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What is the default output data rate of INA219 current sensor?

Hnin Wai Lynn
Prodigy 50 points
Other Parts Discussed in Thread: INA219

Hi all,

I am currently using INA219 high side DC current breakout board and would like to know how many current values can be returned in 1 second from INA219 sensor. That is how many samples that INA219 can be taken in each second?

According to the datasheet (page 15,under Power management), the configuration by default is 12 bit but I am wondering whether it is 128 samples (per second) by default.

Could anyone help me to answer my question? Thank you in advance.

  • 0
    TI__Mastermind 25775 points
    Hello Hnin,
    I have moved your post to the current shunt monitor forum for further assistance.
  • 0 in reply to Pete%20Semig
    TI__Intellectual 2480 points

    Hello Hnin,


    The fastest conversion rate is for a 9-bit mode conversion, which corresponds to an 84us conversion time.  With a continuous conversion mode, this means that you could get 11904 conversions per second.


    The datasheet highlights the default ADC settings for both shunt and bus measurements in Table 6. ADC Settings on page 27.  The default setting is a 12-bit mode conversion with no averaging.  The number of samples you see do not refer to "number of samples per second", rather "number of samples per average".  A 12-bit mode conversion with 128 samples averages 128 conversions of 12-bits each, and only takes 68.10ms.

    Best regards,

    Kareem Moulana

  • 0
    Prodigy 10 points
    Hi Hnin,

    I suggest you to add I2C response time, delay of 4uS, to ADC conversion time value.
    Note: In INA219 to get current reading, ADC conversion value of the shunt voltage is getting divided by shunt resistor value. so you have to consider this conversion time also.
  • 0 in reply to Kareem Moulana
    Prodigy 50 points
    Hi Kareem,

    Thanks for the reply. I would like to clarify two more questions.
    Question 1:
    I would like to check with you more on the statement you mentioned "A 12-bit mode conversion with 128 samples averages 128 conversions of 12-bits each, and only takes 68.10ms.".

    Does that mean when it comes to 12-bit mode with 128 samples averaging, there will be total 128 samples and it averages out to get one sensor output value and the whole process takes 68.10 ms as there are 128 conversions needed?

    So every 68.1 ms, there will be 1 sensor output value. For 1 sec, there will be about 14 output values and the total conversions and samples needed will be about 1879 conversions and 1879 samples?

    Please correct me if I am wrong.

    Question 2:
    If I am using it in the default state and since there is no averaging, the number of samples with 12 bit that I receive are 128 ? So am I getting 128 sensor output values within 68.1ms ? My application is such that the current consumption from battery changes dynamically with the wireless transmission, that’s why I don’t want to miss any data values for the current consumption.

    Thank you.

    Regards,
    Hnin
  • 0 in reply to SUDHEEERKUMARREDDY KAKANI
    Prodigy 50 points
    Thanks , I will consider about it in my application .
  • 0 in reply to Hnin Wai Lynn
    TI__Intellectual 2480 points

    Hnin,


    Regarding Question 1, you are correct.

    Regarding Question 2, with the default settings the conversion time for 1 reading is 532us.  Yes, this should work out to 128 readings every 68.10ms in continuous conversion mode.

    Best regards,

    Kareem Moulana

  • 0 in reply to Kareem Moulana
    Prodigy 50 points
    Thanks a lot for your information Kareem .

    Regards,
    Hnin