Conventional switched-mode power supplies (SMPSs) have intrinsic instantaneous power pulsation at the switching frequency thus require bulky filters. To improve the power density, this paper proposes a concept named the Mixed Analog-Digital (MAD) which can be applied as DC-DC converters. By inserting an analog voltage component between the load and source, the output voltage naturally has much smaller fluctuation thereby much smaller passive filter is required. Simulations and experiments validate that the proposed MAD concept can be applied as DC-DC converters to significantly increase the power density