A 240V to 47.5 V Fully Integrated Switched-Capacitor Converter in GaN Achieving 62.6% Efficiency at 220 mW/mm2

Abstract

This paper presents a fully integrated high-voltage switched-capacitor DC-DC converter in a GaN-on-SOI process. This technology offers high-quality GaN HEMTs with a higher breakdown voltage and lower parasitic capacitances for the same on-resistance as conventional silicon transistors. The presented series-parallel converter integrates the whole converter on a single GaN-die, including the power switches, the gate drivers, and the capacitors. Simulations show an efficiency of 62.6% at a power density of 220 mW/m$\text{m}^{2}$ while converting a 240 V input voltage into an output voltage of 47.5 V. To the author’s knowledge, the proposed converter is the first fully integrated DC-DC converter in GaN. Additionally, it has a 3x higher power density and a higher efficiency compared to previously reported monolithic high-voltage converters.