TVS tube online self-test and switching circuit and control method

Abstract

The present invention discloses a TVS tube online self-test and switching circuit, including an input power supply, the input power supply is connected to a DC / DC conversion circuit and an adjustable boost circuit through a diode, the DC / DC conversion circuit is connected to an MCU processor system, the MCU processor system is connected to a communication circuit, the communication circuit is connected to an upper system, the MCU processor system is also connected to an isolation circuit, the adjustable boost circuit is respectively connected to an adjustable current source circuit and a TVS tube circuit, the TVS tube circuit is respectively connected to a voltage sampling circuit, a current sampling circuit and a switch switching circuit, the voltage and current sampling circuit and the switch switching circuit are both connected to the isolation circuit, and the isolation circuit is also respectively connected to the adjustable current source circuit and the adjustable boost circuit. The present invention also discloses a control method for a TVS tube online self-test and switching circuit, and the present invention solves the problem of complex fault inspection and repair of existing TVS.

Description

Technical Field

[0001] The invention belongs to the technical field of self-test circuits, and in particular relates to an online self-test and switching circuit for a TVS tube, and also relates to a control method for the online self-test and switching circuit for a TVS tube. Background Art

[0002] Transient voltage suppressor diodes (TVS tubes) have two failure modes: open circuit and short circuit. In most cases, TVS tubes are mainly short-circuited, and open circuit is rare. The existing technology for handling faulty TVS is to disassemble the device, check the appearance of the TVS tube device, use instruments to measure whether the TVS tube is conductive, and use a soldering iron or other equipment to remove the faulty TVS tube, replace it with a new TVS tube, and then carry out each subsequent process, and finally perform assembly testing. In this process, manpower, material resources, time, cost, etc. will be consumed, and the product delivery node will be extended. Summary of the invention

[0003] The purpose of the present invention is to provide an online self-checking and switching circuit for a TVS tube, thereby solving the problem of complicated fault inspection and repair of the existing TVS tube.

[0004] Another object of the present invention is to provide a method for controlling an online self-test and switching circuit of a TVS tube.

[0005] The first technical solution adopted by the present invention is a TVS tube online self-test and switching circuit, including an input power supply, the input power supply is connected to a DC / DC conversion circuit and an adjustable boost circuit through a diode, the DC / DC conversion circuit is connected to an MCU processor system, the MCU processor system is connected to a communication circuit, the communication circuit is connected to a host system, the MCU processor system is also connected to an isolation circuit, the adjustable boost circuit is respectively connected to an adjustable current source circuit and a TVS tube circuit, the TVS tube circuit is respectively connected to a voltage sampling circuit, a current sampling circuit and a switch switching circuit, the voltage and current sampling circuit and the switch switching circuit are both connected to the isolation circuit, and the isolation circuit is also respectively connected to the adjustable current source circuit and the adjustable boost circuit.

[0006] The first technical solution of the present invention is also characterized in that:

[0007] The TVS tube circuit includes several TVS tubes, each of which is connected to a switching switch SW at both ends. One end of the TVS tube is connected to an adjustable current source circuit, a voltage sampling circuit, a current sampling circuit and a switch switching circuit, and the other end of the TVS tube is connected to an adjustable boost circuit. Each switching switch SW is connected to the MCU processor system through wiring.

[0008] The adjustable current source circuit includes a PMOS tube U3 and an optocoupler U2. The PMOS tube U3 and the optocoupler U2 are connected to the TVS tube. The optocoupler U2 is connected to the first operational amplifier U1. The first operational amplifier U1 is connected to the fourth resistor R4. A third resistor R3 and a resistor R0 are connected in parallel between the first operational amplifier U1 and the fourth resistor R4. A first resistor R1 is connected between the first operational amplifier U1 and the optocoupler U2. A fifth resistor R5 is connected between the PMOS tube U3 and the TVS tube. The optocoupler U2 is connected to the second resistor R2.

[0009] The voltage sampling circuit includes a ninth operational amplifier U9, the ninth operational amplifier U9 is connected to an eighth isolation operational amplifier U8, the input positive end of the eighth isolation operational amplifier U8 is connected to a fifteenth resistor R15, the other end of the fifteenth resistor R15 is connected to a thirteenth resistor R13 and a fourteenth resistor R14, the fourteenth resistor R14 is connected to the system ground, the other end of the thirteenth resistor R13 is connected to one end of the TVS tube, the input negative end of the eighth isolation operational amplifier U8 is connected to a twelfth resistor R12, the other end of the twelfth resistor R12 is connected to an eleventh resistor R 11 and the tenth resistor R10, the tenth resistor R10 is connected to the system ground, the other end of the eleventh resistor R11 is connected to the other end of the TVS tube, the output end of the eighth isolation amplifier U8 is respectively connected to the sixteenth resistor R16 and the seventeenth resistor R17, the sixteenth resistor R16 and the seventeenth resistor R17 are respectively connected to the input end of the ninth operational amplifier U9, the input end and the output end of the ninth operational amplifier U9 are respectively connected to the eighteenth resistor R18 and the nineteenth resistor R19, and the output end of the ninth operational amplifier U9 is connected to the isolation circuit.

[0010] The current sampling circuit includes an eleventh operational amplifier U11, a tenth isolation operational amplifier U10 and a twelfth operational amplifier U12 which are connected in series in sequence. The positive input terminal of the eleventh operational amplifier U11 is respectively connected to a thirtieth resistor R30 and a thirty-second resistor R32. The thirtieth resistor R30 is connected to a fifth capacitor C5. The fifth capacitor C5 is connected to the TVS tube. The negative input terminal of the eleventh operational amplifier U11 is respectively connected to a ninety-ninth resistor R99 and a thirty-third resistor R33. The ninety-ninth resistor R99 is connected to the system ground. The output terminal of the eleventh operational amplifier U11 is respectively connected to the thirty-second resistor R32, the thirty-third resistor R33 and the thirty-fourth resistor R34. The thirty-fourth resistor R34 is connected to the tenth isolation operational amplifier U10. The input end of the operational amplifier U10, the input end of the tenth isolation operational amplifier U10 is also connected to the thirty-fifth resistor R35, the thirty-sixth resistor R36 and the thirty-seventh resistor R37 are respectively connected between the tenth isolation operational amplifier U10 and the twelfth operational amplifier U12, the positive input end of the twelfth operational amplifier U12 is respectively connected to the thirty-seventh resistor R37, the thirty-ninth resistor R39, the first capacitor C1 and the third capacitor C3, the negative input end of the twelfth operational amplifier U12 is respectively connected to the thirty-sixth resistor R36, the thirty-eighth resistor R38, the first capacitor C1 and the second capacitor C2, the first capacitor C1 is connected between the second capacitor C2 and the third capacitor C3, and the output end of the twelfth operational amplifier U12 is connected to the isolation circuit.

[0011] The second technical solution adopted by the present invention is:

[0012] The TVS tube online self-test and switching circuit control method is specifically implemented according to the following steps:

[0013] Step 1: Input power and turn on the power. After each circuit completes self-check, it enters normal working state;

[0014] Step 2: The MCU processor system controls the voltage value of the adjustable boost circuit and the current value of the adjustable current source circuit, controls the TVS tube switching circuit, applies the voltage value and the current value to the TVS tube, and the voltage sampling circuit and the current sampling circuit detect the current and voltage of the TVS tube;

[0015] Step 3: The voltage sampling circuit and the current sampling circuit send the collected voltage and current values ​​to the MCU processor system respectively. The system determines whether the collected data is within the preset value range. If it is within the range, the TVS tube is marked as available and the data is stored in the memory, waiting to be called. If it is not within the preset value range, it is marked as destroyed, the TVS tube control instruction is isolated from the memory, and a disconnect control instruction is given to control the faulty TVS tube to always be in the disconnected state. The system skips the faulty TVS tube every time it runs.

[0016] Step 4: Upload the judgment result to the upper system for other tasks.

[0017] The beneficial effects of the present invention are:

[0018] The TVS tube online self-test and switching circuit of the present invention can detect the quality of the TVS tube inside the device under different working environments, and determine whether to start fault isolation and whether to switch the redundant TVS tube to the circuit according to the detection result. If the TVS tube fails, the faulty TVS tube is immediately isolated, and the redundant TVS tube is switched to the circuit to ensure that the indirect lightning protection function is not lost when the circuit functions normally. The present invention can isolate the faulty TVS tube without disassembling the device and switch to the backup TVS tube, thereby reducing the equipment disassembly work and improving the equipment utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the TVS tube online self-test and switching circuit of the present invention;

[0020] Figure 2 It is a structural schematic diagram of a TVS circuit and a switch switching circuit in the TVS tube online self-test and switching circuit of the present invention;

[0021] Figure 3 It is a structural schematic diagram of an adjustable current source circuit in an online self-test and switching circuit of a TVS tube of the present invention;

[0022] Figure 4 It is a structural schematic diagram of a voltage sampling circuit in an online self-test and switching circuit of a TVS tube of the present invention;

[0023] Figure 5 It is a structural schematic diagram of a current sampling circuit in an online self-test and switching circuit of a TVS tube of the present invention;

[0024] Figure 6 It is a control flow chart of the online self-test and switching circuit of the TVS tube of the present invention. DETAILED DESCRIPTION

[0025] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] The TVS tube online self-test and switching circuit of the present invention is as follows: Figure 1As shown, the TVS tube online self-test and switching circuit includes an input power supply, which is connected to a DC / DC conversion circuit and an adjustable boost circuit through a diode, the DC / DC conversion circuit is connected to an MCU processor system, the MCU processor system is connected to a communication circuit, the communication circuit is connected to a host system, the MCU processor system is also connected to an isolation circuit, the adjustable boost circuit is respectively connected to an adjustable current source circuit and a TVS tube circuit, the TVS tube circuit is respectively connected to a voltage sampling circuit, a current sampling circuit and a switch switching circuit, the voltage and current sampling circuit and the switch switching circuit are both connected to the isolation circuit, and the isolation circuit is also respectively connected to an adjustable current source circuit and an adjustable boost circuit. The input power supply is divided into two paths through a diode and connected to a DC / DC conversion circuit and an adjustable boost circuit, the DC / DC conversion circuit converts the input voltage to the DC power supply voltage required by the MCU processor system and other circuits, and the adjustable current source circuit outputs a stable DC current for testing the avalanche breakdown voltage V of the TVS tube. BR The adjustable boost circuit increases the input DC voltage to the voltage required for testing. The voltage sampling circuit collects the voltage value at both ends of the TVS tube. The current sampling circuit collects the current value of the TVS tube. The task of the MCU processor system is to process voltage and current acquisition signals, control the output of other circuits, and perform data storage and communication. The communication circuit is used to complete the communication task with the upper system. The switch switching circuit has two states. One is that when the TVS tube is in the self-detection state, the TVS tube is disconnected from the normal working circuit and switched to the self-detection circuit. The other is that when a TVS tube fault is detected, the switch switching circuit receives the MCU processor system instruction and connects the backup TVS tube to the working circuit. The faulty TVS tube always remains disconnected from the working circuit. The isolation circuit isolates the sampling signal and controls the switch signal to prevent the MCU processor system from being damaged by interference.

[0027] Example 1

[0028] like Figure 2As shown in the figure, it is a connection diagram of the TVS tube circuit and the switch switching circuit. The TVS tube circuit includes several TVS tubes. Both ends of each TVS tube are connected to a switch SW. One end of the TVS tube is connected to the adjustable current source circuit, the voltage sampling circuit, the current sampling circuit and the switch switching circuit. The other end of the TVS tube is connected to the adjustable boost circuit. Each switch SW is connected to the MCU processor system through wiring. SW1, SW2, SW3, SW4, SW5, SW6, SW7, and SW8 are all TVS tube switching switches that control the connection and disconnection of the TVS tube. They can be relays or semiconductor switch devices. D1, D2, D3, and D4 are all TVS tubes. The switching switch SW receives the MCU processor system instruction through the routing, switches the corresponding TVS tube to the protected circuit or the test circuit, and controls other TVS tubes to be in the disconnected state. For example, if the TVS tube with the power terminal number D3 needs to be detected, first apply a control signal to control the SW5-5 pin, disconnect the SW5-4 pin from the SW5-1 pin, and connect SW5-4 to the SW5-3 pin. Similarly, control the SW6-5 pin, disconnect the SW6-4 pin from the SW6-1 pin, and connect SW6-4 to the SW5-3 pin. At this time, apply a test signal "+" to the SW5-3 pin, and apply a test signal "-" to the SW6-3 pin. The voltage sampling circuit detects the voltage across the TVS tube, transmits the voltage value back to the MCU processor system, and compares it with the preset value. If the TVS tube is qualified, the TVS tube is moved into the available area. If the test fails, the TVS tube is moved into the unavailable area. The unavailable area is skipped each time it is detected or switched. The detection method of TVS tubes with position numbers D1, D2, and D4 is the same as that of TVS tube with position number D3. After all TVS tubes have been detected, a TVS tube in the available area is connected to the power supply by controlling the SW-5 switch according to the method specified by the user for lightning protection.

[0029] Example 2

[0030] like Figure 3As shown, the adjustable current source circuit includes a PMOS tube U3 and an optocoupler U2, the PMOS tube U3 and the optocoupler U2 are connected to the TVS tube, the optocoupler U2 is connected to the first operational amplifier U1, the first operational amplifier U1 is connected to the fourth resistor R4, the third resistor R3 and the resistor R0 are connected in parallel between the first operational amplifier U1 and the fourth resistor R4, the first resistor R1 is connected between the first operational amplifier U1 and the optocoupler U2, the fifth resistor R5 is connected between the PMOS tube U3 and the TVS tube, and the optocoupler U2 is connected to the second resistor R2. The third resistor R3 and the fourth resistor R4 form an adding circuit, when the output current is small, by controlling the voltage of DAC_1, the output current is stabilized to a specified current value, the first resistor R1 is a current limiting resistor, controlling the linear change of the optocoupler U2, the second resistor R2 mainly controls the circuit output I_sample current value, and the fifth resistor R5 is a protection resistor to prevent damage to the optocoupler U2 after the TVS tube is short-circuited. The first operational amplifier U1, the first resistor R1, the optocoupler U2 and the second resistor R2 form a voltage follower circuit. According to the virtual short and virtual open characteristics of the first operational amplifier U1, the voltage of the first operational amplifier U1 is equal to the voltage of the first operational amplifier U1, which is also equal to the voltage value U at both ends of the second resistor R2. R2 The optocoupler U2 is also used to isolate the input and output voltages to prevent high voltage from damaging the first operational amplifier U1 and other front-end circuits; the PMOS tube U3 is used as a power supply protection. When the TVS tube is disconnected, the PMOS tube U3 is in the cut-off state.

[0031] After the product is powered on, a VCC voltage value and an HV voltage value are generated first. When VTVS+ and VTVS- are connected to the TVS tube under test, the first operational amplifier U1 controls the optocoupler U2 to be linearly turned on. After being turned on, the PMOS tube U3, the fifth resistor R5, the TVS tube, the optocoupler U2 and the second resistor R2 form a path. This circuit generates an I_sample current value. The MCU processor system collects the current value and compares it with the pre-stored test current value. If it does not meet the actual test current, the DAC_1 value is adjusted to make I_sample meet the pre-stored test current value.

[0032] Example 3

[0033] like Figure 4As shown, the voltage sampling circuit includes a ninth operational amplifier U9, the ninth operational amplifier U9 is connected to an eighth isolation operational amplifier U8, the input positive terminal of the eighth isolation operational amplifier U8 is connected to a fifteenth resistor R15, the other end of the fifteenth resistor R15 is connected to a thirteenth resistor R13 and a fourteenth resistor R14, the fourteenth resistor R14 is connected to the system ground, the other end of the thirteenth resistor R13 is connected to one end of the TVS tube, the input negative terminal of the eighth isolation operational amplifier U8 is connected to a twelfth resistor R12, the other end of the twelfth resistor R12 is connected to an eleventh resistor R11 and the tenth resistor R10, the tenth resistor R10 is connected to the system ground, the other end of the eleventh resistor R11 is connected to the other end of the TVS tube, the output end of the eighth isolation amplifier U8 is respectively connected to the sixteenth resistor R16 and the seventeenth resistor R17, the sixteenth resistor R16 and the seventeenth resistor R17 are respectively connected to the input end of the ninth operational amplifier U9, the input end and the output end of the ninth operational amplifier U9 are respectively connected to the eighteenth resistor R18 and the nineteenth resistor R19, and the output end of the ninth operational amplifier U9 is connected to the isolation circuit. The tenth resistor R10, the eleventh resistor R11, the twelfth resistor R12, the thirteenth resistor R13, the fourteenth resistor R14, and the fifteenth resistor R15 constitute a sampling attenuation circuit to collect the voltage value at both ends of the TVS tube, the sixteenth resistor R16, the seventeenth resistor R17, the eighteenth resistor R18, the nineteenth resistor R19 and the ninth operational amplifier U9 constitute an amplification circuit to amplify the sampling value; the eighth isolation amplifier U8 is used for signal isolation to prevent the front and rear end signals from being interfered. After the circuit is powered on, the switch SW is switched to the corresponding TVS tube. The voltage values ​​VTVS+ and VTVS- at both ends of the TVS tube under test are attenuated through the thirteenth resistor R13, the fourteenth resistor R14, the tenth resistor R10, and the eleventh resistor R11 respectively, and enter the input end of the eighth isolation amplifier U8, and then pass through the differential output of the eighth isolation amplifier U8 and send to the ninth operational amplifier U9. After the sampling value is amplified, a V_OUT signal is generated and transmitted to the MCU processor system.

[0034] Example 4

[0035] like Figure 5As shown, the current sampling circuit includes an eleventh operational amplifier U11, a tenth isolation operational amplifier U10 and a twelfth operational amplifier U12 which are connected in series in sequence, the positive input terminal of the eleventh operational amplifier U11 is respectively connected to a thirtieth resistor R30 and a thirty-second resistor R32, the thirtieth resistor R30 is connected to a fifth capacitor C5, the fifth capacitor C5 is connected to the TVS tube, the negative input terminal of the eleventh operational amplifier U11 is respectively connected to a ninety-ninth resistor R99 and a thirty-third resistor R33, the ninety-ninth resistor R99 is connected to the system ground, the output terminal of the eleventh operational amplifier U11 is respectively connected to the thirty-second resistor R32, the thirty-third resistor R33 and the thirty-fourth resistor R34, the thirty-fourth resistor R34 is connected to the tenth The input end of the isolation amplifier U10, the input end of the tenth isolation amplifier U10 is also connected to the thirty-fifth resistor R35, the thirty-sixth resistor R36 and the thirty-seventh resistor R37 are respectively connected between the tenth isolation amplifier U10 and the twelfth operational amplifier U12, the positive input end of the twelfth operational amplifier U12 is respectively connected to the thirty-seventh resistor R37, the thirty-ninth resistor R39, the first capacitor C1 and the third capacitor C3, the negative input end of the twelfth operational amplifier U12 is respectively connected to the thirty-sixth resistor R36, the thirty-eighth resistor R38, the first capacitor C1 and the second capacitor C2, the first capacitor C1 is connected between the second capacitor C2 and the third capacitor C3, and the output end of the twelfth operational amplifier U12 is connected to the isolation circuit. The 30th resistor R30, the 32nd resistor R32, the 33rd resistor R33, the 99th resistor R99, the 34th resistor R34, the 35th resistor R35 and the 11th operational amplifier U11 form an amplification circuit to amplify the sampled value. The 10th isolation operational amplifier U10 is used for signal isolation to prevent the front-end and rear-end signals from being interfered with. The 12th operational amplifier U12 and the 36th resistor R36, the 37th resistor R37, the 38th resistor R38, and the 39th resistor R39 form an amplification circuit. The measured TVS tube current value I_sample is converted into a voltage value V_sample through the second resistor R2, filtered by the fifth capacitor C5, and enters the attenuation, isolation, and amplification circuit to generate an I_V voltage value, which is transmitted to the MCU processor system to achieve the purpose of TVS tube current sampling.

[0036] The TVS tube online self-test and switching circuit control method of the present invention is as follows: Figure 6 As shown, the specific implementation steps are as follows:

[0037] Step 1: Input power and turn on the power. After each circuit completes self-check, it enters normal working state;

[0038] Step 2: The MCU processor system controls the voltage value of the adjustable boost circuit and the current value of the adjustable current source circuit, controls the TVS tube switching circuit, applies the voltage value and the current value to the TVS tube, and the voltage sampling circuit and the current sampling circuit detect the current and voltage of the TVS tube;

[0039] Step 3: The voltage sampling circuit and the current sampling circuit send the collected voltage and current values ​​to the MCU processor system respectively. The system determines whether the collected data is within the preset value range. If it is within the range, the TVS tube is marked as available and the data is stored in the memory, waiting to be called. If it is not within the preset value range, it is marked as destroyed, the TVS tube control instruction is isolated from the memory, and a disconnect control instruction is given to control the faulty TVS tube to always be in the disconnected state. The system skips the faulty TVS tube every time it runs.

[0040] Step 4: Upload the judgment result to the upper system for other tasks.

Claims

1. TVS tube online self-test and switching circuit, characterized by: It includes an input power supply, the input power supply is connected to a DC / DC conversion circuit and an adjustable boost circuit through a diode, the DC / DC conversion circuit is connected to an MCU processor system, the MCU processor system is connected to a communication circuit, the communication circuit is connected to a host system, the MCU processor system is also connected to an isolation circuit, the adjustable boost circuit is respectively connected to an adjustable current source circuit and a TVS tube circuit, the TVS tube circuit is respectively connected to a voltage sampling circuit, a current sampling circuit and a switch switching circuit, the voltage and current sampling circuit and the switch switching circuit are both connected to the isolation circuit, and the isolation circuit is also respectively connected to the adjustable current source circuit and the adjustable boost circuit; The TVS tube circuit includes several TVS tubes, each of which is connected to a switch SW at both ends, one end of the TVS tube is connected to an adjustable current source circuit, a voltage sampling circuit, a current sampling circuit and a switch switching circuit, and the other end of the TVS tube is connected to an adjustable boost circuit, and each switch SW is connected to an MCU processor system through wiring; The adjustable current source circuit includes a PMOS tube U3 and an optocoupler U2, the PMOS tube U3 and the optocoupler U2 are connected to the TVS tube, the optocoupler U2 is connected to the first operational amplifier U1, the first operational amplifier U1 is connected to the fourth resistor R4, a third resistor R3 and a resistor R0 are connected in parallel between the first operational amplifier U1 and the fourth resistor R4, a first resistor R1 is connected between the first operational amplifier U1 and the optocoupler U2, a fifth resistor R5 is connected between the PMOS tube U3 and the TVS tube, and the optocoupler U2 is connected to the second resistor R2.

2. The TVS tube online self-test and switching circuit according to claim 1 is characterized in that: The voltage sampling circuit includes a ninth operational amplifier U9, the ninth operational amplifier U9 is connected to an eighth isolation operational amplifier U8, the input positive end of the eighth isolation operational amplifier U8 is connected to a fifteenth resistor R15, the other end of the fifteenth resistor R15 is connected to a thirteenth resistor R13 and a fourteenth resistor R14, the fourteenth resistor R14 is connected to the system ground, the other end of the thirteenth resistor R13 is connected to one end of the TVS tube, the input negative end of the eighth isolation operational amplifier U8 is connected to a twelfth resistor R12, the other end of the twelfth resistor R12 is connected to an eleventh resistor R11 and the tenth resistor R10, the tenth resistor R10 is connected to the system ground, the other end of the eleventh resistor R11 is connected to the other end of the TVS tube, the output end of the eighth isolation amplifier U8 is respectively connected to the sixteenth resistor R16 and the seventeenth resistor R17, the sixteenth resistor R16 and the seventeenth resistor R17 are respectively connected to the input end of the ninth operational amplifier U9, the input end and the output end of the ninth operational amplifier U9 are respectively connected to the eighteenth resistor R18 and the nineteenth resistor R19, and the output end of the ninth operational amplifier U9 is connected to the isolation circuit.

3. The TVS tube online self-test and switching circuit according to claim 1 is characterized in that: The current sampling circuit includes an eleventh operational amplifier U11, a tenth isolation operational amplifier U10 and a twelfth operational amplifier U12 which are connected in series in sequence. The positive input end of the eleventh operational amplifier U11 is respectively connected to a thirtieth resistor R30 and a thirty-second resistor R32. The thirtieth resistor R30 is connected to a fifth capacitor C5. The fifth capacitor C5 is connected to the TVS tube. The negative input end of the eleventh operational amplifier U11 is respectively connected to a ninety-ninth resistor R99 and a thirty-third resistor R33. The ninety-ninth resistor R99 is connected to the system ground. The output end of the eleventh operational amplifier U11 is respectively connected to the thirty-second resistor R32, the thirty-third resistor R33 and the thirty-fourth resistor R34. The thirty-fourth resistor R34 is connected to the The input end of the tenth isolation amplifier U10 is also connected to the thirty-fifth resistor R35, the thirty-sixth resistor R36 and the thirty-seventh resistor R37 are respectively connected between the tenth isolation amplifier U10 and the twelfth operational amplifier U12, the positive input end of the twelfth operational amplifier U12 is respectively connected to the thirty-seventh resistor R37, the thirty-ninth resistor R39, the first capacitor C1 and the third capacitor C3, the negative input end of the twelfth operational amplifier U12 is respectively connected to the thirty-sixth resistor R36, the thirty-eighth resistor R38, the first capacitor C1 and the second capacitor C2, the first capacitor C1 is connected between the second capacitor C2 and the third capacitor C3, and the output end of the twelfth operational amplifier U12 is connected to the isolation circuit.

4. The method for controlling the TVS tube online self-test and switching circuit according to any one of claims 1 to 3, characterized in that: Follow the steps below to implement it: Step 1: Input power and turn on the power. After each circuit completes self-check, it enters normal working state; Step 2: The MCU processor system controls the voltage value of the adjustable boost circuit and the current value of the adjustable current source circuit, controls the TVS tube switching circuit, applies the voltage value and the current value to the TVS tube, and the voltage sampling circuit and the current sampling circuit detect the current and voltage of the TVS tube; Step 3: The voltage sampling circuit and the current sampling circuit send the collected voltage and current values ​​to the MCU processor system respectively. The system determines whether the collected data is within the preset value range. If it is within the range, the TVS tube is marked as available and the data is stored in the memory, waiting to be called. If it is not within the preset value range, it is marked as destroyed, the TVS tube control instruction is isolated from the memory, and a disconnect control instruction is given to control the faulty TVS tube to always be in the disconnected state. The system skips the faulty TVS tube every time it runs. Step 4: Upload the judgment result to the upper system for other tasks.

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