A surge protection circuit and device

Abstract

The application discloses a surge protection circuit and device, which comprises a discharge circuit, a voltage division circuit, a driving circuit and a leakage circuit. The discharge circuit and the leakage circuit are connected in series between a power line and a PE line. The voltage division circuit is connected in parallel with the discharge circuit. The first end of the driving circuit is connected to the input end of the leakage circuit, the second end is connected to the output end of the leakage circuit, and the third end is connected to the control end of the leakage circuit. When high-voltage electricity is transmitted through the power line, the voltage division circuit and the driving circuit are connected in series to divide the voltage, so as to improve the voltage resistance of the discharge circuit. When a surge voltage is transmitted through the power line, the driving circuit detects the surge voltage and controls the leakage circuit to be turned on, so that the surge voltage is discharged to the PE line through the voltage division circuit and the leakage circuit. The device has the functions of high-voltage resistance and surge voltage absorption, is safe, and can continuously perform voltage resistance test and surge test in the production process, so as to facilitate production and reduce cost.

Description

Technical Field

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

[0002] In existing technologies, when transmitting high-voltage electricity through a high-voltage power line, a varistor and a gas discharge tube are connected in series between the power line and the PE line to form a surge protection circuit to discharge surge voltage. In practical situations, surge protection circuits also need to have high-voltage withstand capability. Therefore, manufactured surge protection circuits need to undergo both surge protection testing and high-voltage withstand testing. However, during high-voltage withstand testing, the leakage current transmitted to the circuit cannot exceed a set value, which is incompatible with the working principle of surge protection. In other words, existing surge protection circuits cannot simultaneously demonstrate both high-voltage withstand and surge protection characteristics.

[0003] To address these issues, testing personnel typically need to disconnect the discharge circuit before performing the withstand voltage test, and then reconnect the discharge circuit after the withstand voltage test is completed. This significantly impacts the production process, severely affecting assembly efficiency. Utility Model Content

[0004] The main objective of this application is to provide a surge protection circuit and device that aims to solve the technical problem of how to ensure that the surge protection circuit is compatible with both high voltage resistance and surge protection characteristics.

[0005] To achieve the above objectives, embodiments of this application provide a surge protection circuit, the surge protection circuit comprising:

[0006] A discharge circuit, wherein the input terminal of the discharge circuit is connected to the power supply line, and the output terminal of the discharge circuit is connected to the input terminal of the discharge circuit;

[0007] The output terminal of the discharge circuit is connected to the PE line;

[0008] A voltage divider circuit, connected in parallel with the discharge circuit, is used to divide the voltage transmitted by the power line;

[0009] A driving circuit, wherein the first end of the driving circuit is connected to the input end of the discharge circuit, the second end of the driving circuit is connected to the output end of the discharge circuit, and the third end of the driving circuit is connected to the control end of the discharge circuit.

[0010] The driving circuit is configured to keep the discharge circuit disconnected during a withstand voltage test of the surge protection circuit; and / or to control the discharge circuit to conduct when a surge voltage is detected during a surge test of the surge protection circuit, so as to discharge the surge voltage.

[0011] In one embodiment, the surge voltage includes a positive surge voltage and a negative surge voltage, the discharge circuit includes a first discharge sub-circuit and a second discharge sub-circuit, and the driving circuit includes a first driving sub-circuit and a second driving sub-circuit.

[0012] The input terminal of the first discharge sub-circuit, the input terminal of the second discharge sub-circuit, the first terminal of the first driving sub-circuit, and the first terminal of the second driving sub-circuit are connected to the output terminal of the discharge circuit; the output terminals of the first discharge sub-circuit, the second discharge sub-circuit, the second terminal of the first driving sub-circuit, and the second terminal of the second driving sub-circuit are connected to the PE line; the third terminal of the first driving sub-circuit is connected to the control terminal of the first discharge sub-circuit, and the third terminal of the second driving sub-circuit is connected to the control terminal of the second discharge sub-circuit.

[0013] The first driving sub-circuit is used to control the first discharge sub-circuit to conduct when the positive surge voltage is detected, so as to discharge the positive surge voltage;

[0014] The second driving sub-circuit is used to control the second discharge sub-circuit to conduct when the negative surge voltage is detected, so as to discharge the negative surge voltage.

[0015] In one embodiment, the first discharge sub-circuit includes: a first thyristor;

[0016] The anode of the first thyristor is connected to the output terminal of the discharge circuit, the cathode of the first thyristor is connected to the PE line, and the gate of the first thyristor is connected to the output terminal of the first driving sub-circuit.

[0017] In one embodiment, the first driving sub-circuit includes: a first resistor, a second resistor, a first capacitor, and a first Zener diode;

[0018] The first end of the first resistor is connected to the output terminal of the discharge circuit, the second end of the first resistor is connected to the first end of the first capacitor, the second end of the first capacitor is connected to the first end of the second resistor and the cathode of the first Zener diode, the second end of the second resistor is connected to the control terminal of the first discharge circuit, and the anode of the first Zener diode is connected to the PE line.

[0019] In one embodiment, the second discharge sub-circuit includes: a second thyristor;

[0020] The cathode of the second thyristor is connected to the output terminal of the discharge circuit, the anode of the second thyristor is connected to the PE line, and the gate of the second thyristor is connected to the output terminal of the second driving sub-circuit.

[0021] In one embodiment, the second driving sub-circuit includes: a third resistor, a fourth resistor, a second capacitor, and a second Zener diode;

[0022] The anode of the second Zener diode is connected to the output terminal of the discharge circuit, the cathode of the second Zener diode is connected to the first terminal of the third resistor and the first terminal of the fourth resistor, the second terminal of the third resistor is connected to the control terminal of the second discharge sub-circuit, the second terminal of the fourth resistor is connected to the first terminal of the second capacitor, and the second terminal of the second capacitor is connected to the PE line.

[0023] In one embodiment, the discharge circuit includes: a first discharge tube, a second discharge tube, and a third discharge tube;

[0024] The first end of the first discharge tube is connected to the power line, the second end of the first discharge tube is connected to the first end of the second discharge tube and the first end of the third discharge tube, the second end of the second discharge tube is connected to the input terminal of the first discharge sub-circuit, and the second end of the third discharge tube is connected to the input terminal of the second discharge sub-circuit.

[0025] In one embodiment, the voltage divider circuit includes: a third capacitor, a fourth capacitor, and a fifth capacitor;

[0026] The first end of the third capacitor is connected to the first end of the first discharge tube, and the second end of the third capacitor is connected to the second end of the first discharge tube; the first end of the fourth capacitor is connected to the first end of the second discharge tube, and the second end of the fourth capacitor is connected to the second end of the second discharge tube; the first end of the fifth capacitor is connected to the first end of the third discharge tube, and the second end of the fifth capacitor is connected to the second end of the third discharge tube.

[0027] In one embodiment, the surge protection circuit further includes a varistor circuit;

[0028] The varistor circuit is connected to the power supply line and the input terminal of the discharge circuit, respectively.

[0029] In addition, to achieve the above objectives, this application also provides a surge protection device, which employs the surge protection circuit described above.

[0030] This application provides a surge protection circuit and device. The surge protection circuit includes: a discharge circuit, the input terminal of which is connected to a power line, and the output terminal of which is connected to the input terminal of a bleeder circuit; the bleeder circuit, the output terminal of which is connected to a PE line; a voltage divider circuit, connected in parallel with the discharge circuit, for dividing the voltage transmitted through the power line; and a drive circuit, the first terminal of which is connected to the input terminal of the bleeder circuit, the second terminal of which is connected to the output terminal of the bleeder circuit, and the third terminal of which is connected to the control terminal of the bleeder circuit. The drive circuit is used to keep the bleeder circuit disconnected during a withstand voltage test of the surge protection circuit; and / or, during a surge test of the surge protection circuit, when a surge voltage is detected, to control the bleeder circuit to conduct, thereby discharging the surge voltage.

[0031] When high voltage is transmitted through the power line without surge voltage, a series voltage divider circuit and a drive circuit divide the high voltage to improve the withstand voltage capability of the discharge circuit, ensuring that the discharge circuit does not conduct and discharge solely due to receiving high voltage. However, when a surge voltage is transmitted through the power line, the discharge circuit conducts and discharges due to receiving high voltage. The drive circuit connected to the subsequent stage detects the surge voltage transmitted by the preceding discharge circuit and controls the conduction of the bleeder circuit, allowing the surge voltage to be discharged to the PE line through the voltage divider circuit and the bleeder circuit. This design combines high voltage withstand and surge voltage absorption, offering high safety. Furthermore, withstand voltage and surge tests can be performed continuously during production, facilitating production and reducing costs. Attached Figure Description

[0032] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a structural connection diagram provided for Embodiment 1 of the surge protection circuit of this application;

[0035] Figure 2 This application provides a circuit connection diagram for a second embodiment of the surge protection circuit.

[0036] Figure 3 This is a circuit connection diagram provided for Embodiment 3 of the surge protection circuit of this application.

[0037] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0038] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0039] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0040] This application presents a surge protection circuit according to a first embodiment. Please refer to [link / reference]. Figure 1 The surge protection circuit includes:

[0041] The discharge circuit 10 has its input terminal connected to a power supply line and its output terminal connected to the input terminal of the discharge circuit 20.

[0042] The output terminal of the discharge circuit 20 is connected to the PE line;

[0043] Voltage divider circuit 30, connected in parallel with discharge circuit 10, is used to divide the voltage transmitted by the power line;

[0044] A driving circuit 40, the first end of which is connected to the input end of the discharge circuit 20, the second end of which is connected to the output end of the discharge circuit 20, and the third end of which is connected to the control end of the discharge circuit 20.

[0045] The driving circuit 40 is used to control the discharge circuit 20 to conduct when a surge voltage is detected, so as to discharge the surge voltage.

[0046] It should be understood that the discharge circuit 10 can be regarded as an insulated state under normal circumstances. However, when a high voltage surge occurs in the power line, the discharge circuit 10 will be in a low resistance state due to receiving the high voltage surge, which can be regarded as a conducting state, and will discharge to protect the downstream circuit connected to the power line from damage by the high voltage surge.

[0047] It should be noted that, in this embodiment, as one scenario, if a high-voltage surge (voltage surge) occurs in the power line, the discharge circuit 10 will be in a low-resistance state and discharge. At this time, the drive circuit 40 connected in series after the discharge circuit 10 can detect the high-voltage surge (voltage surge) transmitted by the discharge circuit 10 and generate a corresponding trigger signal, which is then transmitted to the bleeder circuit 20. Upon receiving the trigger signal from the drive circuit 40, the bleeder circuit 20 enters a conducting state, directly connecting the output of the discharge circuit 10 to the PE line, thereby completely discharging the high-voltage surge (voltage surge) to the PE line.

[0048] In another scenario, if there is no high-voltage surge in the power line, or if it is understood as only high voltage present that prevents the discharge circuit 10 from reaching a low-resistance state, then the discharge circuit 10 is essentially open-circuited. In this case, the voltage divider circuit 30, connected in parallel with the discharge circuit 10, can divide the high voltage. Since the voltage divider circuit 30 and the discharge circuit 10 are connected in parallel, their voltages remain the same, thus stabilizing the voltage across the discharge circuit 10 within a range that prevents it from entering a conducting state. Simultaneously, the high-voltage current can be transmitted to the subsequent drive circuit 40. At this time, the drive circuit 40 does not detect a high-voltage surge, therefore it will not send a trigger signal to the bleeder circuit 20, and the bleeder circuit 20 will not discharge the high voltage transmitted by the voltage divider circuit 30. The drive circuit 40 and the voltage divider circuit 30 form a series structure, connected between the power line and the PE line, respectively bearing a portion of the high voltage through voltage division, thus giving the entire circuit excellent voltage withstand capability.

[0049] It is easy to understand that, in specific implementations, structurally, the discharge circuit 10 is connected in parallel with the voltage divider circuit 30, in series with the drive circuit 40, and also in series with the bleeder circuit 20. Functionally, the discharge circuit 10 conducts when it receives a surge voltage, and the drive circuit 40 conducts the bleeder circuit 20 when it detects a surge voltage. Therefore, when there is high voltage in the power line but no surge voltage, the high voltage can be divided by the voltage divider circuit 30 and the drive circuit 40 connected in series between the power line and the PE line, thereby improving the withstand voltage of the entire surge protection circuit. When a surge voltage exists in the power line, the discharge circuit 10 can be turned on to discharge, and at the same time, when the drive circuit 40 connected in the subsequent stage detects the surge voltage transmitted by the discharge circuit 10, it controls the bleeder circuit 20 to directly discharge the surge voltage to the PE line, thereby effectively absorbing the surge voltage. Through this circuit structure, it has both excellent withstand voltage and effective surge voltage absorption, greatly improving the safety of the entire surge protection circuit.

[0050] More importantly, the surge protection circuit described above allows for both withstand voltage and surge testing without requiring modifications to the circuit structure. This enables the merging of two critical production processes, allowing for rapid completion of both withstand voltage and surge tests and saving production time.

[0051] This application provides a surge protection circuit, comprising: a discharge circuit, the input terminal of which is connected to a power line, and the output terminal of which is connected to the input terminal of a bleeder circuit; the bleeder circuit, the output terminal of which is connected to a PE line; a voltage divider circuit, connected in parallel with the discharge circuit, for dividing the voltage transmitted through the power line; and a drive circuit, the first terminal of which is connected to the input terminal of the bleeder circuit, the second terminal of which is connected to the output terminal of the bleeder circuit, and the third terminal of which is connected to the control terminal of the bleeder circuit; wherein, the drive circuit is used to keep the bleeder circuit disconnected during a withstand voltage test of the surge protection circuit; and / or, during a surge test of the surge protection circuit, when a surge voltage is detected, to control the bleeder circuit to conduct in order to bleed the surge voltage. When high voltage is transmitted through the power line without surge voltage, a series voltage divider circuit and a drive circuit divide the high voltage to improve the withstand voltage capability of the discharge circuit, ensuring that the discharge circuit does not conduct and discharge solely due to receiving high voltage. However, when a surge voltage is transmitted through the power line, the discharge circuit conducts and discharges due to receiving high voltage. The drive circuit connected to the subsequent stage detects the surge voltage transmitted by the preceding discharge circuit and controls the conduction of the bleeder circuit, allowing the surge voltage to be discharged to the PE line through the voltage divider circuit and the bleeder circuit. This design combines high voltage withstand and surge voltage absorption, offering high safety. Furthermore, withstand voltage and surge tests can be performed continuously during production, facilitating production and reducing costs.

[0052] Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to that in Embodiment 1 above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 2 The surge voltage includes positive surge voltage and negative surge voltage. The discharge circuit 20 includes a first discharge sub-circuit 21 and a second discharge sub-circuit 22. The drive circuit 40 includes a first drive sub-circuit 41 and a second drive sub-circuit 42.

[0053] The input terminals of the first discharge sub-circuit 21, the second discharge sub-circuit 22, the first terminal of the first driving sub-circuit 41, and the first terminal of the second driving sub-circuit 42 are connected to the output terminal of the discharge circuit 10; the output terminals of the first discharge sub-circuit 21, the second discharge sub-circuit 22, the second terminal of the first driving sub-circuit 41, and the second terminal of the second driving sub-circuit 42 are connected to the PE line; the third terminal of the first driving sub-circuit 41 is connected to the control terminal of the first discharge sub-circuit 21, and the third terminal of the second driving sub-circuit 42 is connected to the control terminal of the second discharge sub-circuit 22.

[0054] The first driving sub-circuit 41 is used to control the first discharge sub-circuit 21 to conduct when the positive surge voltage is detected, so as to discharge the positive surge voltage;

[0055] The second driving sub-circuit 42 is used to control the second discharge sub-circuit 22 to conduct when the negative surge voltage is detected, so as to discharge the negative surge voltage.

[0056] It should be noted that surge voltage typically includes positive surge voltage in the positive direction and negative surge voltage in the negative direction. In this embodiment, the discharge circuit 20 may include a first discharge sub-circuit 21 for discharging positive surge voltage and a second discharge sub-circuit 22 for discharging negative surge voltage. Simultaneously, the drive circuit 40 also includes a first drive sub-circuit 41 for detecting positive surge voltage and controlling the on / off state of the first discharge sub-circuit 21 based on the detection result, and a second drive sub-circuit 42 for detecting negative surge voltage and controlling the on / off state of the second discharge sub-circuit 22 based on the detection result.

[0057] It is easy to understand that in this embodiment, when the first driving sub-circuit 41 detects a positive surge voltage transmitted by the discharge circuit 10, it generates a corresponding first trigger signal and sends it to the first discharge sub-circuit 21. Upon receiving the first trigger signal, the first discharge sub-circuit 21 enters a conducting state, transmitting the positive surge voltage to the PE line for discharge. Correspondingly, when the second driving sub-circuit 42 detects a negative surge voltage transmitted by the discharge circuit 10, it generates a corresponding second trigger signal and sends it to the second discharge sub-circuit 22. Upon receiving the second trigger signal, the second discharge sub-circuit 22 enters a conducting state, transmitting the negative surge voltage to the PE line for discharge. With the above structure, both positive and negative discharge voltages can be transmitted to the PE line for discharge, thereby effectively absorbing all types of surge voltages and improving surge protection capability.

[0058] Furthermore, in this embodiment, the first discharge sub-circuit 21 includes: a first thyristor D1;

[0059] The anode of the first thyristor D1 is connected to the output terminal of the discharge circuit 10, the cathode of the first thyristor D1 is connected to the PE line, and the gate of the first thyristor D1 is connected to the output terminal of the first driving sub-circuit 41.

[0060] It is easy to understand that in this embodiment, when the first thyristor D1 receives a positive voltage at its anode, it needs to also receive a pulse voltage at its gate in order to conduct the connection loop between the discharge circuit 10 and the PE line and discharge the positive voltage to the PE line.

[0061] In a specific implementation, when the first driving sub-circuit 41 detects the positive surge voltage transmitted by the discharge circuit 10, it can transmit a first trigger signal of pulse voltage to the gate of the first thyristor D1 to turn on the first thyristor D1 and transmit the positive surge voltage of the discharge circuit 10 directly to the PE line for discharge through the first thyristor D1.

[0062] Furthermore, in this embodiment, the first driving sub-circuit 41 includes: a first resistor R1, a second resistor R2, a first capacitor C1, and a first Zener diode Z1;

[0063] The first end of the first resistor R1 is connected to the output terminal of the discharge circuit 10, the second end of the first resistor R1 is connected to the first end of the first capacitor C1, the second end of the first capacitor C1 is connected to the first end of the second resistor R2 and the cathode of the first Zener diode Z1, the second end of the second resistor R2 is connected to the control terminal of the first discharge sub-circuit 21, and the anode of the first Zener diode Z1 is connected to the PE line.

[0064] It should be noted that in this embodiment, the first Zener diode Z1 is used to limit the amplitude of the operating voltage transmitted by the current discharge circuit 10 and generate a first trigger signal. The first capacitor C1 is used as a DC blocking capacitor, the first resistor R1 is used as a current limiting resistor for the first capacitor C1 and the first Zener diode Z1, and the second resistor R2 is used as a driving resistor for the first discharge sub-circuit 21, or can be understood as a current limiting resistor.

[0065] In practical implementation, as one scenario, when a high voltage is normally applied, due to the presence of the first capacitor C1 in the voltage divider circuit 30, the high voltage is first divided before charging the first capacitor C1. The first resistor R1 can limit the current passing through the first capacitor C1. Because the current transmitted through the first capacitor C1 is too small, the voltage across the first Zener diode Z1 is too small to be reverse-broken. At this time, the first Zener diode Z1 is equivalent to an open circuit, and no first trigger signal of the pulse voltage is generated, and the first discharge sub-circuit 21 does not work. The entire surge protection circuit divides the received high voltage through a series structure, thereby achieving high withstand voltage characteristics.

[0066] In another scenario, when a positive surge voltage is transmitted by the discharge circuit 10, the surge voltage is first transmitted directly to the first Zener diode Z1 through the first capacitor C1, causing the first Zener diode Z1 to break down in reverse. When the first Zener diode Z1 breaks down in reverse, a pulse trigger signal is generated and sent to the first bleeder sub-circuit 21 through the second resistor R2, causing the first bleeder sub-circuit 21 to conduct and transmit the positive surge voltage transmitted by the discharge circuit 10 to the PE line. The entire surge protection circuit transmits the received positive surge voltage to the PE line, thereby achieving the characteristics of positive surge protection.

[0067] Furthermore, in this embodiment, the second discharge sub-circuit 22 includes: a second thyristor D2;

[0068] The cathode of the second thyristor D2 is connected to the output terminal of the discharge circuit 10, the anode of the second thyristor D2 is connected to the PE line, and the gate of the second thyristor D2 is connected to the output terminal of the second driving sub-circuit 42.

[0069] It is easy to understand that in this embodiment, when the second thyristor D2 receives a negative voltage at its cathode, it needs to receive a pulse voltage at its gate in order to conduct the connection circuit between the discharge circuit 10 and the PE line.

[0070] In a specific implementation, when the second drive sub-circuit 42 detects the negative surge voltage transmitted by the discharge circuit 10, it can transmit a second trigger signal of pulse voltage to the gate of the second thyristor D2 to turn on the second thyristor D2 and transmit the negative surge voltage of the discharge circuit 10 directly to the PE line for discharge through the second thyristor D2.

[0071] Furthermore, in this embodiment, the second driving sub-circuit 42 includes: a third resistor R3, a fourth resistor R4, a second capacitor C2, and a second Zener diode Z2;

[0072] The anode of the second Zener diode Z2 is connected to the output terminal of the discharge circuit 10. The cathode of the second Zener diode Z2 is connected to the first terminal of the third resistor R3 and the first terminal of the fourth resistor R4. The second terminal of the third resistor R3 is connected to the control terminal of the second discharge sub-circuit 22. The second terminal of the fourth resistor R4 is connected to the first terminal of the second capacitor C2. The second terminal of the second capacitor C2 is connected to the PE line.

[0073] It should be noted that in this embodiment, the second Zener diode Z2 is used to limit the amplitude of the operating voltage transmitted by the discharge circuit 10 and generate a second trigger signal. The second capacitor C2 is used as a DC blocking capacitor. The fourth resistor R4 is used as a current limiting resistor for the second capacitor C2 and the second Zener diode Z2. The third resistor R3 is used as a driving resistor for the second discharge sub-circuit 22, or can be understood as a current limiting resistor.

[0074] In practical implementation, as one scenario, when high voltage is applied normally, due to the presence of the voltage divider circuit 30 and the second capacitor C2, the high voltage first charges the second capacitor C2. Because the current transmitted through the second capacitor C2 is too small, the voltage across the second Zener diode Z2 is too small, and no second trigger signal is generated, so the second discharge sub-circuit 22 does not operate. The fourth resistor R4 limits the current passing through the second capacitor C2. The entire surge protection circuit uses a series structure to divide the received high voltage, thereby achieving high voltage withstand characteristics.

[0075] In another scenario, when a negative surge voltage is transmitted by the discharge circuit 10, the negative surge voltage is first transmitted directly to the second Zener diode Z2 through the second capacitor C2 and the fourth resistor R4, causing the second Zener diode Z2 to break down in reverse. When the second Zener diode Z2 breaks down in reverse, a pulsed second trigger signal is generated and sent to the second bleeder sub-circuit 22 through the third resistor R3, causing the second bleeder sub-circuit 22 to conduct and transmit the negative surge voltage transmitted by the discharge circuit 10 to the PE line. The entire surge protection circuit transmits the received negative surge voltage to the PE line, thereby achieving the characteristics of negative surge protection.

[0076] Based on the first and / or second embodiments of this application, in the third embodiment of this application, the content that is the same as or similar to that in embodiments one and two above can be referred to the above description, and will not be repeated hereafter. Based on this, please refer to... Figure 3 The discharge circuit 10 includes: a first discharge tube F1, a second discharge tube F2, and a third discharge tube F3;

[0077] The first end of the first discharge tube F1 is connected to the power line, the second end of the first discharge tube F1 is connected to the first end of the second discharge tube F2 and the first end of the third discharge tube F3 respectively, the second end of the second discharge tube F2 is connected to the input end of the first discharge sub-circuit 21, and the second end of the third discharge tube F3 is connected to the input end of the second discharge sub-circuit 22.

[0078] It should be noted that the discharge circuit 10 can usually be implemented with only one discharge tube. In this embodiment, a first discharge tube F1, a second discharge tube F2, and a third discharge tube F3 can be placed in the discharge circuit 10, with the second discharge tube F2 and the third discharge tube F3 connected in parallel. This parallel structure is then connected in series with the first discharge tube F1 to perform voltage division and discharge. This requires the power line to transmit a voltage that can break down at least three discharge tubes to discharge, further improving the voltage withstand characteristics of the surge protection circuit.

[0079] Furthermore, in this embodiment, the voltage divider circuit 30 includes: a third capacitor C3, a fourth capacitor C4, and a fifth capacitor C5;

[0080] The first end of the third capacitor C3 is connected to the first end of the first discharge tube F1, and the second end of the third capacitor C3 is connected to the second end of the first discharge tube F1; the first end of the fourth capacitor C4 is connected to the first end of the second discharge tube F2, and the second end of the fourth capacitor C4 is connected to the second end of the second discharge tube F2; the first end of the fifth capacitor C5 is connected to the first end of the third discharge tube F3, and the second end of the fifth capacitor C5 is connected to the second end of the third discharge tube F3.

[0081] It is easy to understand that if the discharge circuit 10 has only one discharge tube, then the corresponding voltage divider circuit 30 only needs to set one capacitor, which is connected in parallel across the corresponding discharge tube. Thus, when only a high voltage exists, the voltage divider circuit 30 can divide the voltage with the subsequent circuit (e.g., the drive circuit 40), making the entire surge protection circuit have withstand voltage characteristics. When only a surge voltage exists, the discharge tube is broken down, and the surge voltage is transmitted to the subsequent circuit for discharge, making the entire surge protection circuit have surge absorption characteristics. In this embodiment, since the discharge circuit 10 has a first discharge tube F1, a second discharge tube F2, and a third discharge tube F3, the corresponding voltage divider circuit 30 can be designed with a third capacitor C3, a fourth capacitor C4, and a fifth capacitor C5, with the third capacitor C3 connected in parallel with the first discharge tube F1, the fourth capacitor C4 connected in parallel with the second discharge tube F2, and the fifth capacitor C5 connected in parallel with the third discharge tube F3, achieving the aforementioned desired effect.

[0082] Furthermore, in this embodiment, the surge protection circuit further includes: a varistor circuit 50;

[0083] The varistor circuit 50 is connected to the power supply line and the input terminal of the discharge circuit 10, respectively.

[0084] It should be noted that, in this embodiment, a varistor circuit 50 containing one or more varistors can also be designed between the discharge circuit 10, which consists of one or more discharge tubes, and the power line. When there is no surge voltage, the varistor circuit 50 has a high resistance value, exhibiting a high-resistance state; when the surge voltage exceeds a certain threshold, the resistance value of the varistor will decrease significantly, exhibiting a low-resistance state, thereby transmitting the surge voltage to the subsequent discharge circuit 10, further improving the surge voltage protection effect.

[0085] It is worth noting that in this embodiment, the power supply line can be a three-phase power supply line, with lines A, B, C, and N (neutral). Therefore, the varistor circuit 50 can also be designed with four sets of varistors (including the fifth resistor R5 to the eighth resistor R8), which are respectively connected between each power supply line and the input terminal of the discharge circuit 10. Specifically, the fifth resistor R5 is connected between line A and the discharge circuit 10, the sixth resistor is connected between line B and the discharge circuit 10, the seventh resistor is connected between line C and the discharge circuit 10, and the eighth resistor is connected between line D and the discharge circuit 10. This effectively protects against surge voltages transmitted through lines A, B, C, and N (neutral).

[0086] Furthermore, to achieve the above objectives, this application also proposes a surge protection device, which employs all embodiments of the surge protection circuit described above. Compared with the prior art, the beneficial effects of the surge protection device provided by this application are the same as those of the surge protection circuit provided in the above embodiments, and other technical features of the surge protection device are the same as those disclosed in the above embodiments, and will not be repeated here.

[0087] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent scope of this application.

Claims

1. A surge protection circuit, characterized in that, The surge protection circuit includes: A discharge circuit, wherein the input terminal of the discharge circuit is connected to the power supply line, and the output terminal of the discharge circuit is connected to the input terminal of the discharge circuit; The output terminal of the discharge circuit is connected to the PE line; A voltage divider circuit, connected in parallel with the discharge circuit, is used to divide the voltage transmitted by the power line; A driving circuit, wherein the first end of the driving circuit is connected to the input end of the discharge circuit, the second end of the driving circuit is connected to the output end of the discharge circuit, and the third end of the driving circuit is connected to the control end of the discharge circuit. The driving circuit is configured to keep the discharge circuit disconnected during a withstand voltage test of the surge protection circuit; and / or to control the discharge circuit to conduct when a surge voltage is detected during a surge test of the surge protection circuit, so as to discharge the surge voltage.

2. The surge protection circuit as described in claim 1, characterized in that, The surge voltage includes positive surge voltage and negative surge voltage; the discharge circuit includes a first discharge sub-circuit and a second discharge sub-circuit; the driving circuit includes a first driving sub-circuit and a second driving sub-circuit. The input terminal of the first discharge sub-circuit, the input terminal of the second discharge sub-circuit, the first terminal of the first driving sub-circuit, and the first terminal of the second driving sub-circuit are connected to the output terminal of the discharge circuit; the output terminals of the first discharge sub-circuit, the second discharge sub-circuit, the second terminal of the first driving sub-circuit, and the second terminal of the second driving sub-circuit are connected to the PE line; the third terminal of the first driving sub-circuit is connected to the control terminal of the first discharge sub-circuit, and the third terminal of the second driving sub-circuit is connected to the control terminal of the second discharge sub-circuit. The first driving sub-circuit is used to control the first discharge sub-circuit to conduct when the positive surge voltage is detected, so as to discharge the positive surge voltage; The second driving sub-circuit is used to control the second discharge sub-circuit to conduct when the negative surge voltage is detected, so as to discharge the negative surge voltage.

3. The surge protection circuit as described in claim 2, characterized in that, The first discharge sub-circuit includes: a first thyristor; The anode of the first thyristor is connected to the output terminal of the discharge circuit, the cathode of the first thyristor is connected to the PE line, and the gate of the first thyristor is connected to the output terminal of the first driving sub-circuit.

4. The surge protection circuit as described in claim 2, characterized in that, The first driving sub-circuit includes: a first resistor, a second resistor, a first capacitor, and a first Zener diode; The first end of the first resistor is connected to the output terminal of the discharge circuit, the second end of the first resistor is connected to the first end of the first capacitor, the second end of the first capacitor is connected to the first end of the second resistor and the cathode of the first Zener diode, the second end of the second resistor is connected to the control terminal of the first discharge sub-circuit, and the anode of the first Zener diode is connected to the PE line.

5. The surge protection circuit as described in claim 2, characterized in that, The second discharge sub-circuit includes: a second thyristor; The cathode of the second thyristor is connected to the output terminal of the discharge circuit, the anode of the second thyristor is connected to the PE line, and the gate of the second thyristor is connected to the output terminal of the second driving sub-circuit.

6. The surge protection circuit as described in claim 2, characterized in that, The second driving sub-circuit includes: a third resistor, a fourth resistor, a second capacitor, and a second Zener diode; The anode of the second Zener diode is connected to the output terminal of the discharge circuit, the cathode of the second Zener diode is connected to the first terminal of the third resistor and the first terminal of the fourth resistor, the second terminal of the third resistor is connected to the control terminal of the second discharge sub-circuit, the second terminal of the fourth resistor is connected to the first terminal of the second capacitor, and the second terminal of the second capacitor is connected to the PE line.

7. The surge protection circuit as described in claim 2, characterized in that, The discharge circuit includes: a first discharge tube, a second discharge tube, and a third discharge tube; The first end of the first discharge tube is connected to the power line, the second end of the first discharge tube is connected to the first end of the second discharge tube and the first end of the third discharge tube, the second end of the second discharge tube is connected to the input terminal of the first discharge sub-circuit, and the second end of the third discharge tube is connected to the input terminal of the second discharge sub-circuit.

8. The surge protection circuit as described in claim 7, characterized in that, The voltage divider circuit includes: a third capacitor, a fourth capacitor, and a fifth capacitor; The first end of the third capacitor is connected to the first end of the first discharge tube, and the second end of the third capacitor is connected to the second end of the first discharge tube; the first end of the fourth capacitor is connected to the first end of the second discharge tube, and the second end of the fourth capacitor is connected to the second end of the second discharge tube; the first end of the fifth capacitor is connected to the first end of the third discharge tube, and the second end of the fifth capacitor is connected to the second end of the third discharge tube.

9. The surge protection circuit as described in any one of claims 1-8, characterized in that, The surge protection circuit also includes: a varistor circuit; The varistor circuit is connected to the power supply line and the input terminal of the discharge circuit, respectively.

10. A surge protection device, characterized in that, The surge protection device employs a surge protection circuit as described in any one of claims 1-9.

Images