Wolfspeed Reference Design for SiC MOSFETs Achieves 80+ Titanium Rating

Wolfspeed, a Cree company that supplies of silicon carbide (SiC) power products implemented an innovative totem-pole PFC topology that leverages the company’s latest low-inductance SiC MOSFETs to exceed an 80+ Titanium rating.
According to Wolfspeed, achieving the 80+ Titanium rating is critical for lessening the overall power consumption for data centers, which is estimated to exceed 70 billion kWh annually in the US.

Wolfspeed recently developed a comprehensive reference design that demonstrates the implementation of a totem-pole PFC topology in a 2kW bridgeless power supply. At 230V redundant operation the reference design can easily exceed the 80+ Titanium standards. The design achieved actual results of 98.7% peak efficiency at half load and 98.55% efficiency at full load.

“Using Wolfspeed’s latest SiC MOSFETs in a totem-pole PFC design allows our server power systems to achieve an 80+ Titanium efficiency rating,” said Nash Chen, staff engineer for cloud computing at Chicony Power Technology. Wolfspeed’s MOSFETs also enabled higher frequency operation, reduced harmonic distortion, improved thermal management, and smaller overall system size.”

“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 commercialize, 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.”

Wolfspeed engineers Dr. Adam Barkley and Edgar Ayerbe presented the reference design in a webinar available here: http://www.globalspec.com/events/eventdetails?eventid=1506&evtsrc=ws-release.