• State TI Thinks Resolved
  • Locked Locked
  • Replies 11 replies
  • Answers 4 answers
  • Subscribers 65 subscribers
  • Views 448 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.

BQ27427: 12000mA reading

Marvn Arcangel
Genius 11240 points
Part Number: BQ27427
Other Parts Discussed in Thread: BQSTUDIO

Hi Team,

Can you please help assist with the inquiry below?

The current which I can read is 12000mA When the device draws around 200mA What should I do?

Now I'm using BQ27427. This is a common schematic - the same as in the reference manual. The battery is 2000mAh, 3.V LiPo battery I make test and the bq27427 fuel gague is compatible with my battery.

I have very strange readings. II have board designed for bq27421 but I can see that bq27427 and bq27421 are pin compatible. Now I put new chip and I can read more real values but still when battery is discharging I see it as a charging in bqStudio.

Here are the logs and configuration. 1643.OutputFiles.zip

Regards,

Marvin

  • 0
    TI__Mastermind 34951 points

    Hello Marvin,

    Sorry for the late response. Did you calibrate the gauge? This could be the cause for the gauge to
    be misreading the current value.
    Also, can you share the schematic for the board you are using for the gauge. I want to verify that everything
    is connected correctly.

    Sincerely,
    Nick Richards

  • 0 in reply to Adrian
    TI__Genius 11240 points

    Hi Nick,

    Can you please clarify what you by calibration? do you mean the learning cycle? The customer was not able to calibrate every fuel gauge.

    Can you confirm if the bq27421 does not need any calibration? the part shows the proper current when the basic information is entered (capacity, energy, taper rate, and empty cell voltage).

    Here is the customer schematic:

    Let me know if you need more information

    Regards,

    Marvin

  • 0 in reply to Marvn Arcangel
    TI__Mastermind 34951 points

    Hello Marvin,

    The schematic seems fine.

    Calibration is different from the Learning Cycle. The Learning Cycle is for learning about the battery being used
    by the system (so updating the Qmax and the Ra table for the battery). Calibration on the other hand refers to making
    sure the gauge is reading in the correct Voltage and Current. There is a tab in BQStudio that can be used for
    calibrating the gauge. It is simple to use, you just input the actual applied voltage and current and press the
    "Calibrate Gas Gauge" button.

    It is recommended that the gauge is calibrated before use. So, I would try to calibrate the gauge for the BQ27427 to
    see if it fixes the problem. Since the BQ27421 is already showing the correct current, then I don't think it's necessary
    to calibrate it.

    Sincerely,
    Nick Richards

  • 0 in reply to Adrian
    Prodigy 80 points

    Hello Nick,
    I want to say that bq27421 work fine without any calibration. So this is quite strange for me that the bq27427 need something like that.
    Can you tell me how I can move the calibration values to my driver - I'm not be able to calibrate every device.

  • 0 in reply to Bartosz Pospiech
    TI__Mastermind 34951 points

    Hello Bartosz,

    The calibratation data can be found in the Data Memory section of BQStudios. There will be a section called "Calibration".
    You can press the "Export" button on top of the Data Memory section and this will create a csv file for all the data in
    the settings.

    Sincerely,
    Nick Richards

  • 0 in reply to Adrian
    Prodigy 80 points

    Hello Nick
    Ok, so if I understood it right I need to put to one of fuel gauges known current, calibrate it and to the other gauges during initialization I need to put calibration data?

    Best regards,

    Bartosz

  • 0 in reply to Bartosz Pospiech
    TI__Mastermind 34951 points

    Hello Bartosz,

    If you are seeing the same issue from multiple gauges then you should be able to reuse the calibration data. (The same
    issue being that the a current of 200mA is being reported as 12000 mA, or any value close to that). However,
    it is recommended that each gauge is calibrated independently, if possible.

    Sincerely,
    Nick Richards

  • 0 in reply to Adrian
    Prodigy 80 points

    Hello Nick,
    I'm be able to make calibration process on one of my device and current reading looks good now.
    But please let me know how I can implement calibration function in my code - I want to put calibration values into other device (part of chip driver).
    In RM i can't find any information about:
    CC Offset
    CC Gain
    CC Delta.
    Can you share some part of code or provide documentation number where I can find informations about implementing that parameters changing?

    Best regards,
    Bartosz

  • 0 in reply to Bartosz Pospiech
    TI__Mastermind 34951 points

    Hello Bartosz,

    For the gauge you were able to calibrate successfully, using BQStudio go to the "Golden Image" tab.
    Here you can get the gm.fs file, which will include the calibration data. You can press the "Create
    Image Files" and this will create the gm.fs file. This file can be uploaded onto the other gauges
    using the "Programming" tab on BQstudio. 

    Sincerely,
    Nick Richards

  • 0 in reply to Adrian
    Prodigy 80 points

    Hello Nick,
    I have no possibility to upload any file using BqStudio during production. I need to do this in my software. Please let me know how to do this - without that feature that gauge is useless for me.

    Best regards,
    Bartosz

  • 0 in reply to Bartosz Pospiech
    TI__Mastermind 34951 points

    Hello Bartosz,

    Please refer to this document, which explains the file format for flash stream files. Using the gm.fs file, you can use I2C to transfer the data from this file to the gauge using your own software.

    Sincerely,

    Nick Richards

    7183.Flash Stream File Format.pdf