[sdiy] Re: stupid PSU!!!

[John Luciani]

On Wed, Feb 20, 2008 at 9:05 AM, Tim Daugard <daugard at sprintmail.com> wrote:
>
>  ----- Original Message -----
>  From: "mike ruberto" <somnium7 at gmail.com>
>  To: "KA4HJH" <ka4hjh at gte.net>; "Synth DIY" <synth-diy at dropmix.xs4all.nl>
>  >
>  >
>  > Anyway I'm rambling again. I really don't think the gear this PSU is
>  > for actually pulls a full load from it. I'd say they over-designed the
>  > unit and gave it extra headroom. Not to mention the fact that it is
>  > for powering a modular system which depending on initial size and
>  > options installed has a great deal of variability in power
>  > consumption.
>
>  I discovered problems with my power supply by adding modules to the system. The in rush
>  currents to all the bypass caps kept the power supply from being able to turn on properly
>  and regulate. I had to disconnect a string of modules and then when the rest of the
>  modules powered up and charged up, I connected the final string.
>
>  I solved the problem but building a bigger power supply (and making a slight modification
>  to the design of some modules).
>
>  You might want to add some large capacitors to your test load. If you but a resistor
>  inline with the cap, you should be able to control the in rush current to make up that
>  final .75 amps.

Using a programmable current-sink (op-amp, FET and shunt) let's you
simulate a lot
of these conditions. If you scale the control voltage input for 10V you could
use your synth modules to drive it ;-)

Testing for adding a load with a positive pulse, removing a load with a negative
pulse. You could probably simulate caps charging with an envelope generator.

In power supply testers the programmable current-sink is usually called an
electronic load.

(* jcl *)

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