Apple keeps lots of design details secret. You can see some of the previous charging mysteries revealed here. The current Apple devices use the new Lightning Connector. The details behind this connector was unknown until recently.  Here is some info on the chip that is inside. Ramtin Amin has recently taken reverse engineering to the next level by first making a breakout board. It was made to inspect the main WLCSP chip which has 36 BGAs spaced at 0.35mm. The board needed to be a 4 layer PCB with laser drilled blind vias! There is a lot more to be explored but we are a lot closer to knowing the secrets now.
Via: Hack a Day