A Novel Design of High Step-down Non-Isolated DC/DC Converter

This paper presents a high-gain DC/DC buck-derived converter topology, utilizing two active power semiconductors. Unlike many other multi-stage high step-down DC/DC converters, this topology uses relatively a smaller number of passive LC components. Due to the duty cycle limitation and deadtime constraints, high gain factor (more than 10) is very challenging to be achieved in a single-stage regular buck DC/DC converter. In the proposed converter, the net voltage gain is a nonlinear function of duty-cycles of the power devices, which produces step-down gain of 10 to 15 without pushing the duty cycles towards their extremums. For the concept verification of the converter operation, a voltage conversion from 48V to 1V DC at 200W using the proposed converter topology is simulated in MATLAB environment. An output voltage ripple of ±1% and a conversion efficiency of 94% are achieved according to the obtained results. Dynamic performance of the converter is also studied by implementing closed loop control using various control strategies. The converter is designed considering all the relevant conditions required for a typical Point of Load (PoL) application.