Universal input voltage AC/DC adapter

Abstract

Low power AC/DC adapters require a small size to be competitive. Among their components, the bulk capacitor is one of the largest because it should keep the input voltage with low ripple. Also, the size of this capacitor is penalized due to the universal line voltage application. A smaller size AC/DC adapter is proposed in this paper. Based on a topology for power factor correction, the capacitance of the bulk capacitor is reduced to one third, allowing a reduction of the volume of the circuit. An experimental prototype confirms this result.