On Thu, 06 Feb 2014 07:59:10 -0800, Jeff Liebermann wrote:

It's not quite a neat as it could have been.

Hi Jeff,
You picked an EXCELLENT article to read!

That article was interesting in that it explained the Chinese standard,
the EU standard, and the Apple standard of USB charging circuits:
http://blog.curioussystem.com/2010/0...vice-charging/

It was interesting that apple used voltages for their charging circuitry:
- low current: 2.8 volts across Data(+)
- high current: 2.0 volts across Data(-)

While the Chinese used shorts, and the EU used a resistor.

The five 1/8 watt resistor "hybrid" circuit in that article nicely explains how
a charger can work *either* for Apple (voltage) & EU (resistance) & Chinese
(short) charge circuits; but not all three at the same time!