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BQ78350-R1A: Data Flash mismatch and recalculation of remaining charge

Part Number: BQ78350-R1A
Other Parts Discussed in Thread: BQSTUDIO, , BQ78350-R1

Hello,

When editing the "CEDV Gauging Configuration" register and comparing the content of the Data Flash, we discovered a mismatch:
- the bqStudio changes the address 0x4599-0x459A;
- the "BQ78350-R1A Technical Reference" document (SLUUC78, Initial Release, December 2019) claims that this register resides at 0x458B-0x458C, and 0x4599-0x459B are "Age Factor" and "Fixed EDV 0";
- the "BQ78350-R1 Technical Reference" document (SLUUBD3E, E Revision, January 2020) also defines the "CEDV Gauging Configuration" at 0x458B-0x458C.

We tested some other registers ("Fuse Blow Timeout", "Charger Request Timer") and verified they are fine, so this issue affects only part of the set.

If the bqStudio is right, we would be glad to have an updated "Data Flash Summary Table".
If the documents are right, it would be nice to get a patched bqStudio.

Another question is a values recalculation during battery self-discharge.
We artificially speeded up this process with a direct connection of a resistor to the battery (for the testing purposes). During that, we periodically reading the SBS commands.
We see the Temperature(), CellVoltage1..15(), Voltage(), ExtAveCellVoltage() are steadily decreasing with time, but the rest remain unchanged: RelativeStateOfCharge(), AbsoluteStateOfCharge(), RemainingCapacity(), etc. And the charging doesn't start until we send the "ManufacturerAccess() 0x0041 Device Reset".

How could we set up that, or probably trigger a recalculation of remaining charge with a command?

  • Hi Boris,

    BQStudio and the TRM do match for R1A (v1.04 firmware) and R1 (v1.03 firmware) device. It looks like you might be loading the R2 (v2.02 firmware) in BQStudio from the register addresses you describe. The R2 data flash addresses do change a bit and there is currently no independent TRM for the R2 version, so you need to use the BQStudio addresses if using R2.

    The Remaining Capacity (RelativeStateOfCharge and AbsoluteStateOfCharge are calculated from Remaining Capacity) is initially determined by the Cell voltages after initial power up, coming out of Shutdown, or after a RESET command is sent. The result depends on the ChemID that has been programmed to the device. After that point the capacity is tracked by measuring the charge flowing into and out of the battery (coulomb counting). The Full Charge Capacity (total capacity of the battery does change with age) is recalculated after a full discharge. The CEDV gauging algorithm is more fully described in the TRM gauging section.

    Determining the ChemID and configuration of the CEDV gauging parameters is described in the "Using the BQ78350-R1" application document: https://www.ti.com/lit/an/slua924/slua924.pdf

    Best regards,

    Matt