Electronic – Is it possible to make a non-inverting difference amplifier

diff-ampoperational-amplifier

For a crude current sense application I am wondering whether it is possible to build a non-inverting difference amplifier without common mode offset on the output.

Reason: I would like to avoid having to create a negative supply voltage just for this function.

I.e. I am looking for the following output:
Vout = gain * (V2 – V1) where V2 > V1

Best Answer

I don't see any problem. Connect your V1 and V2 as shown here

Schematic

and make

gain\$=\dfrac{R_f}{R_1}=\dfrac{R_g}{R_2}\$.

Use precision resistors, to have an acceptable common-mode rejection ratio. If you need a high CMRR, use an integrated difference amplifier.

Related Topic