A robust low-RMS-current passive auxiliary circuit for ZVS operation of both legs in full bridge converters

A single passive and robust auxiliary circuit is proposed to maintain ZVS operation of both switch legs in full bridge converters. For the same auxiliary peak current value, a minimum of 20 percent less rms current is achieved compared with single-inductor auxiliary circuit in steady-state operation. This results in the same ZVS functionality with reduced conduction losses. Experimental results are in agreement with the analytical predictions.