[sdiy] DIY Power Supply

[patchell]

Darren Reid wrote:

> "patchell" <patchell at silcom.com> sez:
>
> >     One of my latest projects...a lot simpler than most...a +/-15,+5
> > volt power supply:
> >
> > http://www.silcom.com/~patchell/synthmodules/powersupply.html
>
> Thanks Jim. I'll probably go with a pre-built model, but it's nice to see an
> option to build.
>
> How do boards that want +-15 work with +-12? If I want to mix the two types,
> what is the recommended strategy? Use +-15,+5 and add a couple of regulators
> to make +-12 as well, for a true 5 output supply? Use two power supplies?
> Drive everything from +-12 or +-15?
>

    It depends on how much work the +/-12 volts supply is going to do.  For
example, if the 12 volt supply is going to be running at 0.5 amps, and the 15
volt supply is going to be running at .5 amps (excluding the 12 volts), then you
can probably get away with just regulating the 15 volts down to 12 volts (this
would make the 15 volt regulators run at 1 amp).  If the total current through
the 15 volt regulators is going to go above 1 amp, you will want to consider
multiple supplies.  Even though the 78xx/79xx series is rated at 1.5 amps, I
don't like running much more than 1 amp through these things.  You want them to
run as cool as posible.



>
> -Darren
>
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--
 -Jim
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