• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 62 subscribers
  • Views 213 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.

BQ27426: IRateAVG1 and IRateAVG2

Koji Ikeda
Expert 6425 points
Part Number: BQ27426


Hello support team,

Customer inquiries IRateAVG1 and IRateAVG2 definition. Could you explain what IRateAVG1 and IRateAVG2?

By referring TRM "7.4.2.3.10 Taper Rate, Taper Voltage", bq27426 detects charge termination by comparing them with Taper Rate,  "IRateAvg1 < Taper Rate and IRateAvg2 < Taper Rate". However, they feel that these looks to be different factor, this makes them confused.

*Taper Rate: Taper Rate = Design Capacity / (0.1 × taper current) from Quick start guide. This seems to mean 10 times taper ratio, based on Design Capacity

* IRateAVG1 and IRateAVG2: 40-second periods average current. Unit of IRateAVG seems to be mAh or Coulomb.


Thanks,
Koji Ikeda

  • 0
    TI__Guru** 105870 points

    Hello Koji-san,

    These are just average current values for the period, it wouldn't be in mAh or coulombs.

    If you look at the current thresholds for example, they are represented in the same units but the equivalent value is C/16.7 (a mA value)

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    TI__Expert 6425 points

    Wyatt-san,

    Does "C/16.7" mean Discharge current threshold? I assume that C means 1C(mA), in other word, design capacity. If "Design Capacity/(Dsg Current Threshold × 0.1)" is ratio and the current is 1C X the ratio, it makes sense. Similarly, IRateAVG1/2(mA) is compared by 1C x taper Rate (Ratio) directly, it also makes sense.

    Is my understanding correct?

    Thanks,

    Koji Ikeda

  • 0 in reply to Koji Ikeda
    TI__Guru** 105870 points

    Hello Koji-san,

    The C rate is the design capacity if it was current, so just remove the time unit from design capacity.

    Sincerely,

    Wyatt Keller