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

Werner Almesberger werner at
Thu Sep 18 17:32:25 CEST 2008

Andy Green wrote:
> The charger was plugged into the wallsocket all the time, it's dealt
> with its inrush current hours ago.  I was sat there plugging and
> unplugging on USB socket side.

Ah, so much about my theory :-) I did a few tests with my own wall
adapter, all with a 10R load and a parallel capacitance of 0F, 100uF,
or 470uF. Here are the results:

Seems that the charger doesn't like capacitative loads that violate
the USB spec by more than an order of magnitude. But besides that,
it's performing nicely.

- Werner

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