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

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.