A 94.1% Efficiency 20-180W GaN-Based Full-Bridge Wireless Power Receiver for High-Power Wireless Chargers

In this paper, a 6.78MHz GaN-based full-bridge active rectifier with enhanced power conversion efficiency (PCE) and voltage conversion ratio (VCR) is proposed. The design features a bootstrap driver to actively switch the high-side GaN transistors, as well as real-time calibration loops to automatically compensate the circuit delays in the low-side control paths, such that the PCE and VCR are maximized with eliminated reverse current and optimal conduction time. The proposed active rectifier is designed and simulated in a 180nm BCD process, and verified under process, voltage and temperature (PVT) variations with power capacity from 20 to 180 W. Thanks to the proposed calibration loops, up to 25% and 20% PCE and VCR improvements, respectively, are observed under various PVT and loading conditions, with a peak PCE of 94.1% at 90-W output power and a peak VCR at 98% at 20-W output power.