Silicon Carbide Diodes vs Fastest Silicon Diodes

Silicon carbide has 0 reverse recovery...wow!

For switchmode power supplies, I wonder how often Silicon Carbide power diodes are used?

Doesn't silicon carbide have about four volts of forward drop? And thus negligible efficiency for power supply uses?

Synchronous inverters offer by far the best solution today.

Not that bad, 2 volts maybe.

SiC diodes are good for high-voltage, high-frequency flybacks, like PFC boost front-ends. A synchronous rectifier still has substrate diode recovery issues. I've used them in high-voltage, ns pulse steering apps and they worked very well.

John

A SiC _Shottkey_ diode has 2-4 volts of forward drop, and a 600V PIV. So for _some_ power applications they should be very good indeed.

Synchronous inverters are certainly cool, but would have many ramifications when operating on a 400V rail.

At low voltages, this is true but when you are working at high voltages the gate drive to the rectifier MOSFET becomes a problem. For a given Rds(on), the power for the gate driver grows at something like the square of the breakdown voltage.

At the moment they are still a little pricey.

RL

SiC rectifiers from Cree and Infineon have come down quite a bit in price lately. They so much reduce heat dissipation and EMI that they can pay for themselves if you have to comply with EMI regs (eliminating need for snubbers and/or reducing size of EMI filters) and/or have high enough power output to use heatsinks on the rectifier. As posted earlier, this is most true for PFC front-ends and flybacks at the high end of their power output range. Paul Mathews