PoE port overvoltage comprehensive protection circuit and method for realizing same

The invention discloses a Power over Ethernet (PoE) port overvoltage comprehensive protection circuit and a method for realizing the circuit. The PoE port overvoltage comprehensive protection circuit comprises two-stage protection circuits, wherein the first-stage protection circuit adopts a triode gas discharge tube and is used for discharging lightning stroke current to the ground; the second-stage protection circuit adopts a clamp type overvoltage protection device and is used for carrying out first-stage residual voltage and electrostatic protection; a resistor and common-mode inductor combination circuit is adopted between the first-stage protection circuit and the second-stage protection circuit and is used for coordinating performance characteristics among the two-stage protection circuits and the device so as to achieve the effect of decoupling between the first-stage protection circuit and the second-stage protection circuit. Owing to the PoE port overvoltage comprehensive protection circuit, the balance of protection circuits can be enhanced and the amplitude and energy for conversion from common-mode overvoltage to differential-mode overvoltage can be reduced so as to improve the protection effect.