Help identifying a circuit component

Discussion in 'General Electronics Chat' started by BarryT, Jul 28, 2011.

  1. BarryT

    Thread Starter New Member

    Jul 28, 2011
    Hi everyone.

    So I'm new to breaking down circuits, and have made a recent hobby of trying to figure out how some integrated circuits work. I recently busted my iPhone beyond repair, and figured 'well, why not!' so I took out the battery and noticed a circuit connected between the phone and the battery...I assume its function is battery management, and I'm having trouble identifying some of the components. Can anyone help me?? (pics link below). The items I'm having trouble with are the big one (with bq 7541 T1 K 05V0) and the three smaller black ones (2 are 8-pin with '5A' engraved on them, and 1 is a 6-pin with no markings).

    Thanks for all of your help!

    - Barry
  2. KJ6EAD

    Senior Member

    Apr 30, 2011
  3. BarryT

    Thread Starter New Member

    Jul 28, 2011
    Thanks! That definitely helps. Couldn't find a teardown of the iPhone 4 there, but I'll keep a wary eye. Also, does anyone have any recommendations for a good circuit simulation software package?
  4. SgtWookie


    Jul 17, 2007
    For the bq 7541, Have a look at this Application Note:
    It's part of an authentication and battery charging system. There have been problems with people using counterfeit batteries in products, and the batteries explode. The OEM of the product is then blamed instead of the counterfeit battery supplier, who would probably be hard to track down. So, OEM's are responding with systems to ensure that various components being used were in fact the correct OEM component that has been approved via testing for use with the main product.