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BQ76952: CC2 Current

jeong hun lee
Prodigy 140 points
Part Number: BQ76952

hi.

I am measuring the current using a shunt resistor.
The current unit was set to 10mA. (The default value is 1mA.)
CC Gain and Capacity Gain are also set according to the shunt resistance value, and the desired value can be obtained.
The problem is that the value of ±254 comes out intermittently.
A bigger problem is that this value appears regardless of the setting unit.
If the setting unit is 1mA, it becomes 254mA, but in case of 10mA, it becomes 2.5A.
Since I need to measure 100A, I have to use the 10mA unit.

The video above is a video that measures the current value in a state where no current flows.

The above video is a video when it is increased by 1A and raised to 10A.

I was able to find similar questions on TI forums.
See link below.
https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1092192/bq76952-wrong-values-for-cc2-current?tisearch=e2e-sitesearch&keymatch=bq76952%25252525252520cc2#


I tried the same, but couldn't solve the problem.

Is there a timing to read CC2?

  • 0
    TI__Mastermind 27321 points

    Hello jeong hun lee,

    The CC2() reports its current measurement every 3ms in Normal mode. The 3-ms conversions can be changed to 1.5-ms conversions by setting the [FASTADC] configuration bit, with a reduction in conversion resolution. More details can be found in this technical article.

    As the linked thread mentions, the best that could be done here is to ignore when bad data is received. Hopefully this bad data has a pattern and it is easy to detect. As mentioned, I2C will not have this issue, but I am assuming SPI is a must for your application.

    Regards,
    Jose Couso