A Comparative Evaluation of an Un-regulated and a Regulated Input Isolated DC-DC Converter using WBG devices

Power supply systems for low voltage, high current applications often have a front-end ac-dc converter followed by an un-regulated input or a regulated input isolated dc-dc converter. This paper illustrates the design, analysis and comparison of an un-regulated and a regulated input isolated dc-dc converter utilizing wide band-gap (WBG) devices. For the comparison and evaluation, SiC devices are used at the primary side and GaN devices at the secondary side of the converter. Due to the high voltage requirement at the input side of the dc-dc converter, SiC MOSFETs are selected instead of GaN devices. The analysis reveals that for higher switch efficiency and smaller chip area, it is better to have a regulated input, isolated dc-dc converter. This paper also demonstrates that, by the usage of a regulated input isolated dc-dc converter half the switching power device chip area can be saved compared to an unregulated input dc-dc converter, thereby the cost of the converter can be reduced drastically.