[Cialug] redundant power supplies

[L. V. Lammert]

On Sat, 17 Mar 2012, Todd Walton wrote:

> On Mar 17, 2012 4:59 AM, "Dave Hala Jr" <dave at 58ghz.net> wrote:
> >
> > Has anyone considered making a low cost redundant power supply?  Maybe
> > taking two off the shelf power supplies and making a Y connector that
> > essentially hooks the two power supplies output up in parrallel?  Is
> > this even workable?
>
> You'd have to have a transistor or two in there.
>
Won't work - to connect two DC outputs you would have to use two forward
biased diodes that would 'OR' the voltage sources, but in doing so you
would reduce the output voltage by the junction voltage of the diode.
(Without diodes, the power supplies would fight each other every time
their respective output voltage varied by even a few millivolts, burning
them out in short order.)

The only way to do it is to increase the voltage output of each source
power supply by the diode drop, which is why they are so expensive -
really small market and specialized builds.

	Lee