Quote:
Originally Posted by rsisk
Question: why was a 100K ohm resistor used on the gate?
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100K is extremely conservative. I generally put as large an R in series as I can get away with for a given switching speed, others will put as small an R in as necessary to damp gate ringing. For reference, I'm putting ~5 ohms in gate series for a 400kHz switcher for a hobby project.
So, the PM Ether quoted explains why a resistor is necessary. The reason it is so much larger than you might expect is just to over-protect the gate. It costs the same and lets you rest a bit easier.