[sdiy] Re: stupid PSU!!!

[Seb Francis]

Tim Daugard 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.
>   

On this subject, I've seen done before small power resistors in series 
with the power rails, bypassed after a second or so with a relay on a 
simply time-lag circuit.  Solves this kind of start-up problem for power 
supplies with current foldback limiting.

Seb