Design and Characterization of a 10-MHz GaN Gate Driver Using On-Chip Feed-Forward Gaussian Switching Regulation for EMI Reduction

Abstract

Aiming at electromagnetic interference (EMI) suppression for multiple applications, this article demonstrates a 10-MHz 4- to 40-V <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V _{\text {IN}}}$ </tex-math></inline-formula> , gallium nitride (GaN)-based buck converter with multiple EMI reduction techniques. A Gaussian switching scheme is realized on chip for the first time for GaN power switches to effectively reduce the conducted EMI level in the high-frequency domain. Meanwhile, spread-spectrum frequency dithering (SSFD) technique is adopted to compress the spurious switching noise in the low-frequency domain. To handle high-speed Gaussian switching, a feed-forward segmented driving scheme is proposed to generate precise Gaussian trajectories. The Gaussian slopes are reconfigurable to enable optimization of the power efficiencies for different EMI standards. Implemented in a 180-nm BCD process, the presented GaN-based buck converter reduces the EMI noise by 35.8 and 38.7 dB at 10 and 100 MHz, respectively. From 100 to 250 MHz and from 250 to 400 MHz, the measured peak EMI noise is reduced by 20 and 30 dB, respectively. While the EMI is greatly reduced, the maximum power efficiency is 85.2%, comparable to that of other state-of-the-art GaN gate driving schemes.