Tool/software:
Introduction
Hi,
this is my first project with more complex ICs, so apologies if I'm missing something obvious.
My goal is a PCB with battery charging, power management and battery monitoring. For the battery charging part, I'm using the BQ24250RGER.
I created the Layout based on the application example in the datasheet.
I had the PCBs assembled and tested by JLCPCB, so I'm pretty sure the PCBs themselves are according to my schematic.
Problem Description
Now, for the problem:
- with a Lab power supply at 7V to VIN and GND, the IC gets warm and draws around 0.3A. LDO is at 2.1V in this case. No voltage at SW and SYS.
- When attaching only a Battery (18650 Li-Ion cell) to BAT and GND (GND via a 10 mΩ current sensing resistor for a battery gauge on the PCB), everything is fine, no current towards the BQ24250, no heating
- with the Lab power supply AND the battery, the current through the battery immediately jumps to about 2.6A. At this point, I immediately disconnect.
Troubleshooting
To spot the issue, I disconnected the traces to everything not immediately necessary for the BQ24250, to get as close to the datasheet example as possible.
I also attached the schematic for this simplified "reduced" version as well as the schematic for the complete PCB, just for reference.
I suspect there is something fundamentally wrong with the way I set up the BQ24250, considering the high current with no load and the shorting battery, but I can't spot the issue.
