Using totem-pole PFC topology, the latest low-inductance silicon carbide (SiC) MOSFETs from power products supplier Wolfspeed have exceeded an 80+ Titanium rating, which is critical for reducing the overall power consumption for data centres.

Wolfspeed recently developed a comprehensive reference design that demonstrates the implementation of a totem-pole PFC topology in a 2kW bridgeless power supply that is capable of easily exceeding the 80+ Titanium standards, with actual results of 98.7% peak efficiency at half load and 98.55% efficiency at full load—both taken at 230V redundant operation. According to the company, power supply design engineers have faced significant challenges in attaining these efficiency levels using conventional silicon switching devices due to their higher losses and the need for more complex topologies.

“Our objective was to design the simplest totem-pole PFC topology using our latest generation of 900V SiC MOSFETs, combined with low cost silicon diodes, that could achieve 80+ Titanium system efficiency levels,” said Guy Moxey, Wolfspeed’s senior director of power products. “Moreover, we set the additional requirements that the design would use only established and proven commercially-available wide bandgap devices in full production, be the most practical circuit to implement and commercialise, as well as be smaller in volume than existing silicon-based systems at the lower 80+ Platinum efficiency level. And finally, the overall system bill-of-materials (BOM) cost had to be comparable or less than silicon.”