How to drive MOSFETs fast

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This might be of use to others that are living in a cave electronically
speaking, like me.

Recently spent a day trying to drive MOSFETs fast using bipolars. I'm after
a switch time of < 1uSec, and nothing I tried came close. In the end I
googled driving mosfets, and up came lots of ads for MOSFET drivers. Turns
out these things are a dream solution to the problem. They'll switch a half
bridge in a few tens of nanoseconds, with configurable deadtime. They'll
handle a bridge with both devices N-channel, and best of all, they'll work
with a rail that can be up to hundreds of volts. AND they can be obtained in
DIP-8 package. AND, they aren't expensive.



Re: How to drive MOSFETs fast



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Just make sure you supply them with a low impedance source - good thick
power supply rail and good ground. Decoupling write next to the Vcc and GND
pins is always advisable - as recommended in the datasheet.

If you want to kick 4A into the gate of a MOSFET, that current has to come
from somewhere. If the supply to the chip cannot provide it, your fantastic
MOSFET driver will not be as good as advertised..

-
Bill Naylor
www.electronworks.co.uk
Electronic Kits for Education and Fun



Re: How to drive MOSFETs fast




Bruce Varley wrote:

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Depending on the application they're very likely emitter followers. These can
charge Cg very quickly.

Graham


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