Implementation and modeling of low power AC-DC converter with indirect feedback

In this paper, implementation of a low power, low voltage AC-DC converter is presented. Unlike DC-DC converters, direct AC-DC converters generally do not have a common ground. Such a structure makes implementation of feedback and control difficult. A novel indirect feedback strategy is proposed to solve this problem. The idea is to emulate the load impedance referenced to the system ground. The feedback circuit is very simple to implement and consumes very low power. Modeling and analysis is presented to elaborate the operation of the converter and the feedback circuit. Both simulation and experimental results are presented to verify the proposed feedback strategy and the converter.