Hi,
We are using BQ25120 part as charger IC in our wearable device. We are facing an issue during the low battery condition. The BUVLO is programmed to 2.8V. There is PCM circuit inside the battery pack. The over-discharge protect FET of the PCM activation range is 2.3V (min) to 3.0V (Max). i.e. the PCM IC turns-off the discharge FET at any voltage between 2.3V to 3.0V. So when the PCM discharge protection is activated the battery voltage drops to very low (0.2V) or no voltage. The charge IC does not see the voltage on BAT pin in such case. The issues that we are facing are as follows
1. some of the wearable devices are not charging at all if it enters the low battery.
2. On the other hand some of the devices are charging but it is taking hours (5-6) to start charging normally.
The second issue is understandable that, the battery is deep discharge and it is charged with Pre-charge current till it reaches the BUVLO. But the 1st issue is main concern here in which the devices are going dead.
Please let me know does the BQ25120 not generate the charging voltage when there is no voltage across the battery terminals?
Thanks
Rineet
