Patent ID: 8089784

Claim:
A synchronous rectifier comprising: a square wave generator including a first switch and a second switch, generating a square wave corresponding to an input voltage by alternately turning on/off the first switch and the second switch; a resonator including a first coil of a primary coil of a transformer, generating a resonance waveform corresponding to the square wave; and an output unit including a second coil and a third coil of a secondary coil of the transformer, outputting a first voltage corresponding to currents that are generated in the second coil and the third coil corresponding to the resonance waveform, wherein the output unit includes: a third switch coupled between the second coil and a ground; a fourth switch coupled between the third coil and the ground; and a switching controller turning on/off the third switch and the fourth switch, wherein the switching controller maintains the third switch in an On state for a first period from a first time in which a second voltage at the third switch is reduced from a first level to a second level that is less than the first level, and maintains the fourth switch in the On state for a second period from a second time in which a third voltage at the fourth switch is reduced from the first level to the second level.