Design and verification of a low-power AC/DC converter

This paper deals with the development and experimental verification of a low-power AC/DC converter. The proposed solution is aimed at the sub 0.5 W output power domain, commonly encountered in applications such as always-on wireless sensing nodes. To implement the proposed converter topology, a prototype application specific integrated circuit was designed and manufactured in a high voltage 0.35 µm CMOS technology, able to handle the maximum voltage of up to 120 V. The proposed design was first analyzed by transistor-level simulations showing high power efficiency and low no-load consumption of the developed converter. To facilitate experimental verification and measurement, an printed circuit board with the necessary external components was developed, as the available technology is unable to handle the AC line voltage directly. While the developed converter operated well with decreased input AC voltage, reliability issues arose during operation with the full AC line voltage of 230 Vrms. These are linked to digital control circuitry of the implemented chip and could be addressed in the second manufacturing run in the future.