iPhone 3Gs does not work with my minty boost 2.0

[Fr33k]

And another quick question from two confusing schems b/w
http://www.ladyada.net/make/mintyboost/faq.html
and
http://www.adafruit.com/blog/2010/02/09 ... phone-3gs/

The first one says
USB1 (V-in):5v,
USB2 (D-): ~2.0v
USB3 (D+): ~2.7v
USB4 (GND)

and the second one changes the connection b/w USB2 & USB3

Can someone tell me which one is correct?

thanks

According to my tests, the blog should be correct. So the FAQ : http://www.ladyada.net/make/mintyboost/faq.html
is incorrect. You can test it easily by measuring the voltags of an Apple USB Charger.

I did some measurements with my own charger an came to the same resluts as the a.m. blog.

Voltages on powered charger:
V14=5.1 V (pin 1-4)
V24=2.7 V (D-)
V14=2.0 V (D+)

Resistances on non-powered charger:
R14= 0 Ohm
R24=R21= 23.2 k
R34=R31= 30.0 k

Based on the scheme in the blog and the FAQ you can calculate the R5, R6, R7 and R9 values:
(1/R5)+(1/R7)=(/23.2k)
and
R7/(R7+R5)= 2.7/5.1
This gives: R5= 44.2 k and R7= 48.8 k.
Similarly R6= 77.7 k and R9= 48.9 k.

So basically the same values as reported in the Blog.
A good confirmation and my charger is still OK, while in the blog a destructive test was done!

So the scheme in the FAQ of the MB website is incorrect.
Pin 2 and 3 are mixed up.

I build one according to the correct scheme with all 4 resistors and the thing works perfectly.
Works with Itouch and Garmin Edge 705.

Frederick P

[xlines]

Anyone here tried replacing the electrolitic capacitors with a higher rating? I Replaced the battery side capacitor to 470uf and another 470uf for the 5v side. I also found that 1000uf on the 5v side works better.
I know it will be bigger but it works in my 3gs.
I never got anywhere with the voltage division side though.
My iPhone just needs a little more boost from the capacitor to be able to charge.
http://flic.kr/p/8rRzhX