At 10:49 AM 7/9/2003 -0400, Spehro Pefhany wrote:

>At 08:59 AM 7/9/2003 -0500, you wrote:
>>Driving a large mosfet directly from any micro is a bad idea.
>
>I think that's an over-generalization. Driving a power logic-level
>MOSFET from a micro output pin is okay, preferably with a series gate
>resistor to limit the current, PROVIDED the switching frequency is low.

And provided you and your mosfet can deal with the power dissipation while it's in the linear region.


>At 500kHz you sure *NEED* a nice driver like that.

It's a tradeoff. I need 18W output and don't have much room for the inductor.

>Note that Microchip also
>has such drivers in their lineup- they can supply AMPS of current to the
>gate. Eg. the TC4429 (6A drive).

Layout and decoupling into these drivers is very important as well.
Those current pulses have to come from, and go to somewhere, and you'd probably prefer to choose where. :)

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