GaN FET-based Ultra-thin DC-DC Step-down Converter

Abstract:
Over the past decade computers, displays, smart phones and other consumer electronics systems have become thinner and more powerful, thus increasing demand for addressing the challenges of thinner power supply solutions while extracting more power out of this limited space. This paper will look into the feasibility of adopting various non-isolated DC-DC step-down topologies for an ultra-thin 48 V to 20 V power solution. Two topologies, namely the two-phase and the three-level buck converters, are selected to design an ultra-thin 48 V-to-20 V, 250 W converter. GaN FETs are used to further reduce the converter size and improve efficiency. Both converters feature 3.5 ⁠mm component thickness. The three-level converter achieves 98% peak efficiency.