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Original question:

AWR1243: Sequencing of 3 frames

BQ78350-R1A: bq studio app through not able to set current deadband value

rohsik_j
Prodigy 165 points
Part Number: BQ78350-R1A
Other Parts Discussed in Thread: BQ78350, BQSTUDIO, INA237

Hi,

I am configuring BQ78350_RA1 and for some reason, I am getting the garbage value of the positive current reading. So not able to do shutdown my BMS system.

To solve this garbage value of the positive current reading I plan to use the current deadband option from the BQ Studio app. I can configure the current deadband limit like 100mA it can flash also But the same file gg.csv if do exported and for other hardware BMS board if imported and flashed then those current headband limit values are not changed other parameters are properly configured

what is preventing this current headband limit values from importing and flash ?

BMS_S1.gg.csv

  • 0
    TI__Guru** 105760 points

    Hello Rohsik,

    When the .gg file is uploaded in BQStudio the calibration data is not included, you should be using the SREC file to transfer configuration information, the .gg file does not contain many private parameters as well, like the chem ID.

    Also a deadband of 100mA seems very high, I assume you may be using a sense resistor which is very small and possibly below our recommended value. Keep in mind the deadband is only for reported Current() and the gauge will still coulomb count below the programmed deadband. What size sense resistor are you using for the application?

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 165 points

    Hi, Wyatt Keller

    thank you for your quick response.

    Can you give some ideas on the " SREC file to transfer configuration"

    0.25mOhms shunt what we used in our design.

    what is the TI Recommended value for BQ7694001 AFE? 

    We are facing some issues at AFE & Guge shutdown because of some positive current readings like 10 to 20 mA so it prevents shutdown  I tried this option of the current deadband limit.

    for the current colomb count, it uses other current senses like INA237 and MCU 

  • +1 in reply to rohsik_j
    TI__Guru** 105760 points

    Hello Rohsik,

    Generally 1mOhm is what we recommend, going lower than this then higher errors should be expected in current accuracy. The SREC is on the product page you can download it and upload with BQStudio.

    https://www.ti.com/tool/download/BQ78350-DEVICE-FW

    With such a low sense resistor you may need to increase the deadband in order to enter sleep or shutdown modes.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 165 points

    Hi, Wyatt Keller thank you so much for this information it is working nicely now 

    what would be the disadvantage of setting a higher current deadband limit?

  • +1 in reply to rohsik_j
    TI__Guru** 105760 points

    Hello Rohsik,

    The gauge will still coulomb count, so if there is a small offset error and the battery is in relax for a long time SOC may start to drift due to low sense resistance causing higher current measurement error.

    The deadband adjustment doesn't necessarily have any large impact since it just stops the gauging from reporting values below the threshold, but it still coulomb counts. If you have thresholds for other things, like protections, that are below the threshold, they may be impacted.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 165 points

    Hi, Wyatt Keller thank you for your support