Styx
Active Member
Not really a tangentRoff said:That's what I was originally talking about, but styx went off on a tangent about gate resistor dissipation: Then he posted an equation, but as far as I can tell, he never said what it applied to. Maybe I missed that part. I thought the equation was for gate resistor dissipation, since that was the topic of his previous post.
TOPIC title: FET Gate Driver w/ BJTs
Post #1
Post #3Hi. I am trying to put together a PNP/NPN totem pole FET gate driver since I added an isolator and theh bootstrap IC doesn't work anymore (or is more than needed).
Problem seems to of arrisen here, the discussion kinda started to tangent here to switching losses but I failed to pick up on it in time (concidering I deal with 2-3W worth of gate resistance losses I didn't see a differenence)Yeah. 252nC gate charge and even if I switch at 50ns which is what 3A gets me, I still get 3W of switching losses. The other 4W comes from I^2R.
BUT since switching speeds and thus losses can only really be influenced (with some degree of predictivity) by the gate-drive it seemed logical to probe from that way
That equation, as following the discusion is todo with the switching losses of a FET (if prev posts are followed AND that post is followed).
Seems the thread got lost due to what is needed and what info is/was provided differed
To me everything to the initial title and posts after were todo with gate-drive
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