Asymmetrical drive circuit for full-wave bridge

摘要

A full-wave bridge switching power supply includes first and third "serially" connected switches and second and fourth serially connected switches. An output transformer has one end of its primary winding connected to the juncture of the first and third switches and the other end connected to the juncture of the second and fourth switches. The switches are provided with zero-voltage switching signals by way of transformers. In order to avoid the switch-slowing effects of transformer inductance, a subsidiary power supply is associated with each switch. The subsidiary power supplies of the first and third switches are coupled to the control electrodes (gates) of the first and third switches at turn-on, and the subsidiary power supplies of the second and fourth switches are applied during turn-off.