Silicon Carbide Diodes vs Fastest Silicon Diodes

[D from BC]

Silicon carbide has 0 reverse recovery...wow!

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

 

[Don Lancaster]

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.

--
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Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
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[John Larkin]

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

Not that bad, 2 volts maybe.

Synchronous inverters offer by far the best solution today.

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

 

[Tim Wescott]

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.

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.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

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"Applied Control Theory for Embedded Systems" came out in April.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[Ken Smith]

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.

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.

 

[legg]

Silicon carbide has 0 reverse recovery...wow!

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

At the moment they are still a little pricey.

RL

 

[Paul Mathews]

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