LCC Zero-Voltage-Switching Buck Converter with Synchronous Rectifier

LCC cell is proposed in this paper to achieve zero-voltage-switching (ZVS) and eliminate body-diode conduction and reverse recovery in buck converter with synchronous rectifiers (SRs). In low-voltage dc-dc converters, SRs are widely utilized to reduce rectifier conduction loss. However, during switches' transition, SRs' parasitic body diodes unavoidably carry load current, which result in extra body diode conduction loss. In addition, body diodes' reverse recovery leads to significant switching losses and electromagnetic interference (EMI) problem, which is the key obstacle for SR applications for high-voltage and high switching frequency. With the proposed LCC cell in buck converter, the SR body diode never involves during switching transition, therefore, body diode conduction loss is saved, and reverse-recovery-related switching loss and ringing are eliminated. The experimental results show that the proposed converter achieves significant improvement in efficiency running at 1MHz switching frequency compared to the conventional buck converter and QSW buck converter