ESD protection circuit, ESD protection device and ESD test equipment
By designing an ESD protection circuit and utilizing components such as transient voltage suppression diodes and varistors, the problem of damage risk to automotive electronic products during ESD testing was solved, achieving effective protection of coaxial cable interfaces and circuits, and improving equipment stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TIANJIN JINGWEI HIRAIN TECH CO LTD
- Filing Date
- 2025-06-03
- Publication Date
- 2026-05-15
AI Technical Summary
Existing automotive electronic products, especially controllers for analog signals, lack effective protection measures during ESD testing, resulting in a significant risk of damage during ESD testing.
An ESD protection circuit was designed, including a first protection circuit and a second protection circuit. Through components such as transient voltage suppression diodes and varistors, electrostatic voltage is discharged when different voltage levels are detected, limiting the inter-electrode voltage and protecting the coaxial cable interface and the front and rear circuits.
It effectively reduces the risk of equipment damage during ESD testing, improves protection measures during signal transmission, reduces damage to optical bridges and other equipment, and enhances equipment stability.
Smart Images
Figure CN224249356U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electromagnetic compatibility testing technology, specifically to ESD protection circuits, devices, and ESD testing equipment. Background Technology
[0002] The main purpose of ESD (Electro-Static Discharge) testing in EMC (Electro Magnetic Compatibility) tests for automotive electronic products and even complete vehicles is to verify whether the device or vehicle under test can maintain normal operation or be undamaged under ESD interference.
[0003] In current automotive electronics ESD testing, two types of tests are typically performed: direct discharge and indirect discharge. Direct discharge is further divided into discharge tests targeting the controller and wiring harness. The ESD test method involves directly discharging static electricity into the device under test (DUT), its connecting wiring harness, or the space in which it resides, thereby determining whether the DUT can maintain normal operation or has suffered permanent damage. Automotive electronic products typically have external CAN (Controller Area Network) / LIN (Local Interconnect Network) / Ethernet or analog signal outputs / communications, etc., which are monitored or communicated using oscilloscopes and CAN / LIN-CASE (LIN communication cards) during ESD testing.
[0004] In current ESD testing of controllers containing analog signals, traditional CAN protectors prevent damage to CAN communication, ensuring opto-isolation or the CAN card itself is not damaged. However, there are no effective protection measures for analog signal outputs / monitoring from signal generators or oscilloscopes. They can only rely on the hardware capabilities of the analog optical bridge to withstand ESD, which carries a significant risk of damage. Utility Model Content
[0005] In view of this, the present invention provides an ESD protection circuit, device, and ESD testing equipment to solve the problem of damage risk in ESD testing in the prior art.
[0006] In a first aspect, this utility model provides an ESD protection circuit, wherein each ESD protection circuit is connected between each first coaxial cable interface and each second coaxial cable interface, and the ESD protection circuit includes:
[0007] A first protection circuit has a first terminal connected to the signal terminal of the first coaxial cable interface and the signal terminal of the second coaxial cable interface, and a second terminal connected to the signal ground terminal. The signal ground terminal is connected to the ground terminal of the first coaxial cable interface and the ground terminal of the second coaxial cable interface. The first protection circuit is used to conduct and discharge the current voltage to the signal ground terminal when it detects that the current voltage is greater than a first preset voltage.
[0008] The second protection circuit has its first terminal connected to the signal terminals of the first and second coaxial cable interfaces, respectively, and its second terminal connected to the signal ground terminal. The second protection circuit receives the discharged voltage and outputs a preset inter-electrode voltage when it detects that the discharged voltage is greater than a second preset voltage, so as to protect the first and second coaxial cable interfaces.
[0009] The ESD protection circuit proposed in this invention uses a first protection circuit to discharge electrostatic voltage. However, due to the high clamping voltage of the first protection circuit, it may damage the first and second coaxial cable interfaces, as well as the circuits at the front and rear ends. Therefore, a second protection circuit is needed for further discharge. Specifically, the second protection circuit further limits the inter-electrode voltage after discharge. Thus, when ESD occurs, the first and second protection circuits discharge the ESD, thereby protecting the first and second coaxial cable interfaces, as well as the circuits at the front and rear ends. Compared to traditional methods that rely solely on the hardware capabilities of analog optical bridges to withstand ESD, this application incorporates protection measures during signal transmission, such as output or monitoring, greatly eliminating the risks associated with ESD testing.
[0010] In one optional implementation, the first protection circuit includes:
[0011] A transient voltage suppressor diode is provided, wherein the first terminal of the transient voltage suppressor diode is connected to the signal terminal of the first coaxial cable interface and the signal terminal of the second coaxial cable interface, and the second terminal of the transient voltage suppressor diode is connected to the signal ground terminal.
[0012] In one optional embodiment, the second protection circuit includes:
[0013] A varistor, wherein the first end of the varistor is connected to the signal end of the first coaxial cable interface and the signal end of the second coaxial cable interface, respectively;
[0014] A gas discharge tube, wherein the first end of the gas discharge tube is connected to the varistor, and the second end of the gas discharge tube is connected to the signal ground terminal.
[0015] In one optional embodiment, the second protection circuit further includes:
[0016] A first resistor, the first end of which is connected to the signal terminal of the first coaxial cable interface, and the second end of which is connected to the signal terminal of the second coaxial cable interface.
[0017] In one optional implementation, the ESD protection circuit further includes:
[0018] A short-circuit protection circuit, wherein the first terminal of the short-circuit protection circuit is connected to the signal ground terminal, and the second terminal of the short-circuit protection circuit is connected to the ground terminal.
[0019] In one optional embodiment, the short-circuit protection circuit further includes:
[0020] The second resistor has a first end connected to the signal ground terminal and a second end connected to the ground terminal.
[0021] A first capacitor, the first end of which is connected to the signal ground terminal, and a second resistor, the second end of which is connected to the ground terminal.
[0022] Secondly, this utility model provides an ESD protection device, which includes a bypass power supply circuit and an ESD protection circuit as described above. The ESD protection device includes:
[0023] The housing has multiple holes for first coaxial cable interfaces and multiple holes for second coaxial cable interfaces.
[0024] The ESD protection circuit is located inside the housing.
[0025] In one alternative embodiment, the housing is a metal housing, and the ground end is connected to the metal housing.
[0026] In one optional implementation, the ESD protection device further includes:
[0027] Two brackets are fixed on both sides of the housing, and the brackets are used to support the ESD protection device.
[0028] Thirdly, this utility model provides an ESD testing device, which includes the ESD protection device described above. Attached Figure Description
[0029] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0030] Figure 1 This is a structural diagram of an ESD protection circuit according to an embodiment of the present utility model;
[0031] Figure 2 This is another ESD protection circuit structure diagram according to an embodiment of the present utility model;
[0032] Figure 3 This is a structural diagram of an ESD protection device according to an embodiment of the present utility model;
[0033] Explanation of icon numbers:
[0034] 10-First protection circuit; 20-Second protection circuit; 30-Short circuit protection circuit; G1-Gas discharge tube; R0-Varistor; D1-Transient voltage suppressor diode; R2-Second resistor; C1-First capacitor; A-Housing; B-Support. Detailed Implementation
[0035] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.
[0036] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the module or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0037] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0038] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.
[0039] The main purpose of ESD (Electro-Static Discharge) testing in EMC (Electro Magnetic Compatibility) tests for automotive electronic products and even complete vehicles is to verify whether the device or vehicle under test can maintain normal operation or be undamaged under ESD interference.
[0040] In current automotive electronics ESD testing, two types of tests are typically performed: direct discharge and indirect discharge. Direct discharge is further divided into discharge tests targeting the controller and wiring harness. The ESD test method involves directly discharging static electricity into the device under test (DUT), its connecting wiring harness, or the space in which it resides, thereby determining whether the DUT can maintain normal operation or has suffered permanent damage. Automotive electronic products typically have external CAN (Controller Area Network) / LIN (Local Interconnect Network) / Ethernet or analog signal outputs / communications, etc., which are monitored or communicated using oscilloscopes and CAN / LIN-CASE (LIN communication cards) during ESD testing.
[0041] In current ESD testing of controllers containing analog signals, traditional CAN protectors prevent damage to CAN communication, ensuring opto-isolation or the CAN card itself is not damaged. However, there are no effective protection measures for analog signal outputs / monitoring from signal generators or oscilloscopes. They can only rely on the hardware capabilities of the analog optical bridge to withstand ESD, which carries a significant risk of damage.
[0042] The main purpose of ESD testing in EMC testing of automotive electronic products and even complete vehicles is to verify whether the device or vehicle under test can maintain normal operation or be undamaged under ESD interference.
[0043] In current automotive electronics ESD testing, two types of tests are typically performed: direct discharge and indirect discharge. Direct discharge is further divided into discharge tests targeting controllers and wiring harnesses. The ESD test method involves directly discharging static electricity into the device under test (DUT), its connecting wiring harness, or the space in which it resides, thereby determining whether the DUT can maintain normal operation or has suffered permanent damage. Automotive electronic products typically have external CAN / LIN / Ethernet or analog signal outputs / communications, which are monitored or communicated using oscilloscopes and CAN / LIN-CASE devices during ESD testing.
[0044] In current ESD testing of controllers containing analog signals, traditional CAN protectors prevent damage to CAN communication, ensuring opto-isolation or the CAN card itself is not damaged. However, there are no effective protection measures for analog signal outputs / monitoring from signal generators or oscilloscopes. They can only rely on the hardware capabilities of the analog optical bridge to withstand ESD, which carries a significant risk of damage.
[0045] To address this, this embodiment provides an ESD protection circuit, such as... Figure 1 As shown, an ESD protection circuit is provided, wherein each ESD protection circuit is connected between each first coaxial cable interface B1 and each second coaxial cable interface B2, and the ESD protection circuit includes:
[0046] A first protection circuit 10 has a first terminal connected to the signal terminal of the first coaxial cable interface B1 and the signal terminal of the second coaxial cable interface B2, and a second terminal connected to a signal ground terminal. The signal ground terminal is connected to the ground terminal of the first coaxial cable interface B1 and the ground terminal of the second coaxial cable interface B2, respectively. The first protection circuit 10 is used to conduct and discharge the current voltage to the signal ground terminal when it detects that the current voltage is greater than a first preset voltage.
[0047] The second protection circuit 20 has its first terminal connected to the signal terminal of the first coaxial cable interface B1 and the signal terminal of the second coaxial cable interface B2, respectively, and its second terminal connected to the signal ground terminal. The second protection circuit receives the discharged voltage and outputs a preset inter-electrode voltage when it detects that the discharged voltage is greater than a second preset voltage, so as to protect the first coaxial cable interface and the second coaxial cable interface.
[0048] Specifically, the first coaxial cable interface B1 and the second coaxial cable interface B2 can be analog signal interfaces, signal generators, or display devices, respectively. The display device can specifically be an oscilloscope. For example, the first coaxial cable interface B1 can be a signal generator, and the second coaxial cable interface B2 can be an analog signal interface. Alternatively, the first coaxial cable interface B1 can be an analog signal interface, and the second coaxial cable interface B2 can be a display device. Specifically, the first coaxial cable interface B1 and the second coaxial cable interface B2 are BNC interfaces (basic network cards). The signal terminals of the first coaxial cable interface B1 and the second coaxial cable interface B2 are the inner diameter, and the ground terminals of the first coaxial cable interface B1 and the second coaxial cable interface B2 are the outer diameter.
[0049] Specifically, when a normal signal is transmitted between the first coaxial cable interface B1 and the second coaxial cable interface B2, it indicates that no ESD occurs. At this time, the voltage between the first coaxial cable interface B1 and the second coaxial cable interface B2 is lower than a first preset voltage, and the first protection circuit 10 is in a high-resistance state, which is equivalent to an insulation state and does not affect normal signal transmission. When ESD occurs between the first coaxial cable interface B1 and the second coaxial cable interface B2, the first protection circuit 10 conducts, discharges the ESD, and outputs the discharged voltage. Optionally, the first protection circuit 10 is a high-voltage resistant device, used to protect against electrostatic discharge voltages greater than a preset voltage. That is, the first protection circuit 10 protects against high-voltage electrostatic discharge. The first protection circuit 10 is a device that can switch from a high-resistance state to a low-resistance state when it detects that the current voltage is greater than the first preset voltage.
[0050] Specifically, when a normal signal is transmitted between the first coaxial cable interface B1 and the second coaxial cable interface B2, it indicates that no ESD occurs. At this time, the second protection circuit 20 is in a high-insulation state and does not affect the normal signal transmission. When ESD occurs between the first coaxial cable interface B1 and the second coaxial cable interface B2, if the voltage discharged from the first protection circuit 10 is detected to be greater than a second preset voltage, the inter-electrode voltage is limited, i.e., a preset inter-electrode voltage is output to protect the first and second coaxial cable interfaces. Optionally, the second protection circuit 20 can be a low-voltage protection device. Optionally, the second protection circuit 20 is used to protect against protection devices with voltages lower than a preset electrostatic voltage. That is, the second protection circuit 20 protects against the residual low-voltage electrostatic voltage after the first protection circuit 10 discharges the high voltage.
[0051] The ESD protection circuit proposed in this utility model has a first protection circuit 10 used to discharge electrostatic voltage. However, due to the high clamping voltage of the first protection circuit 10, it may damage the first coaxial cable interface B1, the second coaxial cable interface B2, and the circuits at the front and rear ends. Therefore, a second protection circuit 20 is needed for further discharge. Specifically, the second protection circuit 20 further limits the inter-electrode voltage after discharge. Thus, when ESD occurs, the first protection circuit 10 and the second protection circuit 20 discharge the ESD, thereby protecting the first coaxial cable interface B1, the second coaxial cable interface B2, and the circuits at the front and rear ends. Compared to traditional methods that rely solely on the hardware capabilities of analog optical bridges to withstand ESD, this application incorporates protection measures during signal transmission, such as output or monitoring, greatly eliminating the risks present in ESD testing. Furthermore, the ESD protection circuit is small in size and can achieve ESD protection for multiple analog signals, reducing the risk of damage caused by direct ESD exposure when using optical bridges or other equipment, and improving equipment stability in ESD testing during electromagnetic compatibility testing.
[0052] In some alternative implementations, such as Figure 2 As shown, the first protection circuit 10 includes:
[0053] A transient voltage suppression diode D1 is provided, wherein the first terminal of the transient voltage suppression diode D1 is connected to the signal terminal of the first coaxial cable interface B1 and the signal terminal of the second coaxial cable interface B2, and the second terminal of the transient voltage suppression diode D1 is connected to the signal ground terminal.
[0054] Specifically, the transient voltage suppressor diode D1 is a bidirectional transient voltage suppressor (TVS). When the circuit is operating normally, the TVS diode D1 is in a high-resistance state and does not affect normal circuit operation. When the protection device receives an abnormal overvoltage from an ESD event that reaches the breakdown voltage of the TVS diode D1, the TVS diode D1 rapidly changes from a high-resistance state to a low-resistance state, discharging the transient overcurrent caused by the abnormal overvoltage to ground and clamping the abnormal overvoltage to a lower level, thereby protecting the downstream circuits from damage caused by the abnormal overvoltage. When the abnormal overvoltage disappears, the resistance of the TVS diode D1 returns to the high-resistance state.
[0055] In some alternative implementations, such as Figure 2 As shown, the second protection circuit 20 includes:
[0056] A varistor R0, the first end of which is connected to the signal end of the first coaxial cable interface B1 and the signal end of the second coaxial cable interface B2 respectively;
[0057] A gas discharge tube G1 is provided, with its first end connected to the varistor R0 and its second end connected to the signal ground terminal.
[0058] Specifically, the gas discharge tube G1 is filled with a certain amount of inert gas and contains two or more protective devices with electrodes. When no gas discharge occurs, it is in a high-insulation state, typically at the GΩ level. When the voltage across the gas discharge tube G1 exceeds the gas breakdown voltage, the emitted gas discharges through a gap, limiting the inter-electrode voltage and protecting the downstream parallel devices, namely the signal terminal of the first coaxial cable interface B1 and the second coaxial cable interface B2. It should be noted that the gas discharge tube G1 should be selected with a voltage greater than 1.5-2 times the circuit operating voltage, and the junction capacitance inside the gas discharge tube G1 should be as small as possible to avoid affecting the analog signal waveform quality.
[0059] Specifically, the freewheeling voltage of the gas discharge tube G1 is typically over ten volts, and the freewheeling time is relatively long. Therefore, a varistor R0 is used to reduce the freewheeling current, thereby preventing signal short circuits. The varistor R0 itself is a voltage-sensitive element with non-linear volt-ampere characteristics, and it also has the ability to suppress abnormal overvoltages in the circuit, protecting the circuit from overvoltage damage. Both the varistor R0 and the gas discharge tube G1 have fast response speeds.
[0060] In some alternative implementations, such as Figure 2 As shown, the second protection circuit 20 further includes:
[0061] A first resistor R1 is connected at its first end to the signal terminal of the first coaxial cable interface B1, and at its second end to the signal terminal of the second coaxial cable interface B2.
[0062] Specifically, when the second coaxial cable interface B2 is an analog signal device, R1 consumes the residual charge in the subsequent stage to prevent ESD from directly damaging the analog signal device.
[0063] In some alternative implementations, such as Figure 2 As shown, the ESD protection circuit further includes:
[0064] A short-circuit protection circuit 30 is provided, wherein the first terminal of the short-circuit protection circuit 30 is connected to the signal ground terminal, and the second terminal of the short-circuit protection circuit 30 is connected to the ground terminal.
[0065] Specifically, the short-circuit protection circuit 30 prevents short circuits caused by accidental contact, thereby preventing damage to equipment or injury to the human body. In addition, it ensures indirect discharge to the grounded earth terminal, and its resistance is usually selected to be at least MΩ.
[0066] In some alternative implementations, such as Figure 2 As shown, the short-circuit protection circuit further includes:
[0067] The second resistor R2 has its first end connected to the signal ground terminal and its second end connected to the ground terminal.
[0068] The first capacitor C1 has its first end connected to the signal ground terminal, and the second resistor R2 has its second end connected to the ground terminal.
[0069] Specifically, the signal ground terminal is connected to the earth ground terminal through the second resistor R2 and the first capacitor C1, thereby preventing short circuits caused by accidental contact, which could damage equipment or injure people. In addition, it ensures indirect discharge to the grounded earth terminal. The resistor is usually selected to be in the MΩ range or above.
[0070] This utility model also proposes an ESD protection device, such as Figure 3 As shown, the ESD protection device includes the ESD protection circuit described above, and the ESD protection device includes:
[0071] Housing A, which is provided with a plurality of holes for first coaxial cable interfaces B1 and a plurality of holes for second coaxial cable interfaces B2;
[0072] The ESD protection circuit is located inside the housing.
[0073] Specifically, refer to Figure 3 , Figure 3 (A) in the diagram represents the front of the ESD protection device, which includes multiple holes for first coaxial cable interfaces B1, and the first coaxial cable interfaces B1 are connected to the holes for the first coaxial cable interfaces B1. Figure 3 (B) in the diagram represents the reverse side of the ESD protection device. It includes multiple holes for second coaxial cable interfaces B2, through which second coaxial cable interfaces B2 are connected. The ESD protection circuit is housed within the casing.
[0074] In some alternative implementations, such as Figure 2 and Figure 3 As shown, the casing is a metal casing, and the ground end is connected to the metal casing.
[0075] Specifically, the second resistor R2 and the first capacitor C1 indirectly discharge to the grounded metal casing copper plate, and will not affect the analog signal through the metal casing path.
[0076] In some alternative implementations, such as Figure 3 As shown, the ESD protection device further includes:
[0077] Two brackets B are fixed on both sides of the housing A, and the brackets are used to support the ESD protection device.
[0078] Specifically, the two brackets B are used to ground the earth terminal and also to support the housing A.
[0079] In addition, the ESD protection device is small in size and can realize ESD protection with multi-channel analog signal interaction, which reduces the risk of damage caused by direct ESD when using optical bridges or other equipment, and can provide equipment stability for ESD testing in electromagnetic compatibility testing.
[0080] This invention also proposes an ESD testing device, which includes the aforementioned ESD protection device, CAN protector, and discharge equipment. The first protection circuit 10 in the ESD protection circuit is used to discharge electrostatic voltage. However, due to the high clamping voltage of the first protection circuit 10, it may damage the first coaxial cable interface B1, the second coaxial cable interface B2, and the circuits at the front and rear ends. Therefore, a second protection circuit 20 is needed for further discharge. Specifically, the second protection circuit 20 further limits the inter-electrode voltage after discharge. Thus, when ESD occurs, the first protection circuit 10 and the second protection circuit 20 discharge the ESD, thereby protecting the first coaxial cable interface B1, the second coaxial cable interface B2, and the circuits at the front and rear ends. Compared to traditional methods that rely solely on the hardware capabilities of analog optical bridges to withstand ESD, this application incorporates protective measures during signal transmission, such as output or monitoring, greatly eliminating the risks present in ESD testing.
[0081] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.
Claims
1. An ESD protection circuit, characterized in that, Each of the aforementioned ESD protection circuits is connected between each of the first coaxial cable interfaces and each of the second coaxial cable interfaces, and the ESD protection circuit includes: A first protection circuit has a first terminal connected to the signal terminal of the first coaxial cable interface and the signal terminal of the second coaxial cable interface, and a second terminal connected to the signal ground terminal. The signal ground terminal is connected to the ground terminal of the first coaxial cable interface and the ground terminal of the second coaxial cable interface. The first protection circuit is used to conduct and discharge the current voltage to the signal ground terminal when it detects that the current voltage is greater than a first preset voltage. The second protection circuit has its first terminal connected to the signal terminals of the first and second coaxial cable interfaces, respectively, and its second terminal connected to the signal ground terminal. The second protection circuit receives the discharged voltage and outputs a preset inter-electrode voltage when it detects that the discharged voltage is greater than a second preset voltage, so as to protect the first and second coaxial cable interfaces.
2. The ESD protection circuit according to claim 1, characterized in that, The first protection circuit includes: A transient voltage suppressor diode is provided, wherein the first terminal of the transient voltage suppressor diode is connected to the signal terminal of the first coaxial cable interface and the signal terminal of the second coaxial cable interface, and the second terminal of the transient voltage suppressor diode is connected to the signal ground terminal.
3. The ESD protection circuit according to claim 2, characterized in that, The second protection circuit includes: A varistor, wherein the first end of the varistor is connected to the signal end of the first coaxial cable interface and the signal end of the second coaxial cable interface, respectively; A gas discharge tube, wherein the first end of the gas discharge tube is connected to the varistor, and the second end of the gas discharge tube is connected to the signal ground terminal.
4. The ESD protection circuit according to claim 3, characterized in that, The second protection circuit also includes: A first resistor, the first end of which is connected to the signal terminal of the first coaxial cable interface, and the second end of which is connected to the signal terminal of the second coaxial cable interface.
5. The ESD protection circuit according to claim 4, characterized in that, The ESD protection circuit also includes: A short-circuit protection circuit, wherein the first terminal of the short-circuit protection circuit is connected to the signal ground terminal, and the second terminal of the short-circuit protection circuit is connected to the ground terminal.
6. The ESD protection circuit according to claim 5, characterized in that, The short-circuit protection circuit also includes: The second resistor has a first end connected to the signal ground terminal and a second end connected to the ground terminal. A first capacitor, the first end of which is connected to the signal ground terminal, and a second resistor, the second end of which is connected to the ground terminal.
7. An ESD protection device, characterized in that, The ESD protection device includes the ESD protection circuit as described in any one of claims 1 to 6, the ESD protection device comprising: The housing has multiple holes for first coaxial cable interfaces and multiple holes for second coaxial cable interfaces. The ESD protection circuit is located inside the housing.
8. The ESD protection device according to claim 7, characterized in that, The casing is a metal casing, and the ground end is connected to the metal casing.
9. The ESD protection device according to claim 8, characterized in that, The ESD protection device also includes: Two brackets are fixed on both sides of the housing, and the brackets are used to support the ESD protection device.
10. An ESD testing device, characterized in that, The ESD testing equipment includes the ESD protection device as described in any one of claims 7 to 9.