A circuit integrated with overcurrent, overtemperature and transient suppression protection functions

Abstract

The application discloses a kind of integrated overcurrent, overtemperature and transient suppression protection function circuit, can realize the transient current suppression of overcurrent, short circuit, overtemperature and other fault protection and high voltage power-on simultaneously, and the circuit integration is high. High-voltage loop current sampling is carried out using resistance sampling and two-stage sampling circuit of voltage division after triode triggering, which can effectively reduce high-power interference noise and component selection difficulty, reduce product size, improve the anti-interference ability and reliability of full-bridge inverter circuit. Using multi-triode temperature protection scheme, single-point to multi-point temperature monitoring protection can be realized, which effectively reduces the circuit complexity of multi-point temperature monitoring, improves the universality of the circuit, and can realize automatic locking of circuit failure, effectively preventing fault trigger jitter problem. The application uses power resistor and MOSFET to combine soft control signal and power-on signal, to realize the switching of high-voltage input circuit through and current limiting, to ensure the output efficiency of the product while realizing the transient overcurrent suppression of high-voltage power-on.

Description

Technical Field

[0001] This invention belongs to the field of circuit design technology, specifically a circuit that integrates overcurrent, overtemperature, and transient suppression protection functions. Background Technology

[0002] In practical use, high-voltage power supply inverter circuits will inevitably encounter faults such as overcurrent, short circuit, and overtemperature. Therefore, overcurrent and overtemperature protection are essential in the design.

[0003] Currently, common overcurrent protection methods include: 1) Using resistor sampling, conditioning the sampled voltage, comparing it with a reference voltage, and then triggering overcurrent protection. This method requires that the operational amplifiers in the sampling voltage conditioning circuit and the comparator circuit be selected with high withstand voltage based on the bus voltage. Furthermore, because the sampling voltage is generally in the millivolt range due to resistor power requirements, interference noise after amplification can cause signal distortion, leading to false protection. 2) Using Hall effect current sensors to convert the current in the bus circuit into an isolated voltage value. However, Hall effect current sensors are generally powered by dual power supplies and are relatively large, which cannot meet the design requirements of miniaturized modular products.

[0004] Currently, common over-temperature protection methods involve using a temperature sensor or thermistor to convert the temperature signal into a corresponding voltage signal. The corresponding software protection scheme involves converting this voltage signal via an analog-to-digital converter (ADC) and sending it to a processor for threshold judgment, after which the processor outputs a protection signal. Because this method is software-based, the protection trigger cycle is relatively long and requires program calculations by the processor. The corresponding hardware protection scheme involves conditioning the voltage signal before outputting it to the subsequent protection execution circuit. This method requires a separate conditioning circuit to process the over-temperature signal.

[0005] For high-voltage inverter circuits, the instantaneous current of the input filter capacitor charging is very large when the bus voltage is turned on, which may burn out the signal source. Therefore, a current-limiting resistor is usually added between the power supply and the capacitor. However, this resistor will generate a voltage drop during normal circuit operation, thereby reducing the output efficiency of the product. Summary of the Invention

[0006] The purpose of this invention is to provide a circuit that integrates overcurrent, overtemperature, and transient suppression protection functions to address the problems existing in the prior art.

[0007] The technical solution to achieve the purpose of this invention is: a circuit that integrates overcurrent, overtemperature and transient suppression protection functions, the circuit including: an overcurrent sampling circuit, a voltage comparison circuit, a fault self-locking circuit with integrated overtemperature protection, a logic processing circuit and a transient suppression switching circuit;

[0008] The overcurrent sampling circuit is used to acquire overcurrent signals and output overcurrent trigger signals;

[0009] The voltage comparison circuit is used to compare the overcurrent / overtemperature voltage divider signal with the reference source voltage, and to flip the fault signal output when an overcurrent fault occurs.

[0010] The integrated over-temperature protection fault self-locking circuit is used to complete multi-point detection of over-temperature faults and to perform self-locking processing on overcurrent / over-temperature faults to prevent fault signal jitter.

[0011] The logic processing circuit is used to perform logical combination processing of overcurrent signal, soft control signal and high voltage power-on signal, and output transient switching signal;

[0012] The transient suppression switching circuit is used to switch between direct-through and current-limiting in the high-voltage input circuit.

[0013] Furthermore, the overcurrent sampling circuit includes a current sampling circuit and an overcurrent triggering circuit. The current sampling circuit includes a sampling resistor. The high-voltage circuit current is input through PIN1, passes through the sampling resistor R1, and is output to PIN2. The sampling voltage of the sampling resistor is sent to the overcurrent triggering circuit. The overcurrent triggering circuit includes a first PNP transistor, a second MOSFET, a second resistor, and a first capacitor. The sampling voltage of the sampling resistor controls the first PNP transistor to trigger an overcurrent fault. The second MOSFET acts as a constant current source to control the current of the overcurrent triggering circuit. The overcurrent triggering signal passes through the second resistor, the first PNP transistor, and the second MOSFET before being output to the voltage comparison circuit. Specifically, one end of the sampling resistor is connected to the emitter of the first PNP transistor through the second resistor, and the other end of the sampling resistor is connected to the base of the first PNP transistor. The collector of the first PNP transistor is connected to the drain of the second MOSFET. The gate and source of the second MOSFET are grounded through the first capacitor, and a signal is simultaneously output to the voltage comparison circuit.

[0014] Furthermore, the voltage comparison circuit includes a third resistor, a fourth resistor, and a comparator. The third resistor, the fourth resistor, the second resistor, the first PNP transistor, and the second MOSFET form a voltage divider circuit. The signal output by the overcurrent sampling circuit is grounded through the third and fourth resistors connected in series. The common terminal of the third and fourth resistors is connected to the negative input terminal of the comparator. The positive input terminal of the comparator is connected to the reference source voltage output by the fault self-locking circuit with integrated over-temperature protection, ensuring that the comparator output reverses when a fault occurs. The output terminal of the comparator outputs a fault protection signal to the logic processing circuit.

[0015] Furthermore, the integrated over-temperature protection fault-locking circuit includes a third PNP transistor, a fourth PNP transistor, a fifth PNP transistor, a sixth PNP transistor, a seventh PNP transistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, and a second capacitor. The overcurrent trigger signal of the overcurrent sampling circuit is connected to the base of the third PNP transistor and one end of the second capacitor through the tenth resistor, and simultaneously connected to the fourth PNP transistor and the fifth PNP transistor through the ninth resistor. The collectors of the PNP transistors 6, 7, and 8 are connected to the power supply ground. The other end of the second capacitor and the emitter of the third PNP transistor are connected to the power supply ground. The collector of the third PNP transistor is connected to the base of the fourth, fifth, sixth, and seventh PNP transistors through the eighth resistor, and then connected to the power supply VDD through the seventh resistor. The collectors of the fourth, fifth, sixth, and seventh PNP transistors are connected to the power supply ground. The emitter of the P-type transistor is connected to the power supply VDD; the seventh resistor, the sixth resistor, and the fifth resistor form a voltage divider circuit, and the common terminal of the seventh and eighth resistors is grounded through the sixth and fifth resistors connected in series; the fourth, fifth, sixth, and seventh PNP transistors are placed at locations requiring temperature monitoring. When overheating occurs at any location, the corresponding transistor conducts, ultimately raising the voltage at the negative input terminal of the comparator and lowering the reference source voltage at its positive input terminal, thereby achieving… Over-temperature protection function: After an over-temperature or over-current fault occurs, the base voltage of the third PNP transistor increases and turns on. The VDD-to-ground circuit composed of the seventh and eighth resistors, the base voltages of the fourth, fifth, sixth, and seventh PNP transistors decrease and turn on. The VDD-to-ground circuit composed of the ninth, third, and fourth resistors ultimately raises the voltage at the negative input terminal of the comparator and lowers the reference source voltage at its positive input terminal, thereby realizing the self-locking function for over-temperature and over-current faults.

[0016] Furthermore, the logic processing circuit includes a second AND gate, a third AND gate, and a first diode. The second AND gate performs "logical AND" processing on the fault protection signal and the high-voltage power-on signal. The output of the second AND gate is connected to one input of the third AND gate. The soft control signal output by the microprocessor is connected to the other input of the third AND gate. The third AND gate outputs the final transient switching signal to the transient suppression switching circuit. The VCC terminals of the second AND gate and the third AND gate are connected to the power supply VC through the first diode, and the VCC terminal is connected to the negative terminal of the first diode.

[0017] Furthermore, the transient suppression switching circuit includes a power circuit, a twelfth resistor, a second diode, an eighth MOSFET, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a seventh capacitor, and an eighth capacitor. The eighth MOSFET is connected in parallel with the power circuit as a direct-through and current-limiting channel for the external high-voltage power supply, respectively. The gate of the eighth MOSFET receives the transient switching signal output by the logic processing circuit to switch between the high-voltage input direct-through and current-limiting channels. Specifically, the output of the third AND gate is grounded through the parallel twelfth resistor and the second diode, and this output is connected to the negative terminal of the second diode and the gate of the eighth MOSFET. The sixth and seventh capacitors are connected in series and then in parallel with the third, fourth, fifth, and eighth capacitors, and this parallel structure is connected to the source of the eighth MOSFET.

[0018] Furthermore, the number of the third, fourth, fifth, and sixth PNP transistors in the fault self-locking circuit with integrated over-temperature protection can be one or more, and they are placed at the location where temperature monitoring is required.

[0019] Furthermore, the second and third AND gates in the logic processing circuit can be replaced by chips that integrate multiple AND gates.

[0020] Furthermore, the soft control signal in the logic processing circuit can be issued by any type of controller. The high-voltage power-on signal can be a software control signal issued by the controller or a hardware control signal output by the power-on detection circuit.

[0021] Furthermore, the first to twelfth resistors can each be composed of one or more resistors connected in series or in parallel, and the first to eighth capacitors can each be composed of one or more capacitors connected in series or in parallel.

[0022] Compared with the prior art, the significant advantages of this invention are:

[0023] 1) The protection circuit used in this invention can simultaneously realize fault protection such as overcurrent, short circuit, and overtemperature, as well as transient current suppression when high voltage is applied, and the circuit has a high degree of integration.

[0024] 2) This invention uses a two-stage sampling circuit with resistor sampling and transistor-triggered voltage division to sample the high-voltage circuit current, which can effectively reduce high-power interference noise and component selection difficulty, reduce product size, and improve the anti-interference capability and reliability of the inverter circuit.

[0025] 3) This invention adopts a multi-transistor temperature protection scheme, which can realize single-point to multi-point temperature monitoring and protection functions, effectively reducing the circuit complexity of multi-point temperature monitoring and improving the versatility of the circuit.

[0026] 4) This invention adopts an automatic fault locking design to automatically lock faults such as overcurrent, short circuit, and overtemperature, which can effectively prevent fault triggering jitter.

[0027] 5) This invention uses power resistors and MOSFETs in combination with soft control signals and power-on signals to achieve the switching between direct pass and current limiting in the high-voltage input circuit, thereby ensuring product output efficiency while suppressing transient overcurrent during high-voltage power-on.

[0028] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a circuit that integrates overcurrent, overtemperature, and transient suppression protection functions in one embodiment.

[0030] Figure 2 This is a schematic diagram of an overcurrent sampling circuit in one embodiment.

[0031] Figure 3 This is a schematic diagram of a voltage comparison circuit in one embodiment.

[0032] Figure 4 This is a schematic diagram of a fault self-locking circuit with integrated over-temperature protection in one embodiment.

[0033] Figure 5 This is a schematic diagram of the logic processing circuit in one embodiment.

[0034] Figure 6 This is a schematic diagram of a transient suppression switching circuit in one embodiment. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0036] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0037] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0038] In one embodiment, combined Figure 1 A circuit integrating overcurrent, overtemperature, and transient suppression protection functions is provided, including:

[0039] Overcurrent sampling circuit 10: used to collect the overcurrent signal of the high-voltage circuit and convert the high-voltage overcurrent signal into a low-voltage small current signal for output.

[0040] The sampling input terminal of the overcurrent sampling circuit 10 is connected to the current output terminal of the circuit under test. After the current flows through the overcurrent sampling circuit 10, it flows back to the circuit under test through the sampling output terminal. The overcurrent sampling circuit 10 converts the high voltage overcurrent signal into a low voltage small current signal and outputs it to the output terminal.

[0041] Voltage Comparison Circuit 20: Used to compare the overcurrent / overtemperature voltage divider signal with the reference source voltage, and to flip the fault signal output when an overcurrent fault occurs.

[0042] The first input terminal of the voltage comparison circuit 20 is connected to the output terminal of the overcurrent sampling circuit 10. The low-voltage, low-current signal is compared with the voltage at the second input terminal of the voltage comparison circuit 20 after being divided by a voltage divider, and the status signal is output to the output terminal.

[0043] The fault self-locking circuit 30 with integrated over-temperature protection is used to complete multi-point detection of over-temperature faults and to lock out overcurrent / over-temperature faults to prevent fault signal jitter.

[0044] The first port of the fault self-locking circuit 30 with integrated over-temperature protection is connected to the output terminal of the overcurrent sampling circuit 10, and the second port of the fault self-locking circuit 30 with integrated over-temperature protection is connected to the second input terminal of the voltage comparison circuit 20.

[0045] Logic processing circuit 40: performs logical combination processing of overcurrent signal, soft control signal and high voltage power-on signal, and outputs transient switching signal.

[0046] The input terminals of the logic processing circuit 40 are respectively connected to the output terminal of the voltage comparison circuit, the soft control signal, and the high voltage power-on signal, and output a transient switching signal to the output terminal.

[0047] Transient suppression switching circuit 50: Completes the switching between direct pass and current limiting of the high voltage input circuit.

[0048] The input of the transient suppression switching circuit 50 is connected to the output of the logic processing circuit 40.

[0049] Furthermore, in one embodiment, combined with Figure 2 The overcurrent sampling circuit includes a current sampling circuit and an overcurrent triggering circuit. The current sampling circuit includes a sampling resistor R1. The high-voltage circuit current is input from one end of the sampling resistor R1, output from the other end, and the sampling voltage of the sampling resistor R1 is sent to the overcurrent triggering circuit. The overcurrent triggering circuit includes a first PNP transistor Q1, a second MOSFET Q2, a second resistor R2, and a first capacitor C1. The sampling voltage of the sampling resistor R1 controls the first PNP transistor Q1 to complete the overcurrent fault triggering, and the second MOSFET Q2 acts as a constant current source to control the overcurrent trigger. The current of the sampling circuit, the overcurrent trigger signal passes through the second resistor R2, the first PNP transistor Q1 and the second MOSFET Q2 and is then output to the voltage comparison circuit; specifically: one end of the sampling resistor R1 is connected to the emitter of the first PNP transistor Q1 through the second resistor R2, and the other end of the sampling resistor R1 is connected to the base of the first PNP transistor Q1; the collector of the first PNP transistor Q1 is connected to the drain of the second MOSFET Q2, and the gate and source of the second MOSFET Q2 are grounded through the first capacitor C1, and at the same time, the output signal is sent to the voltage comparison circuit.

[0050] Furthermore, in one embodiment, combined with Figure 3 The voltage comparison circuit includes a third resistor R3, a fourth resistor R4, and a comparator U1. The third resistor R3, the fourth resistor R4, the second resistor R2, the first PNP transistor Q1, and the second MOSFET Q2 form a voltage divider circuit. The signal output from the overcurrent sampling circuit is grounded through the third resistor R3 and the fourth resistor R4 connected in series. The common terminal of the third resistor R3 and the fourth resistor R4 is connected to the negative input terminal of the comparator U1. The positive input terminal of the comparator U1 is connected to the reference source voltage output by the fault self-locking circuit with integrated over-temperature protection. The output terminal of the comparator U1 outputs a fault protection signal to the logic processing circuit.

[0051] Here, the output level after a fault occurs can be either low or high.

[0052] Furthermore, in one embodiment, combined with Figure 4The integrated over-temperature protection fault-locking circuit includes a third PNP transistor Q3, a fourth PNP transistor Q4, a fifth PNP transistor Q5, a sixth PNP transistor Q6, a seventh PNP transistor Q7, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, and a second capacitor C2. The overcurrent trigger signal of the overcurrent sampling circuit is connected to the base of the third PNP transistor Q3 and one end of the second capacitor C2 through the tenth resistor R10, and simultaneously connected to the fourth PNP transistor Q7 through the ninth resistor R9. 4. The collectors of the fifth PNP transistor Q5, the sixth PNP transistor Q6, and the seventh PNP transistor Q7, the other end of the second capacitor C2, and the emitter of the third PNP transistor Q3 are connected to the power supply ground. The collector of the third PNP transistor Q3 is connected to the base of the fourth PNP transistor Q4, the fifth PNP transistor Q5, the sixth PNP transistor Q6, and the seventh PNP transistor Q7 through the eighth resistor R8, and then connected to the power supply VDD through the seventh resistor R7. The fourth PNP transistor Q4, the fifth PNP transistor Q5, and the sixth PNP transistor Q7 are connected to the power supply ground. The emitters of Q6 and Q7, the seventh PNP transistors, are connected to the power supply VDD. The seventh resistor R7, the sixth resistor R6, and the fifth resistor R5 form a voltage divider circuit. The common terminal of the seventh resistor R7 and the eighth resistor R8 is grounded through the series connection of the sixth resistor R6 and the fifth resistor R5. The fourth PNP transistor Q4, the fifth PNP transistor Q5, the sixth PNP transistor Q6, and the seventh PNP transistor Q7 are positioned at locations requiring temperature monitoring. When overheating occurs at any location, the corresponding transistor conducts, ultimately raising the voltage at the negative input terminal of comparator U1 and lowering the reference voltage at its positive input terminal. The voltage is adjusted to achieve over-temperature protection. After an over-temperature or over-current fault occurs, the base voltage of the third PNP transistor Q3 increases and turns on. The VDD-to-ground circuit composed of the seventh resistor R7 and the eighth resistor R8, the base voltage of the fourth PNP transistor Q4, the fifth PNP transistor Q5, the sixth PNP transistor Q6, and the seventh PNP transistor Q7 decrease and turn on. The VDD-to-ground circuit composed of the ninth resistor R9, the third resistor R3, and the fourth resistor R4 ultimately raises the voltage at the negative input terminal of comparator U1 and lowers the reference source voltage at its positive input terminal, thereby achieving the self-locking function for over-temperature and over-current faults.

[0053] Furthermore, in one embodiment, combined with Figure 5The logic processing circuit includes a second AND gate U2, a third AND gate U3, and a first diode D1. The second AND gate U2 performs "logical AND" processing of the fault protection signal and the high-voltage power-on signal. The output of the second AND gate U2 is connected to one input of the third AND gate U3. The soft control signal output by the microprocessor is connected to the other input of the third AND gate U3. The third AND gate U3 outputs the final transient switching signal to the transient suppression switching circuit. The VCC terminals of the second AND gate U2 and the third AND gate U3 are connected to the power supply VC through the first diode D1, and the VCC terminal is connected to the negative terminal of the first diode D1.

[0054] Furthermore, in one embodiment, combined with Figure 6 The transient suppression switching circuit includes a power circuit R11, a twelfth resistor R12, a second diode D2, an eighth MOSFET Q8, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, and an eighth capacitor C8. The eighth MOSFET Q8 is connected in parallel with the power circuit R11, serving as the direct-through and current-limiting channels for the external high-voltage power supply, respectively. The gate of the eighth MOSFET Q8 receives the transient switching signal output by the logic processing circuit to switch between the high-voltage input direct-through and current-limiting channels. Specifically, the output terminal of the third AND gate U3 is grounded through the parallel twelfth resistor R12 and the second diode D2, and this output terminal is connected to the negative terminal of the second diode D2 and the gate of the eighth MOSFET Q8. The sixth capacitor C6 and the seventh capacitor C7 are connected in series and then in parallel with the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, and the eighth capacitor C8, and this parallel structure is connected to the source of the eighth MOSFET Q8.

[0055] It should be further noted that the number of the third PNP transistor Q3, the fourth PNP transistor Q4, the fifth PNP transistor Q5, and the sixth PNP transistor Q6 in the fault self-locking circuit with integrated over-temperature protection can be one or more, and they are placed at the location where temperature monitoring is required.

[0056] The second AND gate U2 and the third AND gate U3 in the logic processing circuit can be replaced by a chip with integrated multiplex AND gates.

[0057] The soft control signal in the logic processing circuit can be issued by any type of controller. The high voltage power-on signal can be a software control signal issued by the controller or a hardware control signal output by the power-on detection circuit.

[0058] The first resistor R1 to the twelfth resistor R12 can each be composed of one or more resistors connected in series or in parallel, and the first capacitor C1 to the eighth capacitor C8 can each be composed of one or more capacitors connected in series or in parallel.

[0059] In summary, the protection circuit proposed in this invention can simultaneously provide protection against overcurrent, short circuit, and overtemperature faults, as well as suppress transient current during high-voltage power-up, exhibiting high circuit integration. This invention employs a two-stage sampling circuit with resistor sampling and transistor-triggered voltage division for high-voltage loop current sampling, effectively reducing high-power interference noise and component selection difficulty, decreasing product size, and improving the anti-interference capability and reliability of the full-bridge inverter circuit. Furthermore, this invention utilizes a multi-transistor temperature protection scheme, enabling single-point to multi-point temperature monitoring and protection functions, effectively reducing the circuit complexity of multi-point temperature monitoring and improving circuit versatility.

[0060] Finally, it should be noted that the above embodiments are only one specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A circuit integrating overcurrent, overtemperature, and transient suppression protection functions, characterized in that, The circuit includes: Overcurrent sampling circuit, voltage comparison circuit, fault self-locking circuit with integrated over-temperature protection, logic processing circuit and transient suppression switching circuit; The overcurrent sampling circuit is used to acquire overcurrent signals and output overcurrent trigger signals; The voltage comparison circuit is used to compare the overcurrent / overtemperature voltage divider signal with the reference source voltage, and to flip the fault signal output when an overcurrent fault occurs. The integrated over-temperature protection fault self-locking circuit is used to complete multi-point detection of over-temperature faults and to perform self-locking processing for overcurrent / over-temperature faults. The logic processing circuit is used to perform logical combination processing of the output signal of the voltage comparator circuit, the soft control signal and the high voltage power-on signal, and output a transient switching signal. The transient suppression switching circuit is used to switch between pass-through and current limiting in the high-voltage input circuit; The integrated over-temperature protection fault-locking circuit includes a third NPN transistor (Q3), a fourth PNP transistor (Q4), a fifth PNP transistor (Q5), a sixth PNP transistor (Q6), a seventh PNP transistor (Q7), a fifth resistor (R5), a sixth resistor (R6), a seventh resistor (R7), an eighth resistor (R8), a ninth resistor (R9), a tenth resistor (R10), and a second capacitor (C2). The overcurrent trigger signal of the overcurrent sampling circuit is connected to the base of the third NPN transistor (Q3) and one end of the second capacitor (C2) through the tenth resistor (R10), and simultaneously connected to the fourth PNP transistor through the ninth resistor (R9). The collectors of transistors Q4, Q5, Q6, and Q7, the other end of capacitor C2, and the emitter of transistor Q3 are connected to the power supply ground. The collector of transistor Q3 is connected to the base of transistors Q4, Q5, Q6, and Q7 via resistor R8, and then to the power supply VDD via resistor R7. Transistors Q4, Q5, Q6, and Q7 are connected to the power supply ground. The emitters of the seventh PNP transistor (Q6) and the eighth PNP transistor (Q7) are connected to the power supply VDD; the seventh resistor (R7), the sixth resistor (R6), and the fifth resistor (R5) form a voltage divider circuit, and the common terminal of the seventh resistor (R7) and the eighth resistor (R8) is grounded through the sixth resistor (R6) and the fifth resistor (R5) connected in series; the fourth PNP transistor (Q4), the fifth PNP transistor (Q5), the sixth PNP transistor (Q6), and the seventh PNP transistor (Q7) are distributed in the locations where temperature monitoring is required. When overheating occurs at any location, the corresponding transistor conducts, ultimately raising the voltage at the negative input terminal of the comparator (U1) and lowering its positive input voltage. The base voltage of the third NPN transistor (Q3) is increased and then turned on after an over-temperature or over-current fault occurs. The VDD-to-ground circuit composed of the seventh resistor (R7) and the eighth resistor (R8), the base voltage of the fourth PNP transistor (Q4), the fifth PNP transistor (Q5), the sixth PNP transistor (Q6), and the seventh PNP transistor (Q7) are decreased and then turned on. The VDD-to-ground circuit composed of the ninth resistor (R9), the third resistor (R3), and the fourth resistor (R4) ultimately raises the voltage at the negative input terminal of the comparator (U1) and lowers the reference source voltage at its positive input terminal, thereby realizing the self-locking function for over-temperature and over-current faults.

2. The circuit with integrated overcurrent, overtemperature, and transient suppression protection functions according to claim 1, characterized in that, The overcurrent sampling circuit includes a current sampling circuit and an overcurrent triggering circuit. The current sampling circuit includes a first resistor (R1). The high-voltage circuit current is input from one end of the first resistor (R1), output from the other end, and the sampling voltage of the first resistor (R1) is sent to the overcurrent triggering circuit. The overcurrent triggering circuit includes a first PNP transistor (Q1), a second MOSFET (Q2), a second resistor (R2), and a first capacitor (C1). The sampling voltage of the first resistor (R1) controls the first PNP transistor (Q1) to trigger an overcurrent fault. The second MOSFET (Q2) acts as a constant current source to control the overcurrent triggering circuit. The current in the circuit, the overcurrent trigger signal passes through the second resistor (R2), the first PNP transistor (Q1) and the second MOSFET (Q2) and is then output to the voltage comparison circuit; specifically: one end of the first resistor (R1) is connected to the emitter of the first PNP transistor (Q1) through the second resistor (R2), and the other end of the first resistor (R1) is connected to the base of the first PNP transistor (Q1); the collector of the first PNP transistor (Q1) is connected to the drain of the second MOSFET (Q2), and the gate and source of the second MOSFET (Q2) are grounded through the first capacitor (C1), and at the same time, the output signal is sent to the voltage comparison circuit.

3. The circuit with integrated overcurrent, overtemperature, and transient suppression protection functions according to claim 2, characterized in that, The voltage comparison circuit includes a third resistor (R3), a fourth resistor (R4), and a comparator (U1). The third resistor (R3), the fourth resistor (R4), the second resistor (R2), the first PNP transistor (Q1), and the second MOSFET (Q2) form a voltage divider circuit. The signal output from the overcurrent sampling circuit is grounded through the series-connected third resistor (R3) and fourth resistor (R4). The common terminal of the third resistor (R3) and fourth resistor (R4) is connected to the negative input terminal of the comparator (U1). The positive input terminal of the comparator (U1) is connected to the reference source voltage output by the fault self-locking circuit with integrated over-temperature protection. The output terminal of the comparator (U1) outputs a fault signal to the logic processing circuit.

4. The circuit with integrated overcurrent, overtemperature, and transient suppression protection functions according to claim 3, characterized in that, The logic processing circuit includes a second AND gate (U2), a third AND gate (U3), and a first diode (D1). The second AND gate (U2) performs "logical AND" processing on the fault protection signal and the high-voltage power-on signal. The output of the second AND gate (U2) is connected to one input of the third AND gate (U3). The soft control signal output by the microprocessor is connected to the other input of the third AND gate (U3). The third AND gate (U3) outputs the final transient switching signal to the transient suppression switching circuit. The VCC terminals of the second AND gate (U2) and the third AND gate (U3) are connected to the power supply VC through the first diode (D1), and the VCC terminal is connected to the negative terminal of the first diode (D1).

5. The circuit with integrated overcurrent, overtemperature, and transient suppression protection functions according to claim 4, characterized in that, The transient suppression switching circuit includes a power circuit (R11), a twelfth resistor (R12), a second diode (D2), an eighth MOSFET (Q8), a third capacitor (C3), a fourth capacitor (C4), a fifth capacitor (C5), a sixth capacitor (C6), a seventh capacitor (C7), and an eighth capacitor (C8). The eighth MOSFET (Q8) is connected in parallel with the power circuit (R11) to serve as the direct-through and current-limiting channels for the external high-voltage power supply, respectively. The gate of the eighth MOSFET (Q8) receives the transient switching signal output from the logic processing circuit. The signal switching enables the switching between high-voltage input pass-through and current-limiting channels; specifically: the output terminal of the third AND gate (U3) is grounded through the parallel twelfth resistor (R12) and the second diode (D2), and the output terminal is connected to the negative terminal of the second diode (D2) and the gate of the eighth MOSFET (Q8). The sixth capacitor (C6) and the seventh capacitor (C7) are connected in series, and then connected in parallel with the third capacitor (C3), the fourth capacitor (C4), the fifth capacitor (C5), and the eighth capacitor (C8), and this parallel structure is connected to the source of the eighth MOSFET (Q8).

6. The circuit with integrated overcurrent, overtemperature, and transient suppression protection functions according to claim 5, characterized in that, The number of the third NPN transistor (Q3), the fourth PNP transistor (Q4), the fifth PNP transistor (Q5), and the sixth PNP transistor (Q6) in the fault self-locking circuit with integrated over-temperature protection is one or more, and they are placed in the positions where temperature monitoring is required.

7. The circuit with integrated overcurrent, overtemperature, and transient suppression protection functions according to claim 6, characterized in that, The second AND gate (U2) and the third AND gate (U3) in the logic processing circuit are replaced by chips with integrated multiplexed AND gates.

8. The circuit with integrated overcurrent, overtemperature, and transient suppression protection functions according to claim 7, characterized in that, The soft control signal in the logic processing circuit is issued by any type of controller, and the high voltage power-on signal is either a software control signal issued by the controller or a hardware control signal output by the power-on detection circuit.

9. The circuit with integrated overcurrent, overtemperature, and transient suppression protection functions according to claim 8, characterized in that, The first resistor (R1) to the twelfth resistor (R12) are each composed of one or more resistors connected in series or in parallel, and the first capacitor (C1) to the eighth capacitor (C8) are each composed of one or more capacitors connected in series or in parallel.

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