High-voltage protection circuit and high-voltage protection system

Abstract

The utility model discloses a high-voltage protection circuit and a high-voltage protection system, and relates to the technical field of high-voltage protection, and the impedance of a voltage stabilization module is changed from high impedance to low impedance when the voltage at the two ends of a low-voltage source is greater than a preset withstand voltage value, and the voltage at the two ends of the low-voltage source is maintained at the preset withstand voltage value. Meanwhile, the comparison module compares the voltage, collected by the voltage collection module, of the two ends of the low-voltage source with preset voltage, when the voltage, collected by the voltage collection module, of the two ends of the low-voltage source is larger than the preset voltage, a prompt signal is generated, and the prompt signal is fed back to the prompt device. It can be seen that the voltage collection module collects the voltage at the two ends of the low-voltage source, the comparison module compares the collected voltage at the two ends of the low-voltage source with the preset voltage, and when the voltage at the two ends of the low-voltage source is larger than the preset voltage, the prompt signal is generated and fed back to the prompt device; therefore, the safety of the high-voltage protection circuit is improved.

Description

Technical Field

[0001] This utility model relates to the field of high voltage protection technology, and in particular to a high voltage protection circuit and a high voltage protection system. Background Technology

[0002] With the rapid development of the semiconductor industry, semiconductor manufacturers have increasingly higher demands for product testing, and correspondingly, the requirements for voltage are also becoming more stringent. When testing devices under test (DUTs) in some products, both a high-voltage source and a low-voltage source must be connected to the DUT to achieve parameter testing under high-voltage characteristics. When the DUT breaks down or conducts abnormally, the transient voltage suppressor diode connected in parallel across the DUT absorbs surge power to isolate the effects of high voltage. Although this method can utilize the transient voltage suppressor diode to quickly absorb most of the energy, thus protecting the low-voltage source from impact, the user cannot immediately detect when the DUT has experienced high-voltage protection, reducing the safety of the high-voltage protection circuit. Utility Model Content

[0003] The purpose of this invention is to provide a high-voltage protection circuit and system. When the voltage across the low-voltage source acquired by the comparison module is greater than a preset voltage, a prompt signal is generated and fed back to the prompting device to promptly inform the user that the device under test has experienced high-voltage protection, thereby improving the safety of the high-voltage protection circuit.

[0004] To solve the above-mentioned technical problems, this utility model provides a high-voltage protection circuit, comprising:

[0005] A voltage regulator module, the two ends of which are connected to the two ends of a low-voltage source, is used to clamp the voltage across the low-voltage source to the preset withstand voltage value when the voltage across the low-voltage source is greater than the preset withstand voltage value; the low-voltage source is also connected to the device under test;

[0006] A voltage acquisition module, wherein the input terminal of the voltage acquisition module is connected to both ends of the low voltage source, and is used to acquire the voltage across the two ends of the low voltage source;

[0007] A comparison module is connected to the output terminal of the voltage acquisition module, and is used to generate a prompt signal when the voltage is greater than a preset voltage, and to feed the prompt signal back to the prompting device.

[0008] Optionally, the positive output terminal of the low-voltage source is connected to the device under test via a triaxial cable.

[0009] Optionally, the voltage regulator module includes:

[0010] A first gas discharge tube, wherein a first end of the first gas discharge tube is connected to the high end of the three-coaxial cable, and a second end is connected to the first end of the second gas discharge tube and the protection end of the three-coaxial cable respectively, is used to clamp the voltage difference between the two ends of the first gas discharge tube at the first preset voltage difference threshold when the voltage difference between the two ends of the first gas discharge tube is greater than the first preset voltage difference threshold.

[0011] The second gas discharge tube has its second end connected to the negative output terminal of the low-pressure source. It is used to clamp the voltage difference between the two ends of the second gas discharge tube at the second preset differential voltage threshold when the voltage at the protection terminal is greater than the second preset differential voltage threshold.

[0012] Optionally, the voltage acquisition module includes a first voltage divider resistor and a second voltage divider resistor. The first end of the first voltage divider resistor is connected to the first end of the second gas discharge tube, and the second end is connected to the first end of the second voltage divider resistor. The common terminal of the connection is connected to the comparison module. The second end of the second voltage divider resistor is connected to the second end of the second gas discharge tube.

[0013] Optional, also includes:

[0014] A first switch, wherein the first end of the first switch is connected to the second end of the first gas discharge tube, and the second end is connected to the first end of the second gas discharge tube and the protection end of the three coaxial cables, respectively, for disconnecting during parameter testing under low-pressure characteristics and closing during parameter testing under high-pressure characteristics.

[0015] Optional, also includes:

[0016] A voltage follower, wherein the input terminal of the voltage follower is connected to the output terminal of the voltage acquisition module, and the output terminal is connected to the comparison module.

[0017] Optional, also includes:

[0018] An absolute value circuit is provided, wherein the input terminal of the absolute value circuit is connected to the output terminal of the voltage acquisition module, and the output terminal is connected to the comparison module, for converting the output voltage of the voltage acquisition module into a positive voltage when the output voltage of the voltage acquisition module is negative.

[0019] Optionally, the absolute value circuit includes:

[0020] The first resistor has its first end connected to the output terminal of the voltage acquisition module and its second end connected to the inverting input terminal of the first amplifier.

[0021] The first amplifier has its non-inverting input terminal grounded and its output terminal connected to the anode of a diode, and is used to convert the output voltage of the voltage acquisition module into a positive voltage when the output voltage is negative.

[0022] The second amplifier has its non-inverting input connected to the cathode of the diode and its output connected to the comparator module, and is used to output the positive voltage.

[0023] The second resistor has its first end connected to the output terminal of the voltage acquisition module and its second end connected to the non-inverting input terminal of the second amplifier.

[0024] The third resistor has its first end connected to the second end of the first resistor, and its second end connected to the non-inverting input terminal of the second amplifier.

[0025] The diode is configured to not conduct when the output voltage of the voltage acquisition module is positive, and to conduct when the output voltage of the voltage acquisition module is negative.

[0026] Optional, also includes:

[0027] The second switch has a first end connected to the device under test and a second end connected to the positive output terminal of the low-voltage source.

[0028] A processor, connected to the output of the comparison module, is used to control the second switch to open when the prompt signal is received.

[0029] To solve the above-mentioned technical problems, this utility model also provides a high-voltage protection system, including a device under test and a high-voltage protection circuit as described above, wherein the high-voltage protection circuit is connected to the device under test.

[0030] This invention provides a high-voltage protection circuit, which includes a voltage regulator module, a voltage acquisition module, and a comparison module. The voltage regulator module changes its impedance from high to low when the voltage across the low-voltage source exceeds a preset withstand voltage value, maintaining the voltage across the low-voltage source at the preset withstand voltage. Simultaneously, the comparison module compares the voltage across the low-voltage source acquired by the voltage acquisition module with a preset voltage. When the voltage across the low-voltage source exceeds the preset voltage, an alert signal is generated and fed back to an alerting device. Therefore, the voltage acquisition module acquires the voltage across the low-voltage source, and the comparison module compares this acquired voltage with a preset voltage. When the voltage across the low-voltage source exceeds the preset voltage, an alert signal is generated and fed back to the alerting device, promptly informing the user that the device under test has experienced high-voltage protection, thus improving the safety of the high-voltage protection circuit.

[0031] This invention also provides a high-voltage protection system, which has the same beneficial effects as the high-voltage protection circuit described above. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the prior art and embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 A schematic diagram of a high-voltage protection circuit provided by this utility model;

[0034] Figure 2 This is a schematic diagram of the structure of a voltage follower provided by this utility model;

[0035] Figure 3 A schematic diagram of an absolute value circuit provided by this utility model;

[0036] Figure 4 The schematic diagram of a specific high-voltage protection circuit provided by this utility model. Attached Figure Description

[0038] 1. Voltage regulator module; 2. Voltage acquisition module; 3. Comparison module; 4. Low voltage source; 5. Voltage follower; 6. Absolute value circuit; 7. Processor. Detailed Implementation

[0039] The core of this utility model is to provide a high-voltage protection circuit and a high-voltage protection system. When the voltage across the low-voltage source acquired by the comparison module is greater than a preset voltage, a prompt signal is generated and fed back to the prompting device to promptly inform the user that the device under test has experienced high-voltage protection, thereby improving the safety of the high-voltage protection circuit.

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0041] When testing devices under test (DUTs) in some products, both a high-voltage source and a low-voltage source must be connected to the DUT to achieve parameter testing under high-voltage characteristics. When the DUT breaks down or conducts abnormally, the transient voltage suppressor (VTS) diode connected across the DUT absorbs surge power to isolate the high-voltage effect. While this method effectively protects the low-voltage source from impact by quickly absorbing most of the energy using the VTS diode, it prevents the user from promptly noticing the high-voltage protection circuit, thus reducing its safety.

[0042] Please refer to Figure 1 As shown, Figure 1 The schematic diagram of a high-voltage protection circuit provided by this utility model.

[0043] The high-voltage protection circuit includes:

[0044] Voltage regulator module 1, with its two ends connected to the two ends of low voltage source 4, is used to clamp the voltage across low voltage source 4 to the preset withstand voltage value when the voltage across low voltage source 4 exceeds the preset withstand voltage value; low voltage source 4 is also connected to the device under test.

[0045] Voltage acquisition module 2, the input terminal of voltage acquisition module 2 is connected to both ends of low voltage source 4, and is used to acquire the voltage at both ends of low voltage source 4;

[0046] Comparison module 3 is connected to the output of voltage acquisition module 2. It is used to generate a prompt signal when the voltage is greater than the preset voltage and to feed the prompt signal back to the prompting device.

[0047] When performing parameter testing on the device under test (DUT) under high voltage conditions, it is usually necessary to provide both a high-voltage source and a low-voltage source 4 simultaneously. When the DUT is broken down by the high voltage provided by the high-voltage source, the high voltage will be directly transmitted to the low-voltage source 4, causing the low-voltage source 4 to be subjected to abnormally high voltage, thus reducing the safety of the low-voltage source 4. Here, the low-voltage source 4 becomes the protected circuit. To protect the low-voltage source 4 from high voltage damage, this embodiment uses a voltage regulator module 1 connected in parallel across the low-voltage source 4. When the device under test is broken down by the high voltage provided by the high voltage source, the voltage across the low-voltage source 4 is equal to the high voltage provided by the high voltage source. If the high voltage provided by the high voltage source is greater than the breakdown voltage of the voltage regulator module 1, the low-voltage source 4 will be subjected to a high voltage surge. At this time, the voltage regulator module 1 conducts, and the impedance between the two ends of the voltage regulator module 1 changes from high impedance to low impedance. At the same time, the voltage regulator module 1 absorbs surge power to isolate the effects of the high voltage surge, clamping the voltage between the two ends of the voltage regulator module 1 at the preset withstand voltage value of the voltage regulator module 1, effectively protecting the low-voltage source 4 from the high voltage provided by the high voltage source. The breakdown voltage of the voltage regulator module 1 is the preset withstand voltage value of the voltage regulator module 1. In practical applications, the comparator module 3 can be a latch comparator, and the voltage regulator module 1 can be a high-voltage resistant gas discharge tube. The gas discharge tube can effectively discharge when high voltage is applied across its two ends, making the high-voltage part of the wiring suspended and preventing leakage.

[0048] Furthermore, to inform the user that the device under test (DUT) has experienced high-voltage protection and triggered the corresponding protection mechanism to prevent further damage, a prompt signal needs to be generated after the high-voltage surge occurs and fed back to the prompting device. In this embodiment, the voltage acquisition module 2 can collect the voltage across the low-voltage source 4 in real time, and the comparison module 3 compares the voltage across the low-voltage source 4 with a preset voltage. When the voltage across the low-voltage source 4 is not greater than the preset voltage, it indicates that the high voltage provided by the high-voltage source has not been transmitted to the low-voltage source 4, and the low-voltage source 4 is not affected by the high voltage provided by the high-voltage source. When the voltage across the low-voltage source 4 is greater than the preset voltage, it indicates that the DUT is subjected to the high voltage provided by the high-voltage source. The comparison module 3 needs to generate a prompt signal when the high-voltage surge occurs and feed the prompt signal back to the prompting device to inform the user that the DUT has experienced high-voltage protection.

[0049] It should be noted that, considering that the signal transmission and processing process takes time, the voltage transmission and processing begins before the high voltage at both ends of the low voltage source 4 exceeds the breakdown voltage of the voltage regulator module 1, so as to send a warning signal to the warning device in advance and ensure the safety of the high voltage protection circuit. Therefore, the preset voltage can be less than the breakdown voltage of the voltage regulator module 1, and the breakdown voltage of the voltage regulator module 1 is the preset withstand voltage value of the voltage regulator module 1. Therefore, the preset voltage is less than the preset withstand voltage value.

[0050] In addition, to avoid the risks caused by continuous high voltage impact and further improve the safety of the high voltage protection circuit, the processor 7 can control the connection between the low voltage source 4 and the device under test after receiving the prompt signal, thus eliminating the connection between the high voltage source and the low voltage source 4 from the source. At this time, even if the device under test is broken down by high voltage, since the low voltage source 4 is not connected to the device under test, the high voltage of the high voltage source will no longer be applied to the two ends of the low voltage source 4, and the high voltage will not affect the low voltage source 4.

[0051] As can be seen, the voltage acquisition module 2 acquires the voltage across the low-voltage source 4, and the comparison module 3 compares the acquired voltage across the low-voltage source 4 with the preset voltage. When the voltage across the low-voltage source 4 is greater than the preset voltage, a prompt signal is generated and fed back to the prompting device to inform the user in a timely manner that the device under test has experienced high voltage protection, thereby improving the safety of the high-voltage protection circuit.

[0052] Based on the above embodiments:

[0053] As an alternative embodiment, the positive (+) output terminal of the low-voltage source 4 is connected to the device under test via a triaxial cable.

[0054] Specifically, a triaxial cable includes three terminals: Force (high-side), Guard (protection terminal), and CHGND (ground terminal). The Force and Guard terminals are connected to the device under test (DUT). Under normal operating conditions, the Force and Guard terminals have the same potential, resulting in a high insulation resistance and low leakage current. The design of the triaxial cable provides high interference immunity. The outer and middle grounding shielding materials effectively shield against external electromagnetic interference and electrostatic noise, ensuring the safety and reliability of voltage transmission. Furthermore, the triaxial cable effectively reduces mutual interference between voltages and energy loss during transmission, improving transmission quality. It also offers a large bandwidth and long transmission distance, meeting the requirements of high-speed voltage transmission. In addition, the triaxial cable has high insulation and high-temperature resistance, enabling it to adapt to complex electrical environments.

[0055] As can be seen, this embodiment uses a triaxial cable to connect the positive terminal (+) of the low-voltage source 4 to the device under test, which can effectively shield external electromagnetic interference, thereby ensuring the stability and reliability of transmission. In addition, the triaxial cable can effectively reduce mutual interference between voltages and energy loss of voltage during transmission, ensuring the transmission quality of voltage during transmission.

[0056] As an optional embodiment, the voltage regulator module 1 includes:

[0057] The first gas discharge tube GDT1 has its first end connected to the high end Force of the three-coaxial cable, and its second end connected to the first end of the second gas discharge tube GDT2 and the protection end Guard of the three-coaxial cable, respectively. It is used to clamp the voltage difference between the two ends of the first gas discharge tube GDT1 to the first preset voltage difference threshold when the voltage difference between the two ends of the first gas discharge tube GDT1 is greater than the first preset voltage difference threshold.

[0058] The second gas discharge tube GDT2 has its second end connected to the negative output terminal of the low-pressure source 4. It is used to clamp the voltage difference between the two ends of the second gas discharge tube GDT2 to the second preset voltage difference threshold when the voltage of the protection terminal Guard is greater than the second preset voltage difference threshold.

[0059] Specifically, when the voltage across the second gas discharge tube GDT2 increases to the point that the electric field strength between its electrodes exceeds the insulation strength of the gas, the gap between the electrodes of the second gas discharge tube GDT2 will break down, and the second gas discharge tube GDT2 will change from its original insulating state to a conductive state. After the second gas discharge tube GDT2 is turned on, the voltage between its electrodes will be maintained at the residual voltage level determined by the discharge arc of the second gas discharge tube GDT2. The residual voltage determined by the discharge arc of the second gas discharge tube GDT2 is very low, thereby clamping the voltage difference across the second gas discharge tube GDT2 to the second preset voltage difference threshold, that is, clamping the voltage value of the protection terminal Guard of the three coaxial cable to the second preset voltage difference threshold; when the voltage across the first gas discharge tube GDT1... When the voltage increases to the point that the electric field strength between the two electrodes of the first gas discharge tube GDT1 exceeds the insulation strength of the gas, the gap between the two electrodes of the first gas discharge tube GDT1 will break down, and the first gas discharge tube GDT1 will change from its original insulating state to a conductive state. After the first gas discharge tube GDT1 is turned on, the voltage between its two electrodes will be maintained at the residual voltage level determined by the discharge arc of the first gas discharge tube GDT1. The residual voltage determined by the discharge arc of the first gas discharge tube GDT1 is very low, so that the voltage difference between the two ends of the first gas discharge tube GDT1 is clamped at the first preset voltage difference threshold. That is, if the voltage value of the Guard of the three coaxial cable is clamped at the first preset voltage difference threshold, then the voltage across the low voltage source 4 is clamped at the sum of the first preset voltage difference threshold and the second preset voltage difference threshold. Among them, the residual voltage level determined by the discharge arc of the first gas discharge tube GDT1 is less than the residual voltage level determined by the discharge arc of the second gas discharge tube GDT2.

[0060] It should be noted that the gas discharge tube can quickly conduct under high-pressure impact, which can provide effective protection for low-pressure source 4.

[0061] For example, the residual voltage level determined by the discharge arc of the first gas discharge tube GDT1 can be 75V, and the residual voltage level determined by the discharge arc of the second gas discharge tube GDT2 can be 230V. When the device under test is broken down by the high voltage provided by the high voltage source, the voltage at the high-side Force and protection terminals of the three-coaxial cable increases instantaneously. If the voltage at the protection terminal Guard of the three-coaxial cable is greater than 230V, the second gas discharge tube GDT2 changes from its original insulating state to a conductive state. After the second gas discharge tube GDT2 is turned on, the voltage between its two poles will be maintained at... 230V, meaning the voltage at the Guard terminal of the triaxial cable is maintained at 230V; if the difference between the Force terminal and the Guard terminal of the triaxial cable is greater than 75V, the first gas discharge tube GDT1 changes from its original insulating state to a conductive state. After the first gas discharge tube GDT1 is turned on, the voltage between its two poles will be maintained at 75V, meaning the difference between the Force terminal voltage and the Guard terminal voltage of the triaxial cable will be maintained at 230V, meaning the Force terminal voltage of the triaxial cable will be maintained at 305V.

[0062] As can be seen, in this embodiment, a gas discharge tube is used as a voltage regulator module 1. When the gas discharge tube is in the discharge state, its voltage drop hardly changes with the current, and it has good voltage regulation characteristics. It can clamp the voltage across the low-voltage source 4 to the sum of the first preset voltage difference threshold and the second preset voltage difference threshold.

[0063] As an optional embodiment, the voltage acquisition module 2 includes a first voltage divider resistor R111 and a second voltage divider resistor R222. The first end of the first voltage divider resistor R111 is connected to the first end of the second gas discharge tube GDT2, the second end is connected to the first end of the second voltage divider resistor R222, and the common terminal of the connection is connected to the comparison module 3. The second end of the second voltage divider resistor R222 is connected to the second end of the second gas discharge tube GDT2.

[0064] Specifically, considering the time required for signal transmission and processing, voltage transmission and processing begin before the high voltage across the low-voltage source 4 exceeds the breakdown voltage of the voltage regulator module 1. This ensures that a warning signal is sent to the warning device before the voltage across the low-voltage source 4 falls below the breakdown voltage of the voltage regulator module 1, guaranteeing the safety of the high-voltage protection circuit. Therefore, this embodiment uses a first voltage divider resistor R111 and a second voltage divider resistor R222 connected in series as the voltage acquisition module 2. The common terminal of the two voltage divider resistors is connected to the comparison module 3. The voltage at the common terminal of the two voltage divider resistors is compared with a preset voltage. The preset voltage must be less than the breakdown voltage of the voltage regulator module 1, and the breakdown voltage of the voltage regulator module 1 is its preset withstand voltage value. The preset withstand voltage value of the voltage regulator module 1 is consistent with the preset withstand voltage value of the low-voltage source 4. Therefore, the preset voltage is less than the preset withstand voltage value. When the voltage at the common terminal of the two voltage divider resistors exceeds the preset voltage, the comparison module 3 can make a judgment in advance to inform the user that the device under test has experienced high-voltage protection, allowing the user to take appropriate action and ensuring the safety of the high-voltage protection circuit.

[0065] As can be seen, in this embodiment, the first voltage divider resistor R111 and the second voltage divider resistor R222 are connected in series as the voltage acquisition module 2, and the common terminal of the two voltage divider resistors is connected to the comparison module 3. The voltage at the common terminal of the two voltage divider resistors is compared with a preset voltage. Since the preset voltage is less than the preset withstand voltage value, a prompt signal can be sent to the prompting device before the high voltage at both ends of the low voltage source 4 exceeds the preset withstand voltage value, thus ensuring the safety of the high voltage protection circuit.

[0066] As an optional embodiment, it also includes:

[0067] The first switch K1 has its first end connected to the second end of the first gas discharge tube GDT1, and its second end connected to the first end of the second gas discharge tube GDT2 and the protection end Guard of the three coaxial cable. It is used to disconnect during parameter testing under low-voltage characteristics and close during parameter testing under high-voltage characteristics.

[0068] Specifically, in order to increase insulation during parameter testing under low voltage characteristics, ensure low current accuracy, and reduce line-to-ground capacitance, this embodiment sets a first switch K1 between the first gas discharge tube GDT1 and the second gas discharge tube GDT2. The first switch K1 is closed during parameter testing under high voltage characteristics to maintain the normal operation of the high voltage protection circuit; the first switch K1 is open during parameter testing under low voltage characteristics. The first switch K1 can be a relay.

[0069] As can be seen, in this embodiment, a first switch K1 is set between the first gas discharge tube GDT1 and the second gas discharge tube GDT2. The first switch K1 is disconnected during parameter testing under low voltage characteristics, which ensures the accuracy of small current and reduces the line-to-ground capacitance, thereby reducing reactive power loss and improving the power factor and voltage transmission stability of the high voltage protection circuit.

[0070] As an optional embodiment, it also includes:

[0071] Voltage follower 5, the input terminal of voltage follower 5 is connected to the output terminal of voltage acquisition module 2, and the output terminal is connected to comparison module 3.

[0072] Specifically, in this embodiment, a voltage follower 5 is provided before the comparison module 3. By increasing the input impedance, the voltage follower 5 effectively isolates the preceding and following circuits, preventing the voltage source from affecting subsequent devices, thereby improving the stability and determinism of the output voltage. Please refer to... Figure 2 As shown, Figure 2 This is a schematic diagram of a voltage follower provided by the present invention. The voltage follower 5 includes two power supply terminals, VDD1 and VDD2, two ground terminals, GND1 and GND2, a LATCH latch terminal, a REF reference terminal, an IN input terminal, and an OUT output terminal. It also includes three capacitors, C1, C2, and C3, and two resistors, R1 and R2.

[0073] As can be seen, this embodiment uses voltage follower 5 to isolate the preceding and following stage circuits, increases the input impedance, and ensures the stability and determinism of the output voltage.

[0074] As an optional embodiment, it also includes:

[0075] Absolute value circuit 6, the input terminal of absolute value circuit 6 is connected to the output terminal of voltage acquisition module 2, and the output terminal is connected to comparison module 3, used to convert the output voltage of voltage acquisition module 2 into a positive voltage when the output voltage is negative.

[0076] Specifically, since the preset voltage, i.e. the reference voltage, set by the comparison module 3 is usually positive, in order to convert the output voltage of the voltage acquisition module 2 into a positive voltage when the output voltage is negative, so that the comparison module 3 can compare the output voltage of the voltage acquisition module 2 with the preset voltage, this embodiment sets an absolute value circuit 6 before the comparison module 3. This circuit can convert the positive and negative output voltages of the voltage acquisition module 2 into a unified positive output voltage, thereby facilitating subsequent processing and analysis.

[0077] For example, when the output voltage of voltage acquisition module 2 is a sine wave, the output voltage of absolute value circuit 6 is also positive and unchanged when the output voltage of voltage acquisition module 2 is positive. When the output voltage of voltage acquisition module 2 is negative, the output voltage of absolute value circuit 6 becomes the opposite of the output voltage of voltage acquisition module 2, so that the input voltage of comparison module 3 is always positive.

[0078] As can be seen, in this embodiment, an absolute value circuit 6 is set before the comparison module 3, which can convert the positive and negative output voltages of the voltage acquisition module 2 into a unified positive output voltage, thereby facilitating subsequent processing and analysis.

[0079] As an optional embodiment, the absolute value circuit 6 includes:

[0080] The first resistor R11 has its first end connected to the output terminal of the voltage acquisition module 2, and its second end connected to the inverting input terminal of the first amplifier.

[0081] The first amplifier has its non-inverting input terminal grounded and its output terminal connected to the anode of the diode VD. It is used to convert the output voltage of the voltage acquisition module 2 into a positive voltage when the output voltage is negative.

[0082] The second amplifier has its non-inverting input connected to the cathode of diode VD and its output connected to comparator module 3, and is used to output a positive voltage.

[0083] The second resistor R22 has its first end connected to the output terminal of the voltage acquisition module 2 and its second end connected to the non-inverting input terminal of the second amplifier.

[0084] The third resistor R33 has its first end connected to the second end of the first resistor R11, and its second end connected to the non-inverting input of the second amplifier.

[0085] The diode VD is used to turn off when the output voltage of the voltage acquisition module 2 is positive and turn on when the output voltage of the voltage acquisition module 2 is negative.

[0086] Specifically, when the output voltage of voltage acquisition module 2 is positive, the output of the first amplifier is in a near-ground saturation state, and diode VD becomes high impedance. The output voltage of voltage acquisition module 2 is directly transmitted to the second amplifier without inversion. The second amplifier acts as a buffer to protect other circuit devices from voltage fluctuations. When the output voltage of voltage acquisition module 2 is negative, the first amplifier acts as a closed-loop inverter with a gain of -1. The output voltage of the first amplifier is positive, diode VD conducts, and the second amplifier acts as a buffer to protect other circuit devices from voltage fluctuations. Please refer to [reference needed]. Figure 3 As shown, Figure 3 The present invention provides a schematic diagram of an absolute value circuit.

[0087] As can be seen, this embodiment uses two operational amplifiers, three resistors and a diode VD to form an absolute value circuit 6, which converts the positive and negative output voltages of the voltage acquisition module 2 into a unified positive output voltage, facilitating subsequent processing and analysis, while also protecting other circuit devices from the effects of voltage fluctuations.

[0088] As an optional embodiment, it also includes:

[0089] The second switch K2 has its first end connected to the device under test and its second end connected to the positive output terminal of the low-voltage source 4.

[0090] Processor 7 is connected to the output of comparison module 3 and is used to control the second switch K2 to open when a prompt signal is received.

[0091] In this embodiment, to further protect the high-voltage protection circuit and avoid the risks caused by continuous high-voltage surges, during parameter testing under high-voltage characteristics, when the device under test (DUT) experiences breakdown or abnormal conduction, the comparison module 3 sends a prompt signal to the prompting device. Afterward, the connection between the low-voltage source 4 and the high-voltage source needs to be disconnected to cut off the high voltage at its source. This embodiment includes a processor 7, and a second switch K2 is placed between the DUT and the low-voltage source 4. When the processor 7 receives the prompt signal from the comparison module 3, it controls the second switch K2 between the DUT and the low-voltage source 4 to disconnect the connection between the low-voltage source 4 and the high-voltage source. The second switch K2 can be, but is not limited to, a relay. Furthermore, if the aforementioned first switch K1 exists, the processor 7 can control the first switch K1 to remain on or off.

[0092] The protection terminal guard of the triaxial cable has two actions. First, when the preset voltage threshold is reached, the comparison module 3 sends a prompt signal to the prompting device, reporting an anomaly in the channel of the corresponding low-voltage source 4. Then, after receiving the prompt signal, the processor 7 performs a series of operations, including shutting down the high-voltage source, the relay matrix (which can be set at the output of each low-voltage source 4 in actual settings), and the relays. Second, when the protection terminal guard of the triaxial cable exceeds the preset withstand voltage value, the second gas discharge tube GDT2 will discharge. The preset voltage (e.g., 213V) is less than the preset withstand voltage value, allowing more time for related processing actions. At this time, the equipotential between the high-side force and the protection terminal guard of the triaxial cable is broken. When the voltage difference between the two exceeds the first preset voltage difference threshold, the first gas discharge tube GDT1 between them will also start discharging to ensure that the voltage of the high-side force of the triaxial cable is not too high.

[0093] As can be seen, when the device under test (DUT) experiences a breakdown or abnormal conduction, the high-voltage Force and Guard terminals of the three-coaxial cable will be subjected to a high voltage provided by the high-voltage source. When the voltage exceeds the preset voltage, the comparison module 3 generates a prompt signal and feeds the prompt signal back to the prompting device. At the same time, the processor 7 will also receive the prompt signal from the comparison module 3. The processor 7 will control the second switch K2 between the DUT and the low-voltage source 4 to disconnect the connection between the low-voltage source 4 and the high-voltage source, further protecting the high-voltage protection circuit and avoiding the risks caused by continuous high-voltage impacts.

[0094] This utility model also provides a high-voltage protection system, including a device under test and a high-voltage protection circuit as described above, wherein the high-voltage protection circuit is connected to the device under test.

[0095] Specifically, the device under test (DUT) is a device that needs to be connected to both a high-voltage source and a low-voltage source 4. If the positive (+) output terminal of the low-voltage source 4 is connected to the DUT via a three-coaxial cable, during parameter testing under high-voltage characteristics, the voltage acquisition module 2 consists of two voltage divider resistors, and the common terminal of the two voltage divider resistors is connected to the input terminal of the voltage follower 5. The output terminal of the voltage follower 5 is connected to the input terminal of the absolute value circuit 6, and the output terminal of the absolute value circuit 6 is connected to the input terminal of the comparison module 3. The first switch K1 and the second switch K2 are both relays, and the processor 7 is an IO expansion chip. When the device under test (DUT) is simultaneously connected to both low-voltage source 4 and high-voltage source 4, the relay between the DUT and low-voltage source 4 is activated, as is the relay between the first gas discharge tube GDT1 and the second gas discharge tube GDT2. When the DUT experiences breakdown or abnormal conduction, the high-voltage source provides high voltage to the high-side Force and protection terminals Guard of the three-coaxial cable. The two voltage divider resistors divide the voltage. The voltage at the input of comparator module 3 is the product of the voltage at the protection terminal Guard of the three-coaxial cable and the ratio of the first resistor R11 to the second resistor R22. After voltage follow-up, this voltage is converted into a positive voltage value by absolute value circuit 6. This positive voltage value is compared with a preset voltage. When the positive voltage value is greater than the preset voltage, comparator module 3 outputs a low level and sends it to the IO expansion chip. The IO expansion chip then controls the relay between the DUT and low-voltage source 4 to turn off. Please refer to [reference needed]. Figure 4 As shown, Figure 4 The schematic diagram of a specific high-voltage protection circuit provided by this utility model.

[0096] Furthermore, for an introduction to the high-voltage protection system provided by this utility model, please refer to the above-described embodiment of the high-voltage protection circuit; this utility model will not be described in detail here.

[0097] As can be seen, the high voltage protection system provided by this utility model acquires the voltage across the low voltage source 4 through the voltage acquisition module 2, and compares the acquired voltage across the low voltage source 4 with the preset voltage using the comparison module 3. When the voltage across the low voltage source 4 is greater than the preset voltage, a prompt signal is generated and fed back to the prompting device to promptly inform the user that the device under test has experienced high voltage protection, thereby improving the safety of the high voltage protection circuit.

[0098] It should be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0099] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-voltage protection circuit, characterized in that, include: A voltage regulator module, the two ends of which are connected to the two ends of a low-voltage source, is used to clamp the voltage across the low-voltage source to the preset withstand voltage value when the voltage across the low-voltage source is greater than the preset withstand voltage value; the low-voltage source is also connected to the device under test; A voltage acquisition module, wherein the input terminal of the voltage acquisition module is connected to both ends of the low voltage source, and is used to acquire the voltage across the two ends of the low voltage source; The comparison module is connected to the output terminal of the voltage acquisition module and is used to generate a prompt signal when the voltage is greater than a preset voltage, and to feed the prompt signal back to the prompting device; Also includes: A voltage follower, wherein the input terminal of the voltage follower is connected to the output terminal of the voltage acquisition module, and the output terminal is connected to the comparison module.

2. The high-voltage protection circuit as described in claim 1, characterized in that, The positive output terminal of the low-voltage source is connected to the device under test via a triaxial cable.

3. The high-voltage protection circuit as described in claim 2, characterized in that, The voltage regulator module includes: A first gas discharge tube and a second gas discharge tube, wherein the first end of the first gas discharge tube is connected to the high end of the three coaxial cables, and the second end is connected to the first end of the second gas discharge tube and the protection end of the three coaxial cables respectively, for clamping the voltage difference between the two ends of the first gas discharge tube at the first preset voltage difference threshold when the voltage difference between the two ends of the first gas discharge tube is greater than the first preset voltage difference threshold. The second end of the second gas discharge tube is connected to the negative output terminal of the low-pressure source, and is used to clamp the voltage difference between the two ends of the second gas discharge tube at the second preset differential voltage threshold when the voltage at the protection terminal is greater than the second preset differential voltage threshold.

4. The high-voltage protection circuit as described in claim 3, characterized in that, The voltage acquisition module includes a first voltage divider resistor and a second voltage divider resistor. The first end of the first voltage divider resistor is connected to the first end of the second gas discharge tube, and the second end is connected to the first end of the second voltage divider resistor. The common terminal of the connection is connected to the comparison module. The second end of the second voltage divider resistor is connected to the second end of the second gas discharge tube.

5. The high-voltage protection circuit as described in claim 3, characterized in that, Also includes: A first switch, wherein the first end of the first switch is connected to the second end of the first gas discharge tube, and the second end is connected to the first end of the second gas discharge tube and the protection end of the three coaxial cables, respectively, for disconnecting during parameter testing under low-pressure characteristics and closing during parameter testing under high-pressure characteristics.

6. The high-voltage protection circuit as described in claim 1, characterized in that, Also includes: An absolute value circuit is provided, wherein the input terminal of the absolute value circuit is connected to the output terminal of the voltage acquisition module, and the output terminal is connected to the comparison module, for converting the output voltage of the voltage acquisition module into a positive voltage when the output voltage of the voltage acquisition module is negative.

7. The high-voltage protection circuit as described in claim 6, characterized in that, The absolute value circuit includes: A first resistor, with its first end connected to the output terminal of the voltage acquisition module and its second end connected to the inverting input terminal of the first amplifier; The first amplifier has its non-inverting input terminal grounded and its output terminal connected to the anode of a diode, and is used to convert the output voltage of the voltage acquisition module into a positive voltage when the output voltage is negative. The second amplifier has its non-inverting input connected to the cathode of the diode and its output connected to the comparator module, and is used to output the positive voltage. The second resistor has its first end connected to the output terminal of the voltage acquisition module and its second end connected to the non-inverting input terminal of the second amplifier. The third resistor has its first end connected to the second end of the first resistor, and its second end connected to the non-inverting input terminal of the second amplifier. The diode is configured to not conduct when the output voltage of the voltage acquisition module is positive, and to conduct when the output voltage of the voltage acquisition module is negative.

8. The high-voltage protection circuit as described in any one of claims 1 to 7, characterized in that, Also includes: The second switch has a first end connected to the device under test and a second end connected to the positive output terminal of the low-voltage source. A processor, connected to the output of the comparison module, is used to control the second switch to open when the prompt signal is received.

9. A high-voltage protection system, characterized in that, It includes a device under test (DUT) and a high-voltage protection circuit as described in any one of claims 1 to 8, wherein the high-voltage protection circuit is connected to the DUT.

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