I want to make a iphone 4 compatible 9v charger. How would I simulate an apple charger?

I went to ladyadas website, but I don't understand exactly how one would do that.  I am using a switching 5v regulator for more efficient power.  Please no circuit diagrams because I don't understand them, unless they have explantions.

Comments

[steveastrouk]

Try this link, with a video.

[furrysalamander]

But this doesn't work on the iphone 4 does it? I thought that's why we have the mintyboost 3.

[steveastrouk]

Its near enough.

[furrysalamander]

What do you mean? It says here: http://ladyada.net/make/mintyboost/icharge.html
(at least I think so) that you needed something different. If you are right, then can you explain, in simple terms, how to do it with this and a switching regulator?

[steveastrouk]

It says
"This time both voltages on the data lines are = 49.9K / (49.9K+ 75K) * 5.0V = 2.0V

We did some experimenting (see the video up top) and determined that in fact the different voltages/resistances did effect the charging rates! Using the 2.8V&2.0V setup resulted in a 1 Amp charge rate and the 2.0V&2.0V setup resulted in a 500mA charge rate. This made us very happy, because 500mA is within the capability of the MintyBoost chip.

We redesigned the PCB to allow us to have 4 resistors on the datalines and put two 75K and two 49.9K resistors in each kit. So far we have had no problems charging any of the latest Apple devices. Hooray!"

In other words messing around with the resistors affects the charge rate that the IPHONE will demand FROM the charger.

Copy the MB resistor configuration from the circuit. If you're doing electronics, reading circuits is just  something you have to learn,

Steve