the root cause of flip-flop charging logic if you insert wall charger

Werner Almesberger werner at
Thu Sep 18 10:32:06 CEST 2008

Andy Green wrote:
> I took pictures of it when I did the destructive test, here is repeated
> insertion of adapter.

Hmm, couldn't this be just the adapter's regulation getting started,
charging internal capacitors, and all that ? The charger seems to
have an output capacitance of something like 1000-1500uF.

It may be interesting to observer what happens if the load is applied
after the adapter has been plugged in for a while. I would expect it
to recover a bit more rapidly.

> It seems doubtful the 500mA USB limit that is meant to be active from
> cold actually is.

Could be. We also have a bunch of specification-violatingly large
capacitors right on VBUS, which certainly don't make things easier.

- Werner

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