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BQ20Z95: bq20z95

jie xu2
Prodigy 90 points

Part Number: BQ20Z95

Hello,

We have been experiencing some issue from bq20z95 device bases BMS. The findings include

1. After voltage calibration, the voltage measurement reading of bq20z95 did take 1-2min to settle down and stable.  

2. Our ATE followed Ti "SLUA355B-August 2005-Revised January 2010" instruction Section5"Calibration" to process CC Offset Cal,  while no load connects to Pack terminal. After calibration we did see CC Offset period of time jump from 0mA to 7mA then fall back to 0mA from some device, other constant 5mA error while no load connected.  We tried to use bqEasy instead of our ATE to confirm the finding and also got 5mA-7mA error after CC Offset even Board Offset calibration through bqEasy. 

Question:

  1. Regarding Voltage settling time: why does device operate with so long settling time? Is any way from hardware or FG configuration could eliminate such  operation behavior from FG?

  2. Regarding CC Offset error: why the CC-Offset calibration could not eliminate the error to 0mA, Board Offset also seemed not help? Is this error associates with FG configuration(dead band) or  bad performance

     by digit filter?

Thanks,

Jenny  

  

  • 0
    TI__Guru** 105590 points

    Hello Jenny,

    The voltage calibration should be quick and not need time to stabilize, can you outline how you perform the calibration?

    The dead band parameter will prevent the gauge from entering charge or discharge for small currents, I don't believe the default range is this large though.

    The gauge should calculate the CC offset automatically, you shouldn't need to program the value in.

    If there is noise on the SRP and SRN lines this could cause these brief fluctuations while there is no current.

    Sincerely,

    Wyatt Keller