LIGHTNING PROTECTION CIRCUIT AND METHOD FOR DIRECT-CURRENT POWER SUPPLY PORT OF COMMUNICATION DEVICE

摘要

A lightning protection circuit and method for a direct-current power supply port of a communication device. The circuit comprises: a differential-mode first-stage lightning protection circuit, which roughly limits an abruptly changing voltage of a direct-current power supply of the communication device; an uncoupling network, which forms a time-lag effect on the abruptly changing voltage and current of the direct-current power supply of the communication device, and carries out the function of uncoupling between the differential-mode first-stage lightning protection circuit and a differential-mode second-stage lightning protection circuit; the differential-mode second-stage lightning protection circuit, which accurately limits the residue of a differential-mode first-stage lightning voltage, so that the direct-current power supply of the communication device can be protected from the surge of over-voltage and over-current energy; and a common-mode lightning protection circuit, which connects the abruptly changing current of the direct-current power supply of the communication device to the protective earth (PE). By means of the lightning protection circuit and method, the efficiency of lightning protection is high, the lasting time of the residual voltage is short, and the risk that the direct-current power supply port of the communication device is damaged by lightning and the risk that direct-current power supply ports of service disks are subjected to the over-voltage and over-current surge can be decreased.