There is the diagram posted above: http://i.imgur.com/wOWIbiC.png, and text at: ~toykeeper/flashlight-firmware/trunk : contents of ToyKeeper/blf-a6/blf-a6.txt at revision 249.
I guess the only description of the hardware is here: Code now public! BLF A6 FET+7135 Light. Short 18350 tubes and Unanodized Lights Available