www.webx.dk Start page
OZ2CPU Radioamateur mainpage
Homemade electronics Stuff old and new
Phone USB charge how to hack it

If your original Iphone, Ipad, HTC or other original phone charger gets lost or blow up..
you can use any other 5V source as a charger.. but you need to hack a bit
Many Phone/Pad devices measure the voltage on the Data pins and this way know what type of current level the charger can deliver,
and this way the Phone/Pad draw the correct max current.
if you leave the data pins floating or at wrong level, Apple devices refuces to charge,
while HTC devices at least charge at minumum level.
Here I explain the standards, and how you can hack your own charger to handle this.

The USB type A connector
1 +5V supply RED wire
2 D- data WHITE wire
3 D+ data GREEN wire
4 GND ground BLACK wire
-----
Iphone 1A charger :
1 = 5.08V
2 = 2.71V
3 = 2.03V
4 = 0.0V
-----

Ipad 2A charger :
1 = 5.10V
2 = 2.03V
3 = 2.72V
4 = 0.0V
-----

HTC 1A charger :
1 = 5.12V
2 = 0.0V (how ever the HTC desire charge at 300-500mA with data pins floating
3 = 0.0V (and 1A with Iphone standard voltages)
4 = 0.0V
-----

how to make the voltages for the data pins:

here are some different ways, the smartes is to use only 3 resistors to create both voltages.

Thomas Scherrer OZ2CPU 2013