Small-signal characterization of the forward-flyback converters with active clamp

Linear equivalent models of the forward-flyback converters with active clamp are deduced, using the Vorperian model of the PWM switch. Control-to-output transfer functions are plotted against frequency, for a 36-72 V-to-5 V converter, for different load resistances, thus allowing the design of the error amplifier as to ensure circuit stability. Experimental results confirm the models' validity.