Multiple-output DC-DC converters with the shared leg structure: Basic topologies, ZVS analysis and experimental results

Abstract

A family of multiple-output converters with the shared leg structure is analyzed, summarized and generalized in this paper. Since the full bridge (FB) and half bridge (HB) converters include the same bridge-leg structure, one of these legs can be shared by the appropriate design. With the shared leg, many benefits can be obtained: the structure is compact; all the outputs are still tightly regulated; moreover, the zerovoltage-switching (ZVS) range in the shared legs is extended naturally. The basic shared leg topologies, including the FB-AHB (asymmetrical half bridge), FB-RHB (resonant half bridge) and FB-FB topologies are discussed in this paper. Three types of ZVS characteristics in the shared leg are extracted from these basic shared leg topologies. The experiment results are also given to verify the validity of the analysis.Index Terms--dc-dc power conversion, shared leg, PWM, PFM, zero-voltage-switching (ZVS)