Self clamping zero voltage switching DC transformers

摘要

A DC transformer circuit which accomplishes zero voltage switching for all switches for all transitions is revealed. The DC transformer is also self clamping so that clamping can be accomplished without compromising tight magnetic coupling and without using valuable window area for a clamp winding. The wave forms generated at the secondary windings are suitable for synchronous rectifier self drive. The combination of lossless switching, tight coupling, synchronous rectifier self drive, and maximum window utilization results in a DC transformer circuit which is suitable for high frequency, high efficiency operation. The DC transformer circuit uses two independent transformers with primary windings activated in anti-synchronization. The primary windings of the transformers are driven by a half bridge, a full bridge, or a push pull switching network.