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BQ77915: BQ77915

Part Number: BQ77915

Hello,

I made a PCB with the BQ77915, but the design doesn't work

Schematic:

Please let me know what i should do

  • Hi Aleksey,

    The protectors don't have a status output so it can take some thought to see what could be wrong. 

    The cell voltages look normal.  PRES is pulled up and recognized since AVDD at 3V shows the part is on.  CTRC and CTRD are low so FET outputs should be enabled.  LD is low so it should not be stuck waiting on a load removal fault.  CBI is open which is ok.  ROCD (R13) is a normal value.  R9 for the thermistor is 100k, for the 103AT thermistor type this would be about -28 C.  For BQ7791508 UTC is -5 and UTD is -20.  The part likely has both faults.  Replace R9 with 10 k or stick about 12k in parallel to test if this is the issue.