Comments on: iPhone Charger

By: T. Tran

T. Tran — Sat, 31 Jul 2010 01:27:41 +0000

In fact I read that in the real Apple USB charger the resistors are 75k/49.9k and 43k/49.9k, interestingly pin 2 thus see 2.7v not just 2.5v.

In any case I have converted many USB charger using your resistor value and they worked very well. Many thanks.

By: T. Tran

T. Tran — Fri, 30 Jul 2010 12:21:39 +0000

Can the 2x 50k resistor be replaced with 2x 100k? All they do is dividing the 5v into 2.5v to satisfy the requirement, I don’t think it needs to provide any current.
The reason for asking is that then all I have to do is to but plenty of 100k resistor since the circuit uses 3.
Alternatively the 150k can be reduced to 75k and thenthe bottom 100k be changed to a 50k? I am simply trying to simplify it further with either 3x100k or 3x 50k and either a 150k or a 75k resistor respectively.

By: darko

darko — Mon, 28 Jun 2010 10:41:27 +0000

this didnt work for me. did everything as on picture but when i plug iphone cable into a female usb, iphone does not start to charge

By: Dacia Merring

Dacia Merring — Tue, 08 Jun 2010 17:04:24 +0000

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By: kk

kk — Wed, 30 Dec 2009 07:18:14 +0000

this makes your iphone 3gs unstable, and will crash until you pull the cable out. I just tried this and it is a bit flaky.

By: bob

bob — Tue, 29 Dec 2009 17:14:53 +0000

except the resistance is not added in the power path. pin 2 and 3 are the data lines.

By: Rico

Rico — Fri, 23 Oct 2009 11:49:26 +0000

hi,

I just pulled my charger cable by mistake (the end that connects to the iPhone ver.2g) and need to reinsert them, but there 4 openings and the charger has 2 wires.

Any advice on how to?

By: dejswa

dejswa — Sat, 10 Oct 2009 18:20:24 +0000

I would be surprise if this circuit would charge anything!

You are describing a pseudo 2 volt power supply with an output impedance of 150 kohms. Thus, this charger could supply around 1 microamp of power with about a 10% voltage drop on the ‘power supply’.

This about 2 microwatts of power!!

By: eBatteryChargers.com

eBatteryChargers.com — Wed, 09 Sep 2009 21:16:10 +0000

You are right, I have modified the picture.

By: barak

barak — Wed, 09 Sep 2009 15:39:41 +0000

Hi,
in the first picture you connected pin4 to gnd while in the second picture pin4 in usb is marked as 5v,

what is the correct one?