Marc wrote:

> In a project of mine I want to switch 12V loads on and off.  The loads
> are various and typically consume 1A @ 12V (3A max), and contain
> electromechanical components such as motors, steppers, etc.
>
> In the prototype I use a Relais to connect/disconnect those to the 12V
> supply. For space and endurance reasons I'd prefer to have them
> electronically connected.
>
> Note that the loads are external, and they are connected to my device
> by an operator.  I plan to activate the 12V supply only when everything
> is connected, but you never know if somebody is pulling the plug
> during operation.   My device must withstand all occasions without
> failure.
>
> Do you think that power MOSFETs are the right way to go? Or will they
> soon become a victim of ESD, inductive kickback, and similar issues? What
> circuit arrangement do you recommend?

I've used a 10 amp or so P Channel Power FET as a High side switch,
driven by an N- Channel FET and a pull up resistor.
The P channel Source to +12, a 1K or so resistor form +12 to the gate,
the drain to the load.  Connect the drain of the N-channel to the gate of
the P-Channel, Source to ground, drive the gate.

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  |  __O    Thomas C. Sefranek   tcs@cmcorp.com
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