Modular GaN reference design scales to 108 kW configurations

Efficient Power Conversion Corporation has released a 5 kW AC-to-48 V DC reference design using enhancement-mode gallium nitride power devices. The system achieves 96.5% efficiency and 116 W/in³ power density while meeting Open Rack V3 size specifications.

The design consists of two stages. The EPC91107KIT front-end stage converts 240 VAC to 400 VDC using a 4-level flying capacitor totem-pole power factor correction topology with EPC2304 GaN FETs rated at 200 V and 5 mΩ. This configuration reduces PFC inductor size by a factor of nine and EMI filter size by 40% compared to two-level designs. The stage operates at 98.5% efficiency at full load with 25 A input current and 140 kHz switching frequency.

The EPC91110KIT isolation stage converts the 400 V bus to 50 VDC through four modular 1.375 kW LLC converters in an input-series output-parallel configuration. Each module uses EPC2305 GaN FETs rated at 150 V and 3 mΩ, achieving 98.2% peak efficiency. The four modules provide 5.5 kW total output.

The reference design addresses power delivery requirements for AI workloads and data centers where high-frequency operation and low conduction losses reduce filter size and thermal management requirements. The modular architecture scales to 33 kW, 48 kW, and 108 kW rack configurations.

Design files and documentation for both kits are available through EPC’s website.