17 Aug
2016
17 Aug
'16
11:30 a.m.
On 8/17/2016 1:19 PM, tony duell wrote:
But loading the +5V output also reduces the
ripple on the +12V
output. Loading the +5V output would, I think, vary the mark-space
ratio of the drive to the main chopper and thus the drive signal to
the 555 in the +12V regulator. Not that I can see how that would
affect things.
-tony
And yet, I've had several times where more load smoothed out a whining SMPS.
The most simple explanation is a cap problem somewhere causing an instability.
Mattis, have you checked ALL the electrolytic caps in your power supply, and beyond just
simple ESR testing? Have you properly reformed all these caps?
- John
More load _reduces_ the ripple? That's very
unusual.
Perhaps a parasitic oscillation that's defeated by more load
because now the loop gain is below 1?