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BQ78350-R1: BQ78350-R1 coupled with bq76940 Monitor Family

Part Number: BQ78350-R1
Other Parts Discussed in Thread: BQ76940, BQ78350, BQSTUDIO, GPCCEDV

Dear,

In our design, we are using a CEDV Li-Ion Gas Gauge and Battery Management Controller BQ78350-R1 coupled with  bq76940 Monitor Family which is managing 14S cells. And we need your assessment:

First, we need a help to generate a golden file and to adjust different calibrations (Cell Voltage, courant….etc) for production process? any procedure, datasheet, either an example is welcome!

Secondly, when a permanent fail (PF) arises, we need to know how to erase it and to know if it’s secure to do so, especially for a production process?

Lastly, how to set a Packet Error (PEC) Checking on BQ78350, and how to set the PEC calculation ? (The datasheet is not so clear)

Notices:

The datasheet (Literature Number: SLUUAN7B July 2014–Revised June 2015), indicates (page 112):

- That when 0x0024 is written to ManufacturerAccess() when ManufacturingStatus()[PF_EN] = 0, then the Permanent Failure feature is enabled and ManufacturingStatus()[PF_EN] is set to 1. If 0x0024 is written to ManufacturerAccess() once again, then the Permanent Failure feature is disabled and ManufacturingStatus()[PF_EN] is cleared to 0.

- This command resets PF data in data flash for ease of manufacturing. When 0x0029 is written to ManufacturerAccess(), the Permanent Failure data stored in data flash is cleared.

Best Regards,

  • Hi Omar,

    It looks like you've solved (2) PF Erasure in your notices section below. I'll try to cover the rest.

    A great getting started guide for the bq78350-R1 couple with the bq76940 is found here: www.ti.com/.../slua726a.pdf and www.ti.com/.../slvu925b.pdf if you're using the EVM.
    This guide will familiarize you with the bqStudio SMbus read/write block interface: www.ti.com/.../slua742.pdf

    1) Golden File Generation
    Before we create the "golden image" used in programming all of you devices in production, once device will need to be set up first. Generally speaking, the "golden image" is the average values from 10-30 devices that are properly configured, assuming a low variance between parameters. To configure the gauge, please follow the detailed steps in section 9.2.3 of the Datasheet titled, "Detailed Design Procedure". The datasheet is found here: www.ti.com/.../bq78350-r1.pdf

    Using the gauge with bqStudio, or a separate system such as an Arbin, you will need to determine the CEDV parameters for the pack by performing several tests and the GPCCEDV tool. More information on the tests to be run and how to format the data can be found at: www.ti.com/.../sluub45a.pdf

    2) PF erasure
    Some other details about PF:

    When the device is in permanent fail mode, and new SafetyAlert(), SafetyStatus(), PFAlert() and PFStatus() flags that are set are added to the permanent fail log.

    The AFE read/write fail counter and XREADY counters will increment until reaching a configurable limit, at which point the device will disable the pack permanently.

    3) PEC Checksum Calculation
    For a great guide on SMBUS and PEC calculation, please check out section 1.2.3.1 of the SMBus made simple app note found here: www.ti.com/.../slua475.pdf

    Sincerely,
    Bryan Kahler
  • Hi Omar,

    If the above response helped resolve your question, please click on the 'This Resolved my Issue' button below to improve the find-ability of this response for others that may have the same issue. Thanks!

    Sincerely,
    Bryan Kahler