Is GaN the Enabler of High Power Density Converters? An Overview of the Technology, Devices, Circuits, and Applications

The growing demand for electric vehicles, renewable energy, and portable electronics has increased the prevalence of power conversion systems, as exemplified by the architecture of electric automobiles. While silicon devices and circuits are widespread due to their cost-effectiveness, and structures such as the superjunction MOSFET have helped maintain its competitiveness in power applications, the technology remains fundamentally limited by its physical properties. Research and development in semiconductor technologies aim to reduce system size and improve power efficiency in these applications. The Gallium Nitride wide-bandgap semiconductor, with its critical electric field of 3.75 MV/cm, which is 12.5 times higher than that of silicon, has emerged as a strong candidate to meet these demands. This paper reviews key milestones of GaN technology; covering devices, compact modeling, packaging, circuit design, and converter implementation; highlighting its suitability for power electronics. For example, a monolithically integrated GaN Buck converter employing soft-switching achieves a peak efficiency of 95.4% when stepping down from 250V to 150V. In the case of a synchronous boost converter using discrete GaN transistors, delivered power can be increased by 37.5% while maintaining an efficiency of 99%. Additionally, GaN has enabled new converter topologies, achieving a power density of 123.3kW/L and an efficiency of 90.9%.