Effect of Coupling on Discontinuous Conduction Mode of Coupled Inductor SIDO Boost Converter

A single-input dual-output (SIDO) converter with a coupled inductor is a widely used converter to generate two outputs from a single input. The analysis presented in the literature is for continuous conduction mode, where the converters are operating in heavily loaded conditions. While operating, the load may reduce, leading to the discontinuous conduction mode (DCM) of the converter. A coupled inductor SIDO (CI-SIDO) boost converter is analyzed in this article. As this converter combines two boost converters with a common input and a coupled inductor, the DCM operation of one boost affects the other. Due to coupling, it is found that the body diode of the mosfet turns on in the DCM operation of the CI-SIDO boost converter. This article finds the conditions to turn on body diode and its effect on the average values of the inductor current, diode current, and input current. The article also analyzes the CI-SIDO boost when the body diode is not turned on. This article finds the effect of change in input voltage, load current, and duty ratios on the DCM operation of the CI-SIDO boost. Simulations verify all the obtained conditions in MATLAB/Simulink and experiments using a laboratory prototype. This article is accompanied by a supplementary online document with additional illustrative diagrams and experimental results.