Active snubbers to eliminate diode reverse recovery and achieve zero-current turn-off in DC-DC converters

This paper presents a new active snubber topology for bridge-type converters. The snubber circuit reduces the turn-off current of the primary switches to zero prior to their turn-off, and thus significantly reduces their turnoff loss. The snubber circuit also clamps all secondary diodes at their turn-off and recovers all the diode reverse recovery energy. There is no duty cycle loss associated with the soft commutation, and the power loss of the auxiliary circuit is kept low even at extreme operating points (e.g. full duty cycle, short-circuit, or light load DCM operation)