• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 637 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.

bq27621-g1: bq27621-g1 state of charge

Mason Noh
Expert 2490 points
Part Number: BQ27621-G1
Other Parts Discussed in Thread: GPCCHEM

I have used BQ27621-G1 to perform the fuel gauge of the battery of my design. Application is mobile POS.

Ideally, the system should be designed so that the bq27621-G1 is always powered by the battery, even

during system shutdown, but my system is designed that the bq27621-G1 is only powered when mobile is turned on.

The problem is that If mobile is being charged while turned off then turn on mobile, read the battery voltage level incorrectly. (ex:20%-->50%)

Can I fix it in other ways except the power rail? Initialization? If yes, How do we implement it?



  • 0
    TI__Guru* 76230 points
    Hi Mason,
    The bq27621 is a ROM based gauge. This means that it is not designed to have power being cutt off from it otherwise you will loose any configuration settings you have programmed on the gauge and that will introduce errors upon initialization when power is reapplied if the battery is not well relaxed. So that being said, you will need to ensure you do not have any current flow into or out of the battery during power on otherwise you will inevitably have errors. The gauge needs to have a well relaxed battery in order to take an OCV reading to ensure proper gauge accuracy

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Expert 2490 points
    the system has be designed bq27621-G1 is always powered by the battery.
    But issue isn’t solved. Could you advise please?
  • 0 in reply to Mason Noh
    TI__Guru* 76230 points
    HI Mason
    Also, given the fact that this is a ROM gauge, the default hard coded chem id has to be match for your cells otherwise you will still have errors. Did you run our online gpcchem tool to determine if the bq27621 is a good gauge for your application? Because if none of the hard coded chem ids come up as a close match, you will always have huge errors like you are seeing.
    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Expert 2490 points
    Hi
    BQ27621's algorithm is dynamic voltage correlation. So I mistook it doesn't need run gpcchem tool.
    I will do run online gpcchem tool. Thank you