I’m looking to build a Li-Po battery pack out of the spare cell phone batteries I have sitting around, using the TI [BQ25060 charger IC and the TI [TPS61202 boost regulator to get 5V output. The batteries I’m using are from the Galaxy Nexus, which have the [4-pin connection and share a standard size between several phones, including the Galaxy Note II (though the Note’s battery is longer, the other dimensions and the connector are the same). I basically just followed the reference schematics for the two chips, but I was hoping somebody might be willing to take a look at my schematic. I included the feedback resistors on the regulator in case I wanted to swap it out for the adjustable version, but right now, my plan is to just take 5V in (mini/micro USB) and put 5V out (USB-A female). Eventually, I’m planning on modeling a case for this, I’ve been wanting to do some 3-D modeling for awhile, but first I want to make sure I have the schematic right. I’m not sure if the battery has an internal thermistor or not, but I have a pad on the board for an external one anyway.
Potential improvements:
-Switch instead of J1 to select between 500mA and 1A charge rate (or maybe some way to auto-detect a high-current charger, but I’d need to figure out how to do that…).
-Switch to completely disconnect the battery, but 55uA Iq isn’t bad.
-ISet pot to adjust charge current.
-???
-PROFIT!!!
Comments/critiques/suggestions? Or maybe does anybody know what the other two battery pins are (NFC antenna and…)?](http://www.cpkb.org/images/0/03/Samsung_F1-A2GBU_battery_pinout.jpg)](http://www.ti.com/product/tps61202)](BQ25060EVM Evaluation board | TI.com)