My application is a battery charger that provides several 5V ports for external connections (sort of like a re-chargeable USB power distribution board). It contains two TI chips: BQ24266 Li-Ion Charger and TPS61032 5V Boost Converter. I've found that using these two chips together just isn't working and I'm wondering why. I currently have the output of the Li-Ion charger (gets up to 4V or so when charging the battery) to the input of the 5V boost converter and for some reason, every time I begin charging, it fries the 5V boost converter. Both chips are set up as normal, using the "typical application" circuits described in the datasheets and I've double-checked PCB layout, shorts, etc. and have concluded it has something to do with the way these are connected together. When I de-solder the boost converter (using a heat gun), the Li-Ion charger works as normal and charges the battery just fine at 1.5A and I can see it using my multimeter. However, when the boost converter is in it's place and the unit is not charging, it works fine too and outputs a good, clean 5V (battery connected of course). But as soon as I try to charge the battery (put in 5V at VIN of charger) the boost converter is rendered useless, permanently. Any help is much appreciated. Thanks! ~Jason
A couple notes about the schematic: VIN is basically a 5V USB power connection with a 3A fuse and ferrite, the battery is 10Ah Li-Ion, and VBATT is the battery connection with an in-line switch, and 100uF. I tried attaching a second picture to show this but wasn't able to for some reason...
