A Hybrid Driving Scheme for Full-Bridge Synchronous Rectified LLC Resonant DC/DC Converter

A novel hybrid driving scheme for full-bridge synchronous rectified LLC resonant DC/DC converter is proposed in this paper. With the full-bridge type rectifier, the voltage stress of the synchronous rectifiers (SRs) is well clamped to the output voltage. Also the transformer structure is very simple due to only one secondary winding is needed. Therefore, the converter can utilize SRs with lower breakdown voltage rating to improve the efficiency as well as to reduce the transformer core loss and conduction loss. A new hybrid driving scheme combining voltage driving method and current driving method for SRs are proposed to drive the four SRs with simple structure. With the proposed SR driving scheme, the LLC resonant converter achieves good performance and high efficiency. The experimental results from a 200kHz, 120W (16V/7.5A) prototype verifies the theoretical analysis.