High-Efficiency Low Voltage/High Current Power Supplies for High Performance Digital Equipment by using GaN FET Technology

Abstract

High performance processing boards using ASICs and reconfigurable FPGAs require particular power supplies with voltages below 1 V and current capabilities up to 50 A. High efficiency is mandatory for low power consumption and thermal reasons and is considered as most important goal for the DCDC converter. Off-the-shelf radiation hardened point-of-load (POL) converters are not optimized for such an application. Most devices are limited to approximately 10 A and show maximum efficiency at approximately half load current. Only a few parts offer the possibility for parallel operation to increase the current capability. Apart from the non-isolating POL converters also high-current supplies based on an isolated converter topology with good efficiency are available on the market. The efficiency of both concepts relies on high-performance/low-on-resistance FETs, and GaN technology seems to be a very attractive solution. This paper evaluates discrete designs of a non-isolating POL converter and an isolating converter based on GaN FETs regarding their suitability for low voltage/high current applications. Beside of theoretical investigations, experimental results gained from laboratory prototypes are presented.