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BQ34Z100 GG Mode Error

Samuel Vanderwaal
Prodigy 90 points
Other Parts Discussed in Thread: BQ34Z100

I have a bq34z100 chip in an original board design and am experiencing issues with the gas gauge mode. The chip calibrates correctly for voltage and temperature, but gives me an error when I try to push current through the sense resistor to calibrate I get the following error: "Error setting to GG Mode."


In addition, the RAM data displays a high "resting" current of over 100 mA even when no load is applied. When a load is applied the current increases a little but stays around 100-200 mA, instead of the 1.5 A my load draws. This board design has worked in the past, and the chip correctly reads voltage and temperature, LEDs light up correctly, etc. so it seems to be some problem or setting with the chip. I'm wondering if the chip is bad and needs to be replaced or if I need to try changing some of the chip's settings.


Below are some screen shots.

  • 0
    TI__Guru 73830 points

    Samuel, 

    I have not seen that error message before. I would try reloading the senc file, ChemID, and gg file to start with a fresh configuration. Calibrate the pack before sending the IT Enable command.


    Regards
    Tom

  • 0 in reply to ThomasCosby
    Prodigy 60 points

    Hi Tom,

    The error message "Error setting to GG mode" occurs when I try to calibrate the pack current calibration in step 4. 

    I noticed this occurs only when Bat + is not connected or when there is a short between Bat + and Pack -. 

    I managed to run the calibration successfully once, but am having trouble doing it again.

    The documentation says to connect Pack - to the positive lead of the current source...

    And to measure a stable current source between Bat - and Pack -.

    What is the connection to Bat + ? Without Bat + connected I can't seam to communicate with the application.

    Could you please send me the setup to perform the pack current calibration ?

    A wiring diagram would be extremely helpful :) 

    Thank you for your time.

    Mat 

  • 0 in reply to Mathew Brown
    TI__Guru 73830 points

    Mat,

    Power will still have to be applied to the pack for it to communicate. You can either calibrate the current by using a current limited power supply to shunt current through the sense resistor by using the BAT- and PACK- terminals. You can also just place a load from Pack+ to Pack- and enter the discharge current in the actual current field on the calibration screen. Be sure to enter the current as a negative value.

    Regards

    Tom

  • 0 in reply to ThomasCosby
    Prodigy 60 points

    Hi Tom,

    Thank you for the information and the quick reply.

    Mat

  • 0 in reply to ThomasCosby
    Prodigy 60 points

    Hi Tom,

    I'm having some more issues with calibrating the pack current. I connected a load from Pack+ to Pack- and entered the actual discharge current which was only -20mA.  When I try to calibrate I received the message "Measured Current is too small". I then modified my circuit to provide 1.8A, then 2.8A and received the same message with regards to the current being too small. Next I tried using a current limited power supply to shunt current through the sense resistor... This resulted in the same message. I also tried entering calibration mode using the I2C commands and calibrating this way, with no luck for calibrating the current, everything else was good. 

    Everything else is working perfectly and accurately... and I have calibrated the pack current for other packs in the past with success (after multiple tries on pack current calibration). Do you think my Evaluation board could be damaged or maybe there is something I missed ? Each time I tried to calibrate the current I measured the voltage across the sense resistor and checked the connections up to the IC itself. Everything appears to be fine. 

    I suppose there is no way to override the current calibration step by forcing it to simply just report back the measured current regardless of value?

    My design is very low power and I need to report back the number of hours remaining on the battery. 

    Thank you for your help.

    Mat Brown

  • 0 in reply to Mathew Brown
    Prodigy 60 points

    Hi Tom,

    Sorry to bother you again... I found my error and everything including the pack current calibration is working excellent now. My belief is that it was a corrupt senc file because I loaded the default senc file and ran through the procedure again and everything went well.

    Thank you.

    Mat