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BQ4050: Power saving or ultra low power modes

Dan1
Intellectual 865 points
Part Number: BQ4050
Other Parts Discussed in Thread: BQ40Z50, BQ2980, BQ77915

Hi,

We would like to use the BQ4050 or BQ40z0 on a product that has a few different power modes.

  • Load removed. We plan to use the ManufacturerAccess() MAC Shutdown mode.
  • Low power mode. Battery protection active but saving as much power as possible.
  • high power mode. All the awesome features of this chip active.

In the low power mode, how can we reduce the power consumption of the BQ4050 or BQ40z50?
The 336µA stated on page 8 of either datasheet is far too much, especially when our previous 1S product used the BQ2980 with 4µA current consumption in normal mode.

What would the operating current consumption be with cell balancing and gas gauging disabled?
Can gas gauging be disabled?
Are there other features that can be disabled to help reduce power?

BQ4050
Datashee (page 8)t: https://www.ti.com/lit/ds/symlink/bq4050.pdf#page=8
Technical Reference Manual: http://www.ti.com/lit/ug/sluuaq3/sluuaq3.pdf

BQ40z50
Datasheet (page 8): https://www.ti.com/lit/ds/symlink/bq40z50.pdf#page=8
Technical Reference Manual: http://www.ti.com/lit/ug/sluubu5a/sluubu5a.pdf

Kind regards,

  • 0
    TI__Mastermind 24870 points

    1. There is no good way to reduce the power consumption. The typ you see is an average for this device.

    2. We do not have this characterized. The only way to determine this is to measure it on an EVM to get a good idea or in your system.

  • 0 in reply to Kang Kang
    Intellectual 865 points

    From my original post:

    Can gas gauging be disabled?

    Are there other features that can be disabled to help reduce power?

  • 0 in reply to Dan1
    TI__Genius 10370 points

    Dan,

    Our gauge has 3 modes that can be used.

    1) Normal (327uA)- Actively discharging/charging taking lots of measurements and calculations to do gauging. 

    2) Sleep (75uA/52uA) - Gauge wakes every X seconds to check voltage/current. Gauge still does protections and keeps track of gauging information. 

    3) Shutdown (0.5uA) - Gauge not doing anything, completely powered off. 

    You could extend the sleep measurement time, but the savings is minimal for a great cost in functionality. I also do not think it is fair to compare a gauge to a protector. We will not be able to compete for current consumption, but we do provide unparalleled accuracy

    Thanks,

    Eric Vos

  • 0 in reply to Vos
    Intellectual 865 points

    Thanks Eric,

    I agree that it's not a fair comparison, but BQ4050 and BQ40z50 are the only ICs that can serve as a protector and meet the rest of our requirements.
    The high power consumption is what is preventing us from using them.

    If there's a dedicated protector with the ManufacturerAccess() MAC shutdown, then I'd be very happy to use that. The only one I've found so far is BQ77915 which unfortunately can't disable it's balancing or adjust it to a better value.
    That was discussed here:
    https://e2e.ti.com/support/power-management/f/196/t/871568?tisearch=e2e-sitesearch&keymatch=%25252525252520user%2525252525253A434479

    The BQ4050 without gauging would be the perfect solution if it exists.

    Kind regards,