Ken,
Ok, writing those down and researching later. Thanks!
John, thanks for the link, I'll check it out too.
Nuge
Warrend Greenway <dub@linuxmail.org> wrote:
Driving isn't a problem, assuming you aren't going for a 100kH here. At work
we drive 4 amp coolers with an H bridge made of a SMT P and an N channel half
bridge. We drive this directly with a MSP430, and have proven long-term reliability.
A lot of people would rpobably be quite happy with a "speed knob" on a simple 555
timer circuit, which can drive reasonably large FETs.What I would like for the
OSS is a dual-mode speed controller: You would have a knob on the board, and a
serial interface for controll via a cooler controller...Like a joystick interface.
Warren.
> At least, and a bridge is what I would go with. You would probably have to
> parallel several in each leg of the bridge to avoid dissipation problems.
>
> There are a number of ICs on the market to do the drive functions. I think
> ONSEMI has one. You would have to do the power stages. Layout of the power
> stages are the bear.
>
> I would suggest IXYS as a starting vendor for the FETs. I think their site is
> "WWW.IXYS.com" they are not the only vendor.
>
> Ken Martindale
>
> >
> > One other note on the price issue you brought up, though. A
> > reversible speed controller requires a FET H bridge, which means
> > twice the FETs. A forward only could be made for $5.00. A good
> > reversible would easily hit $10.00.
> >
>
--
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