Design and Implementation of a GaN-based Synchronous Buck Converter as the Power Control Stage of an LED Driver

This work presents the analysis, design and implementation of a Gallium Nitride (GaN)-based Synchronous Buck converter and its comparison with conventional Si-based Buck and LLC resonant converters. These topologies are used as the Power Control (PC) stage of a two-stage LED driver to supply an 180W LED load. The proposed GaN-based topology uses GaN transistors monolithic solution, which integrates two eGaN transistors in half-bridge configuration and their gate drivers, as well as other additional protections and functionalities, inside the same case. The GaN-based Synchronous Buck converter is experimentally evaluated, at three different switching frequencies, and compared in terms of efficiency and thermal behavior with the Si-based topologies. The efficiency curves, from 20% to 100% of the nominal load and at different switching frequencies, are also presented. Finally, the proposed GaN-based converter is compared with other works in the literature that are focused on a GaN-based LED driver PC stage, especially those with similar power ratings.