Surge suppression circuit and electronic product using same

Abstract

The utility model discloses a surge suppression circuit and an electronic product using the same. The circuit comprises a rectification filtering unit, a surge suppression unit, a PFC boost unit, a voltage detection unit and a relay control unit. The input end of the rectifying and filtering unit is connected with a power live wire and a power zero wire, and the rectifying and filtering unit is used for converting an alternating-current power supply signal into a direct-current power supply signal; the PFC boost unit is used for adjusting the current waveform of the power supply signal; the voltage detection unit outputs a first voltage detection signal when receiving a power supply signal exceeding a preset voltage threshold, and outputs a second voltage detection signal when receiving a power supply signal not exceeding the preset voltage threshold; the relay control unit outputs a first switching signal to the surge suppression unit, and the surge suppression unit outputs a surge control signal when receiving the first switching signal to control the surge voltage to be reduced. The utility model provides a technology capable of effectively suppressing surge current and reducing power supply loss.

Description

Technical Field

[0001] This application relates to the field of power protection technology, and in particular to a surge suppression circuit and electronic products using the same. Background Technology

[0002] Surge current is a peak current or overload current that is much larger than the steady-state current when the power is turned on or when a circuit malfunctions. Large surge voltages can easily cause voltage breakdown of semiconductor devices and thyristor components, damage the metallized surface of components, or cause partial damage to data files, premature aging of parts, and a significant reduction in the lifespan of electrical appliances.

[0003] The driver power supply for lighting equipment is a key component connecting the power supply and the lighting equipment. When powered on, the transformer, capacitor, and inductor in the power supply need to be charged, which requires a high current, resulting in instantaneous surge current. Based on this, a technology that can effectively suppress surge current and reduce power loss is provided, which has practical application value and significance. Utility Model Content

[0004] In order to provide a technology that can effectively suppress surge current and reduce power loss, this application provides a surge suppression circuit and an electronic product using it.

[0005] Firstly, this application provides a surge suppression circuit that employs the following technical solution:

[0006] A surge suppression circuit includes a rectifier filter unit, a surge suppression unit, a PFC boost unit, a voltage detection unit, and a relay control unit;

[0007] The input terminal of the rectifier and filter unit is connected to the power supply live wire and the power supply neutral wire, and the output terminal of the rectifier and filter unit is connected to the input terminal of the PFC boost unit, which is used to convert the AC power supply signal into the DC power supply signal.

[0008] The output terminal of the PFC boost unit is connected to the voltage detection unit, and the PFC boost unit is used to adjust the current waveform of the power supply signal.

[0009] The output terminal of the voltage detection unit is connected to the relay control unit. When the voltage detection unit receives a power supply signal that exceeds a preset voltage threshold, it outputs a first voltage detection signal. When it receives a power supply signal that does not exceed the preset voltage threshold, it outputs a second voltage detection signal.

[0010] The relay control unit is connected to the controlled terminal of the surge suppression unit, and the control terminal of the surge suppression unit is connected to the rectifier and filter unit. When the relay control unit receives a first voltage detection signal, it outputs a first switching signal to the surge suppression unit. When the surge suppression unit receives the first switching signal, it outputs a surge control signal to control the surge voltage to decrease. When the relay control unit receives a second voltage detection signal, it outputs a second switching signal to the surge suppression unit. When the surge suppression unit receives the second switching signal, it outputs a voltage maintenance signal to maintain the current voltage value.

[0011] By adopting the above technical solution, in the lighting equipment driver power supply, to provide surge current suppression safety protection during power-on, this application uses a rectifier and filter unit to convert the AC power supply signal into a DC power supply signal to remove noise and fluctuations in the AC power. Then, a PFC boost unit adjusts the current waveform of the power supply signal to make it more synchronized with the voltage waveform, reducing harmonic pollution of the power grid. Next, a voltage detection unit monitors the output voltage of the power supply signal in real time, and when the output voltage exceeds a voltage threshold, it outputs a first voltage detection signal. At this time, the voltage in the circuit or equipment is too high, and the relay control unit receives the signal. When a first voltage detection signal with a large voltage value is detected, a first switching signal is output to the surge suppression unit. At this time, the surge suppression unit outputs a surge control signal to control the surge voltage to decrease, thereby effectively suppressing the surge voltage and protecting subsequent circuits and equipment from overvoltage surges. When the voltage is within the normal range, a voltage maintenance signal is output to ensure stable operation of the circuit system. The surge suppression voltage of this invention integrates multiple units such as rectification and filtering, PFC boost, voltage detection, relay control, and surge suppression to form a high-efficiency, intelligent, and reliable power protection system, thereby achieving the goal of providing a technology that can effectively suppress surge current and reduce power loss.

[0012] Preferably, it further includes a feedback loop unit connected between the voltage detection unit and the relay control unit; the feedback loop unit includes a feedback resistor and a feedback diode, one end of the feedback resistor is connected to the anode of the feedback diode, the other end of the feedback resistor is connected to the output terminal of the relay control unit, and the cathode of the feedback diode is connected to the voltage detection unit.

[0013] By adopting the above technical solution, the feedback loop unit forms a closed-loop control system through the introduction of a feedback resistor and a feedback diode. This design enables the circuit to sense the output of the voltage detection unit in real time and adjust the state of the relay control unit according to the output, thereby achieving rapid response and effective suppression of surge voltage.

[0014] Preferably, the rectifier and filter unit includes a common-mode inductor, a first filter capacitor, and a rectifier bridge. One end of the common-mode inductor is connected to the power supply live wire and the power supply neutral wire. The other end of the common-mode inductor is connected in sequence to the first filter capacitor and the input terminal of the rectifier bridge. The output terminal of the rectifier bridge is connected to the PFC boost unit, and the output terminal of the rectifier bridge is connected to a second filter capacitor.

[0015] By adopting the above technical solution, the common-mode inductor, as part of the electromagnetic interference (EMI) filter, can effectively suppress common-mode noise on the power line and reduce the impact of external electromagnetic interference on the circuit; the first filter capacitor works in conjunction with the common-mode inductor to form a primary filter network, which performs preliminary filtering on the AC voltage at the power input terminal; the rectifier bridge converts the filtered AC voltage into DC voltage, providing a stable DC power supply for subsequent circuits.

[0016] Preferably, the surge suppression unit includes a surge relay and a surge resistor. The input terminal of the surge relay is connected to the output terminal of the relay control unit, and the output terminal of the surge relay is connected to the surge resistor. The surge resistor includes an NTC thermistor or a cement resistor.

[0017] One end of the NTC thermistor or cement resistor is connected to the output terminal of the common mode inductor, and the other end of the NTC thermistor or cement resistor is connected to the first filter capacitor.

[0018] or,

[0019] One end of the NTC thermistor or cement resistor is connected to the output terminal of the rectifier bridge, and the NTC thermistor or cement resistor is connected to the output terminal of the relay control unit.

[0020] By adopting the above technical solution, when a surge voltage occurs at the power input terminal, the relay control unit will respond quickly and control the surge relay to close. At this time, the surge current will be limited by the surge resistor (whether it is an NTC thermistor or a cement resistor). The introduction of the surge resistor provides a safe current path for the circuit. When a surge occurs, most of the surge current will be absorbed and consumed by the surge resistor, thereby protecting the subsequent circuits (such as PFC boost units, rectifier bridges, etc.) and connected equipment from damage caused by the surge current.

[0021] Preferably, the PFC boost unit includes a boost inductor, a boost switching transistor, a boost resistor, a boost diode, and a boost capacitor. One end of the boost inductor is connected to the output terminal of the rectifier bridge, and the other end of the boost inductor is connected in series with the anode of the boost diode. The cathode of the boost diode is connected to the anode of the boost capacitor. The cathode of the boost capacitor is connected in sequence to the boost resistor and the source of the boost switching transistor. The drain of the boost switching transistor is connected to the anode of the boost diode, and the gate of the boost switching transistor is connected to an external auxiliary signal.

[0022] By adopting the above technical solutions, the PFC boost unit precisely controls the on and off of the boost switching transistor, and in conjunction with components such as the boost inductor and boost diode, it achieves the shaping of the input current, keeping it synchronized with the input voltage waveform, thereby improving the power factor of the circuit. The PFC boost unit can stably output a DC voltage higher than the input voltage through the energy storage and release process of the boost inductor and the filtering effect of the boost capacitor. In the PFC boost unit, the introduction of the boost resistor can limit the current peak to a certain extent, preventing damage to the circuit and equipment due to overcurrent.

[0023] Preferably, the voltage detection unit includes a first voltage-dividing resistor, a second voltage-dividing resistor, a third voltage-dividing resistor, a first voltage-dividing capacitor, a second voltage-dividing capacitor, a first diode, and a first Zener diode; the first voltage-dividing resistor is connected to the boost capacitor, the first voltage-dividing capacitor is connected in series with the second voltage-dividing resistor and the first voltage-dividing capacitor, the third voltage-dividing resistor is connected in parallel with the first voltage-dividing capacitor, the anode of the first diode and the anode of the first Zener diode are connected in series, the cathode of the first diode is connected to the relay control unit, and the anode of the first Zener diode is connected to the connection node of the second voltage-dividing resistor and the first voltage-dividing capacitor; one end of the second voltage-dividing capacitor is connected to the third voltage-dividing resistor, and the other end of the second voltage-dividing capacitor is connected to the cathode of the first Zener diode.

[0024] By adopting the above technical solution, the voltage detection unit can accurately detect the voltage across the boost capacitor through the filtering effect of a carefully designed voltage divider resistor network (including a first voltage divider resistor, a second voltage divider resistor, and a third voltage divider resistor) and voltage divider capacitors (a first voltage divider capacitor and a second voltage divider capacitor). When the detected voltage exceeds a preset threshold, the first Zener diode will start to conduct, clamping the voltage at its regulated value to prevent the voltage from rising further and damaging the circuit. By introducing voltage divider capacitors, the voltage detection unit can effectively filter out high-frequency noise and interference in the voltage signal, improving the stability and reliability of the detection.

[0025] Preferably, the boost switch is an NMOS transistor, and the boost capacitor is an electrolytic capacitor.

[0026] By adopting the above technical solution, using NMOS transistors as boost switching transistors, the NMOS transistors have lower on-resistance when conducting, thus enabling more efficient current transfer, thereby reducing energy loss and improving boost efficiency during the boost process; electrolytic capacitors can store more charge, thus providing sufficient energy buffering during surges and reducing the impact on the circuit.

[0027] Preferably, the relay control unit includes a first control switch, a second control switch, a control Zener diode, and a control capacitor. The base of the first control switch is connected to the anode of the control Zener diode, the emitter of the first control switch is grounded, the collector of the first control switch is connected to a resistor and to the base of the second control switch, and the cathode of the control Zener diode is connected to the cathode of the first Zener diode. The emitter of the second control switch is connected to the input terminal of the surge suppression unit, and the collector of the second control switch is connected to a power supply. One end of the control capacitor is connected to the emitter of the first control switch, and the other end of the control capacitor is connected to the emitter of the second control switch.

[0028] By adopting the above technical solution, the relay control unit achieves rapid response and precise control of the surge suppression circuit through the combination of the first and second control switches. When the voltage detection unit detects an overvoltage, the control Zener diode clamps the voltage and quickly transmits a signal to the second control switch via the first control switch, causing it to rapidly cut off or adjust the power input, thereby effectively suppressing surge current and protecting the circuit and equipment. The control Zener diode plays a role in stabilizing the voltage in the circuit, ensuring the accuracy of the control signal.

[0029] Preferably, both the first control switch and the second control switch are NPN transistors.

[0030] By adopting the above technical solution, the NPN transistor, due to its inherent fast switching characteristics, enables the relay control unit to quickly respond to the signal from the voltage detection unit. When an overvoltage is detected, the NPN transistor can quickly switch from the cutoff state to the saturation state (or vice versa), thereby rapidly cutting off or adjusting the power input and effectively suppressing surge current.

[0031] Secondly, this application provides an electronic product that uses a surge suppression circuit, employing the following technical solution: an electronic product that uses a surge suppression circuit includes a housing and a circuit board, the circuit board being installed inside the housing, and the circuit board carrying the surge suppression circuit.

[0032] In summary, this application includes at least one of the following beneficial technical effects:

[0033] 1. In the power supply for lighting equipment, to provide surge current suppression and safety protection during power-on, this application uses a rectifier and filter unit to convert the AC power supply signal into a DC power supply signal to remove noise and fluctuations in the AC power. Then, a PFC boost unit adjusts the current waveform of the power supply signal to better synchronize it with the voltage waveform, reducing harmonic pollution from the power grid. Next, a voltage detection unit monitors the output voltage of the power supply signal in real time. When the output voltage exceeds a voltage threshold, a first voltage detection signal is output. At this point, the voltage in the circuit or equipment is too high, and the relay control unit receives the signal indicating a large voltage value. When the first voltage detection signal is received, a first switching signal is output to the surge suppression unit. At this time, the surge suppression unit outputs a surge control signal to control the surge voltage to decrease, thereby effectively suppressing the surge voltage and protecting subsequent circuits and equipment from overvoltage surges. When the voltage is within the normal range, a voltage maintenance signal is output to ensure the stable operation of the circuit system. The surge suppression voltage of the present invention integrates multiple units such as rectification and filtering, PFC boost, voltage detection, relay control and surge suppression to form an efficient, intelligent and reliable power protection system, thereby achieving the purpose of providing a technology that can effectively suppress surge current and reduce power loss.

[0034] 2. When a surge voltage occurs at the power input terminal, the relay control unit will respond quickly and control the surge relay to close. At this time, the surge current will be limited by the surge resistor (whether it is an NTC thermistor or a cement resistor). The introduction of the surge resistor provides a safe current path for the circuit. When a surge occurs, most of the surge current will be absorbed and consumed by the surge resistor, thereby protecting the subsequent circuits (such as PFC boost unit, rectifier bridge, etc.) and connected equipment from damage by the surge current.

[0035] 3. Due to its inherent fast switching characteristics, the NPN transistor enables the relay control unit to respond quickly to signals from the voltage detection unit. When an overvoltage is detected, the NPN transistor can quickly switch from the cutoff state to the saturation state (or vice versa), thereby rapidly cutting off or adjusting the power input and effectively suppressing surge current. Attached Figure Description

[0036] Figure 1 This is a circuit diagram of a surge suppression circuit according to Embodiment 1 of this application.

[0037] Figure 2 This is a circuit diagram of a second embodiment of a surge suppression circuit according to Embodiment 1 of this application.

[0038] Figure 3 This is a circuit diagram of a third embodiment of a surge suppression circuit according to Embodiment 1 of this application.

[0039] Figure 4 This is a circuit diagram of a fourth embodiment of a surge suppression circuit according to Embodiment 1 of this application.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1. Rectifier and filter unit; 2. Surge suppression unit; 3. PFC boost unit; 4. Voltage detection unit; 5. Relay control unit; 6. Feedback loop unit. Detailed Implementation

[0042] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0043] Example 1

[0044] This application discloses a surge suppression circuit. (Refer to...) Figure 1 ,by Figure 1 Taking the circuit diagram shown as an example, the surge suppression circuit includes a rectifier filter unit 1, a surge suppression unit 2, a PFC boost unit 3, a voltage detection unit 4, and a relay control unit 5. The input terminal of the rectifier filter unit 1 is connected to the live wire (L line) and the neutral wire (N line) of the power supply. The output terminal of the rectifier filter unit 1 is connected to the input terminal of the PFC boost unit 3, which is used to convert the AC power supply signal into a DC power supply signal. The output terminal of the PFC boost unit 3 is connected to the voltage detection unit 4, which is used to adjust the current waveform of the power supply signal. The output terminal of the voltage detection unit 4 is connected to the relay control unit 5. When the voltage detection unit 4 receives a power supply signal that exceeds a preset voltage threshold, it outputs a first voltage detection signal. When it receives a power supply signal that does not exceed the preset voltage threshold, it outputs a second voltage detection signal.

[0045] The relay control unit 5 is connected to the controlled terminal of the surge suppression unit 2, and the control terminal of the surge suppression unit 2 is connected to the rectifier and filter unit 1. When the relay control unit 5 receives the first voltage detection signal, it outputs a first switching signal to the surge suppression unit 2. When the surge suppression unit 2 receives the first switching signal, it outputs a surge control signal to control the surge voltage to decrease. When the relay control unit 5 receives the second voltage detection signal, it outputs a second switching signal to the surge suppression unit 2. When the surge suppression unit 2 receives the second switching signal, it outputs a voltage maintenance signal to maintain the current voltage value.

[0046] The surge suppression circuit also includes a feedback loop unit 6, which is connected between the voltage detection unit 4 and the relay control unit 5. The feedback loop unit 6 includes a feedback resistor R3 and a feedback diode D2. One end of the feedback resistor R3 is connected to the anode of the feedback diode D2, and the other end of the feedback resistor R3 is connected to the output terminal of the relay control unit 5. The cathode of the feedback diode D2 is connected to the voltage detection unit 4.

[0047] The rectifier and filter unit 1 includes a common-mode inductor LF1, a first filter capacitor CX1, and a rectifier bridge BD1. One end of the common-mode inductor LF1 is connected to the power supply live wire and the power supply neutral wire. The other end of the common-mode inductor LF1 is connected to the first filter capacitor CX1 and the input terminal of the rectifier bridge BD1 in sequence. The output terminal of the rectifier bridge BD1 is connected to the PFC boost unit 3. The output terminal of the rectifier bridge BD1 is connected to the second filter capacitor CBB1.

[0048] The surge suppression unit 2 includes a surge relay K1 and a surge resistor NTC1. The input terminal of the surge relay K1 is connected to the output terminal of the relay control unit 5, and the output terminal of the surge relay K1 is connected to the surge resistor NTC1. The surge resistor NTC1 includes an NTC thermistor or a cement resistor. One end of the NTC thermistor or cement resistor is connected to the output terminal of the common mode inductor LF1, and the other end of the NTC thermistor or cement resistor is connected to the first filter capacitor CX1.

[0049] The PFC boost unit 3 includes a boost inductor L1, a boost switch Q1, a boost resistor R1, a boost diode D1, and a boost capacitor EC1. The boost switch Q1 is an NMOS transistor, and the boost capacitor is an electrolytic capacitor. One end of the boost inductor L1 is connected to the output terminal of the rectifier bridge BD1, and the other end of the boost inductor L1 is connected in series with the anode of the boost diode D1. The cathode of the boost diode D1 is connected to the anode of the boost capacitor EC1. The cathode of the boost capacitor EC1 is connected in sequence to the boost resistor R1 and the source of the boost switch Q1. The drain of the boost switch Q1 is connected to the anode of the boost diode D1. The base of the boost switch Q1 is connected to an external auxiliary signal, which is a sine wave signal.

[0050] The voltage detection unit 4 includes a first voltage divider resistor R5, a second voltage divider resistor R8, a third voltage divider resistor R12, a first voltage divider capacitor C1, a second voltage divider capacitor C3, a first diode D4, and a first Zener diode Q4; the first control switch Q3 and the second control switch Q2 are both NPN transistors; the first voltage divider resistor R5 is connected to the boost capacitor EC1, the first voltage divider capacitor C1 is connected in series with the second voltage divider resistor R8 and the first voltage divider capacitor C1, the third voltage divider resistor R12 is connected in parallel with the first voltage divider capacitor C1, the anode of the first diode D4 and the anode of the first Zener diode Q4 are connected in series, the cathode of the first diode D4 is connected to the relay control unit 5, and the anode of the first Zener diode Q4 is connected to the connection node of the second voltage divider resistor R8 and the first voltage divider capacitor C1; one end of the second voltage divider capacitor C3 is connected to the third voltage divider resistor R12, and the other end of the second voltage divider capacitor C3 is connected to the cathode of the first Zener diode Q4.

[0051] The relay control unit 5 includes a first control switch Q3, a second control switch Q2, a control Zener diode D5, and a control capacitor C2. The base of the first control switch Q3 is connected to the anode of the control Zener diode D5, the emitter of the first control switch Q3 is grounded, the collector of the first control switch Q3 is connected to a resistor and to the base of the second control switch Q2, and the cathode of the control Zener diode D5 is connected to the cathode of the first Zener diode Q4. The emitter of the second control switch Q2 is connected to the input terminal of the surge suppression unit 2, and the collector of the second control switch Q2 is connected to the power supply. One end of the control capacitor C2 is connected to the emitter of the first control switch Q3, and the other end of the control capacitor C2 is connected to the emitter of the second control switch Q2.

[0052] Furthermore, there are multiple possible connection schemes between the rectifier filter unit 1 and the surge suppression unit 2. Figure 1 This is one of the solutions. Below are circuit diagrams for the connection methods of the other three solutions, for reference. Figure 2-4 The different connection methods of rectifier filter unit 1 and surge suppression unit 2 are listed respectively.

[0053] Preferably, in another embodiment, such as Figure 2 As shown, with Figure 2 Taking the circuit diagram shown as an example, the connection method between the first filter capacitor CX1 in the surge suppression unit 2 and the common-mode inductor LF1 and rectifier bridge BD1 in the rectifier filter unit 1 can be adopted as follows: Figure 2 The connection method shown.

[0054] Preferably, in another embodiment, such as Figure 3 and Figure 4 As shown, with Figure 3 and Figure 4 Taking the circuit diagram shown as an example, the surge suppression unit 2 is connected to the output terminal of the rectifier bridge BD1, that is, one end of the NTC thermistor or cement resistor is connected to the output terminal of the rectifier bridge BD1, and the NTC thermistor or cement resistor is connected to the output terminal of the relay control unit 5.

[0055] The implementation principle of a surge suppression circuit in this application embodiment is as follows: The instantaneous current on the input L / N power line is charged by the common-mode inductor LF1 and the rectifier filter circuit through the thermistor or cement resistor of the surge suppression unit 2 to charge the capacitive and inductive components in the circuit. Under the condition that the capacitor is fully charged, the larger the NTC in the circuit, the smaller the surge current, and the better the stability of the semiconductors and products in the circuit. However, in actual work, due to the product's startup time and chip operating timing, it is generally not possible to wait for the large capacitor to be fully charged. Therefore, a voltage detection unit 4 is introduced. Upon power-up, due to the first voltage regulator diode... When the voltage across the reference pin of transistor Q4, the third voltage divider resistor R12, and the first voltage divider capacitor C1 is below 2.5V, the cathode of the first Zener diode Q4 outputs a high voltage (less than or equal to VCC) under auxiliary power supply conditions. This controls the Zener diode D5 to conduct, causing the VBE voltage of the first control switch Q3 to exceed 0.7V, thus turning on Q3. Resistor R6 is short-circuited to ground, resulting in the emitter voltage of the second control switch Q2 being less than or equal to 3V. Consequently, the surge relay K1 does not operate. The emitter voltage of Q2 is low, and the feedback resistor R3 and feedback diode D2 cannot forward-sink voltage to the reference pin of the first Zener diode Q4, resulting in the reference pin voltage of the first Zener diode Q4 being lower than 2.5V. The thermistor or cement resistor remains connected in series in the circuit, keeping the input surge voltage relatively small. When the voltage across the voltage divider capacitor is greater than 2.5V after being divided and filtered by resistor R2, the first voltage divider resistor R5, the second voltage divider resistor R8, the third voltage divider resistor R12, and the first voltage divider capacitor C1, the single operational amplifier characteristic of the first Zener diode Q4 is utilized. The cathode of the first Zener diode Q4 outputs a low-level voltage of less than 2.5V, which controls the Zener diode D5 to be cut off. The first control switch Q3 is not turned on, while the second control switch Q2 is turned on. The surge relay K1 is closed, and the thermistor or cement resistor is short-circuited by the surge relay K1. At the same time, after the second control switch Q2 is turned on, under the action of the feedback resistor R3 and the feedback diode D2 in the feedback loop, the reference voltage of the first Zener diode Q4 is continuously greater than 2.5V, and the surge relay K1 continues to work, thereby achieving the purpose of reducing losses and surge current.

[0056] Example 2

[0057] This application also discloses an electronic product that uses a surge suppression circuit.

[0058] This application discloses an electronic product that uses a surge suppression circuit. The electronic product includes a housing and a circuit board. The circuit board is installed inside the housing and carries a surge suppression circuit.

[0059] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A surge suppression circuit, characterized in that, It includes a rectifier filter unit (1), a surge suppression unit (2), a PFC boost unit (3), a voltage detection unit (4), and a relay control unit (5); The input terminal of the rectifier filter unit (1) is connected to the power supply live wire and the power supply neutral wire, and the output terminal of the rectifier filter unit (1) is connected to the input terminal of the PFC boost unit (3) to convert the AC power supply signal into a DC power supply signal. The output terminal of the PFC boost unit (3) is connected to the voltage detection unit (4), and the PFC boost unit (3) is used to adjust the current waveform of the power supply signal; The output terminal of the voltage detection unit (4) is connected to the relay control unit (5). The voltage detection unit (4) outputs a first voltage detection signal when it receives a power supply signal that exceeds a preset voltage threshold, and outputs a second voltage detection signal when it receives a power supply signal that does not exceed the preset voltage threshold. The relay control unit (5) is connected to the controlled terminal of the surge suppression unit (2), and the control terminal of the surge suppression unit (2) is connected to the rectifier filter unit (1). When the relay control unit (5) receives the first voltage detection signal, it outputs a first switching signal to the surge suppression unit (2). When the surge suppression unit (2) receives the first switching signal, it outputs a surge control signal to control the surge voltage to decrease. When the relay control unit (5) receives the second voltage detection signal, it outputs a second switching signal to the surge suppression unit (2). When the surge suppression unit (2) receives the second switching signal, it outputs a voltage maintenance signal to maintain the current voltage value. The voltage detection unit (4) includes a first voltage divider resistor, a second voltage divider resistor, a third voltage divider resistor, a first voltage divider capacitor, a second voltage divider capacitor, a first diode, and a first Zener diode; the first voltage divider resistor is connected to a boost capacitor, the first voltage divider capacitor is connected in series with the second voltage divider resistor and the first voltage divider capacitor, the third voltage divider resistor is connected in parallel with the first voltage divider capacitor, the anode of the first diode and the anode of the first Zener diode are connected in series, the cathode of the first diode is connected to the relay control unit (5), and the anode of the first Zener diode is connected to the connection node of the second voltage divider resistor and the first voltage divider capacitor; one end of the second voltage divider capacitor is connected to the third voltage divider resistor, and the other end of the second voltage divider capacitor is connected to the cathode of the first Zener diode; It also includes a feedback loop unit (6), which is connected between the voltage detection unit (4) and the relay control unit (5); the feedback loop unit (6) includes a feedback resistor and a feedback diode, one end of the feedback resistor is connected to the anode of the feedback diode, the other end of the feedback resistor is connected to the output terminal of the relay control unit (5), and the cathode of the feedback diode is connected to the voltage detection unit (4). The relay control unit (5) includes a first control switch, a second control switch, a control Zener diode, and a control capacitor. The base of the first control switch is connected to the anode of the control Zener diode, the emitter of the first control switch is grounded, the collector of the first control switch is connected to a resistor and to the base of the second control switch, and the cathode of the control Zener diode is connected to the cathode of the first Zener diode. The emitter of the second control switch is connected to the input terminal of the surge suppression unit (2), and the collector of the second control switch is connected to a power supply. One end of the control capacitor is connected to the emitter of the first control switch, and the other end of the control capacitor is connected to the emitter of the second control switch. Both the first control switch and the second control switch are NPN transistors.

2. The surge suppression circuit according to claim 1, characterized in that, The rectifier and filter unit (1) includes a common-mode inductor, a first filter capacitor, and a rectifier bridge. One end of the common-mode inductor is connected to the power supply live wire and the power supply neutral wire. The other end of the common-mode inductor is connected to the first filter capacitor and the input terminal of the rectifier bridge in sequence. The output terminal of the rectifier bridge is connected to the PFC boost unit (3). The output terminal of the rectifier bridge is connected to a second filter capacitor.

3. The surge suppression circuit according to claim 2, characterized in that, The surge suppression unit (2) includes a surge relay and a surge resistor. The input terminal of the surge relay is connected to the output terminal of the relay control unit (5), and the output terminal of the surge relay is connected to the surge resistor. The surge resistor includes an NTC thermistor or a cement resistor. One end of the NTC thermistor or cement resistor is connected to the output terminal of the common mode inductor, and the other end of the NTC thermistor or cement resistor is connected to the first filter capacitor. or, One end of the NTC thermistor or cement resistor is connected to the output terminal of the rectifier bridge, and the NTC thermistor or cement resistor is connected to the output terminal of the relay control unit (5).

4. A surge suppression circuit according to claim 2, characterized in that, The PFC boost unit (3) includes a boost inductor, a boost switch, a boost resistor, a boost diode, and a boost capacitor. One end of the boost inductor is connected to the output terminal of the rectifier bridge, and the other end of the boost inductor is connected in series with the anode of the boost diode. The cathode of the boost diode is connected to the anode of the boost capacitor. The cathode of the boost capacitor is connected in sequence to the boost resistor and the source of the boost switch. The drain of the boost switch is connected to the anode of the boost diode. The gate of the boost switch is connected to an external auxiliary signal.

5. A surge suppression circuit according to claim 4, characterized in that, The boost switch is an NMOS transistor, and the boost capacitor is an electrolytic capacitor.

6. An electronic product employing a surge suppression circuit according to any one of claims 1-5, characterized in that, It includes a housing and a circuit board, the circuit board being mounted inside the housing and carrying the surge suppression circuit.

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