A 265 V Mains Interface Integrated in 0.35 mC M O S

Abstract

A fully integrated 265 V input AC–DC interfac e is demonstrated in a 0.35- m CMOS technology, requiring only one optional external low-voltage SMD capacitor for improved performance. The converter can directly inter face the universal line voltage (50–60 Hz) and converts this into a regulated DC voltage of 3.3 V. High input voltage operation is made possible through separation of the mains input from t he active circuits by custom layout high-voltage capable passive components in be- tween. A compact model of an ideal AC–DC capacitive step-down converter is presented and the proposed c ircuit architecture is designed to mimic ideal operation and approach the maximum at- tainable power throughput accor dingly. The prototype converter demonstrates a maximum output powe r of 12.7 Wo nad i ea r e a of 6 mm and enables integrated circuits to be supplied straight from the ubiquitous mains voltage , hereby circumventing the need for traditional converters usin g expensive and bulky high-voltage discrete components.