Mobile QR Code QR CODE : The Korean Institute of Power Electronics
Title A High Efficiency, High Power-Density GaN-based Triple-Output 48V Buck Converter Design
Authors Sangmin Lee ; Seung-Hwan Lee
DOI 10.6113/TKPE.2020.25.5.412
Page pp.412-419
ISSN 1229-2214
Keywords GaN; Buck converter; PMIC (Power Management Integrated Circuit)
Abstract In this study, a 70 W buck converter using GaN metal-oxide-semiconductor field-effect transistor (MOSFET) is developed. This converter exhibits over 97 % efficiency, high power density, and 48 V-to-12 V/1.2 V/1 V (triple output). Three gate drivers and six GaN MOSFETs are placed in a 1 cm² area to enhance power density and heat dissipation capacity. The theoretical switching and conduction losses of the GaN MOSFETs are calculated. Inductances, capacitances, and resistances for the output filters of the three buck converters are determined to achieve the desired current, voltage ripples, and efficiency. An equivalent circuit model for the thermal analysis of the proposed triple-output buck converter is presented. The junction temperatures of the GaN MOSFETs are estimated using the thermal model. Circuit operation and temperature analysis are evaluated using a circuit simulation tool and the finite element analysis results. An experimental test bed is built to evaluate the proposed design. The estimated switch and heat sink temperatures coincide well with the measured results. The designed buck converter has 130 W/in³ power density and 97.6 % efficiency.