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BQ27621-G1A issues

Rick Adolf
Intellectual 335 points


We’ve been using the BQ27621-G1A and we're were surprised that to initialize properly takes seconds and even then, its accuracy is questionable (plus  you need to have minimal/no load, so the processor can't be booting during this process). Since I’m currently revising the design, would you suggest continuing with this device or changing it to a more traditional current sense/coulomb counter or something else? As this is battery powered, we need to minimize the sleep current, so whatever the solution is, it needs to be low power (especially when the processor is in deep sleep).

  • 0
    TI__Guru 64296 points

    Hello,

    The bq27621's accuracy immediately after booting the gauge depends on the load current as you noted. However, the accuracy will improve after a charging cycle.

    Gauges with a coulomb counter achieve better accuracy because the gauge can measure the load current and compensate.

    The bq27421 is an alternative that doesn't require an external sense resistor for its coulomb counter (it has an integrated sense resistor). The main disadvantage is that the internal sense resistor limits the maximum current that the system may draw from the battery (peaks of 4.5A, sustained 2A).