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BQ20Z95 won't charge or discharge

allen kitchen
Intellectual 320 points
Other Parts Discussed in Thread: EV2400, BQMTESTER

We have a Bq20Z95 in our new design.  This is the first time we've worked with one of these smart charger chips.  It's fed by a 24753 charge controller which seems to be working fine.

Running the BQEasy software and communicating with the chip through a EV2400, we can see the bits and setup the chip.  We've set up for 3 cells at cutoff volts of 4.1v and capacity of 300mahr.  If you bypass the charge fet on the Z95 with a 0ohm resistor, you can charge the cells fine (and see the DFETF flag).  But take that bypass out and no FET ever gets turned on and we cannot charge batteries.

I have battery status INIT, DSG and FD after a discharge run.  With charging power applied the Z95 works, but we have no FETS turning on.  Is there something I'm missing?  That INIT flag makes me think something isn't setup right.  The only thing not done in the BQEasy is the Impedance Tracking.

  • 0
    Intellectual 320 points

    Ooopsie.  Running the BQeasy again, we continued on and pressed the Initialize IT.  And now we have the FETS working.  

    How are we going to be able to program this thing in the final project is a puzzle though.  Will we be able to get a finished dataflash file that we can include in our CPUs firmware to initialize the Z95 properly?

  • 0 in reply to allen kitchen
    TI__Expert 6470 points

    If you finish running through bqEasy, you end up with a DFI "data flash image" file which can be used for mass production. For getting into each device, and setting the individual calibration, serial number, date of mfg, etc. please see the attached document. Alternatively, you can purchase our bqMtester board, or just use the EVSW itself for small production runs.

    slua379.pdf