Patent ID: 8514542

Claim:
A relay drive circuit electrically connected to an alternating current power source for driving a relay, comprising: a zero crossing test circuit that obtains zero crossing regions of the alternating current power source and outputs a zero crossing detect signal, the zero crossing test circuit comprising an optocoupler electrically connected to the alternating current power source and an output port electrically connected to the optocoupler, wherein when the alternating current power source is in the zero crossing regions, the optocoupler is turned off, and the output port outputs a corresponding high zero crossing detect signal to the logic control circuit; a logic control circuit that receives the zero crossing detect signal and a corresponding switch control signal, the logic control circuit electrically connected to the zero crossing circuit; and a switch electrically connected the logic control circuit and the relay, wherein the switch is switched on or off in the zero crossing regions under the control of the output signal from the logic control circuit to correspondingly control the relay.