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BQ2084-V143 Remaining Capacity and Fuel Level not working

Christophe Pinkers
Prodigy 130 points
Other Parts Discussed in Thread: BQ29312A, BQ2084-V143, BQ24618

Hi,

I did a disign with a BQ2084-V143 and a BQ29312A and they working good up to now.

I don't know why but now I have a problem with them... :

The Voltage, Current, Temperature, ... all the datas readed are good but not the remaining capacity. 

The remaining Capacity (and so the fuel level)  are not updated when I charge or discharge my batteries.

I have put the factory dataflash into the BQ2084-V143 but it change nothing.

The batteries I use are 4 cells, 2600mAh. For the moment my Fuel level is 100%, I discharge my batteries with an 1A load, and the Fuel Level stay at 100%

I have the same problem if I reset the system (Fuellevel 0%) I charge my batteries but the fuel level stay at 0%

Can I solve it ?

Thx

  • 0
    TI__Expert 6470 points

    Hi Christophe,

    A few questions to help us understand this:

    1. Sounds like RSOC and ASOC are not changing when you apply current, but how about the Remaing Capacity itself? Are mAh really not counting?

    2. Is only one device "broken" in this way, or are there multiple units?

    3. Do you have a discharge log available for us to review?

     

    Thanks,

    Doug

  • 0 in reply to Doug Williams4811
    Prodigy 130 points

    Hi, First thanks for you reply.

    Here is a log file for a system Discharge. 

    log_FuelLevelProblem.LOG

    I don't know what must do RSOC and ASOC when I apply a current but the remaining capacity is not changing and I have the problem on 2 PCB. Maybe it's a design error but these two card works perfectly last week. (I have already change the two BQ parts and I have the same result). I see that I make a mistake for RSOC because i put a 1% resistor and not a 0.2%, what can it implicate ?

    I have an other problem with my circuit. For charging my batteries I use the BQ24618 charger and I have some problems when I'm charging the batteries. Here is a photo of the AC waveform at the output of the charger (PACK + into the datasheet schematic(figure 1))

    Thx

  • 0
    TI__Expert 6470 points
    Well, this is very strange indeed! i've never seen anything like it before. I'm guessing that something is configured wrong - either the coulomb counter gain or the dead zone. Can you send the .gg file from the dataflash screen?
  • 0 in reply to Doug Williams4811
    Prodigy 130 points

    Here it is the .gg of the gas gauge:

    gas_gauge_not_counting.rar

    I hope there is something wrong in the configuration.

    Thx

  • 0 in reply to Christophe Pinkers
    TI__Expert 6470 points

    The file looks OK to me, although some values appear strange due to the European convention of using the comma instead of a decimal point. I have no reason to think that it should cause any problem.

    Could you please measure the clock signal on pin 35 of the bq2084. It should be running at approximately 32 khz. If it is not there, then please check the 100K resistor on pin 33 and the filter circuit on pin 32. The lack of this clock, due to an external hardware problem, could explain your symptom.

     

  • 0 in reply to Doug Williams4811
    Prodigy 130 points

    I have done the mesure and this clock is present !!

    If needed I can change the BQ2084-V143, I have got one on stock.

    I'have check the communication between the BQ2084 and the BQ29312A and it seems good. I can't save my waveform from my scope so I send you some pick of the I2C signal. Maybe it can help. 

    i2c_waveform.rar

    Thx

  • 0 in reply to Christophe Pinkers
    TI__Expert 6470 points

    Christophe,

    Well, it seems that we have now ruled out everything except hardware damage in the IC, or firmware corruption. Firmware corruption is more likely and can be caused by various types of electrical overstress to the device. In general, that means too much current into or out of some pin for a brief period of time. Root cause could be ESD, hi power RF, etc.

    Yes, i think its time to solder in a new IC and see what happens.

    Regards,

    Doug

  • 0 in reply to Doug Williams4811
    Prodigy 130 points

    Hi,

    First thx for for you support

    It's possible that the IC is damaged because we have some trouble with the charger IC. We have Voltage spikes up to 1V and more (as the picture of the scope I sent you)... I think it's a design error so we are going to investigate it. 

    Thx,

    Christophe

  • 0 in reply to Christophe Pinkers
    Prodigy 130 points

    Hi,

    I reply to help someone have the same trouble than me because I found the solution !

    Reminder, my problem is that my gas gauge chip (BQ2084-V143) stop counting the Remaining Capacity.

    This was because the evaluation software (sluc018c) save wrong data. 

    In the configuration file (.GG file that we save with the elavuation software) there is a parameter named "CC Delta" (for counting the capacity). The evaluaion software save this value with a "," so when we write it, the software don't know this format and replace the value by 0.0000000. If we change this value with a "." (like 0.0000323 instead of 0,0000323, the soflare write the good value and the problem is gone.

    I hope it can help somone.