Self-calibrated valley switching for wide range Flyback active-clamp DC-DC converter

In this paper, we describe a valley-switching self-calibration strategy, which permits to minimize commutation loss in Flyback active-clamp converters working in valley switching mode. This strategy allows an optimal behavior of the converter commutation regardless of its parasitic drain-source capacitance behavior. This strategy can be applied on wide input voltage range Flyback active-clamp converters, in which the soft switching cannot be maintained on the whole working range. Our strategy has been tested on a 17 V to 130 V input voltage converter with a 12 V-40W output. Efficiency increases up to 2% at high input voltages compared to standard converter control strategy.