Analysis of Non-isolated Soft Switching DC-DC Buck Converter

A novel zero-voltage switching (ZVS) step-down converter with a tapped inductor is proposed in this paper. Tapped inductor provides better power density as compared to isolation buck converter. With a simple structure, the tapped-inductor buck converter shows promise for extending the duty cycle. This converter is cost effective and attractive for high performance. Furthermore, with the replacement of transformer by tapped inductor, its efficiency may be maximized for low power application and power quality is improved as low harmonics at input as well as output. The peak current of the main switch is reduced by tapped inductor operation, thus the conduction loss and switching loss levels of the main switch are lowered. Consequently, this tapped inductor scheme alleviates the severe power stress and enhances device utilization. This soft-switching buck converter is suitable for extremely low step-down ratio applications. The principle of the proposed scheme, analysis of the operation, and design guidelines are included. Finally, the experimental result of the 10W prototype DC/DC converter is given for hardware verification.