Overvoltage protection circuit and electronic equipment

Abstract

The embodiment of the present invention discloses an overvoltage protection circuit and an electronic device. The overvoltage protection circuit includes: at least two of the first module, the second module and the third module, and an alarm circuit; the first module includes: a first voltage-limiting device, a first switch-type device and a first rectifier circuit, and the output end of the first rectifier circuit is electrically connected to the alarm circuit; the second module includes: a second voltage-limiting device, a second switch-type device and a second rectifier circuit, and the output end of the second rectifier circuit is electrically connected to the alarm circuit; the third module includes: a third voltage-limiting device, a third switch-type device and a third rectifier circuit; the output end of the third rectifier circuit is electrically connected to the alarm circuit. The technical solution provided by the embodiment of the present invention can realize the monitoring and alarm of the leakage current of multiple voltage-limiting devices through an alarm circuit, and achieve the purpose of preventing the reverse connection of the live wire and the neutral wire.

Description

Technical Field

[0001] The present invention relates to the technical field of overvoltage protection, and in particular to an overvoltage protection circuit and electronic equipment. Background Art

[0002] An overvoltage protection circuit, also called a surge protector or lightning arrester, includes at least one surge protection device. A surge protector is an electronic device that provides safety protection for various electronic devices, instruments, and communication lines. When a spike current or voltage suddenly occurs in an electrical circuit or communication line due to external interference, the surge protector can conduct and shunt in a very short time, thereby preventing the surge from damaging other devices in the circuit.

[0003] Common surge protection devices include: voltage limiting devices, switching devices, etc. However, the voltage limiting devices will have the problem of increased leakage current when used for a long time. Summary of the invention

[0004] The embodiments of the present invention provide an overvoltage protection circuit and an electronic device, which can monitor and alarm the leakage current of multiple voltage-limiting devices through an alarm circuit, and achieve the purpose of preventing the reverse connection of the live wire and the neutral wire.

[0005] In a first aspect, an embodiment of the present invention provides an overvoltage protection circuit, comprising: at least two of a first module, a second module and a third module, and an alarm circuit;

[0006] The first module includes:

[0007] A first voltage limiting device, a first end of the first voltage limiting device is electrically connected to a first end of the overvoltage protection circuit;

[0008] a first switch type device, wherein the second end of the first voltage limiting device is electrically connected to the second end of the overvoltage protection circuit via the first switch type device;

[0009] a first rectifier circuit, wherein a first input terminal of the first rectifier circuit is electrically connected to a second terminal of the first voltage-limiting device; a second input terminal of the first rectifier circuit is electrically connected to a second terminal of the overvoltage protection circuit; a positive output terminal of the first rectifier circuit is electrically connected to a first terminal of the alarm circuit; and a negative output terminal of the first rectifier circuit is electrically connected to a second terminal of the alarm circuit;

[0010] The second module includes:

[0011] A second voltage limiting device, a first end of the second voltage limiting device is electrically connected to a first end of the overvoltage protection circuit;

[0012] A second switch type device, wherein the second end of the second voltage limiting device is electrically connected to the third end of the overvoltage protection circuit via the second switch type device;

[0013] a second rectifier circuit, wherein a first input terminal of the second rectifier circuit is electrically connected to a second terminal of the second voltage-limiting device; a second input terminal of the second rectifier circuit is electrically connected to a second terminal of the overvoltage protection circuit; a positive output terminal of the second rectifier circuit is electrically connected to a first terminal of the alarm circuit; and a negative output terminal of the second rectifier circuit is electrically connected to a second terminal of the alarm circuit;

[0014] The third module includes:

[0015] A third voltage limiting device, a first end of the third voltage limiting device is electrically connected to a second end of the overvoltage protection circuit;

[0016] A third switch type device, wherein the second end of the third voltage limiting device is electrically connected to the third end of the overvoltage protection circuit via the third switch type device;

[0017] A third rectifier circuit, a first input terminal of the third rectifier circuit is electrically connected to the second terminal of the third voltage-limiting device; a second input terminal of the third rectifier circuit is electrically connected to the first terminal of the overvoltage protection circuit; a positive output terminal of the third rectifier circuit is electrically connected to the first terminal of the alarm circuit; and a negative output terminal of the third rectifier circuit is electrically connected to the second terminal of the alarm circuit.

[0018] Furthermore, the alarm circuit includes a first current limiting unit and a first alarm device.

[0019] The first current limiting unit is connected in series with the first alarm device, and two ends of the first current limiting unit and the first alarm device after being connected in series are electrically connected to the first end and the second end of the alarm circuit respectively.

[0020] Furthermore, the alarm circuit also includes a first shunt device, and the first shunt device is connected in parallel with the first alarm device.

[0021] Further, the first current limiting unit includes a first resistor and a voltage-stabilizing diode, the first resistor, the voltage-stabilizing diode and the first alarm device are connected in series, and two ends of the first resistor, the voltage-stabilizing diode and the first alarm device after being connected in series are electrically connected to a first end and a second end of the alarm circuit respectively;

[0022] The first alarm device includes at least one of the following: a light emitting diode and a buzzer.

[0023] Furthermore, the overvoltage protection circuit also includes: a second alarm device and a second current limiting device; the second alarm device and the second current limiting device are connected in series, and the two ends of the second alarm device and the second current limiting device after the series connection are electrically connected to the first end and the second end of the overvoltage protection circuit respectively.

[0024] Furthermore, the second alarm device includes a first light-emitting diode, and the overvoltage protection circuit also includes: a first diode, wherein the first diode, the second alarm device and the second current limiting device are connected in series, and the two ends of the series connection of the first diode, the second alarm device and the second current limiting device are respectively electrically connected to the first end and the second end of the overvoltage protection circuit, and the first light-emitting diode and the first diode are connected in series in the same direction.

[0025] Further, the first rectifier circuit includes a rectifier bridge composed of four diodes; the second rectifier circuit includes a rectifier bridge composed of four diodes; the third rectifier circuit includes a rectifier bridge composed of four diodes; the first voltage-limiting device includes at least one of the following: a varistor and a transient suppression diode; the first switch-type device includes at least one of the following: a gas discharge tube and a semiconductor discharge tube; the second voltage-limiting device includes at least one of the following: a varistor and a transient suppression diode; the second switch-type device includes at least one of the following: a gas discharge tube and a semiconductor discharge tube; the third voltage-limiting device includes at least one of the following: a varistor and a transient suppression diode; the third switch-type device includes at least one of the following: a gas discharge tube and a semiconductor discharge tube;

[0026] The overvoltage protection circuit also includes a first overcurrent protection device,

[0027] Wherein, the first end of the overvoltage protection circuit is electrically connected to the first end of the first overcurrent protection device;

[0028] When the overvoltage protection circuit includes the first module, the first end of the first voltage-limiting device is electrically connected to the second end of the first overcurrent protection device;

[0029] When the overvoltage protection circuit includes the second module, the first end of the second voltage limiting device is electrically connected to the second end of the first overcurrent protection device;

[0030] When the overvoltage protection circuit includes the third module, the second input terminal of the third rectifier circuit is electrically connected to the second terminal of the first overcurrent protection device.

[0031] Further, when the overvoltage protection circuit includes the first module, the overvoltage protection circuit also includes a third current limiting device, and the second input end of the first rectifier circuit is electrically connected to the second end of the overvoltage protection circuit via the third current limiting device, or the first input end of the first rectifier circuit is electrically connected to the second end of the first voltage limiting device via the third current limiting device;

[0032] When the overvoltage protection circuit includes the second module, the overvoltage protection circuit also includes a fourth current limiting device, the second input end of the second rectifier circuit is electrically connected to the second end of the overvoltage protection circuit via the fourth current limiting device, or the first input end of the second rectifier circuit is electrically connected to the second end of the second voltage limiting device via the fourth current limiting device;

[0033] When the overvoltage protection circuit includes a third module, the overvoltage protection circuit also includes a fifth current limiting device, and the second input end of the third rectifier circuit is electrically connected to the first end of the overvoltage protection circuit via the fifth current limiting device, or the first input end of the third rectifier circuit is electrically connected to the second end of the third voltage limiting device via the fifth current limiting device.

[0034] Further, when the overvoltage protection circuit includes the second module, the second switch type device includes an open circuit failure type gas discharge tube, and the overvoltage protection circuit further includes a first voltage divider device, and the first voltage divider device is connected in parallel with the second switch type device;

[0035] When the overvoltage protection circuit includes the third module, the third switch type device includes an open circuit failure type gas discharge tube, and the overvoltage protection circuit further includes a second voltage divider device, which is connected in parallel with the third switch type device.

[0036] In a second aspect, an embodiment of the present invention further provides an electronic device, comprising a circuit to be protected and an overvoltage protection circuit provided by any embodiment of the present invention,

[0037] The third terminal of the overvoltage protection circuit is grounded; the first terminal and the second terminal of the overvoltage protection circuit are electrically connected to the live wire and the neutral wire respectively;

[0038] The circuit to be protected is electrically connected to a first end and a second end of the overvoltage protection circuit.

[0039] The overvoltage protection circuit provided by the embodiment of the present invention includes: at least two of the first module, the second module and the third module, and an alarm circuit; wherein the first module includes: a first voltage limiting device, a first switch device and a first rectifier circuit, the first end of the first voltage limiting device is electrically connected to the first end of the overvoltage protection circuit; the second end of the first voltage limiting device is electrically connected to the second end of the overvoltage protection circuit via the first switch device; the first input end of the first rectifier circuit is electrically connected to the second end of the first voltage limiting device; the second input end of the first rectifier circuit is electrically connected to the second end of the overvoltage protection circuit; the positive output end of the first rectifier circuit is electrically connected to the first end of the alarm circuit; the negative output end of the first rectifier circuit is electrically connected to the second end of the alarm circuit; the second module includes: a second voltage limiting device, a second switch device and a second rectifier circuit, the first end of the second voltage limiting device is electrically connected to the first end of the overvoltage protection circuit; the second end of the second voltage limiting device is electrically connected to the second end of the overvoltage protection circuit via the second switch device The device is electrically connected to the third end of the overvoltage protection circuit; the first input end of the second rectifier circuit is electrically connected to the second end of the second voltage-limiting device; the second input end of the second rectifier circuit is electrically connected to the second end of the overvoltage protection circuit; the positive output end of the second rectifier circuit is electrically connected to the first end of the alarm circuit; the negative output end of the second rectifier circuit is electrically connected to the second end of the alarm circuit; the third module includes: a third voltage-limiting device, a third switch-type device and a third rectifier circuit, the first end of the third voltage-limiting device is electrically connected to the second end of the overvoltage protection circuit; the second end of the third voltage-limiting device is electrically connected to the third end of the overvoltage protection circuit via the third switch-type device; the first input end of the third rectifier circuit is electrically connected to the second end of the third voltage-limiting device; the second input end of the third rectifier circuit is electrically connected to the first end of the overvoltage protection circuit; the positive output end of the third rectifier circuit is electrically connected to the first end of the alarm circuit; the negative output end of the third rectifier circuit is electrically connected to the second end of the alarm circuit. On the basis of realizing overvoltage protection, an alarm circuit can be used to monitor and alarm the leakage current of at least two of the first voltage limiting device, the second voltage limiting device and the third voltage limiting device, and achieve the purpose of preventing the reverse connection of the live wire and the neutral wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A schematic diagram of the structure of an overvoltage protection circuit provided by an embodiment of the present invention;

[0041] Figure 2 A schematic diagram of the structure of another overvoltage protection circuit provided by an embodiment of the present invention;

[0042] Figure 3 A schematic diagram of the structure of another overvoltage protection circuit provided by an embodiment of the present invention;

[0043] Figure 4A schematic diagram of the structure of another overvoltage protection circuit provided by an embodiment of the present invention;

[0044] Figure 5 A schematic diagram of the structure of another overvoltage protection circuit provided by an embodiment of the present invention;

[0045] Figure 6 A schematic diagram of the structure of another overvoltage protection circuit provided by an embodiment of the present invention;

[0046] Figure 7 A schematic diagram of the structure of another overvoltage protection circuit provided by an embodiment of the present invention;

[0047] Figure 8 A schematic diagram of the assembly structure of a focusing element, a first alarm device and a second alarm device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0048] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0049] An embodiment of the present invention provides an overvoltage protection circuit. Figure 1 The schematic diagram of the structure of an overvoltage protection circuit provided by an embodiment of the present invention is as follows: The overvoltage protection circuit 100 comprises: a first module 1 , a second module 2 and an alarm circuit 4 .

[0050] The first module 1 includes: a first voltage-limiting device 10 , a first switch device 20 and a first rectifier circuit 30 .

[0051] Among them, the first end of the first voltage limiting device 10 is electrically connected to the first end V1 of the overvoltage protection circuit 100; the second end of the first voltage limiting device 10 is electrically connected to the second end V2 of the overvoltage protection circuit 100 via the first switch type device 20; the first input end In1 of the first rectifier circuit 30 is electrically connected to the second end of the first voltage limiting device 10; the second input end In2 of the first rectifier circuit 30 is electrically connected to the second end V2 of the overvoltage protection circuit 100; the positive output end V+ of the first rectifier circuit 30 is electrically connected to the first end of the alarm circuit 4; the negative output end V- of the first rectifier circuit 30 is electrically connected to the second end of the alarm circuit 4.

[0052] The second module 2 includes: a second voltage-limiting device 40 , a second switch device 50 and a second rectifier circuit 60 .

[0053] Among them, the first end of the second voltage limiting device 40 is electrically connected to the first end V1 of the overvoltage protection circuit 100; the second end of the second voltage limiting device 40 is electrically connected to the third end V3 of the overvoltage protection circuit 100 via the second switch type device 50; the first input end In1 of the second rectifier circuit 60 is electrically connected to the second end of the second voltage limiting device 40; the second input end In2 of the second rectifier circuit 60 is electrically connected to the second end V2 of the overvoltage protection circuit 100; the positive output end V+ of the second rectifier circuit 60 is electrically connected to the first end of the alarm circuit 4; the negative output end V- of the second rectifier circuit 60 is electrically connected to the second end of the alarm circuit 4.

[0054] Among them, the voltage-limiting device presents high impedance when there is no surge, but its impedance will continue to decrease with the increase of surge current and voltage. When the surge current passes, it will present a certain voltage, which is called residual voltage or clamping voltage. The switch-type device presents high impedance when there is no surge, and suddenly changes to low impedance when a voltage surge occurs, which can reduce the overvoltage to a value close to zero and has a large current-carrying capacity. Optionally, the first voltage-limiting device 10 includes at least one of the following: a varistor and a transient suppression diode. Optionally, the first switch-type device 20 includes at least one of the following: a gas discharge tube and a semiconductor discharge tube. Optionally, the second voltage-limiting device 40 includes at least one of the following: a varistor and a transient suppression diode. Optionally, the second switch-type device 50 includes at least one of the following: a gas discharge tube and a semiconductor discharge tube. The first rectifier circuit 30 may include a controllable rectifier circuit or an uncontrolled rectifier circuit. Optionally, the first rectifier circuit 30 includes a rectifier bridge composed of four diodes. The second rectifier circuit 60 may include a controllable rectifier circuit or an uncontrolled rectifier circuit. Optionally, the second rectifier circuit 60 includes a rectifier bridge composed of four diodes. The first terminal V1 of the overvoltage protection circuit 100 can be electrically connected to the live wire or the neutral wire. The second terminal V2 of the overvoltage protection circuit 100 can be electrically connected to the live wire or the neutral wire. The third terminal V3 of the overvoltage protection circuit 100 can be electrically connected to the ground wire. The first terminal V1 and the second terminal V2 of the overvoltage protection circuit 100 can be electrically connected to different power supply lines. Exemplarily, the first terminal V1 of the overvoltage protection circuit 100 can be electrically connected to the neutral wire, the second terminal V2 of the overvoltage protection circuit 100 can be electrically connected to the live wire, and the third terminal V3 of the overvoltage protection circuit 100 can be electrically connected to the ground wire. The alarm circuit 4 can alarm when the leakage current of the first voltage limiting device 10 and / or the second voltage limiting device 40 is greater than or equal to a preset threshold.

[0055] Under normal power supply conditions, that is, when there is no surge interference such as lightning strike or overvoltage, the first voltage limiting device 10, the first switch device 20, the second voltage limiting device 40, and the second switch device 50 are all turned off, the current output by the first rectifier circuit 30 and the second rectifier circuit 60 is zero, and the alarm circuit 4 does not work. If a surge interference occurs between the first terminal V1 and the second terminal V2 of the overvoltage protection circuit 100, when the voltage between the first terminal V1 and the second terminal V2 is higher than the equivalent turn-on voltage after the first voltage limiting device 10 and the first switch device 20 are connected in series, the first voltage limiting device 10 and the first switch device 20 will be turned on to discharge the surge current and limit the voltage between the first terminal V1 and the second terminal V2 to a voltage range that the circuit to be protected 200 can withstand. At this time, the turned-on first switch device 20 causes the first rectifier circuit 30 to be short-circuited and no current flows through the alarm circuit 4, and thus no false alarm will be generated. If surge interference occurs between the first terminal V1 and the third terminal V3 of the overvoltage protection circuit 100, and the voltage between the first terminal V1 and the third terminal V3 is higher than the equivalent turn-on voltage of the second voltage-limiting device 40 and the second switch-type device 50 connected in series, the second voltage-limiting device 40 and the second switch-type device 50 will be turned on to discharge the surge current and limit the voltage between the first terminal V1 and the third terminal V3 to a voltage range that the protected circuit 200 can withstand. At this time, if the second terminal V2 of the overvoltage protection circuit 100 is electrically connected to the live wire, and the first terminal V1 of the overvoltage protection circuit 100 is electrically connected to the neutral wire, the turned-on second switch-type device 50 makes the voltage between the first input terminal In1 and the second input terminal In2 of the second rectifier circuit 60 equal to the voltage between the live wire and the ground wire, which is close to the phase voltage, causing the alarm circuit 4 to generate a short alarm.

[0056] When the first voltage-limiting device 10 and the second voltage-limiting device 40 are in good condition and the power supply is normal, the leakage current of the first voltage-limiting device 10 and the second voltage-limiting device 40 is small, and the alarm circuit 4 will not sound an alarm. If the first voltage-limiting device 10 fails due to breakdown due to too many conduction times, overcurrent shock, overvoltage shock, aging, etc., when the power supply is normal, that is, when no surge interference occurs, the leakage current of the first voltage-limiting device 10 is too large, the first switch device 20 is turned off, and the leakage current of the first voltage-limiting device 10 will flow through the alarm circuit 4 after being rectified by the first rectifier circuit 30, causing the alarm circuit 4 to sound an alarm. If the second voltage-limiting device 40 fails due to breakdown due to too many conduction times, overcurrent shock, overvoltage shock, aging, etc., under normal power supply conditions, that is, when no surge interference occurs, the leakage current of the second voltage-limiting device 40 is too large, the second switch device 50 is turned off, and the leakage current of the second voltage-limiting device 40 will flow through the alarm circuit 4 after being rectified by the second rectifier circuit 60, causing the alarm circuit 4 to alarm. Therefore, when at least one of the first voltage-limiting device 10 and the second voltage-limiting device 40 fails (specifically, a short-circuit failure occurs), resulting in excessive leakage current, the alarm circuit 4 will alarm, so there is no need to set separate alarm circuits for the first voltage-limiting device 10 and the second voltage-limiting device 40, so as to reduce the use of components.

[0057] It should be noted that no matter the first end V1 of the overvoltage protection circuit 100 is connected to the live wire and the second end V2 is connected to the neutral wire, or the first end V1 of the overvoltage protection circuit 100 is connected to the neutral wire and the second end V2 is connected to the live wire, when the first voltage limiting device 10 fails, the voltage of the circuit where the first voltage limiting device 10 and the first input end In1 and the second input end In2 of the first rectifier circuit 30 are located is the voltage between the live wire and the neutral wire, so as to avoid the voltage between the first end of the first voltage limiting device 10 and the second input end In2 of the first rectifier circuit 30 being too low and the leakage current being too small, resulting in a situation where the alarm cannot be given normally; when the second voltage limiting device 40 fails, the voltage of the circuit where the second voltage limiting device 40 and the first input end In1 and the second input end In2 of the second rectifier circuit 60 are located is the voltage between the live wire and the neutral wire, so as to avoid the voltage between the first end of the second voltage limiting device 40 and the second input end In2 of the second rectifier circuit 60 being too low and the leakage current being too small, resulting in a situation where the alarm cannot be given normally. Therefore, the first terminal V1 and the second terminal V2 of the overvoltage protection circuit 100 can be connected to the live wire and the neutral wire at will, thereby achieving the purpose of preventing the live wire and the neutral wire from being reversely connected.

[0058] The overvoltage protection circuit in the technical solution of this embodiment includes a first module, a second module and an alarm circuit, wherein the first module includes: a first voltage limiting device, a first switch device and a first rectifier circuit, wherein the first end of the first voltage limiting device is electrically connected to the first end of the overvoltage protection circuit; the second end of the first voltage limiting device is electrically connected to the second end of the overvoltage protection circuit via the first switch device; the first input end of the first rectifier circuit is electrically connected to the second end of the first voltage limiting device; the second input end of the first rectifier circuit is electrically connected to the second end of the overvoltage protection circuit; the positive output end of the first rectifier circuit is electrically connected to the first end of the alarm circuit; the first rectifier circuit The negative output end of the second rectifier circuit is electrically connected to the second end of the alarm circuit; the second module includes: a second voltage-limiting device, a second switch-type device and a second rectifier circuit, the first end of the second voltage-limiting device is electrically connected to the first end of the overvoltage protection circuit; the second end of the second voltage-limiting device is electrically connected to the third end of the overvoltage protection circuit via the second switch-type device; the first input end of the second rectifier circuit is electrically connected to the second end of the second voltage-limiting device; the second input end of the second rectifier circuit is electrically connected to the second end of the overvoltage protection circuit; the positive output end of the second rectifier circuit is electrically connected to the first end of the alarm circuit; the negative output end of the second rectifier circuit is electrically connected to the second end of the alarm circuit. On the basis of realizing overvoltage protection, the leakage current of the first voltage-limiting device and the second voltage-limiting device can be monitored and alarmed through an alarm circuit, and the purpose of preventing the reverse connection of the live wire and the neutral wire can be achieved.

[0059] An embodiment of the present invention provides yet another overvoltage protection circuit. Figure 2 A schematic diagram of the structure of another overvoltage protection circuit provided by an embodiment of the present invention. Based on the above embodiment, the overvoltage protection circuit 100 includes: a first module 1 , a third module 3 and an alarm circuit 4 .

[0060] The third module 3 includes: a third voltage-limiting device 70 , a third switch device 80 and a third rectifier circuit 90 .

[0061] Among them, the first end of the third voltage limiting device 70 is electrically connected to the second end V2 of the overvoltage protection circuit 100; the second end of the third voltage limiting device 70 is electrically connected to the third end V3 of the overvoltage protection circuit 100 via the third switch type device 80; the first input end In1 of the third rectifier circuit 90 is electrically connected to the second end of the third voltage limiting device 70; the second input end In2 of the third rectifier circuit 90 is electrically connected to the first end V1 of the overvoltage protection circuit 100; the positive output end V+ of the third rectifier circuit 90 is electrically connected to the first end of the alarm circuit 4; the negative output end V- of the third rectifier circuit 90 is electrically connected to the second end of the alarm circuit 4.

[0062] Wherein, optionally, the third voltage-limiting device 70 includes at least one of the following: a varistor and a transient suppression diode. Optionally, the third switch-type device 80 includes at least one of the following: a gas discharge tube and a semiconductor discharge tube. The third rectifier circuit 90 may include a controlled rectifier circuit or an uncontrolled rectifier circuit. Optionally, the third rectifier circuit 90 includes a rectifier bridge composed of four diodes. The alarm circuit 4 may issue an alarm when the leakage current of the first voltage-limiting device 10 and / or the third voltage-limiting device 70 is greater than or equal to a preset threshold.

[0063] It should be noted that Figure 2 The working principle of the first module 1 in the corresponding technical solution is the same as Figure 1 The working principle of the first module 1 in the corresponding technical solution is the same or similar, so it will not be repeated here.

[0064] When the power supply is normal, that is, when there is no surge interference such as lightning strike or overvoltage, the first voltage limiting device 10, the first switch device 20, the third voltage limiting device 70 and the third switch device 80 are all turned off, the current output by the first rectifier circuit 30 and the third rectifier circuit 90 is zero, and the alarm circuit 4 does not work. If surge interference occurs between the second terminal V2 and the third terminal V3 of the overvoltage protection circuit 100, and the voltage between the second terminal V2 and the third terminal is higher than the equivalent turn-on voltage of the third voltage-limiting device 70 and the third switch-type device 80 connected in series, the third voltage-limiting device 70 and the third switch-type device 80 will be turned on to discharge the surge current and limit the voltage between the second terminal V2 and the third terminal V3 to a voltage range that the protected circuit 200 can withstand. At this time, if the first terminal V1 of the overvoltage protection circuit 100 is electrically connected to the live wire, and the second terminal V2 of the overvoltage protection circuit 100 is electrically connected to the neutral wire, the turned-on third switch-type device 80 makes the voltage between the first input terminal In1 and the second input terminal In2 of the third rectifier circuit 90 equal to the voltage between the live wire and the ground wire, which is close to the phase voltage, causing the alarm circuit 4 to generate a short alarm.

[0065] When the performance of the first voltage-limiting device 10 and the third voltage-limiting device 70 is intact and the power supply is normal, the leakage current of the first voltage-limiting device 10 and the third voltage-limiting device 70 is small, and the alarm circuit 4 will not alarm. If the third voltage-limiting device 70 fails due to breakdown due to too many conduction times, overcurrent shock, overvoltage shock, aging, etc., when the power supply is normal, that is, when no surge interference occurs, the leakage current of the third voltage-limiting device 70 is too large, the third switch-type device 80 is turned off, and the leakage current of the third voltage-limiting device 70 will flow through the alarm circuit 4 after being rectified by the third rectifier circuit 90, so that the alarm circuit 4 will alarm. Therefore, when at least one of the first voltage-limiting device 10 and the third voltage-limiting device 70 fails, resulting in excessive leakage current, the alarm circuit 4 will alarm, so there is no need to set separate alarm circuits for the first voltage-limiting device 10 and the third voltage-limiting device 70, so as to reduce the use of components.

[0066] It should be noted that no matter the first terminal V1 of the overvoltage protection circuit 100 is connected to the live wire and the second terminal V2 is connected to the neutral wire, or the first terminal V1 of the overvoltage protection circuit 100 is connected to the neutral wire and the second terminal V2 is connected to the live wire, when the third voltage limiting device 70 fails, the voltage of the circuit where the first input terminal In1 and the second input terminal In2 of the third voltage limiting device 70 and the third rectifier circuit 90 are located is the voltage between the live wire and the neutral wire, so as to avoid the situation where the voltage of the circuit where the first input terminal In1 and the second input terminal In2 of the third voltage limiting device 70 and the third rectifier circuit 90 are located is too low, the leakage current is too small, and the alarm cannot be normally generated. Therefore, the first terminal V1 and the second terminal V2 of the overvoltage protection circuit 100 can be arbitrarily connected to the live wire and the neutral wire, so as to achieve the purpose of preventing the reverse connection of the live wire and the neutral wire.

[0067] The overvoltage protection circuit in the technical solution of this embodiment includes a first module, a third module and an alarm circuit, wherein the first module includes: a first voltage limiting device, a first switch device and a first rectifier circuit, wherein the first end of the first voltage limiting device is electrically connected to the first end of the overvoltage protection circuit; the second end of the first voltage limiting device is electrically connected to the second end of the overvoltage protection circuit via the first switch device; the first input end of the first rectifier circuit is electrically connected to the second end of the first voltage limiting device; the second input end of the first rectifier circuit is electrically connected to the second end of the overvoltage protection circuit; the positive output end of the first rectifier circuit is electrically connected to the first end of the alarm circuit; the first rectifier circuit The negative output end of the third module is electrically connected to the second end of the alarm circuit; the third module includes: a third voltage-limiting device, a third switch-type device and a third rectifier circuit, the first end of the third voltage-limiting device is electrically connected to the second end of the overvoltage protection circuit; the second end of the third voltage-limiting device is electrically connected to the third end of the overvoltage protection circuit via the third switch-type device; the first input end of the third rectifier circuit is electrically connected to the second end of the third voltage-limiting device; the second input end of the third rectifier circuit is electrically connected to the first end of the overvoltage protection circuit; the positive output end of the third rectifier circuit is electrically connected to the first end of the alarm circuit; the negative output end of the third rectifier circuit is electrically connected to the second end of the alarm circuit. On the basis of realizing overvoltage protection, the leakage current in the first voltage-limiting device and the third voltage-limiting device can be monitored and alarmed through an alarm circuit, and the purpose of preventing the reverse connection of the live wire and the neutral wire can be achieved.

[0068] An embodiment of the present invention provides yet another overvoltage protection circuit. Figure 3 A schematic diagram of the structure of another overvoltage protection circuit provided by an embodiment of the present invention. Based on the above embodiment, the overvoltage protection circuit 100 includes: a second module 2 , a third module 3 and an alarm circuit 4 .

[0069] The alarm circuit 4 may generate an alarm when the leakage current of the second voltage limiting device 40 and / or the third voltage limiting device 70 is greater than or equal to a preset threshold.

[0070] It should be noted that Figure 3 The working principle of the second module 2 in the corresponding technical solution is the same as Figure 1 The working principle of the second module 2 in the corresponding technical solution is the same or similar, so it will not be repeated here. It should be noted that: Figure 3 The working principle of the third module 3 in the corresponding technical solution is the same as Figure 2 The working principle of the third module 3 in the corresponding technical solution is the same or similar, so it is not repeated here. When at least one of the second voltage limiting device 40 and the third voltage limiting device 70 fails, resulting in excessive leakage current, the alarm circuit 4 will alarm, so there is no need to set separate alarm circuits for the second voltage limiting device 40 and the third voltage limiting device 70, so as to reduce the use of components.

[0071] The overvoltage protection circuit in the technical solution of this embodiment includes a second module, a third module and an alarm circuit, wherein the second module includes: a second voltage limiting device, a second switch device and a second rectifier circuit, wherein the first end of the second voltage limiting device is electrically connected to the first end of the overvoltage protection circuit; the second end of the second voltage limiting device is electrically connected to the third end of the overvoltage protection circuit via the second switch device; the first input end of the second rectifier circuit is electrically connected to the second end of the second voltage limiting device; the second input end of the second rectifier circuit is electrically connected to the second end of the overvoltage protection circuit; the positive output end of the second rectifier circuit is electrically connected to the first end of the alarm circuit; the second rectifier circuit The negative output end of the third module is electrically connected to the second end of the alarm circuit; the third module includes: a third voltage-limiting device, a third switch-type device and a third rectifier circuit, the first end of the third voltage-limiting device is electrically connected to the second end of the overvoltage protection circuit; the second end of the third voltage-limiting device is electrically connected to the third end of the overvoltage protection circuit via the third switch-type device; the first input end of the third rectifier circuit is electrically connected to the second end of the third voltage-limiting device; the second input end of the third rectifier circuit is electrically connected to the first end of the overvoltage protection circuit; the positive output end of the third rectifier circuit is electrically connected to the first end of the alarm circuit; the negative output end of the third rectifier circuit is electrically connected to the second end of the alarm circuit. On the basis of realizing overvoltage protection, the leakage current in the second voltage-limiting device and the third voltage-limiting device can be monitored and alarmed through an alarm circuit, and the purpose of preventing the reverse connection of the live wire and the neutral wire can be achieved.

[0072] An embodiment of the present invention provides yet another overvoltage protection circuit. Figure 4 A schematic diagram of the structure of another overvoltage protection circuit provided by an embodiment of the present invention: Based on the above embodiment, the overvoltage protection circuit 100 includes: a first module 1 , a second module 2 , a third module 3 and an alarm circuit 4 .

[0073] Among them, the alarm circuit 4 can alarm when the leakage current of at least one of the first voltage-limiting device 10, the second voltage-limiting device 40 and the third voltage-limiting device 70 is greater than or equal to a preset threshold. When at least one of the first voltage-limiting device 10, the second voltage-limiting device 40 and the third voltage-limiting device 70 fails, resulting in excessive leakage current, the alarm circuit 4 will alarm, so there is no need to set up separate alarm circuits for the first voltage-limiting device 10, the second voltage-limiting device 40 and the third voltage-limiting device 70, so as to reduce the use of components. On the basis of realizing overvoltage protection, the leakage current of the first voltage-limiting device, the second voltage-limiting device and the third voltage-limiting device can be monitored and alarmed through an alarm circuit, and the purpose of preventing the reverse connection of the live wire and the neutral wire can be achieved.

[0074] Optionally, based on the above embodiment, Figure 5This is a schematic structural diagram of another overvoltage protection circuit provided by an embodiment of the present invention. The alarm circuit 4 includes a first current limiting unit 41 and a first alarm device 42.

[0075] The first current limiting unit 41 is connected in series with the first alarm device 42 , and two ends of the first current limiting unit 41 and the first alarm device 42 after being connected in series are electrically connected to a first end and a second end of the alarm circuit 4 , respectively.

[0076] Among them, optionally, the first current limiting unit 41 may include at least one of the following: a resistor and a voltage stabilizing diode. The first current limiting unit 41 has the function of current limiting and voltage dividing to prevent the first alarm device 42 from being damaged by excessive current and voltage. Optionally, the first alarm device 42 includes at least one of the following: a light emitting diode and a buzzer.

[0077] Exemplarily, the first alarm device 42 is a light emitting diode. When the first voltage limiting device 10, the second voltage limiting device 40 and the third voltage limiting device 70 are in good condition and the power supply is normal, that is, when no surge interference occurs, the leakage current of the first voltage limiting device 10, the second voltage limiting device 40 and the third voltage limiting device 70 is small, and the first alarm device 42 will not emit light. If the first voltage limiting device 10 fails due to breakdown due to too many conduction times, overcurrent shock, overvoltage shock, aging and other reasons, when the power supply is normal, that is, when no surge interference occurs, the leakage current of the first voltage limiting device 10 is too large, the first switch device 20 is turned off, and the leakage current of the first voltage limiting device 10 will flow through the first alarm device 42 of the alarm circuit 4 after the rectification of the first rectifier circuit 30, and the first alarm device 42 will emit light, so that the alarm circuit 4 will give an alarm, so as to prompt the maintenance personnel to repair and replace the device in time. If the second voltage limiting device 40 fails due to breakdown due to too many conduction times, overcurrent shock, overvoltage shock, aging, etc., under normal power supply conditions, that is, when no surge interference occurs, the leakage current of the second voltage limiting device 40 is too large, and the second switch device 50 is turned off. The leakage current of the second voltage limiting device 40 will flow through the first alarm device 42 of the alarm circuit 4 after rectification by the second rectifier circuit 60, and the first alarm device 42 will light up, causing the alarm circuit 4 to sound an alarm, so as to prompt maintenance personnel to repair and replace the device in time. If the third voltage-limiting device 70 fails due to breakdown due to too many conduction times, overcurrent shock, overvoltage shock, aging, etc., under normal power supply conditions, that is, when no surge interference occurs, the leakage current of the third voltage-limiting device 70 is too large, and the third switch device 80 is turned off. After the leakage current of the third voltage-limiting device 70 is rectified by the third rectifier circuit 90, it will flow through the first alarm device 42 of the alarm circuit 4, and the first alarm device 42 will emit light, causing the alarm circuit 4 to alarm, so as to prompt maintenance personnel to repair and replace the device in time. It should be noted that the more the number of failures in the first voltage-limiting device 10, the second voltage-limiting device 40 and the third voltage-limiting device 70 is, the greater the current flowing through the alarm circuit 4, and the higher the brightness of the first alarm device 42, so the number of failed voltage-limiting devices can be determined according to the brightness of the first alarm device 42.

[0078] Optionally, based on the above embodiment, continue to refer to Figure 5 The first current limiting unit 41 includes a first resistor R1 and a Zener diode Z1. The first resistor R1, the Zener diode Z1 and the first alarm device 42 are connected in series. The two ends of the series connection of the first resistor R1, the Zener diode Z1 and the first alarm device 42 are electrically connected to the first end and the second end of the alarm circuit 4 respectively.

[0079] Optionally, the voltage regulator diode Z1 is a bidirectional voltage regulator diode or a unidirectional voltage regulator diode. The larger the resistance value of the first resistor R1, the greater the current limiting and voltage dividing effect. The larger the clamping voltage of the voltage regulator diode Z1, the greater the current limiting and voltage dividing effect.

[0080] Optionally, based on the above embodiment, continue to refer to Figure 5 The alarm circuit 4 further includes a first shunt device 43 , which is connected in parallel with the first alarm device 42 .

[0081] Optionally, the first shunt device 43 may include a resistor. The first shunt device 43 is provided to shunt the leakage current flowing through the first alarm device 42, limit the current flowing through the first alarm device 42, and prevent the first alarm device 42 from being damaged due to excessive current.

[0082] Optionally, based on the above embodiment, continue to refer to Figure 5 The overvoltage protection circuit 100 also includes: a second alarm device 11 and a second current limiting device 12; the second alarm device 11 and the second current limiting device 12 are connected in series, and the two ends of the second alarm device 11 and the second current limiting device 12 after the series connection are electrically connected to the first end V1 and the second end V2 of the overvoltage protection circuit 100 respectively.

[0083] Optionally, the second alarm device 11 includes at least one of the following: a light emitting diode and a buzzer. Optionally, the second current limiting device 12 includes a resistor. The second current limiting device 12 has the function of current limiting and voltage dividing to prevent the second alarm device from being damaged due to excessive current and voltage.

[0084] Exemplarily, taking the second alarm device 11 as a light-emitting diode, when the power supply is normal, the voltage between the first terminal V1 and the second terminal V2 of the overvoltage protection circuit 100 is the normal operating voltage, and the voltage between the first terminal V1 and the second terminal V2 will be transmitted to the two ends of the second alarm device 11 and the second current limiting device 12 connected in series, and the second alarm device 11 will emit light; if a power outage occurs, the voltage between the first terminal V1 and the second terminal V2 of the overvoltage protection circuit 100 is 0, and the second alarm device 11 will not emit light, thereby enabling the second alarm device 11 to achieve the purpose of indicating the power supply status.

[0085] Optionally, based on the above embodiment, Figure 6A structural schematic diagram of another overvoltage protection circuit provided in an embodiment of the present invention, wherein the second alarm device 11 includes a first light emitting diode, and the overvoltage protection circuit 100 further includes: a first diode D1, wherein the first diode D1, the second alarm device 11 and the second current limiting device 12 are connected in series, and the two ends of the series connection of the first diode D1, the second alarm device 11 and the second current limiting device 12 are respectively electrically connected to the first end V1 and the second end V2 of the overvoltage protection circuit 100, and the first light emitting diode and the first diode are connected in series in the same direction.

[0086] The first diode D1 can reduce the reverse voltage borne by the first light emitting diode, thereby preventing the first light emitting diode from being damaged due to excessive reverse voltage.

[0087] Optionally, based on the above embodiment, Figure 7 This is a schematic structural diagram of another overvoltage protection circuit provided by an embodiment of the present invention. The overvoltage protection circuit 100 further includes a first overcurrent protection device 13 .

[0088] Wherein, the first terminal V1 of the overvoltage protection circuit 100 is electrically connected to the first terminal of the first overcurrent protection device 13. When the overvoltage protection circuit 100 includes the first module 1, the first terminal of the first voltage limiting device 10 is electrically connected to the second terminal of the first overcurrent protection device 13. When the overvoltage protection circuit 100 includes the second module 2, the first terminal of the second voltage limiting device 40 is electrically connected to the second terminal of the first overcurrent protection device 13. When the overvoltage protection circuit 100 includes the third module 3, the second input terminal In2 of the third rectifier circuit 90 is electrically connected to the second terminal of the first overcurrent protection device 13.

[0089] Wherein, optionally, the two ends of the first diode D1, the second alarm device 11 and the second current limiting device 12 connected in series are electrically connected to the second end V2 of the overvoltage protection circuit 100 and the second end of the first overcurrent protection device 13 respectively. Optionally, the first overcurrent protection device 13 includes at least one of the following: a fuse and a circuit breaker. If the overcurrent detection circuit of the circuit breaker detects that the current flowing into the first end V1 of the overvoltage protection circuit 100 exceeds the rated current, the main contact of the circuit breaker will be automatically disconnected. The overcurrent detection circuit can be an overcurrent release.

[0090] Exemplarily, taking the second alarm device 11 as a light emitting diode and the first overcurrent protection device 13 as a fuse, when the power supply is normal, the voltage between the first terminal V1 and the second terminal V2 of the overvoltage protection circuit 100 is the normal working voltage and working current, the first overcurrent protection device 13 will not act, and remain in the on state, the voltage between the first terminal V1 and the second terminal V2 will be transmitted to the two ends of the second alarm device 11 and the second current limiting device 12 connected in series, and the second alarm device 11 will emit light. When lightning strikes, overvoltage or overload occur, the current flowing through the first overcurrent protection device 13 exceeds the rated current, the first overcurrent protection device 13 will fuse, and the second alarm device 11 will go out, so as to prompt maintenance personnel to perform maintenance.

[0091] Optionally, based on the above embodiment, Figure 8 The schematic diagram of the assembly structure of a light-collecting element, a first alarm device, and a second alarm device provided in an embodiment of the present invention, the overvoltage protection circuit 100 further includes a light-collecting element 14, the first alarm device 42 is a light-emitting diode, the second alarm device 11 is a white light-emitting diode, and the light-emitting color of the first alarm device 42 is different from the light-emitting color of the second alarm device 11. The first alarm device 42 and the second alarm device 11 are located in the hollow inner cavity of the light-collecting element 14.

[0092] The focusing element 14 has the function of increasing the intensity of the central light and has a focusing effect. The focusing element can be a light guide column. When the first alarm device 42 and the second alarm device 11 emit light at the same time, the red light emitted by the first alarm device 42 will cover the white light emitted by the second alarm device 11.

[0093] The luminous color of the first alarm device 42 may be at least one of the following: red, yellow, blue, green, purple, etc. The first alarm device 42 and the second alarm device 11 may realize dual-color indication.

[0094] For example, taking the first alarm device 42 as a red light-emitting diode, if the first voltage-limiting device 10, the second voltage-limiting device 40 and the third voltage-limiting device 70 are in good condition, have not failed, and have not generated a large leakage current, under normal power supply, the second alarm device 11 emits white light, and the first alarm device 42 does not emit light, so the human eye can only see white light; if at least one of the first voltage-limiting device 10, the second voltage-limiting device 40 and the third voltage-limiting device 70 fails, resulting in excessive leakage current, the first alarm device 42 emits red light, and under normal power supply, the second alarm device 11 emits white light, but due to the focusing effect of the focusing element, the white light and the red light are mixed to form red light, so the human eye sees red light. If lightning strikes, overvoltage or overload occur, causing the current flowing through the first overcurrent protection device 13 to exceed the rated current, the first overcurrent protection device 13 will fuse, and the first alarm device 42 and the second alarm device 11 will go out.

[0095] Optionally, based on the above embodiment, continue to refer to Figure 6 When the overvoltage protection circuit 100 includes the first module 1 , the overvoltage protection circuit 100 also includes a third current limiting device 5 , and the second input terminal In2 of the first rectifier circuit 30 is electrically connected to the second terminal V2 of the overvoltage protection circuit 100 via the third current limiting device 5 .

[0096] Among them, optionally, the third current limiting device 5 may include a resistor. The third current limiting device 5 has the function of current limiting and voltage dividing to reduce the reverse voltage and conduction current borne by the diode and other devices in the first rectifier circuit. If the first voltage limiting device 10 fails due to breakdown due to too many conduction times, overcurrent impact, overvoltage impact, aging, etc., under normal power supply conditions, that is, when no surge interference occurs, the leakage current of the first voltage limiting device 10 is too large, and the first switch type device 20 is turned off. After the leakage current of the first voltage limiting device 10 is limited by the current limiting and voltage dividing function of the third current limiting device 5 and the rectification function of the first rectifier circuit 30, it will flow through the alarm circuit 4, causing the alarm circuit 4 to alarm.

[0097] It should be noted that the sum of the resistance values ​​of the third current limiting device 5 and the first current limiting unit 41 can be greater than the impedance when the first switch type device 20 is turned on. The third current limiting device 5 is connected in series with the first voltage limiting device 10 and in parallel with the first switch type device 20, playing a voltage dividing role and increasing the voltage at both ends of the first switch type device 20. If the first switch type device 20 is an open circuit failure type gas discharge tube, when a surge overvoltage appears between the first end V1 and the second end V2 of the overvoltage protection circuit 100, the first voltage limiting device 10 and the first switch type device 20 are turned on, and due to the voltage dividing effect of the third current limiting device 5, the voltage at both ends of the first switch type device 20 increases, and the arc temperature of the open circuit failure type gas discharge tube is very high, and the temperature is quickly transferred to the low temperature solder, and the low temperature solder melts. At this time, the closed environment of the open circuit failure type gas discharge tube is destroyed, and air enters, and the open circuit failure type gas discharge tube fails due to leakage.

[0098] Optionally, based on the above embodiment, continue to refer to Figure 7 The first input terminal In1 of the first rectifier circuit 30 is electrically connected to the second terminal of the first voltage limiting device 10 via the third current limiting device 5 .

[0099] Optionally, based on the above embodiment, continue to refer to Figure 6 When the overvoltage protection circuit 100 includes the second module 2 , the overvoltage protection circuit 100 also includes a fourth current limiting device 6 , and the second input terminal In2 of the second rectifier circuit 60 is electrically connected to the second terminal V2 of the overvoltage protection circuit 100 via the fourth current limiting device 6 .

[0100] Wherein, optionally, the fourth current limiting device 6 may include a resistor. The fourth current limiting device 6 has the function of current limiting and voltage dividing to reduce the reverse voltage and conduction current borne by the diode and other devices in the second rectifier circuit. If the second voltage limiting device 40 fails due to breakdown due to too many conduction times, overcurrent impact, overvoltage impact, aging, etc., under normal power supply conditions, that is, when no surge interference occurs, the leakage current of the second voltage limiting device 40 is too large, and the second switch type device 50 is turned off. After the leakage current of the second voltage limiting device 40 is limited by the current limiting and voltage dividing function of the fourth current limiting device 6 and the rectification function of the second rectifier circuit 60, it will flow through the alarm circuit 4, causing the alarm circuit 4 to alarm.

[0101] Optionally, based on the above embodiment, continue to refer to Figure 7 The first input terminal In1 of the second rectifier circuit 60 is electrically connected to the second terminal of the second voltage limiting device 40 via the fourth current limiting device 6 .

[0102] Optionally, based on the above embodiment, continue to refer to Figure 6When the overvoltage protection circuit 100 includes the third module 3 , the overvoltage protection circuit 100 also includes a fifth current limiting device 7 , and the second input terminal In2 of the third rectifier circuit 90 is electrically connected to the first terminal V1 of the overvoltage protection circuit 100 via the fifth current limiting device 7 .

[0103] Wherein, optionally, the fifth current limiting device 7 may include a resistor. The fifth current limiting device 7 has the function of current limiting and voltage dividing to reduce the reverse voltage and conduction current borne by the diode and other devices in the third rectifier circuit. If the third voltage limiting device 70 fails due to breakdown due to too many conduction times, overcurrent impact, overvoltage impact, aging, etc., under normal power supply conditions, that is, when no surge interference occurs, the leakage current of the third voltage limiting device 70 is too large, and the third switch type device 80 is turned off. After the leakage current of the third voltage limiting device 70 is limited by the current limiting and voltage dividing function of the fifth current limiting device 7 and the rectification function of the third rectifier circuit 90, it will flow through the alarm circuit 4, causing the alarm circuit 4 to alarm.

[0104] Optionally, based on the above embodiment, continue to refer to Figure 7 The first input terminal In1 of the third rectifier circuit 90 is electrically connected to the second terminal of the third voltage limiting device 70 via the fifth current limiting device 7 .

[0105] Optionally, based on the above embodiment, continue to refer to Figure 6 When the overvoltage protection circuit 100 includes the second module 2, the second switch type device 50 includes an open circuit failure type gas discharge tube, and the overvoltage protection circuit 100 also includes a first voltage divider device 8, which is connected in parallel with the second switch type device 50.

[0106] Among them, optionally, the first voltage divider device 8 may include a resistor, and the resistance of the first voltage divider device 8 is greater than the impedance when the second switch type device 50 is turned on. The first voltage divider device 8 is connected in series with the second voltage limiting device 40 and in parallel with the second switch type device 50, playing a voltage dividing role and increasing the voltage across the second switch type device 50. If the second switch type device 50 is an open circuit failure type gas discharge tube, when a surge overvoltage appears between the first terminal V1 and the third terminal V3 of the overvoltage protection circuit 100, the second voltage limiting device 40 and the second switch type device 50 are turned on. Due to the voltage dividing effect of the first voltage divider device 8, the voltage across the second switch type device 50 increases, and the arc temperature of the open circuit failure type gas discharge tube is very high, and the temperature is quickly transferred to the low temperature solder, and the low temperature solder melts. At this time, the closed environment of the open circuit failure type gas discharge tube is destroyed, and air enters, and the open circuit failure type gas discharge tube fails due to leakage. The first voltage divider device 8 is provided to increase the heat generation of the second switch type device 50 and improve the withstand voltage of the second voltage limiting device 40.

[0107] Optionally, based on the above embodiment, continue to refer to Figure 6 When the overvoltage protection circuit 100 includes the third module 3, the third switch type device 80 includes an open circuit failure type gas discharge tube, and the overvoltage protection circuit 100 also includes a second voltage divider device 9, which is connected in parallel with the third switch type device 80.

[0108] Among them, optionally, the second voltage divider device 9 may include a resistor, and the resistance of the second voltage divider device 9 is greater than the impedance when the third switch type device 80 is turned on. The second voltage divider device 9 is connected in series with the third voltage limiting device 70 and in parallel with the third switch type protection device 80, and plays a voltage dividing role, while increasing the voltage across the third switch type device 80. If the third switch type device 80 is an open circuit failure type gas discharge tube, when a surge overvoltage appears between the second terminal V2 and the third terminal V3 of the overvoltage protection circuit 100, the third voltage limiting device 70 and the third switch type device 80 are turned on, and due to the voltage dividing effect of the second voltage divider device 9, the voltage across the third switch type device 80 increases, and the arc temperature of the open circuit failure type gas discharge tube is very high, and the temperature is quickly transmitted to the low temperature solder, and the low temperature solder melts. At this time, the closed environment of the open circuit failure type gas discharge tube is destroyed, and air enters, and the open circuit failure type gas discharge tube fails due to leakage. The second voltage divider device 9 is provided to increase the heat generation of the third switch type device 80 and improve the withstand voltage of the third voltage limiting type device 70 .

[0109] Figure 5 The first voltage-limiting device 10, the second voltage-limiting device 40 and the third voltage-limiting device 70 are varistors, and the first switch-type device 20, the second switch-type device 50 and the third switch-type device 80 are open-circuit failure gas discharge tubes. Each circuit is protected by using a gas discharge tube in combination with a varistor, and the low leakage current characteristic of the gas discharge tube when not conducting is used to overcome the problem of excessive leakage current and easy fire when a single varistor is used. The clamping characteristics of the varistor and the switching characteristics of the gas discharge tube are used to discharge the lightning current.

[0110] Optionally, the gas discharge tube may be an open circuit failure gas discharge tube or a repeatable continuous current breaking type gas discharge tube.

[0111] Optionally, the open-circuit failure type gas discharge tube includes an insulating tube body and two conductive electrodes that are sealed and connected to the two ends of the insulating tube body to form a discharge inner cavity. The discharge inner cavity is filled with discharge gas, and at least one conductive electrode is sealed and connected to the insulating tube body through a low-temperature insulating sealing adhesive. When surge interference occurs at both ends of the open-circuit failure type gas discharge tube, the open-circuit failure type gas discharge tube is turned on to discharge the surge current. After the surge interference disappears, the follow-up current generated by the normal working voltage after the power supply is restored is injected into the open-circuit failure type gas discharge tube, so that the low-temperature insulating sealing adhesive will melt, allowing external air to enter the discharge inner cavity, causing the open-circuit failure type gas discharge tube to fail in the open circuit. If other devices connected to the open-circuit failure type gas discharge tube are short-circuited and fail, the open-circuit failure type gas discharge tube can only withstand one lightning strike or overvoltage and fail.

[0112] Optionally, a repeatable continuous current breaking type gas discharge tube may include: a retractable bellows and two conductive electrodes sealed and connected to the retractable bellows to form a discharge inner cavity, wherein the discharge inner cavity is filled with a discharge gas. The retractable bellows is used to stretch or contract when the discharge gas is heated and expanded by discharge between at least two conductive electrodes, so as to increase the discharge gap between the discharge electrode surfaces of at least two conductive electrodes, so as to interrupt the continuous current of the gas discharge tube. The retractable bellows is also used to restore the retractable bellows to a preset length as the discharge gas cools to a low temperature zone after the continuous current of the gas discharge tube is interrupted. If all other devices connected to the repeatable continuous current breaking type gas discharge tube fail due to short circuit, the repeatable continuous current breaking type gas discharge tube can still withstand multiple lightning strikes or overvoltage failures.

[0113] An embodiment of the present invention provides an electronic device. Based on the above embodiment, continue to refer to Figure 5 The electronic device includes a circuit to be protected 200 and an overvoltage protection circuit 100 provided by any embodiment of the present invention.

[0114] Among them, the third terminal V3 of the overvoltage protection circuit 100 is grounded PE; the first terminal V1 and the second terminal V2 of the overvoltage protection circuit 100 are electrically connected to the live wire L and the neutral wire N respectively; the circuit to be protected 200 is electrically connected to the first terminal V1 and the second terminal V2 of the overvoltage protection circuit 100.

[0115] Among them, the overvoltage protection circuit 100 can be turned on when surge interference such as lightning or overvoltage occurs, and discharge the surge current to protect the circuit to be protected 200. The electronic device can be, for example, a computer, a navigator or a camera in devices such as automotive electronics, communications, new energy, security, consumer electronics, industrial electronics, and medical electronics. The electronic device provided by the embodiment of the present invention includes the overvoltage protection circuit in the above embodiment, so the electronic device provided by the embodiment of the present invention also has the beneficial effects described in the above embodiment, which will not be repeated here.

[0116] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, combinations and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An overvoltage protection circuit, characterized in that: include: at least two of the first module, the second module and the third module, and an alarm circuit; Wherein, the first module includes: A first voltage limiting device, wherein a first end of the first voltage limiting device is electrically connected to a first end of the overvoltage protection circuit; a first switch type device, wherein the second end of the first voltage limiting device is electrically connected to the second end of the overvoltage protection circuit via the first switch type device; a first rectifier circuit, wherein a first input terminal of the first rectifier circuit is electrically connected to a second terminal of the first voltage-limiting device; a second input terminal of the first rectifier circuit is electrically connected to a second terminal of the overvoltage protection circuit; a positive output terminal of the first rectifier circuit is electrically connected to a first terminal of the alarm circuit; and a negative output terminal of the first rectifier circuit is electrically connected to a second terminal of the alarm circuit; The second module includes: A second voltage limiting device, wherein a first terminal of the second voltage limiting device is electrically connected to a first terminal of the overvoltage protection circuit; a second switch type device, wherein the second end of the second voltage limiting device is electrically connected to the third end of the overvoltage protection circuit via the second switch type device; a second rectifier circuit, wherein a first input terminal of the second rectifier circuit is electrically connected to a second terminal of the second voltage-limiting device; a second input terminal of the second rectifier circuit is electrically connected to a second terminal of the overvoltage protection circuit; a positive output terminal of the second rectifier circuit is electrically connected to a first terminal of the alarm circuit; and a negative output terminal of the second rectifier circuit is electrically connected to a second terminal of the alarm circuit; The third module comprises: A third voltage limiting device, a first end of the third voltage limiting device being electrically connected to a second end of the overvoltage protection circuit; a third switch type device, wherein the second end of the third voltage limiting device is electrically connected to the third end of the overvoltage protection circuit via the third switch type device; a third rectifier circuit, wherein a first input terminal of the third rectifier circuit is electrically connected to a second terminal of the third voltage-limiting device; a second input terminal of the third rectifier circuit is electrically connected to a first terminal of the overvoltage protection circuit; a positive output terminal of the third rectifier circuit is electrically connected to a first terminal of the alarm circuit; and a negative output terminal of the third rectifier circuit is electrically connected to a second terminal of the alarm circuit; The alarm circuit generates an alarm when the leakage current of at least one of the first voltage limiting device, the second voltage limiting device and the third voltage limiting device is greater than or equal to a preset threshold; When the overvoltage protection circuit includes a second module, the second switch type device includes an open circuit failure type gas discharge tube, and the overvoltage protection circuit further includes a first voltage divider device, and the first voltage divider device is connected in parallel with the second switch type device; When the overvoltage protection circuit includes a third module, the third switch type device includes an open circuit failure type gas discharge tube, and the overvoltage protection circuit further includes a second voltage divider device, and the second voltage divider device is connected in parallel with the third switch type device; The alarm circuit comprises a first current limiting unit and a first alarm device. The first current limiting unit is connected in series with the first alarm device, and two ends of the first current limiting unit and the first alarm device after being connected in series are electrically connected to a first end and a second end of the alarm circuit respectively.

2. The overvoltage protection circuit according to claim 1, characterized in that: The alarm circuit further includes a first shunt device, which is connected in parallel with the first alarm device.

3. The overvoltage protection circuit according to claim 1, characterized in that: The first current limiting unit includes a first resistor and a voltage-stabilizing diode, the first resistor, the voltage-stabilizing diode and the first alarm device are connected in series, and two ends of the first resistor, the voltage-stabilizing diode and the first alarm device after being connected in series are electrically connected to a first end and a second end of the alarm circuit respectively; The first alarm device includes at least one of the following: a light emitting diode and a buzzer.

4. The overvoltage protection circuit according to claim 1, characterized in that: The overvoltage protection circuit also includes: a second alarm device and a second current limiting device; the second alarm device and the second current limiting device are connected in series, and the two ends of the second alarm device and the second current limiting device after the series connection are electrically connected to the first end and the second end of the overvoltage protection circuit respectively.

5. The overvoltage protection circuit according to claim 4, characterized in that: The second alarm device includes a first light-emitting diode, and the overvoltage protection circuit also includes: a first diode, wherein the first diode, the second alarm device and the second current limiting device are connected in series, and two ends of the series connection of the first diode, the second alarm device and the second current limiting device are respectively electrically connected to the first end and the second end of the overvoltage protection circuit, and the first light-emitting diode and the first diode are connected in series in the same direction.

6. The overvoltage protection circuit according to claim 1, characterized in that: The first rectifier circuit includes a rectifier bridge composed of four diodes; the second rectifier circuit includes a rectifier bridge composed of four diodes; the third rectifier circuit includes a rectifier bridge composed of four diodes; The first voltage-limiting device includes at least one of the following: a varistor and a transient suppression diode; the first switch-type device includes at least one of the following: a gas discharge tube and a semiconductor discharge tube; the second voltage-limiting device includes at least one of the following: a varistor and a transient suppression diode; the third voltage-limiting device includes at least one of the following: a varistor and a transient suppression diode; The overvoltage protection circuit also includes a first overcurrent protection device, Wherein, the first end of the overvoltage protection circuit is electrically connected to the first end of the first overcurrent protection device; When the overvoltage protection circuit includes a first module, a first end of the first voltage-limiting device is electrically connected to a second end of the first overcurrent protection device; When the overvoltage protection circuit includes a second module, the first end of the second voltage-limiting device is electrically connected to the second end of the first overcurrent protection device; When the overvoltage protection circuit includes a third module, the second input terminal of the third rectifier circuit is electrically connected to the second terminal of the first overcurrent protection device.

7. The overvoltage protection circuit according to claim 1, characterized in that: When the overvoltage protection circuit includes the first module, the overvoltage protection circuit further includes a third current limiting device, the second input end of the first rectifier circuit is electrically connected to the second end of the overvoltage protection circuit via the third current limiting device, or the first input end of the first rectifier circuit is electrically connected to the second end of the first voltage limiting device via the third current limiting device; When the overvoltage protection circuit includes a second module, the overvoltage protection circuit further includes a fourth current limiting device, and the second input end of the second rectifier circuit is electrically connected to the second end of the overvoltage protection circuit via the fourth current limiting device, or the first input end of the second rectifier circuit is electrically connected to the second end of the second voltage limiting device via the fourth current limiting device; When the overvoltage protection circuit includes a third module, the overvoltage protection circuit also includes a fifth current limiting device, and the second input end of the third rectifier circuit is electrically connected to the first end of the overvoltage protection circuit via the fifth current limiting device, or the first input end of the third rectifier circuit is electrically connected to the second end of the third voltage limiting device via the fifth current limiting device.

8. An electronic device, characterized in that: comprising a circuit to be protected and an overvoltage protection circuit as claimed in any one of claims 1 to 7, The third terminal of the overvoltage protection circuit is grounded; the first terminal and the second terminal of the overvoltage protection circuit are electrically connected to the live wire and the neutral wire respectively; The circuit to be protected is electrically connected to a first end and a second end of the overvoltage protection circuit.

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