This reference design describes a 3.5kW highvoltage to low-voltage DC-DC converter with 650V Gallium nitride (GaN) high-electron mobility transistors (HEMT). Using LMG3522R030 as primary switches makes the converter work at a high switching frequency. In this design, the converter uses a smaller size transformer. To ease the thermal performance of active clamping metal-oxide semiconductor fieldeffect transistors (MOSFETs), the converter uses twochannel active clamping circuits.
Features
- GaN based phase-shifted full-bridge (PSFB) using LMG3522 and controlled using C29 microcontroller unit (MCU)
- 200kHz switching frequency, magnetic size is 35% less than 100kHz
- 95.48% at 200kHz, 400V Vin, 13.5V Vout, about 1kW
- Dual active clamping circuits for high-frequency scenario and low synchronous rectifier (SR) MOSFET voltage stress
- Light load efficiency optimization promotes maximum 5% efficiency