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INA233: Conversion_time_number_of_averages_affect

Part Number: INA233

Hello,

in what examples could different settings of conversion time and different number of averages results in different current measurements of INA233?
I used 20 mR resistor which limits the maximum current that could be measured to 4.096 A - real current consumption was between 0.02 A and 0.7 A.
In other application I choose 10 mR resistor which limits the maximum current that could be measured to 8.192 A - real current consumption was between 0.05 A and 2.5 A.
I tried also different values of conversion time and number of averages, an I'm not sure but I didn't notice any major difference.
Input filtering is included with 10 R resistors and capacitor 470 nF.

Many thanks!

  • Hey Dejan,

    The conversion time and number of averages become important when the signal is noisey and there are higher frequency components (in the shunt voltage) that you would want to reject. Noise will become more of an issue when measuring smaller load current because signal-to-noise ratio (SNR) will become lower and noise may increase error in any single measurement.

    Measurements can also differ if you are trying to capture/quantize a relatively higher frequency signal that requires more BW than what the programmed conversion time/ averages will allow.

    So to understand how much conversion time and how many averages you will need, you will need to understand your accuracy and system BW requirements at the smallest current you want to measure. Then if you can realistically test your system and its noise, then you can see how the device performs with the noise and reprogram conversion time and/or averages until the data noise and accuracy is satisfactory.

    Sincerely,

    Peter