Tool/software:
Hello,
I am developing a lab-monitoring system right now and as a starting point we are using a Arduino Portenta Max Carrier Board wich comes with a BQ24195 as battery and power path management ic. Right now I'm facing the problem, that I can't get the 5.1V at PMID to work reliably. The system is intended to run on 12V (converted to 5V with a dedicated step down converter) which gives us +5V on the VBUS of the BQ24195. battery loading works fine, the buck converter also gives us the desired voltage, but somehow if I remove the 5V at the VBUS, the boost mode doesn't start and there is no 5.1V at PMID, but 3.5V.
From what I learned so far is that the OTG pin needs to be high to get the device into boost mode, but in this design the OTG-pin is directly connected to the buck converter output (3.8V) of the same ic. So I wonder if the 3.8V are still there when I remove VBUS. Is there a chance that there is a mistake in the schematic? I attach the schematic to this. Is there anything I need to configure by I2C to get the boost mode to work? Do I need to read back the status of VBUS and react to a voltage drop there? In this case I am wondering if the processor will continuer running during the 220ms long voltage drop. I tried several register settings of the BQ24195, but I don't get the processor to keep running when I remove the 12V input.
Thank you for your help
Regards
Holger
