Abstract: When the single-ended flyback synchronous rectifier converter works at light load, the reverse circulating current causes power loss. The zero-point detection circuit has complex structure and is difficult to control, which is usually used to monitor the reverse circulating current. This paper presents a new type of synchronous rectifier circuit with simple structure. Instead of suppressing the reverse circulating current, the rectifier MOS is turned on for the second time in the same cycle by matching the resonance parameters to fully recover the circulating energy. This paper quantitatively calculates the voltage and current expressions and resonance time of each working phase at light load, and gives the experimental waveforms. The verification results show that the structure can make non-destructive feedback of circulating energy, realize zero voltage switching (ZVS) of the switching tube, and effectively suppress low-frequency damped oscillation, which greatly improves the working efficiency of the circuit at light load.