[sdiy] Circon Controller questions (Moog's circuit)

[John Luciani]

On 5/29/07, Mike Beauchamp <mikebeauchamp at gmail.com> wrote:
> The problem I'm running into with the circon controller is exactly
> that my +15 supply isn't as stable as I'd like it. It drifts slowly
> over time, more than .6V over 20 hours. I'm starting to learn the hard
> way why all the talented people on this list really are talented..
> reference voltages, etc, etc. All things I've overlooked...
>
> In the meantime, i'm going to breadboard up a power supply using
> LM317's and 337's over my 78xx and 79xx supply. If I can get a supply
> that only drifts .3% (according to the LM317 datasheet), it will be an
> exponential improvement over my 7815 drifting over 4%.

What is the drift specification for the 78xx that you are using? I
would be surprised
if the drift is 4%. The datasheet that I have states a drift of 1.8mV/DegC. To
get 600mV the Tj would be at 333 DegC and your requlator would be on fire!

The maximum line regulation error is 150mV and the maximum load regulation
error is also 150mV. All of these errors do not add up to 600mV. Have
you measured
the input and output voltage with an oscilloscope? Check to verify
that your input
voltage is not dropping below ~18V.

(* jcl *)


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