48V-to-0.9V Voltage Regulator with GaN Devices and Integrated Magnetic Design

In recent years, the development of artificial intelligence (AI) has been increasingly rapid, posing a huge challenge to the power supply of data centers. Enhancing key performance metrics such as energy conversion efficiency, power density and control bandwidth constitutes pivotal research directions for next-generation voltage regulator modules (VRMs). GaN devices have smaller sizes and higher power densities, making it possible to create more compact power electronics systems. A GaN-based, low-voltage and high-current converter of a multi-phase interleaved current-doubler rectifier is proposed in this article, with an input voltage of 48 V, an output voltage of 0.9 V, and an output current of 120 A. By integrating magnetic design, the power density of the module is enhanced. The structure of the traditional dual-EI magnetic core is optimized to integrate transformers and output inductors. A comprehensive time-domain analysis method combining magnetic and electrical circuits is employed to conduct small-signal modeling of the converter. The final prototype has a current density of 0.2A/mm² and a peak efficiency of 89%.