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BQ27Z561: BQ27z561 gives garbage readings

Part Number: BQ27Z561

Hello,

We are using bq27zz561 IC. During overnight testing we found that we are getting garbage reading sometimes. Can you please help us to get rid of it

During testing, we simply keep the board in charging and leave it overnight with custom script reading the fuel gauge properties such as current, voltage and SOC every 2 seconds.

  • Hello Karan,

    Can you post an example log of your voltage, current, temperature readings?

    Some items to check for would be your I2C driver as well as the speed at which you read it. We suggest no more than twice a second.

  • Kang,

    I am application engr. calling on this account.

    As you have suggested they are reading more than twice in a second. Still they are facing the issue with garbage value & random in nature. When they reads registers twice in a second, during 24 hours they are getting garbage value almost 15 to 20 times. 

    When they speedup the readings/ second then they observed more garbage & on slowing down no. of garbage values are less. Looks like device is throwing garbage values for same no. of times for lower speed or higher speed for sample size of 50K or 100K or whatever the numbers are.

    kindly help resolving the issue. Also we are not able to understand even if we will read at higher speed why device is giving garbage, at the most it should throw same data.

    Mitesh

      

  • Mitesh 

    Kang's response said no more than twice per second. preferable once per second.

    thanks

    Onyx

  • Hi Kang, Onyx

    We did the test again with setting 0.5 seconds delay between every read. So technically the utility will read data only two times in one second. With this change also we are getting garbage values on instantaneous voltage and cycle counts. Below is the voltage reading we are getting,

    This data is collected over during stress test of 7 to 8 hours. Also attached is the script used for testing.

  • What is the frequency of your clock? Perhaps reducing it to around 50kHz would provide better results?

    thanks

    Onyx