Topology derivation and analysis of integrated multiple output isolated DC-DC converters with stacked configuration for low-cost applications

This paper proposes a family of integrated multiple output isolated dc-dc converters, in which switches are hybrid utilized. Compared with the conventional separate N-output isolated converter, which employs 2N primary switches, only N+1 switches are required in the primary side of proposed converters to independently regulate N secondary output voltages. Therefore, the number of switches is greatly reduced, contributing to lower cost. In this paper, detailed topology derivation is first introduced. A diversity of integrated multiple output topologies is derived with different cell connections and different cell configurations, including the asymmetrical flyback, forward as well as a half-bridge. Their performance characteristics are different and thus they are suitable for different applications. Then, in order to obtain a comprehensive insight of the proposed converters, a simplified dual-output asymmetrical flyback converter with three primary switches is taken as an example to be introduced in detail. Each output voltage in the converter is regulated with individual duty cycle, and zero-voltage-switching operation is achieved for all switches over the whole load range. Finally, experimental results based on a prototype circuit with two 12-V/3-A and 5-V/4.8-A outputs are also provided to validate converter effectiveness.