iPhones have a own connector on the phone-side, yes. But those cables often end in a normal USB-plug. You CAN (and normally do) charge iPhones on USB... the added circuit is in the adapter you connect to the iPhone itself.



The thing i was looking for, was the "MightyMintyBoost"... It is a "proper" DC/DC converter using the LT1305.

The magic to make it load a iPhone / iPad is described here:

http://timothyb.net/DIY_iPad_2_USB_Charger.html or www.instructables.com/id/Make-a-USB-iPhone-iPod-Charger-On-The-Cheep and many other places.



Depends on what you call complicated... the LT1305 needs 7 additional parts to the chip itself. So yes: It is more complicated. But i could post a 12V to 400V (DC) converter based on OpAmps and FETs and such stuff. But no dedicated IC there... Only off-the-shelf and standard-components... But it has all the bells and whistles attached like automatic frequency-tune, self-regulating duty-cycle, Charge-and-hold-logic... THAT is complicated i assure you! ;)



Price? Sure it is more expensive to go with a real Boost converter instead of a bit more intelligent resistor like L7805CV...

Farnell lists an L7805CV with $0.68 and a LT1305 with $3.65

So yes: about 5 times more expensive... And additional costs for the Resistors, Coils and diode... But thats where you have to decide:

A: Shall it be a simple project, having more then 6V at hand is OK and efficiency is not important --> Go with the 7805. It will work.

B: If you want to dig deeper in electronics and want to have the options of going from 1.5V to 12V as input and coming out with a iPhone-capable highly efficient charger which accepts almost every voltage source (Solar, peltier, semi-dead batteries, lead and alkaline, handcrank ...) you can go with one opf the MANY DC/DC-converters out there. If you take a monolythic one (Switch inside) you dont have to do much math for the switching-part...

But be sure: a bit math is included to set the proper output-voltage.



As i said:

The instructable here WORKS. It has some limitations you have to be avare of so you arent disapointed if you want to charge a iPhone on 2 alkaline-batteries with the 7805: It is a double-No-Go with the 7805-solution posted here.

But if you have 6V and more, add a pair of resistors to it, you are ready to roll with the thing even for iPones! :)