A single input dual output converter with low cross regulation

Abstract

Nowadays, many applications require multiple power supply voltages for various sub-functional modules, especially in consumer electronics. The single input dual-output (SIDO) converter contains less components is good scheme than adopt two single input single output (SISO) converters. However because of the outputs are coupled with same magnetic component, it would suffer cross regulation problem. This paper presents a cross regulation solution for the SIDO AC/DC converter. By the rectifier diode of upper output winding is replaced with a synchronous rectifier switch and the stacked design of two output windings. The energy of the two output windings can circulate with each other. Therefore cross regulation can be effectively improved. The operation principles, design procedure of the proposed solution are present and descripted. A prototype circuit was built to validate the feasibility of the proposed solution. The main advantages of proposed converter are implemented with low cost analog IC, the synchronous rectification has lower conduction loss, the stacked windings design have less total turns number and lower voltage stress for synchronous rectifier switch.