A Novel High Step-Down DC-DC Converter Based on TSC Buck Converter

A novel high step-down DC-DC converter is proposed in this paper. Its working principle and design method are illustrated in detail. The proposed converter consists of two parts including LLC converter and tapped-series capacitor (TSC) buck converter, forming a stacked and quasi-parallel structure. The LLC converter operates in an unregulated mode, delivering most of the input power to the load. The TSC buck converter operates in a regulated mode to maintain a constant output voltage. Planar matrix transformer is adopted in the unregulated LLC converter (DCX). All the switches are operated under soft switching conditions with optimal design, which further increases the power density and efficiency. The prototype, with 375 V input and 5 V/10 A output is built. The simulation and experimental results are consistent with theoretical analysis, which verifies the feasibility of the proposed converter.