Surge protection circuit and electronic device

Abstract

A surge protection circuit and an electronic device, the surge protection circuit comprising a first signal line, a second signal line, a first overvoltage protection module, a second overvoltage protection module, a third overvoltage protection module and a first voltage divider module. The first overvoltage protection module can take the voltage of the signal ground as a reference, release the surge current on the first signal line and the second signal line to the signal ground, limit the upper limit of the voltage of the first signal line and the second signal line, and the second overvoltage protection module and the third overvoltage protection module can avoid the voltage difference between the first signal line and the second signal line being too large, and further release the differential mode surge current on the first signal line and the second signal line. The first voltage divider module is arranged between the second overvoltage protection module and the third overvoltage protection module, which can avoid the excessively high voltage between the two ends of the second overvoltage protection module from affecting the protected module.

Description

Technical Field

[0001] This application belongs to the field of communication line technology, and in particular relates to a surge protection circuit and electronic device. Background Technology

[0002] Currently, with the rapid development of industrial automation, smart farming, smart pipe corridors and other fields, the application demand for industrial IoT gateways has increased significantly. In order to enable various serial port devices in industrial sites to access IP networks, related devices often need to support RS232 / RS485 multi-standard communication protocol interfaces. In order to adapt to the harsh operating environment, these interfaces need to have strong lightning surge protection capabilities to protect the equipment from damage.

[0003] When there are independent RS232 and RS485 interfaces, it is usually necessary to set up independent surge protection lines for the RS232 and RS485 interfaces respectively. The two sets of surge protection lines occupy a lot of equipment space. When there are RS232 / RS485 compatible interfaces, the surge protection capability of the existing compatible protection lines is usually weak. Utility Model Content

[0004] The purpose of this application is to provide a surge protection circuit and electronic device, which aims to solve the problem of weak surge protection capability of traditional RS232 / RS485 compatible interfaces.

[0005] A first aspect of this application provides a surge protection circuit connected between a protected module and a signal terminal. The signal terminal includes a first signal terminal and a second signal terminal. The surge protection circuit includes: a first signal line connected between the first signal terminal and the protected module; a second signal line connected between the second signal terminal and the protected module; a first overvoltage protection module connected to the first signal line, the second signal line, and the signal ground, respectively. The first overvoltage protection module is used to connect the signal line to the signal ground when the voltage difference between the signal line and the signal ground is greater than a first voltage threshold; and a second overvoltage protection module, the first terminal of which is connected to the first signal terminal. The first signal line is connected to the second signal line, and the second terminal of the second overvoltage protection module is connected to the second signal line. The second overvoltage protection module is used to conduct when the voltage difference between the first signal line and the second signal line is greater than a second voltage threshold. The third overvoltage protection module has its first terminal connected to the first signal line and its second terminal connected to the second signal line. The third overvoltage protection module is used to conduct when the voltage difference between the first signal line and the second signal line is greater than a second voltage threshold. The first voltage divider module is connected in series with the first signal line and the second signal line and is located between the second overvoltage protection module and the third overvoltage protection module.

[0006] In one embodiment, the surge protection circuit further includes a second voltage divider module, and the first overvoltage protection module includes a first protection unit; the first protection unit is connected to the first signal line, the second signal line, and the signal ground respectively; the third protection unit is used to connect the first signal line to the signal ground when the voltage difference between the first signal line and the signal ground is greater than the first voltage threshold, and to connect the second signal line to the signal ground when the voltage difference between the second signal line and the signal ground is greater than the first voltage threshold; the second voltage divider module is connected in series on the first signal line and the second signal line, and is located between the first protection unit and the signal terminal.

[0007] In one embodiment, the first protection unit includes a first transient voltage suppression diode and a second transient voltage suppression diode, wherein the first transient voltage suppression diode is connected between the first signal line and the signal ground, and the second transient voltage suppression diode is connected between the second signal line and the signal ground.

[0008] In one embodiment, the first overvoltage protection module includes a second protection unit, which is connected to the first signal terminal, the second signal terminal, and the signal ground. The second protection unit is used to connect the first signal terminal to the signal ground when the voltage difference between the first signal terminal and the signal ground is greater than a third voltage threshold, and to connect the second signal terminal to the signal ground when the voltage difference between the second signal terminal and the signal ground is greater than the third voltage threshold, wherein the third voltage threshold is greater than the first voltage threshold.

[0009] In one embodiment, the second protection unit includes a first gas discharge tube, which is connected to the first signal terminal, the second signal terminal, and the signal ground.

[0010] In one embodiment, the first overvoltage protection module further includes a third protection unit, and the protected module further includes a ground terminal. The third protection unit is connected between the signal ground and the ground terminal, and the third protection unit is used to conduct when the voltage difference between the signal ground and the ground terminal is greater than a fourth voltage threshold.

[0011] In one embodiment, the third protection unit includes a second gas discharge tube, which is connected to the signal ground and the grounding terminal respectively.

[0012] In one embodiment, the second overvoltage protection module includes a third transient voltage suppression diode, which is connected between the first signal line and the second signal line.

[0013] In one embodiment, the third overvoltage protection module includes a fourth transient voltage suppression diode, which is connected between the first signal line and the second signal line.

[0014] A second aspect of this application provides an electronic device including the surge protection circuit described above.

[0015] The beneficial effects of this application embodiment compared to the prior art are as follows: The first overvoltage protection module can use the voltage of the signal ground as a reference to release the surge current on the first and second signal lines to the signal ground, limiting the upper voltage limit of the first and second signal lines. The second and third overvoltage protection modules can prevent the voltage difference between the first and second signal lines from being too large, further releasing the differential mode surge current on the first and second signal lines. Setting a first voltage divider module between the second and third overvoltage protection modules can prevent excessively high voltages across the second overvoltage protection module from affecting the protected module. Attached Figure Description

[0016] Figure 1 A schematic diagram of a surge protection circuit provided in an embodiment of this application;

[0017] Figure 2 A detailed circuit diagram of a surge protection circuit provided in an embodiment of this application;

[0018] Figure 3 This is a schematic diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0019] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0020] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0021] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device 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 application.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0023] Figure 1 A schematic diagram of a surge protection circuit according to an embodiment of this application is shown. For ease of explanation, only the parts relevant to this embodiment are shown, and are described in detail below:

[0024] A surge protection circuit 10 is connected between a protected module 20 and a signal terminal 30. The signal terminal 30 includes a first signal terminal 31 and a second signal terminal 32. The signal terminal 30 may include interface circuits, interface chips, etc. The protected module 20 may specifically include a signal processing module, a control module, a computing module, etc. The protected module 20 can receive or output corresponding signals through the surge protection circuit 10 and the signal terminal 30.

[0025] The surge protection circuit 10 includes: a first signal line 100, a second signal line 200, a first overvoltage protection module 300, a second overvoltage protection module 400, a third overvoltage protection module 500, and a first voltage divider module 600.

[0026] The first signal line 100 is connected between the first signal terminal 31 and the protected module 20; the second signal line 200 is connected between the second signal terminal 32 and the protected module 20.

[0027] The first overvoltage protection module 300 is connected to the first signal line 100, the second signal line 200, and signal ground GND1, respectively. The first overvoltage protection module 300 is used to connect the signal line to signal ground GND1 when the voltage difference between the signal line and signal ground GND1 exceeds a first voltage threshold. The first end of the second overvoltage protection module 400 is connected to the first signal line 100, and the second end of the second overvoltage protection module 400 is connected to the second signal line 200. The second overvoltage protection module 400 is used to connect the first signal line 100 and the second signal line 200. The third overvoltage protection module 500 is activated when the voltage difference between the first signal line 100 and the second signal line 200 is greater than the second voltage threshold. The first terminal of the third overvoltage protection module 500 is connected to the first signal line 100, and the second terminal of the third overvoltage protection module 500 is connected to the second signal line 200. The third overvoltage protection module 500 is activated when the voltage difference between the first signal line 100 and the second signal line 200 is greater than the second voltage threshold. The first voltage divider module 600 is connected in series with the first signal line 100 and the second signal line 200, and is located between the second overvoltage protection module 400 and the third overvoltage protection module 500.

[0028] The first overvoltage protection module 300 is connected between the signal terminal 30 and the signal ground GND1. Using the voltage of the signal ground GND1 as a reference, when the voltage difference between the signal terminal 30 and the signal ground GND1 exceeds a first voltage threshold, the first overvoltage protection module 300 connects the signal terminal 30 and the signal ground GND1, limiting the upper voltage limit of the first signal line 100 and the second signal line 200, thus achieving surge protection. The second overvoltage protection module 400 and the third overvoltage protection module 500 can also achieve surge protection by connecting the first signal line 100 and the second signal line 200 when the voltage difference between the first signal line 100 and the second signal line 200 is too large.

[0029] Specifically, the first overvoltage protection module 300 can use the voltage of signal ground GND1 as a reference to release the surge current on the first signal line 100 and the second signal line 200 to signal ground GND1, thereby limiting the upper limit of the voltage of the first signal line 100 and the second signal line 200. The second overvoltage protection module 400 and the third overvoltage protection module 500 can prevent the voltage difference between the first signal line 100 and the second signal line 200 from being too large, and further release the differential mode surge current on the first signal line 100 and the second signal line 200.

[0030] It should be noted that the clamping voltage across the overvoltage protection module is positively correlated with the transient current when it breaks down. This can lead to an excessively large transient current causing the clamping voltage to exceed the breakdown voltage of the protected module. By setting up a second overvoltage protection module 400 and a third overvoltage protection module 500 with the same breakdown voltage, and setting a first voltage divider module 600 between the second overvoltage protection module 400 and the third overvoltage protection module 500, the transient current when the third overvoltage protection module 500 breaks down can be made smaller than the transient current when the second overvoltage protection module 400 breaks down. This prevents the excessively high clamping voltage across the second overvoltage protection module 400 from affecting the protected module 20.

[0031] The first signal line 100 and the second signal line 200 work together to achieve both differential signal transmission and single-ended signal transmission. Specifically, the first signal line 100 and the second signal line 200 can be used to transmit RS232 serial port signals and RS485 serial port signals.

[0032] The first voltage threshold and the second voltage threshold are specifically related to the signal type transmitted by the surge protection circuit 10 and the voltage range that the protected device can withstand. They need to avoid exceeding the voltage range that the protected device can withstand without affecting the transmitted signal.

[0033] In one embodiment, such as Figure 2 As shown, the surge protection circuit 10 also includes a second voltage divider module 700, and the first overvoltage protection module 300 includes a first protection unit 310.

[0034] The first protection unit 310 is connected to the first signal line 100, the second signal line 200 and the signal ground GND1 respectively. The first protection unit 310 is used to connect the first signal line 100 and the signal ground GND1 when the voltage difference between the first signal line 100 and the signal ground GND1 is greater than the first voltage threshold, and to connect the second signal line 200 and the signal ground GND1 when the voltage difference between the second signal line 200 and the signal ground GND1 is greater than the first voltage threshold.

[0035] The second voltage divider module 700 is connected in series on the first signal line 100 and the second signal line 200, and is located between the first protection unit 310 and the signal terminal 30.

[0036] The second voltage divider module 700 can divide the input voltage to limit the voltage applied to the first protection unit 310.

[0037] The first protection unit 310 can provide surge protection for the differential or single-ended signals transmitted on the first signal line 100 and the second signal line 200 respectively, and limit the voltage upper limit of the first signal line 100 and the second signal line 200.

[0038] In some embodiments, such as Figure 2 As shown, signal terminal 30 also includes a third signal terminal 33, which is connected to signal ground GND1.

[0039] In one embodiment, such as Figure 2 As shown, the first protection unit 310 includes a first transient voltage suppression diode D1 and a second transient voltage suppression diode D2. The first transient voltage suppression diode D1 is connected between the first signal line and the signal ground GND1, and the second transient voltage suppression diode D2 is connected between the second signal line and the signal ground GND1.

[0040] Understandably, when the voltage difference between the first signal line and signal ground GND1 is greater than the first voltage threshold, the first transient voltage suppression diode D1 will conduct, and when the voltage difference between the second signal line and signal ground GND1 is greater than the first voltage threshold, the second transient voltage suppression diode D2 will conduct, thereby limiting the voltage between the first signal line and the second signal line and achieving surge protection.

[0041] In one embodiment, such as Figure 2 As shown, the first overvoltage protection module 300 includes a second protection unit. The second protection unit is connected to the first signal terminal 31, the second signal terminal 32 and the signal ground GND1 respectively. The second protection unit is used to connect the first signal terminal 31 to the signal ground GND1 when the voltage difference between the first signal terminal 31 and the signal ground GND1 is greater than a third voltage threshold, and to connect the second signal terminal 32 to the signal ground GND1 when the voltage difference between the second signal terminal 32 and the signal ground GND1 is greater than the third voltage threshold. The third voltage threshold is greater than the first voltage threshold.

[0042] The second protection unit can be used to implement high voltage surge protection to prevent the first protection unit 310 from receiving excessively high voltage.

[0043] In one embodiment, the second protection unit includes a first gas discharge tube RV1, which is connected to a first signal terminal 31, a second signal terminal 32 and a signal ground GND1.

[0044] The first gas discharge tube RV1 can connect the first signal terminal 31 to the signal ground GND1 when the voltage difference between the first signal terminal 31 and the signal ground GND1 is greater than the third voltage threshold, and connect the second signal terminal 32 to the signal ground GND1 when the voltage difference between the second signal terminal 32 and the signal ground GND1 is greater than the third voltage threshold.

[0045] Compared to transient voltage suppressor diodes, gas discharge tubes have higher power, can withstand higher voltages, and have higher withstand voltage, making them a primary discharge path for common-mode surges.

[0046] In one embodiment, such as Figure 2 As shown, the first overvoltage protection module 300 also includes a third protection unit, and the protected module 20 also includes a ground terminal GND2. The third protection unit is connected between the signal ground GND1 and the ground terminal GND2. The third protection unit is used to conduct when the voltage difference between the signal ground GND1 and the ground terminal GND2 is greater than a fourth voltage threshold.

[0047] It can protect against surge voltages on signal ground GND1 and grounding terminal GND2, preventing excessive voltage on signal ground GND1 or grounding terminal GND2 from affecting the operation of the protected equipment or external equipment connected to signal terminal 30.

[0048] In one embodiment, the third protection unit includes a second gas discharge tube RV2, which is connected to signal ground GND1 and grounding terminal GND2 respectively.

[0049] The second gas discharge tube RV2 can be turned on when the voltage difference between signal ground GND1 and ground terminal GND2 is greater than the fourth voltage threshold.

[0050] Compared to transient voltage suppressor diodes, gas discharge tubes have higher power, can withstand higher voltages, and have higher withstand voltage capability.

[0051] In one embodiment, such as Figure 2 As shown, the second overvoltage protection module 400 includes a third transient voltage suppression diode, which is connected between the first signal line and the second signal line.

[0052] The minimum reverse breakdown voltage of the third transient voltage suppressor diode is equal to the second voltage threshold. The third transient voltage suppressor diode can conduct when the voltage difference between the first signal line 100 and the second signal line 200 is greater than the second voltage threshold, thereby achieving surge protection.

[0053] In some embodiments, such as Figure 2 As shown, multiple third transient voltage suppression diodes can be connected in parallel between the first signal line and the second signal line to improve the protection level. Figure 2 The diagram shows the third transient voltage suppression diode T1 and the third transient voltage suppression diode T2.

[0054] In one embodiment, such as Figure 2 As shown, the third overvoltage protection module 500 includes a fourth transient voltage suppression diode, which is connected between the first signal line and the second signal line.

[0055] The minimum reverse breakdown voltage of the fourth transient voltage suppressor diode is equal to the second voltage threshold. The fourth transient voltage suppressor diode can conduct when the voltage difference between the first signal line 100 and the second signal line 200 exceeds the second voltage threshold, thus achieving surge protection.

[0056] In some embodiments, such as Figure 2 As shown, multiple fourth transient voltage suppression diodes can be connected in parallel between the first signal line and the second signal line to improve the protection level. Figure 2 The fourth transient voltage suppressor diode T3 and the fourth transient voltage suppressor diode T4 are shown in the figure.

[0057] In one embodiment, the protected module 20 includes an RS232 serial port signal transceiver unit and an RS485 serial port signal transceiver unit. The first voltage threshold is 16.7V, and the second voltage threshold is 26.7V. Specifically, the RS232 serial port signal transceiver unit includes an RS232 serial port chip and its peripheral circuitry, and the RS485 serial port signal transceiver unit includes an RS485 serial port chip and its peripheral circuitry.

[0058] It should be noted that, limited by the selection of transient voltage suppressor diodes, the available transient voltage suppressor diodes include those with a minimum reverse breakdown voltage of 16.7V and those with a minimum reverse breakdown voltage of 26.7V. When transmitting normal RS232 serial signals, the voltage difference between the first signal line 100, the second signal line 200, and signal ground GND1 is typically ±15V. The theoretical maximum voltage between the first signal line 100 and the second signal line 200 is 20.5V, and the maximum withstand voltage of the RS232 serial signal transceiver unit is approximately 40V. When transmitting normal RS485 serial signals, the voltage difference between the first signal line 100 and the second signal line 200 is typically ±15V, and the maximum withstand voltage of the RS485 serial signal transceiver unit is approximately 30V. Therefore, based on the voltages of the RS232 and RS485 serial port signals, the first overvoltage protection module 300 can select a transient voltage suppression diode with a minimum reverse breakdown voltage of 16.7V, while the second overvoltage protection module 400 and the third overvoltage protection module 500 can select transient voltage suppression diodes with a minimum reverse breakdown voltage of 26.7V.

[0059] For a transient voltage suppressor diode with a minimum reverse breakdown voltage of 26.7V, its clamping voltage can reach above 35V. That is, the voltage across the second overvoltage protection module 400 can reach above 35V. After being divided by the first voltage divider module 600, and then clamped by the third overvoltage protection module 500, the voltage across the third overvoltage protection module 500 can be controlled within 30V, preventing excessively high voltage from being transmitted to the protected module 20.

[0060] In some embodiments, such as Figure 2 As shown, the first voltage divider module 600 includes a first voltage divider resistor R1 and a second voltage divider resistor R2, and the second voltage divider module 700 includes a third voltage divider resistor R3 and a fourth voltage divider resistor R4. The first voltage divider resistor R1 and the third voltage divider resistor R3 are connected in series on the first signal line 100, and the second voltage divider resistor R2 and the fourth voltage divider resistor R4 are connected in series on the second signal line 200.

[0061] Figure 3 A schematic diagram of an electronic device according to an embodiment of this application is shown. For ease of explanation, only the parts relevant to this embodiment are shown, and are described in detail below:

[0062] An electronic device 40 includes a surge protection circuit 10 as described in any of the above embodiments, a protected module 20, and a signal terminal 30. The protected module 20 is connected to the signal terminal 30 through the surge protection circuit 10. The surge protection circuit 10 can provide surge protection for the protected module 20.

[0063] Specifically, the protected module 20 can be a communication module, a data processing module, or a main control module, etc.

[0064] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0065] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0066] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A surge protection circuit, characterized in that, Connected between the protected module and the signal terminal, the signal terminal includes a first signal terminal and a second signal terminal, and the surge protection circuit includes: The first signal line is connected between the first signal terminal and the protected module; The second signal line is connected between the second signal terminal and the protected module; The first overvoltage protection module is connected to the first signal line, the second signal line and the signal ground respectively. The first overvoltage protection module is used to connect the signal line to the signal ground when the voltage difference between the signal line and the signal ground is greater than a first voltage threshold. The second overvoltage protection module has a first terminal connected to the first signal line and a second terminal connected to the second signal line. The second overvoltage protection module is used to conduct when the voltage difference between the first signal line and the second signal line is greater than a second voltage threshold. The third overvoltage protection module has a first terminal connected to the first signal line and a second terminal connected to the second signal line. The third overvoltage protection module is used to conduct when the voltage difference between the first signal line and the second signal line is greater than a second voltage threshold. The first voltage divider module is connected in series with the first signal line and the second signal line, and is located between the second overvoltage protection module and the third overvoltage protection module.

2. The surge protection circuit as described in claim 1, characterized in that, The surge protection circuit further includes a second voltage divider module, and the first overvoltage protection module includes a first protection unit; The first protection unit is connected to the first signal line, the second signal line, and the signal ground respectively. The first protection unit is used to connect the first signal line to the signal ground when the voltage difference between the first signal line and the signal ground is greater than the first voltage threshold, and to connect the second signal line to the signal ground when the voltage difference between the second signal line and the signal ground is greater than the first voltage threshold. The second voltage divider module is connected in series on the first signal line and the second signal line, and is located between the first protection unit and the signal terminal.

3. The surge protection circuit as described in claim 2, characterized in that, The first protection unit includes a first transient voltage suppression diode and a second transient voltage suppression diode. The first transient voltage suppression diode is connected between the first signal line and the signal ground, and the second transient voltage suppression diode is connected between the second signal line and the signal ground.

4. The surge protection circuit as described in claim 1, characterized in that, The first overvoltage protection module includes a second protection unit, which is connected to the first signal terminal, the second signal terminal and the signal ground respectively. The second protection unit is used to connect the first signal terminal to the signal ground when the voltage difference between the first signal terminal and the signal ground is greater than a third voltage threshold, and to connect the second signal terminal to the signal ground when the voltage difference between the second signal terminal and the signal ground is greater than the third voltage threshold, wherein the third voltage threshold is greater than the first voltage threshold.

5. The surge protection circuit as described in claim 4, characterized in that, The second protection unit includes a first gas discharge tube, which is connected to the first signal terminal, the second signal terminal, and the signal ground.

6. The surge protection circuit as described in claim 4, characterized in that, The first overvoltage protection module further includes a third protection unit, and the protected module further includes a ground terminal. The third protection unit is connected between the signal ground and the ground terminal, and the third protection unit is used to conduct when the voltage difference between the signal ground and the ground terminal is greater than a fourth voltage threshold.

7. The surge protection circuit as described in claim 6, characterized in that, The third protection unit includes a second gas discharge tube, which is connected to the signal ground and the grounding terminal respectively.

8. The surge protection circuit as described in any one of claims 1 to 6, characterized in that, The second overvoltage protection module includes a third transient voltage suppression diode, which is connected between the first signal line and the second signal line.

9. The surge protection circuit as described in any one of claims 1 to 6, characterized in that, The third overvoltage protection module includes a fourth transient voltage suppression diode, which is connected between the first signal line and the second signal line.

10. An electronic device, characterized in that, Includes the surge protection circuit as described in any one of claims 1 to 9.

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