Other Parts Discussed in Thread: BQSTUDIO, BQ25895, EV2400, PMP4451, PMP11536
My application requires 3.1A (or close to it) at 5V and I'm hoping to draw it from the boost converter built in to the BQ25895. I have a BQ25895EVM, EV2400, and bqStudio. Here are the test conditions:
* Power supplied from battery only (fully-charged 18650 Li-Ion pack, 4.1V, 4 x 3,000 mAh balanced cells in parallel, 12,000 mAh total, each cell capable of high discharge rate ~ 20A)
* Battery pack protected with BQ29700 EVM. Output of BQ29700 EVM attached to BAT and GND of BQ25895EVM.
* BQ25895EVM jumpers all in factory default settings
* OTG mode enabled
* Boost voltage set to 4.998V
* All other registers in system startup defaults
I'm measuring the draw from the battery, and up to 1.5A everything works fine. At 1.6A and above, the BQ25895 EVM throws a boost fault and stops providing boost power. I have also seen the BQ25895 EVM enter a hiccup state.
If I attach external power using the USB input, the system continues to work fine past 1.6A. The failure only occurs when power is drawn exclusively from the battery.
So my question is, can I draw 3.1A from PMID in OTG / boost mode when batteries are the exclusive source of power? Do you have any ideas why the BQ25895 EVM doesn't seem to be able to provide that much without faulting? What other information might you need from me (registers, logs, etc.) to help make suggestions?
Thanks very much - I really appreciate your help!