Dear respected,

This is regarding INA333 in-Amp for using current measuement for battery operated device. Two connections from battery positive terminal connected VIN+ and VIN- of INA333 with 0.1Ohm resistor. See attached

image for reference. When I am not shorting System GND to INA GND , there is no change in output from INA>



When I am connecting System GND and INA GND , I can able to detect current sense. But ideally it has to work without connecting system GND and INA GNDs right????? as we are processing differential inputs

 

Even though it is a diffetential amp, it still has its limits, namely common mode voltage. The path between the two grounds is required so that the voltage at the inputs is in a known relation to the power supply of the amplifier.

 

You could use a resistor to provide some isolation between the two grounds, but they do need to be connected together.

If you can't tolerate that, then you will need an isolation amplifier with galvanic isolation between the input and output.