Off-Grid Commercial LED Driver Optimization using GaN Transistors

Abstract

In the past few years, wide-bandgap (WBG) semiconductors based on gallium nitride (GaN) have appeared as a solution to enable the evolution of power electronics. These devices allow for higher operating frequencies without sacrificing performance, especially in hard-switching topologies. Their use in commercial products is, however, rather modest specially due to their higher cost when compared directly to its silicon (Si) counterparts. This paper presents the optimization process of a commercial low-voltage 100 W LED driver by replacing Si-based semiconductors by their GaN counterparts. The original boost-based converter was redesigned using a synchronous boost topology. We replaced both switches by GaN transistors and two different switching frequencies were tested, 350 kHz and 1 MHz. We present performance and economical analysis of both converters. The proposed driver at 350 kHz exhibited higher efficiency, with a maximum of 97.6%. At 1 MHz, we obtained little improvement in performance. The power density of both GaN converters is 12x higher than the original product. This volume reduction directly impacts system cost as less thermal material is needed to cool the circuit and provide its waterproof rating. These results prove that despite being more expensive than Si MOSFETs in a direct comparison, GaN transistors allow for a lower overall cost.