A Cascaded Buck-Flyback Structure for High Voltage Step Down Applications

This paper proposes an isolated dc-dc converter for high voltage step down applications. The presented configuration cascades conventional buck and flyback converters. Additionally, it enables choosing the switches with reduced voltage stress which consequently reduces the switching losses. The operational principles as well as comparison of the proposed converter with other conventional and possible configurations are discussed in this paper. Further, design considerations and relevant analysis are shown for a 30W system with an input voltage of 400V and regulated output voltage of 15V.