GaN, SiC and Si squeeze 4.5kW out of server PSU

Navitas Semiconductor has demonstrated a 4.5kW 54V server power supply using both GaN and SiC transistors.

Claimed density is “over 130W/in³ with efficiency over 97%.

The architecture replaces the standard four diode bridge (and boost power factor correction) at the front end with an active all-transistor circuit – a multi-phase totem pole power factor corrector.

While often called ‘bridgeless’ because it has done away with the four diodes, this architecture uses a bridge of transistors: two in a half-bridge switching at 80kHz (G3F45MT06L SiC mosfets in this design) and two in another half-bridge switching at the mains line frequency (silicon mosfets here). As this is multi-phase, the SiC half-bridge and its inductor are duplicated.

After this is a 300kHz LLC converter full-bridge converter, using four NV6515 GaN hemts in the driving bridge, with secondary-side synchronous rectification handled by silicon mosfet full-wave bridge.

The company has plans for an 8-10kW version by the end of 2024. “The platform will utilize newer GaN and SiC technologies and advances in architecture,” it said.

The provision of cloud-based AI services is causing data centre power consumption to mushroom.

“The rapid development and deployment of artificial intelligence into global data centers has created a dramatic and unexpected power challenge for our entire industry,” confirmed Navitas CEO Gene Sheridan. “Our investment in GaN and SiC technologies have positioned us well. Our team has really stepped up to the challenge, with a 3x power increase in less than 18 months.”