Zero voltage switching power converters

摘要

A circuit for utilizing the magnetizing current in the transformer of a power converter to reset the transformer's core and to provide a zero voltage switching condition on the converter's primary switch is disclosed. The transformer includes a primary winding and a secondary winding, the secondary winding being coupled to an output load and a primary switch connected in series between the primary winding and a voltage source. The closing of the primary switch causes energy to be stored in the transformer and the opening of the primary switch causes the energy to be released from the transformer. A transformer flux reversal circuit is used to reverse the direction of the magnetic flux built up in the transformer when the primary switch is opened. A secondary switch is coupled in series with the secondary winding of the transformer and is operated to prevent any loading effects of the load from disrupting the creation of the zero voltage switching condition.