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Old 07-12-2010, 09:30 PM   #3543 (permalink)
Mark Weisheimer
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Location: Columbus Ohio
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Originally Posted by MPaulHolmes View Post
The "typical" gate charge for 20 of those IGBTs would be about 2000nC. The revolt controller has a total typical gate charge of about 1600nC. Pretty close. I'm using a 12amp gate driver, but they also have a 14amp inverting driver that is a drop in replacement, but I think Digikey doesn't have any in stock. I would try going way smaller than 200 Ohms. Man, that's huge. I wonder why it was so big? I bet 30 Ohms would be fine.
I agree with Paul on 30 ohms as the end goal. If you used a 15v supply,
That would drive the gate "on" in 250ns at .5 Amp peak gate current.
20 gates at .5 amp would be 10 amp peak gate drive required, so
the 12 amp gate driver should do that just fine.

VA, to get to 30.5 ohms, you could leave the 200 ohm resistors
on top and tack 36 ohm resistors on the bottom.

I think you should stick with the 12v supply and just put the resistors
in first. It won't turn on quite as fast as at 15v, but it would turn on
a heck of a lot faster (and run cooler!) than it is now.

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