Anti-surge protection circuit

Abstract

The invention relates to an anti-surge protection circuit connected between a power supply and electronic equipment. The anti-surge protection circuit comprises a first-stage protection circuit, a second-stage protection circuit and an inductance element, wherein the first-stage protection circuit and the second-stage protection circuit are connected in parallel and instantaneously discharge the surge currents of a signal input end; the inductance element is connected in series between the first-stage protection circuit and the second-stage protection circuit and inhibits the surge currents of the first-stage protection circuit from flowing into the second-stage protection circuit; and the second-stage protection circuit comprises a second voltage dependent resistor and a capacitor. The anti-surge protection circuit not only enables most surges to be discharged on the first-stage protection circuit, but also effectively solves the problems of current following and current leakage of the first-stage protection circuit through the effective matching action of the first-stage protection circuit, the second-stage protection circuit and the inductance element; in addition, spike voltages and clamp voltages which are generated from the first-stage protection circuit are greatly reduced, therefore the surge protection efficiency of the integral protection circuit is enhanced, the service life of the protection circuit is prolonged, and the safety of the protection circuit is greatly enhanced.

Description

technical field [0001] The invention relates to the field of anti-surge technology, in particular to an anti-surge protection circuit. Background technique [0002] Existing anti-surge protection circuits are often connected to power ports of electronic devices to prevent damage to sensitive electronic devices by instantaneous surge voltages at the power ports. like figure 1 As shown, when the voltage of the power supply port is in normal condition, the gas discharge tube GDT and the varistor MOV1 are in a high-resistance state, and the inductors L1 and L2 are similar to very low resistance resistors. The anti-surge protection circuit will not affect the electronic Normal operation of the equipment; when there is a surge voltage at the power port due to lightning strikes or instantaneous plugging and unplugging of the switch, the surge voltage first charges the capacitor C, and the inductance L generates a reverse electromotive force with the voltage change at both ends, an...

AI Technical Summary

Problems solved by technology

[0003] However, the clamping voltage of the varistor MOV1 in the circuit and the peak voltage generated by the gas discharge tube GDT are too high, which will cause damage to the fragile electronic components in the circuit

Moreover, the series circuit of inductors L1, L2 and capacitor C in the circuit will oscillate, which will have an unstable influence on the following circuits

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