48-V Voltage Regulator Module With PCB Winding Matrix Transformer for Future Data Centers

Efficient power delivery architecture is gaining more attention in the design of future generations of data centers in order to minimize the ever increasing trend of power consumption. Silicon-based power delivery architectures and designs have already reached a level of maturity in terms of efficiency and density. Recent studies indicate that 48-V voltage regulator modules (VRMs), instead of 12-V VRMs, are deemed a more efficient and cost effective architecture. In this paper a Gallium Nitride (GaN) based design of a two-stage solution is proposed. The first stage is a 48 V/12 V-250 W LLC converter with a matrix transformer design operating at 1.6 MHz with a peak efficiency of 97.3% and a power density of 870 W/in(3). The second stage is a 12/1.8 V multiphase buck converter which can be either a conventional silicon-based or a GaN-based design with a higher operating frequency and power density. Furthermore, in this proposed two-stage architecture, a novel light load improvement mechanism is proposed by dynamically changing the bus voltage from 12 to 6 V during light load by which the system can achieve a more than 8% efficiency improvement.