Voltage surge prevention power supply filter
By combining anti-electromagnetic interference circuits and anti-voltage surge circuits, the problems of structural instability and poor reliability of existing anti-voltage surge filters are solved, realizing a power filter with high reliability and high filtering performance, which can quickly protect equipment during instantaneous overvoltage.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-05
- Publication Date
- 2026-04-07
AI Technical Summary
Existing voltage surge protection filter circuits are unstable, have poor reliability, and offer only average filtering performance.
The design employs a combination of electromagnetic interference suppression circuitry and voltage surge protection circuitry, including differential-mode capacitors, common-mode capacitors, common-mode inductors, Zener diodes, optocouplers, and MOSFETs, to filter out electromagnetic interference and disconnect the circuit during transient overvoltages, thus protecting the equipment.
It achieves high reliability and high filtering performance, and can disconnect the circuit within 0.14µs to avoid equipment damage and effectively protect the powered equipment.
Smart Images
Figure CN224097603U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of circuit protection technology, specifically to a power supply filter for protection against voltage surges. Background Technology
[0002] Voltage surges refer to transient overvoltage phenomena that occur in power systems. These overvoltages, which may be caused by lightning, grid faults, or large-capacity load switching, can damage electrical equipment and even lead to safety accidents such as fires. Voltage surge protection filters can effectively eliminate voltage surges and electromagnetic interference from the power grid, enabling electrical equipment and the power system to operate safely and stably, thus protecting the electrical equipment.
[0003] Existing voltage surge protection filters mainly utilize the characteristic of TVS diodes, varistors, and gas discharge tubes that their resistance decreases when the voltage changes instantaneously, clamping the instantaneously changing voltage to a certain value while discharging the generated current to ground, thereby achieving the purpose of preventing voltage surges. However, this circuit structure is unstable, has poor reliability, and has mediocre filtering performance. Therefore, a voltage surge protection power supply filter with integration, miniaturization, high reliability, and high filtering performance is proposed. Utility Model Content
[0004] Technical problems to be solved
[0005] To address the shortcomings of existing technologies, this utility model provides a voltage surge protection power supply filter, which solves the problems of unstable circuit structure, poor reliability, and mediocre filtering performance of existing voltage surge protection filters.
[0006] Technical solution
[0007] To achieve the above objectives, this utility model is implemented through the following technical solution: a voltage surge protection power supply filter, comprising an electromagnetic interference protection circuit and a voltage surge protection circuit.
[0008] The input terminal of the electromagnetic interference suppression circuit is connected to the power input terminal, and the output terminal of the electromagnetic interference circuit is connected to the input terminal of the voltage surge protection circuit.
[0009] The power input terminal is provided with a circular connector, and the power output terminal is provided with a rectangular connector.
[0010] The electromagnetic interference suppression circuit includes differential-mode capacitor CX1, differential-mode capacitor CX2, common-mode capacitor CY1, common-mode capacitor CY2, common-mode capacitor CY3, common-mode capacitor CY4, common-mode capacitor CY5, common-mode capacitor CY6, common-mode inductor L1, and common-mode inductor L2, wherein:
[0011] The input terminal of the common-mode inductor L1 is connected to the power input terminal, and the output terminal of the common-mode inductor L1 is electrically connected to the input terminal of the common-mode inductor L2.
[0012] The differential-mode capacitor CX1 is connected in parallel to the positive and negative lines of the input terminal. The first terminals of the common-mode capacitors CY1 and CY2 are respectively connected to the positive and negative lines of the input terminal. The second terminals of the common-mode capacitors CY1 and CY2 are both connected to the chassis ground. The differential-mode capacitor CX2 is connected in parallel to both ends of the output terminal of the common-mode inductor L1. The first terminals of the common-mode capacitors CY3 and CY4 are respectively connected to both ends of the output terminal of the common-mode inductor L1. The second terminals of the common-mode capacitors CY3 and CY4 are both connected to the chassis ground. The first terminals of the common-mode capacitors CY5 and CY6 are respectively electrically connected to both ends of the output terminal of the common-mode inductor L2. The second terminals of the common-mode capacitors CY5 and CY6 are both connected to the chassis ground.
[0013] Preferably, the voltage surge protection circuit includes a Zener diode D1, a Zener diode D2, an optocoupler U1, a MOSFET Q1, a MOSFET Q2, a capacitor C1, a voltage divider resistor R2, a voltage divider resistor R4, a resistor R1, a resistor R3, and a resistor R5, wherein:
[0014] The positive line of the output terminal of the electromagnetic interference suppression circuit is set as the positive line of the output terminal of the voltage surge protection circuit. The positive line of the output terminal of the electromagnetic interference suppression circuit is connected to the cathode of the Zener diode D1. The anode of the Zener diode D1 is connected to the first input terminal of the optocoupler U1 through the resistor R1. The first input terminal of the optocoupler U1 is connected to the negative line of the output terminal of the electromagnetic interference suppression circuit.
[0015] The positive line of the output terminal of the anti-electromagnetic interference circuit is also connected to the first terminal of the voltage divider resistor R2. The second terminal of the voltage divider resistor R2 is connected to the first terminal of the resistor R3. The second terminal of the resistor R3 is connected to the first output terminal of the optocoupler U1. The second output terminal of the optocoupler U1 is connected to the negative line of the output terminal of the anti-electromagnetic interference circuit through the resistor R5.
[0016] The second end of the voltage divider resistor R2 is connected to the first end of the voltage divider resistor R4, the cathode of the Zener diode D2 is connected to the second end of the voltage divider resistor R2, and the anode of the Zener diode D2 is connected to the negative line of the output terminal of the electromagnetic interference suppression circuit.
[0017] The gate of the MOS transistor Q1 is connected to the second output terminal of the optocoupler U1. The drain of the MOS transistor Q1 is connected to the voltage divider resistor R2 through the voltage divider resistor R4. The gate of the MOS transistor Q2 is connected to the drain of the MOS transistor Q1. The sources of the MOS transistor Q1 and the MOS transistor Q2 are both connected to the negative line of the output terminal of the electromagnetic interference suppression circuit. The drain of the MOS transistor Q2 is set as the negative line of the output terminal of the voltage surge protection circuit.
[0018] Beneficial effects
[0019] This invention provides a power supply filter to prevent voltage surges. It has the following advantages:
[0020] In this invention, the anti-voltage surge power filter consists of an anti-electromagnetic interference circuit and an anti-voltage surge circuit. It can filter out electromagnetic interference generated by the power supply and protect the powered equipment when the power supply voltage fluctuates. When the power supply experiences a momentary overvoltage, it immediately disconnects the circuit with a shutdown time of about 0.14us, effectively preventing damage to the powered equipment.
[0021] In this invention, differential-mode interference and common-mode interference are filtered out by an anti-electromagnetic interference circuit.
[0022] In this invention, an anti-voltage surge circuit is used to disconnect the circuit loop when a transient overvoltage occurs, thereby preventing equipment damage. Attached Figure Description
[0023] Figure 1 This is a circuit diagram of a voltage surge protection power supply filter according to the present invention.
[0024] Figure 2 This is a schematic diagram of the structure of a voltage surge protection power supply filter according to the present invention. Detailed Implementation
[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0026] A voltage surge protection power filter includes an electromagnetic interference suppression circuit and a voltage surge protection circuit. The input terminal of the electromagnetic interference suppression circuit is connected to the power input terminal, and the output terminal of the electromagnetic interference suppression circuit is connected to the input terminal of the voltage surge protection circuit.
[0027] The electromagnetic interference suppression circuit is mainly responsible for filtering out differential-mode interference and common-mode interference. High-frequency differential-mode interference is filtered out by short-circuiting through differential-mode capacitors CX1 and CX2 due to their low impedance characteristics. When common-mode current passes through common-mode inductors L1 and L2, it generates a magnetic field in the same direction, which increases the impedance of the common-mode inductors, thereby achieving the purpose of attenuating the common-mode interference current. The low impedance characteristics of common-mode capacitors CY1, CY2, CY3, CY4, CY5, and CY6 at high frequencies will also short-circuit the common-mode current to ground, further filtering out common-mode interference.
[0028] The voltage surge protection circuit is responsible for disconnecting the circuit loop when a transient overvoltage occurs, thus preventing equipment damage. Zener diode D1 determines the upper limit of the normal operating voltage. When the voltage exceeds the regulated value, the circuit loop is disconnected. Zener diode D2 stabilizes the gate voltage of MOSFET Q2, ensuring that MOSFET Q2 is turned on normally. Optocoupler U1 emits light when current flows through the LED side. The photosensitive element on the other side generates current after receiving the light, and a voltage appears at the gate of MOSFET Q1, causing MOSFET Q1 to turn on.
[0029] When there is no transient overvoltage at the power input terminal, the current flows into the electrical equipment through the electromagnetic interference suppression circuit after being filtered. At this time, the MOSFET Q2 is in the normal open state, and the current flows smoothly into the negative line to form a current loop. When a transient overvoltage occurs at the input terminal, the Zener diode D1 is broken down, generating a reverse current. The optocoupler LED emits light, and the photosensitive element generates current after receiving the light. The gate voltage Vg of MOSFET Q1 is greater than the source voltage Vs, causing MOSFET Q1 to conduct. The gate of MOSFET Q2 is shorted to the negative line through MOSFET Q1, and the gate voltage Vg of MOSFET Q2 is equal to the source voltage Vs. MOSFET Q2 is turned off, and the current loop is broken, thus achieving the purpose of protecting the electrical equipment at the output terminal.
[0030] The anti-voltage surge power filter, composed of an anti-electromagnetic interference circuit and an anti-voltage surge circuit, can filter out electromagnetic interference generated by the power supply and protect the powered equipment when the power supply voltage fluctuates. When the power supply experiences a momentary overvoltage, it immediately disconnects the circuit with a shutdown time of approximately 0.14µs, effectively preventing damage to the powered equipment.
[0031] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A power supply filter for protection against voltage surges, characterized in that: Includes electromagnetic interference suppression circuits and voltage surge protection circuits; The input terminal of the electromagnetic interference suppression circuit is connected to the power input terminal, and the output terminal of the electromagnetic interference suppression circuit is connected to the input terminal of the voltage surge protection circuit.
2. The voltage surge protection power supply filter according to claim 1, characterized in that: The power input terminal is connected via a circular connector, and the power output terminal of the voltage surge protection circuit is connected via a rectangular connector.
3. The voltage surge protection power supply filter according to claim 2, characterized in that: The electromagnetic interference suppression circuit includes differential-mode capacitor CX1, differential-mode capacitor CX2, common-mode capacitor CY1, common-mode capacitor CY2, common-mode capacitor CY3, common-mode capacitor CY4, common-mode capacitor CY5, common-mode capacitor CY6, common-mode inductor L1, and common-mode inductor L2, wherein: The input terminal of the common-mode inductor L1 is connected to the power input terminal, and the output terminal of the common-mode inductor L1 is electrically connected to the input terminal of the common-mode inductor L2. The differential-mode capacitor CX1 is connected in parallel to the positive and negative lines of the input terminal. The first terminals of the common-mode capacitors CY1 and CY2 are respectively connected to the positive and negative lines of the input terminal. The second terminals of the common-mode capacitors CY1 and CY2 are both connected to the chassis ground. The differential-mode capacitor CX2 is connected in parallel to both ends of the output terminal of the common-mode inductor L1. The first terminals of the common-mode capacitors CY3 and CY4 are respectively connected to both ends of the output terminal of the common-mode inductor L1. The second terminals of the common-mode capacitors CY3 and CY4 are both connected to the chassis ground. The first terminals of the common-mode capacitors CY5 and CY6 are respectively electrically connected to both ends of the output terminal of the common-mode inductor L2. The second terminals of the common-mode capacitors CY5 and CY6 are both connected to the chassis ground.
4. A voltage surge protection power supply filter according to claim 3, characterized in that: The voltage surge protection circuit includes a Zener diode D1, a Zener diode D2, an optocoupler U1, a MOSFET Q1, a MOSFET Q2, a capacitor C1, a voltage divider resistor R2, a voltage divider resistor R4, a resistor R1, a resistor R3, and a resistor R5, wherein: The positive line of the output terminal of the electromagnetic interference suppression circuit is set as the positive line of the output terminal of the voltage surge protection circuit. The positive line of the output terminal of the electromagnetic interference suppression circuit is connected to the cathode of the Zener diode D1. The anode of the Zener diode D1 is connected to the first input terminal of the optocoupler U1 through the resistor R1. The first input terminal of the optocoupler U1 is connected to the negative line of the output terminal of the electromagnetic interference suppression circuit. The positive line of the output terminal of the anti-electromagnetic interference circuit is also connected to the first terminal of the voltage divider resistor R2. The second terminal of the voltage divider resistor R2 is connected to the first terminal of the resistor R3. The second terminal of the resistor R3 is connected to the first output terminal of the optocoupler U1. The second output terminal of the optocoupler U1 is connected to the negative line of the output terminal of the anti-electromagnetic interference circuit through the resistor R5. The second end of the voltage divider resistor R2 is connected to the first end of the voltage divider resistor R4, the cathode of the Zener diode D2 is connected to the second end of the voltage divider resistor R2, and the anode of the Zener diode D2 is connected to the negative line of the output terminal of the electromagnetic interference suppression circuit. The gate of the MOS transistor Q1 is connected to the second output terminal of the optocoupler U1. The drain of the MOS transistor Q1 is connected to the voltage divider resistor R2 through the voltage divider resistor R4. The gate of the MOS transistor Q2 is connected to the drain of the MOS transistor Q1. The sources of the MOS transistor Q1 and the MOS transistor Q2 are both connected to the negative line of the output terminal of the electromagnetic interference suppression circuit. The drain of the MOS transistor Q2 is set as the negative line of the output terminal of the voltage surge protection circuit.