• State TI Thinks Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 3 answers
  • Subscribers 63 subscribers
  • Views 190 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

BQ27542EVM: BQ27542EVM FCC update query

Star Xu
Genius 9645 points
Part Number: BQ27542EVM
Other Parts Discussed in Thread: BQ27542-G1, BQSTUDIO

Hi

The customer test with BQ27542-G1. battery 4000mAh (3.8V). During the client system test, it was found that RM/FCC increased. The reason for the change and update mechanism need to be explained.

According to the customer's method, use the power supply and load to simulate 500mA charging to 80% and then use 8mA to discharge to simulate the system sleep state. Please check the log data. You can see that the FCC has a slight rebound after charging as reported by the customer. Could you please explain the FCC update mechanism?

565786-0.5A charge 8mA discharge.log

Waiting for your reply.

Thanks

Star

  • 0
    TI__Genius 16836 points

    Hello Star, 

    It looks like the Filtered value is being used to report FCC. If you look at the image below, you can see that the Unfiltered FCC does not reflect this same behavior. 

    The Unfiltered FCC should instead be referred to for a true determinant of the total available battery capacity. 

    Regards, 

    Jonny. 

  • 0 in reply to Robert
    TI__Genius 9645 points

    Hi Jonny

    Thanks for your reply.

    From the gg file we can see Pack Configuration C is b9, and SmoothEn is set. 

    4135.gg file (1).rar

    The customer want to know why does the FCC change like above?

    Thanks

    Star

  • 0 in reply to Star Xu
    TI__Genius 16836 points

    Hello Star, 

    You are seeing this increase with the FCC because the filtered value is being used to report the FCC. If you set the SMOOTHEN bit to 0 then this will result in using the true FCC, and this increase will not be seen, this can be seen in the graph I had previously sent. Ultimately the FCC is increasing because you are using the filtered FCC.

    Regards, 

    Jonny. 

  • 0 in reply to Robert
    Prodigy 50 points

    8468.565786-0.5A charge 8mA discharge.log

    Hi Jonny

    My colleague posted this thread in china e2e forum. We understand the smoothen bit is supposed to prevent RSOC jumping and it's set by default.

    Now our customer wants to know why filterd FCC increased, what's the logic behind this situation, like why the gauge thinks capacity should be higher than previous value? I also included bqStudio log data for you to review.

    Thanks

  • 0 in reply to Long Lu
    TI__Genius 16836 points

    Hello, 

    The filtered FCC is increasing here so that it converges to the true FCC but without a sudden jump. If you look at the graph I previously sent, the true FCC jumps in the beginning, to reflect this change in the reported FCC, the filtered FCC converges to the true FCC in a way to prevent a sudden jump. This is why the filtered FCC is increasing here. I recommend looking at this E2E post as I believe it goes over the filtered FCC. 

    Regards, 

    Jonny.