used to output an isolation detection signal Test-S' to the microcontroller circuit. The microcontroller circuit is powered by a +3.3V digital power supply and is connected to a hardware judgment protection circuit. Based on the isolation detection signal Test-S', the microcontroller circuit outputs a corresponding software detection signal Test-S to the hardware judgment protection circuit. The input of the power supply voltage detection circuit is connected to an analog power supply A+12V, and its output is connected to the hardware judgment protection circuit. Based on whether the analog power supply A+12V is normal, the power supply voltage detection circuit outputs a second hardware detection signal Test2-H to the hardware judgment protection circuit. The hardware judgment protection circuit is powered by a +12V digital power supply. It outputs a valid enable signal EN-SW only when the +12V digital power supply is normal and the first hardware detection signal Test1-H, the second hardware detection signal Test2-H, and the software detection signal Test-S are all valid. When the enable signal EN-SW is valid, the high-voltage power supply control system supplies power to the load.

[0024] In the operation of the composite overvoltage protection circuit of the high-voltage power supply control system of this utility model, the first hardware detection signal Test1-H, the second hardware detection signal Test2-H, and the software detection signal Test-S are all valid only when the analog power supply A+12V and the microcontroller circuit are normal and the load voltage signal V-CH is lower than the voltage output by the reference voltage circuit (i.e., the load is not overvoltage). The hardware judgment protection circuit is powered by the digital power supply +12V, and it only outputs a valid enable signal when the digital power supply +12V is normal and the first hardware detection signal Test1-H, the second hardware detection signal Test2-H, and the software detection signal Test-S are all valid. EN-SW; When the enable signal EN-SW is valid, the high-voltage power supply control system supplies power to the load. This setting ensures that the high-voltage power supply control system supplies power to the load only when the circuit is normal (i.e., the analog power supply A+12V, the digital power supply +12V are normal, and the microcontroller circuit is normal) and the load is not overvoltage. However, if the circuit is abnormal (i.e., the analog power supply A+12V, the digital power supply +12V are normal, and at least one of the microcontroller circuits is abnormal) and / or the load is overvoltage, the hardware determines that the enable signal EN-SW is invalid, thus preventing the high-voltage power supply control system from supplying power to the load. This ensures stable overvoltage protection and avoids the problem of overvoltage protection failure due to circuit abnormalities.

[0025] In an embodiment of this utility model, the hardware judgment and protection circuit includes resistors R64, R65, R66, and R67, transistor Q8, and logic gate chip U12. The logic gate chip U12 can be an HEF4081BT, and it integrates four AND gates. Pin 1A of logic gate chip U12 is connected to the first input terminal of the hardware judgment and protection circuit through resistor R64, and pin 1B of logic gate chip U12 is connected to the third input terminal of the hardware judgment and protection circuit through resistor R65. Pin 1Y of transistor Q12 is connected to pin 4B of logic gate chip U12. Pins 2A and 2B of logic gate chip U12 are connected to the second input terminal of the hardware judgment and protection circuit. Pin 2Y of logic gate chip U12 is connected to pin 4A of logic gate chip U12. Pin 4Y of logic gate chip U12 is connected to pin 3B of logic gate chip U12. Pin 3A of logic gate chip U12 is connected to the first terminal of resistor R66 and the collector of transistor Q8. The second terminal of resistor R66 and the VDD pin of logic gate chip U12 are connected to the digital power supply +1. 2V; The VDD pin of logic gate chip U12 can be grounded through parallel capacitors C33, C34, and C35. The emitter of transistor Q8 and the VSS pin of logic gate chip U12 are connected to ground GND. The base of transistor Q8 is connected to the fourth input terminal of the hardware judgment and protection circuit through resistor R67. The 3Y connection of logic gate chip U12 is connected to the output terminal of the hardware judgment and protection circuit. The first input terminal of the hardware judgment and protection circuit is used to input the first hardware detection signal Test1-H, which is active high. The second input terminal of the hardware judgment and protection circuit is used to input the second hardware detection signal Test2-H, which is active high. The third input terminal of the hardware judgment and protection circuit is used to input the digital power supply +12V. The fourth input terminal of the hardware judgment and protection circuit is used to input the software detection signal Test-S, which is active low. The output terminal of the hardware judgment and protection circuit is used to output the enable signal EN-SW, which is active high. When the first hardware detection signal Test1-H is high, the second hardware detection signal Test2-H is high, the software detection signal Test-S is low, and the digital power supply +12V is normal, all four AND gates of the logic gate chip U12 output a high level, that is, the output terminal of the hardware judgment and protection circuit outputs a high-level enable signal EN-SW; otherwise, the output terminal of the hardware judgment and protection circuit outputs a low-level enable signal EN-SW.

[0026] In an embodiment of this invention, the power supply voltage detection circuit includes resistors R2 and R3 and an optocoupler U1. The first end of resistor R2 is connected to the input terminal of the power supply voltage detection circuit, and the second end of resistor R2 is connected to the positive input terminal of optocoupler U1. The negative input terminal of optocoupler U1 is connected to ground AGND. The positive output terminal of optocoupler U1 is connected to the +12V digital power supply. The negative output terminal of optocoupler U1 and the first end of resistor R3 are connected to the output terminal of the power supply voltage detection circuit, and the second end of resistor R3 is connected to ground GND. When the analog power supply A+12V is undervoltage, the power supply voltage detection circuit outputs a low-level second hardware detection signal Test2-H; when the analog power supply A+12V is normal, the power supply voltage detection circuit outputs a high-level second hardware detection signal Test2-H.

[0027] In an embodiment of this utility model, the load voltage comparison circuit includes a comparator U38. The non-inverting input, inverting input, and output of the comparator U38 are respectively connected to the non-inverting input, inverting input, and output of the load voltage comparison circuit. The power supply terminal of the comparator U38 is connected to the analog power supply A+12V, and the ground terminal of the comparator U38 is connected to the ground terminal AGND.

[0028] In an embodiment of this invention, the first optocoupler isolation circuit includes resistors R5 and R7 and optocoupler U2. The first end of resistor R7 is connected to the analog power supply A+12V, and the second end of resistor R7 is connected to the positive input terminal of optocoupler U2. The negative input terminal of optocoupler U2 is connected to the input terminal of the first optocoupler isolation circuit. The positive output terminal of optocoupler U2 and the first end of resistor R5 are connected to the output terminal of the first optocoupler isolation circuit. The second end of resistor R5 is connected to the digital power supply +12V, and the negative output terminal of optocoupler U2 is connected to ground GND. When the load is overvoltage, the output terminal of the load voltage comparator circuit outputs a low-level signal, which is the first low-level hardware detection signal Test1-H output by the first optocoupler isolation circuit. When the load is not overvoltage, the output terminal of the load voltage comparator circuit outputs a high-level signal, which is the first high-level hardware detection signal Test1-H output by the first optocoupler isolation circuit.

[0029] In an embodiment of this invention, the second optocoupler isolation circuit includes resistors R8 and R9 and optocoupler U5. The first end of resistor R9 is connected to the analog power supply A+12V, and the second end of resistor R9 is connected to the positive input terminal of optocoupler U5. The negative input terminal of optocoupler U5 is connected to the input terminal of the second optocoupler isolation circuit. The positive output terminal of optocoupler U5 and the second end of resistor R8 are connected to the output terminal of the second optocoupler isolation circuit. The second end of resistor R8 is connected to the digital power supply +3.3V, and the negative output terminal of optocoupler U5 is connected to ground GND. When the load is overvoltage, the output terminal of the load voltage comparator circuit outputs a low-level signal, which is the second optocoupler isolation circuit outputting a low-level isolation detection signal Test-S' to the microcontroller circuit. The microcontroller circuit then outputs a high-level software detection signal Test-S. When the load is not overvoltage, the output terminal of the load voltage comparator circuit outputs a high-level signal, which is the second optocoupler isolation circuit outputting a high-level isolation detection signal Test-S' to the microcontroller circuit. The microcontroller circuit then outputs a low-level software detection signal Test-S.

[0030] In an embodiment of this utility model, the reference voltage circuit includes a resistor R4, a capacitor C2, a capacitor C3, and a three-terminal regulator U4. The first end of the resistor R4 is connected to the analog power supply A+12V. The second end of the resistor R4, the first end of the capacitor C2, the positive terminal of the capacitor C3, and the reference terminal and cathode of the three-terminal regulator U4 are connected to the output terminal of the reference voltage circuit. The second end of the capacitor C2, the negative terminal of the capacitor C3, and the anode of the three-terminal regulator U4 are connected to the ground terminal AGND. Through the three-terminal regulator U4, the reference voltage circuit can output a stable reference voltage.

[0031] In an embodiment of this utility model, the load voltage detection and judgment circuit further includes an indicator circuit connected to the output terminal of the load voltage comparison circuit; when the load is overvoltage, the indicator circuit lights up to indicate the overvoltage. Specifically, the indicator circuit includes a resistor R1 and an indicator light LED1. The first end of the resistor R1 is connected to the analog power supply A+12V, the second end of the resistor R1 is connected to the positive terminal of the indicator light LED1, and the negative terminal of the indicator light LED1 is connected to the output terminal of the load voltage comparison circuit; when the load is overvoltage, the output terminal of the load voltage comparison circuit outputs a low-level signal, at which time the indicator light LED1 lights up to indicate the overvoltage; the output terminal of the load voltage comparison circuit can be connected to ground AGND through capacitor C4 to stabilize the output voltage of the load voltage comparison circuit.

[0032] The above embodiments and figures are not intended to limit the product form and style of this utility model. Any appropriate changes or modifications made by those skilled in the art should be considered as not departing from the patent scope of this utility model.

Claims

1. A composite overvoltage protection circuit for a high-voltage power supply control system, characterized in that: It includes a load voltage detection and judgment circuit, a power supply voltage detection circuit, a microcontroller circuit, a hardware judgment and protection circuit, and an auxiliary power supply circuit; The auxiliary power supply circuit provides analog power supply A+12V, digital power supply +12V, and digital power supply +3.3V; The load voltage detection and judgment circuit includes a load voltage comparison circuit, a reference voltage circuit, a first optocoupler isolation circuit, and a second optocoupler isolation circuit; the load voltage comparison circuit and the reference voltage circuit are powered by an analog power supply A+12V; The non-inverting input of the load voltage comparator circuit is connected to the output of the reference voltage circuit. The inverting input of the load voltage comparator circuit is used to input the load voltage signal V-CH. The output of the load voltage comparator circuit is connected to the input of the first optocoupler isolation circuit and the second optocoupler isolation circuit. The output of the first optocoupler isolation circuit is connected to the hardware judgment and protection circuit, and the output of the first optocoupler isolation circuit is used to output the first hardware detection signal Test1-H to the hardware judgment and protection circuit. The output of the second optocoupler isolation circuit is connected to the microcontroller circuit, and the output of the second optocoupler isolation circuit is used to output the isolation detection signal Test-S' to the microcontroller circuit. The microcontroller circuit is powered by a digital power supply of +3.3V. The microcontroller circuit is connected to the hardware judgment and protection circuit, and the microcontroller circuit outputs the corresponding software detection signal Test-S to the hardware judgment and protection circuit according to the isolation detection signal Test-S'. The input terminal of the power supply voltage detection circuit is connected to the analog power supply A+12V, and the output terminal of the power supply voltage detection circuit is connected to the hardware judgment and protection circuit. The power supply voltage detection circuit outputs a second hardware detection signal Test2-H to the hardware judgment and protection circuit according to whether the analog power supply A+12V is normal. The hardware judgment and protection circuit is powered by the digital power supply +12V. The hardware judgment and protection circuit outputs a valid enable signal EN-SW only when the digital power supply +12V is normal and the first hardware detection signal Test1-H, the second hardware detection signal Test2-H, and the software detection signal Test-S are all valid. When the enable signal EN-SW is valid, the high-voltage power supply control system supplies power to the load.

2. The composite overvoltage protection circuit of a high-voltage power supply control system as described in claim 1, characterized in that: The hardware judgment and protection circuit includes resistors R64, R65, R66, and R67, transistor Q8, and logic gate chip U12. Logic gate chip U12 integrates four AND gates. Pin 1A of logic gate chip U12 is connected to the first input terminal of the hardware judgment and protection circuit through resistor R64; pin 1B of logic gate chip U12 is connected to the third input terminal of the hardware judgment and protection circuit through resistor R65; pin 1Y of logic gate chip U12 is connected to pin 4B of logic gate chip U12; and pins 2A and 2B of logic gate chip U12 are connected to the second input terminal of the hardware judgment and protection circuit. Pin 2Y of transistor Q12 is connected to pin 4A of logic gate chip U12. Pin 4Y of logic gate chip U12 is connected to pin 3B of logic gate chip U12. Pin 3A of logic gate chip U12 is connected to the first end of resistor R66 and the collector of transistor Q8. The second end of resistor R66 and the VDD pin of logic gate chip U12 are connected to the digital power supply +12V. The emitter of transistor Q8 and the VSS pin of logic gate chip U12 are connected to ground GND. The base of transistor Q8 is connected to the fourth input terminal of the hardware judgment and protection circuit through resistor R67. Pin 3Y of logic gate chip U12 is connected to the output terminal of the hardware judgment and protection circuit. The first input terminal of the hardware judgment and protection circuit is used to connect to the first hardware detection signal Test1-H, which is active high. The second input terminal of the hardware judgment and protection circuit is used to connect to the second hardware detection signal Test2-H, which is active high. The third input terminal of the hardware judgment and protection circuit is used to connect to the +12V digital power supply. The fourth input terminal of the hardware judgment and protection circuit is used to connect to the software detection signal Test-S, which is active low. The output terminal of the hardware judgment and protection circuit is used to output the enable signal EN-SW, which is active high.

3. The composite overvoltage protection circuit of a high-voltage power supply control system as described in claim 2, characterized in that: The power supply voltage detection circuit includes resistors R2 and R3 and optocoupler U1. The first end of resistor R2 is connected to the input terminal of the power supply voltage detection circuit, the second end of resistor R2 is connected to the positive terminal of the input side of optocoupler U1, the negative terminal of the input side of optocoupler U1 is connected to ground AGND, the positive terminal of the output side of optocoupler U1 is connected to the digital power supply +12V, the negative terminal of the output side of optocoupler U1 and the first end of resistor R3 are connected to the output terminal of the power supply voltage detection circuit, and the second end of resistor R3 is connected to ground GND.

4. The composite overvoltage protection circuit of a high-voltage power supply control system as described in claim 2, characterized in that: The first optocoupler isolation circuit includes resistors R5 and R7 and optocoupler U2. The first end of resistor R7 is connected to the analog power supply A+12V, the second end of resistor R7 is connected to the positive input terminal of optocoupler U2, the negative input terminal of optocoupler U2 is connected to the input terminal of the first optocoupler isolation circuit, the positive output terminal of optocoupler U2 and the first end of resistor R5 are connected to the output terminal of the first optocoupler isolation circuit, the second end of resistor R5 is connected to the digital power supply +12V, and the negative output terminal of optocoupler U2 is connected to ground GND.

5. The composite overvoltage protection circuit of a high-voltage power supply control system as described in claim 2, characterized in that: The second optocoupler isolation circuit includes resistors R8 and R9 and optocoupler U5. The first end of resistor R9 is connected to the analog power supply A+12V, the second end of resistor R9 is connected to the positive input terminal of optocoupler U5, the negative input terminal of optocoupler U5 is connected to the input terminal of the second optocoupler isolation circuit, the positive output terminal of optocoupler U5 and the second end of resistor R8 are connected to the output terminal of the second optocoupler isolation circuit, the second end of resistor R8 is connected to the digital power supply +3.3V, and the negative output terminal of optocoupler U5 is connected to ground GND.

6. A composite overvoltage protection circuit for a high-voltage power supply control system as described in claim 1 or 2, characterized in that: The load voltage comparison circuit includes a comparator U38. The non-inverting input, inverting input, and output of the comparator U38 are respectively connected to the non-inverting input, inverting input, and output of the load voltage comparison circuit. The power supply terminal of the comparator U38 is connected to the analog power supply A+12V, and the ground terminal of the comparator U38 is connected to the ground terminal AGND.

7. A composite overvoltage protection circuit for a high-voltage power supply control system as described in claim 1 or 2, characterized in that: The reference voltage circuit includes a resistor R4, a capacitor C2, a capacitor C3, and a three-terminal regulator U4. The first end of the resistor R4 is connected to the analog power supply A+12V. The second end of the resistor R4, the first end of the capacitor C2, the positive terminal of the capacitor C3, and the reference terminal and cathode of the three-terminal regulator U4 are connected to the output terminal of the reference voltage circuit. The second end of the capacitor C2, the negative terminal of the capacitor C3, and the anode of the three-terminal regulator U4 are connected to the ground terminal AGND.

8. The composite overvoltage protection circuit of a high-voltage power supply control system as described in claim 1, characterized in that: The load voltage detection and judgment circuit also includes an indicator circuit connected to the output terminal of the load voltage comparison circuit.

9. The composite overvoltage protection circuit of a high-voltage power supply control system as described in claim 8, characterized in that: The indicator circuit includes a resistor R1 and an indicator LED1. The first end of the resistor R1 is connected to the analog power supply A+12V, the second end of the resistor R1 is connected to the positive terminal of the indicator LED1, and the negative terminal of the indicator LED1 is connected to the output terminal of the load voltage comparison circuit.

10. The composite overvoltage protection circuit of a high-voltage power supply control system as described in claim 9, characterized in that: The output of the load voltage comparison circuit is connected to ground AGND through capacitor C4.

Images