A synchronous rectified flyback AC-DC converter using capacitor-coupled isolated communication

Abstract

This paper presents a synchronous rectified (SR) flyback AC-DC converter based on capacitor-coupled isolated communication. Instead of bulky opto-couples as isolators, the proposed converter integrates an isolated capacitor to accomplish communication between the primary and secondary side, in an attempt to reduce system size. In secondary side, an adaptive zero-current detector (ZCD) for driving synchronous rectifier is adopted to increase efficiency. The converter is designed and fabricated in a 0.18-µm BCD process. The experimental results demonstrate that our scheme shrinks the isolator size by a factor of 52.24 times and simultaneously improves the system efficiency by 3% with ZCD.