This is a INA159 Dual-Polarity, Bidirectional Current-Shunt-Monitor Circuit. This circuit uses OPA340 because it has near rail-to-rail input and output swing ranges that allow the output voltage of the circut to approach 0 and 5V. The gain of OPA340 is set to +100 and the INA159 gain is +0.2V/V. This circuit has gain of +20V/V. Here is the circuit :
To increase the sensitivity we can use a higher OPA340 closed-loop gain. However, it will increase DC errors and reduces the bandwidth if we use a higher OPA340 closed-loop gain. The output of INA159 can be increased by increasing the value of shunt resistor Rs from 0.1 ohm to a larger value. However we must evaluate the consequences of higher resistor power dissipation and the larger voltage drop. [Source: Texas Instruments Application Note]
