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BQ27220: recommendation for small capacity, low power battery gauge - both rechargeable and non-chargeable

Bart
Expert 6460 points
Part Number: BQ27220
Other Parts Discussed in Thread: BQ27Z561-R1, BQ35100, BQ27426

Hello Battery Gauge experts,

we are using either LiPo rechargeable or coin-cell battery with max capacity 50-60 mAh. Therefore, looking for a suitable gauge:

1- Lowest possible current consumption from the gauge - EDIT: BQ27220 in sleep has 9uA which is way too much for us.

2- Small size. We have severe size limitations.

3- If possible, the model(s) to work with different cell chemistry. If not - then two different candidates will work as well – one for rechargeable LiPo, the second for non-rechargeable;

4- As seen from above, the max battery capacity is in the range of 50-60 mAh. - Is that OK if we use scale factor 10x (like described in user guide for a different gauge, sluuap5a.pdf, point 6.1)

We were looking into BQ27220 (it could also act as coulomb counter, with EOS algorithm on the MCU) - but we would need a lower power recommendation(s).

Thanks a lot

  • 0
    TI__Intellectual 2025 points

    Hi Bart,

    BQ27220 and BQ27426 would be the lowest current option we have in terms of sleep mode. We also have BQ27z561-R1 that can go down to 0.5uA in shutdown mode. For rechargeable LiPo cells, you can use these gauges. For non-rechargeable cells, the only solution we have is BQ35100. For this low capacity and low currents, you will need to increase the sense resistor value to scale correctly. This app note should be of help: https://www.ti.com/lit/an/slua792/slua792.pdf

    Thanks,

    Rushi