Zero-voltage-switched push-pull DC-DC converter

A novel zero-voltage-switched (ZVS) push-pull DC-DC converter with two synchronous rectifiers in the secondary circuit is presented. ZVS is realized using the magnetizing current of the transformer as a current source during the commutation. The output circuit is isolated and the output voltage is controlled by pulsewidth modulation (PWM) with a constant frequency. The synchronous rectifier is employed to get a low forward voltage drop in the rectification. The abnormal increase of the output voltage in the low output current region which is caused by the interaction between the magnetizing current of the transformer and the output inductor current is eliminated. The circuit operation is analyzed in detail and confirmed experimentally.<<ETX>>