Current adaptive resonant loop soft switching PWM converters

In light loading mode, most of the existing soft switching techniques have higher switching loss than their hard switching counterparts as the amplitude of the current in the resonant loop is greater than the load current of the switching instant point. To solve this problem, in the paper, a class of Current Adaptive Resonant Loop (CARL) soft switching PWM converters are proposed, in which, not only all power switches and diodes operate with zero current switching (ZCS), the resonant current amplitude also self adaptively tracks the value of the switching instant point of load current value, at both turn-on and turn-off durations. Compared to their hard switching counterparts, the CARL soft switching PWM converters add only three auxiliary components including one auxiliary switch device, one resonant capacitor and one resonant inductor. The advantages of the proposed CARL soft switching PWM converters are verified by the experimental results of a buck converter.