Iphone charging...

Hello, my name is Martin
I have a very big problem with a 5v usb boost circuit. When i connect the circuit to the power, the led lights up, but no power... to iphones... everything else works, just not iphones. i already tried shorting the data ports with the 5v pin, AND THAT USED TO WORK, but not now!!!??

PLEASE HELP

I have now tried with adding some resistors to data+ and minus, still nothing

HELP!!!

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0 e14 Contributor over 10 years ago

http://www.voltaicsystems.com/blog/choosing-usb-pin-voltages-for-iphones-and-ipads/
Seems that different iphone versions behave differently. Quite picky about voltages at datalines. 2.75V D- and 2.00V D+ seems to work best.
PS3 controller is even worse: It needs to negotiate with a host to initiate charging. I used a ATTiny45 and V-USB, but it works.
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0 e14 Contributor over 10 years ago in reply to e14 Contributor

i have tried 2,75, 2,8, everything now... NOTHING it still says accesory not supported! i've even tried with 2.0 v on both data + and data -, and nothing. PLEASE HELP! i initially thought this was THE ANSWER but nope, not really, still doesnt work. help... please, im losing hope here.
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0 gadget.iom over 10 years ago in reply to e14 Contributor

Check your voltages:

A general observation with the Apple products is that they will attempt to draw the maximum current if and only if the voltage level on Pin 1 with respect to the current draw remains constant between 5 and 5.25 volts. Often, if a charger is unable to supply the proper amount of current the voltage output will drop. For instance, a 5.25V 1A power supply may only output to 4.5V when under a 2A load. For Apple products, when a device is presented with any one of the voltage configurations (500mA, 1A, or 2A) and then presented with a range of Pin 1 voltage levels from 4.5V to 5.25V, the actual current drawn by the device varies. In our tests, we found that when the voltage sent to the iPad 2 was 4.5V, the iPad 2 drew only about 1A, but steadily scaled up the current to 2A as the voltage was incrementally increased to 5V. Additionally, we noted Apple devices will not accept charge from power supplies with Pin 1 voltages of less than 4.5V or greater than 5.5V.

Extract from Peri's link: http://www.voltaicsystems.com/blog/choosing-usb-pin-voltages-for-iphones-and-ipads/
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0 mcb1 over 10 years ago in reply to gadget.iom

Pin 1 voltage levels from 4.5V to 5.25V, the actual current drawn by the device varies

Silicon chip ran an article (August 2013 ??) on the voltages required on both USB pins to make the various Apple products draw their full capability.
It seems that unless the Apple device sees that voltage, it won't use the full current draw of the supplying device (ie 5v x amp supply)

It was quite interesting because the ratios of resistors required was not simple.

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0 mcb1 over 10 years ago in reply to gadget.iom

Pin 1 voltage levels from 4.5V to 5.25V, the actual current drawn by the device varies

Silicon chip ran an article (August 2013 ??) on the voltages required on both USB pins to make the various Apple products draw their full capability.
It seems that unless the Apple device sees that voltage, it won't use the full current draw of the supplying device (ie 5v x amp supply)

It was quite interesting because the ratios of resistors required was not simple.

Mark
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