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Motor Current Sensing

Rasit GOKALAN
Prodigy 110 points
Other Parts Discussed in Thread: INA333, AMC1200, INA826, INA326

Hello,

In my project I will sense motor current through shunt resistor . But in my project inverter ground and micro ground is isolated. Because of this I want to use instrumentation amplifier INA333 to measure  voltage across the current sense resistor. Amplifier ground will be the same with micro ground. Dou you think that this will damage my circuit?

If answer is yes, what is the best way to measure analog voltage which is ground isolated from micro ground?

 

Best Regards,

Rasit GOKALAN

  • 0
    TI__Intellectual 2590 points

    Rasit,

    to make this work, you will have to make sure that the supplies of the INA and the micro are derived from the same supply. If the INA supply is galvanically isolated from the micro supply, this will probably not work as one can move with respect to the other. I.e. if the INA is operated from the primary side supply and the micro is operated from an isolated secondary side supply this will not work. In this case, please have a look at the AMC1200 or other AMC products. They employ a galvanic isolation scheme between the input side and the output side that allows you to float one side vs. the other.

    Also keep in mind that the valid nput range of the INA333 does not include the negative supply (GND in a single supply system). If this is a must the INA826 or INA326 might be a better choice.

    Hope this helps

    Frank