This paper presents a high-power density 500kHz gallium nitride (GaN) based 200V buck-boost PWM converter. State-of-the-art low-voltage buck-boost converters employ Si-MOSFETs and therefore are limited by the device figure of merit (FOM) of silicon technology. GaN power devices with much better FOM provide lower conduction loss and switching loss at the same time even at elevated switching frequencies. The benefits of replacing Si-MOSFETs with GaN FETs are not well-defined. The focus of this paper is to quantify the impact in a buck-boost converter which is becoming increasingly important due to the proliferation of battery-powered electronics systems. Experimental results are presented in order to show the superior performance of the GaN-based converter in comparison to the state-of-the-art Si-MOSFETs converters. The experimental results show very high efficiency (up to 99.3%) in a wide range of operations and high-power density.
