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TMCS1101: Current measuement resolution

AD
Intellectual 300 points
Part Number: TMCS1101

Can someone help advice what's the measurement resolution of TMCS1101, for example, to measure a curent in range 2~8A, with12bit ADC, is it possible to get resolution smaller than 5mA. and how to calculation the resolution, thanks in advance.

Best Regards!

  • +1
    TI__Mastermind 22470 points

    Allen,

    To map the resolution of a magnetic current sensor to an ADC its a two step process. 

    First, you would map the resolution of the ADC least significant bit, Say for example you are using a 5V supply, that means that in the ideal sense, the LSB of a 12bit ADC would be 5V/2^12 = 1.22mV.

    Second, examining the sensitivity of the TMCS1101A1, this is 50mV/A (th e, so we can find the corresponding amperage by dividing by this number, and 1.222mV/50mV/A = 24.4mA

    So the answer here would be no, the resolution of the system is >5mA. To achieve a mA resolution, you can move to higher bit ADC for the A1 variant, or choose a higher sensitivity for the TMCS1101, provided that you're desired measurement range works with the chosen gain. 

  • 0 in reply to Carolus Andrews
    Intellectual 300 points

    Thanks a lot Carolus!