Abstract: The soft switched PWM ZVS full bridge DC to DC converter and push-pull type LLC series resonant converter are compared for use in low output voltage power supply applications. It is shown that push-pull type LLC series resonant converter takes on the desirable characteristics of the conventional push-pull converter and LLC series resonant converter. Push-pull type has less conduction loss than that of full bridge converter. Analyses and simulation shows that for low power applications required turn ratio of the transformer is less so efficiency is more and switching stress is less for push-pull LLC series resonant converter than PWM ZVS full bridge DC to DC converter. The 48V DC is efficiently reduced to 12V DC using both DC to DC converters using 20KHZ switching frequency and all parameters are compared.