Other Parts Discussed in Thread: TPS3838
Tool/software:
I have a BQ25798 charger connected to my 4S1P LiIon pack. My system works fine on DC in or on battery in, but is giving me constant resets when both are plugged in and the charger is active. We see cleaner operation with the charger disabled. Here is a shot of my schematic:
and VSys looks like this when the charger is active:
The output caps are ceramic X5Rs and we've followed the recommendations in the design and layout guides. The input is a 18V 45W wall supply. I was seeing a significant amount of noise on VSys that went away when I changed one of the output caps to tantalum. I would expect my logic supply to reject the periodic pulse, but something is causing my processor to reset only under these conditions. The POR pin from my power monitor (TPS3838) is steady, so the resets are not being generated externally.