• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 200 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

BQ40Z80: BQ40Z80 DSG voltage falls down during discharge

BQ40Z80: Why does current consumption fluctuate so rapidly.

Ankur Aggarwal
Prodigy 50 points
Part Number: BQ40Z80
Other Parts Discussed in Thread: BQ40Z50,

Hi Folks,

We're trying to make our fuel gauge sleep for low quiescent current consumption during storage, but while the average is okay (~80uA), the range is high, from about 48uA to hundreds of uA. I realize that the system is supposed to periodically wake up to measure voltage/current, but it's not obvious how these current spikes track those expectations.

Do you know what might explain this? I've attached our GG file for reference.

reading_from_low_current_fuel_gauge_10_08_21.gg.csv

Best Regards,

Ankur Aggarwal

  • 0
    Prodigy 50 points

    Sorry for the extra message, I just wanted to share a time series of the current values that we were pulling so that you could see the time scale from the spikes.

    The horizontal axis is sample count (1ms/sample, so about 10 seconds worth of data), and the vertical axis is current draw in Amps.

    There is about a ~60uA constant current draw from another chip, and the remainder comes from the BQ.

  • 0 in reply to Ankur Aggarwal
    TI__Guru** 105590 points

    Hello Ankur,

    The multicell gauges like the BQ40Z50 and BQ40Z80 measure 4 times per second, when they're in sleep mode it should be dependent on the Sleep:Voltage Time and the Sleep: Current Time. The average with default settings is what reported in the datasheet. The spikes are expected.

    Sincerely,

    Wyatt Keller