[sdiy] Source for good power supply schematics

[Roy J. Tellason]

On Tuesday 31 May 2005 04:28 pm, Roman wrote:
> > Why that much work for the reference there?  I can't see where anything
> > needs that kind of precision offhand.
>
> most of all - it was good excercise to check if I'm able to make such a
> thing.
> Modules will work with much worse voltage specs, although 5V outputs really
> need to be precise.

Ok.  I can still remember some keyboard (Memorymoog?) where the mfr wanted me 
to go out and buy a 4-1/2 digit meter so I could properly calibrate the power 
supplies.  It was "in process" for quite some time there.  :-)  I never could 
see needing that much precision in terms of anything I was working with.

> > Also,  what do you need -5 for?  I would tend to do things a little
> > differently,  making a +5v output but for things like LEDs and such,  and
>
> I drive LEDs from +15 to -15V. +/-5V are used as voltage reference.
> All pots that set any voltage are tied to those rails. VCO tuning is
> linearly dependent on 5V, as well as triangle shape. It's used whenever any
> module needs reference.

Ok,  that makes sense,  distributing this as a separate supply then.

> > maybe some logic.  I'd use a separate transformer or winding and bridge
> > and filter,  giving it a lot less on the input side of the regulator.  For
> > that matter,  24V going in to the regulators is a bunch of power to
> > dissipate there,  9V difference at what,  2A or so out?  The current
> > limiting is a nice thing to have,  too...
>
> 2A would require huge heatsinks. The ones used are quite big, but they get
> hot even at 1A. 24V is just scheatic symbol. Actualy there's something like
> 21.5V It could be more to have some headroom for mains changes.

Ok,  that makes sense.

For a while there I was really into the idea of fairly high-precision, 
custom-built power supplies for stuff,   probably more because of the idea 
being nifty than anything else,  but I find overall that most of what I'm 
dealing with any more just isn't that fussy about what you feed it,  for the 
most part.  So I end up with a lot of different power supplies,  often 
something I've just thrown together,  and it works okay for me.