I'm just waiting on some IRFP2907s now. It worked decently with the IXYS parts, but I decided that given the amount already invested, I'd spend a bit more and get the rights parts on it before it fails again.

 

Hi... I saw a part advertised and it reminded me of this thread, so I am checking in to see how it has gone, and what resulted.

Here is the part:
http://www.newark.com/ohmite/teh100m5r00fe/resistor-thick-film-5ohm-100w-1/dp/51R4545

It is a 5-Ohm, 100-Watt resistor that could suffice for the gate-drive. I don't think anyone answered my question about the use of a regular, say 1W resistor for high-power pulse applications like this. Even using the 20 Ohm value, I recall you have many Watts of power for a very brief time. How does an underrated resistor handle this?

Cheers,
Sage

 

Resistors have pulse power rating curves based on pulse repetition (tp) and pulse duration (ti). The ratio is usually given, tp/ti, with lower ratios being worse (approaching continuous use)
There is still some maximum pulse no matter how brief it is. I think the spec is usually based on change in resistance rather than horrible failure but I've never really tried exceeding it.

Different varieties (thin film vs thick film, etc) handle it differently, some are just barely above their continuous rating while others can handle 10's of W despite having a 1/4W continuous rating.