Reverse engineering the Apple iPhone power supply

Mike O'Dell mo at
Wed Dec 26 09:48:07 CST 2012

5 watts at 5 volts implies 1 amp

a number of iThings now require a charger capable
of 2 amps @ 5VDC. i *believe* there is an Apple
"ice cube" charger that produces the required 10 watts.

what is amusing/annoying/maddening is that we 3 different
Apple chargers and 4 different kinds of Apple iThings, and
no charger would charge more than 2 of them. The discover
is that the *cable* mattered. With genuine Apple cables, the
(known) high-output charger will charge everything just fine
but with a 3rd-party 30-pin-to-USB cable, the high-output
supply refuses to charge the iPad (which is known to need
the 10 watt charger to actually charge as opposed to operate
while maintaining the current charge level). It took an afternoon
of careful experimentation to sort out the confusion.
(The USB/30pin cable that does "marching ants" down the cable with
embedded blue LEDs & fiber strands as the iThing is charging
is cool enough to have warranted the work. And it works, btw.)

 From a historical perspective, Apple drove development and
adoption of USB devices when it bailed on ADB keyboards
and mice, moving to USB for desktop devices. (how many of
you still use a PS/2 keyboard? it's hard to find an X86 motherboard
that has removed the PS/2 connectors even if they have great
support for USB kbds & mice) As a result of Apple's push into
"high output" USB sources, the USB power control protocol has
been expanded and standardized. Things don't happen instantly
even in consumer electronics, but USB 3.0 requires the high-power
capabilities from the get-go, and USB 2.0 sources on motherboards
are rapidly moving to support it. This makes a lot more devices
able to be "bus powered" and will (eventually) render a lot of
wall-warts unnecessary.

So once again, even the PC world benefits from Apple pushing ahead. (big 

As they say, "You can't make an omelet without breaking some eggs,"
and Apple is not afraid to keep making omelets even if some are
disconcertingly weird now and again.

C'est la vie

Merry and Happy to one and all, as appropriate to your calendrical 


On 12/25/12 11:26 PM, Andre Kesteloot wrote:
> 73
> André N4ICK
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