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  1. #1
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    current sense (0-500mA)

    Dear Friends,

    I want to measure the current range (0-500mA). Input is 6.3VDC.
    please suggest the suitable chip to measure the current. Which can be sensed by the 10-bit ADC . Our ADC's will detect 3mV variation difference. so we require 3mV variation each mA current.



    Thanks
    Sakthivel R

    •   Alt17th February 2017, 10:49

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  2. #2
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    Re: current sense (0-500mA)

    Hi,

    use a "high side current sense amplifier"
    There are many different types from many different manufacturers.
    Read through some datasheets and application notes.

    Klaus



    •   Alt17th February 2017, 11:03

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  3. #3
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    Re: current sense (0-500mA)

    This question has come up many times in the past.

    I would suggest that you go to Linear Tech's webpage and download their "current sensing" app note in .PDF format.

    The note has literally several hundreds circuits, and one of them should fit your application and budget.
    My batteries are recharged by "Helpful Post" ratings.
    If you feel that I've helped you, please indicate it as a Helpful Post



    •   Alt17th February 2017, 16:03

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  4. #4
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    Re: current sense (0-500mA)

    Your proposed schematic show a 0.1 ohm resistor. Assuming this is the shunt you want to use I think you have a major discrepancy here. 3mV/ma = 3V/A = 3 ohms. You are far from 0.1ohm. If you put 500mA into a 0.1ohm resistor you will end-up with only 0.05Volt. That is 50mV, not a lot for accurate reading. At 10bits this is only 50 micro-volts per bit. You are not leaving much room for accuracy. Although feasible with an ADC, reading 50mV may require a bit more expensive chip. Some clarifications required here, I think.

    Please tell us what your application goal is (education, build a lab instrument, repair an expensive apparatus)
    Can you manage with a simple analog meter ? They work great at 50mV



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