I am currently working on an Adjustable Voltage Source, the Voltage Source is built by a voltage regulator with an OpAmp with and a Darlington transistor for current amplifying as the following diagram shows.
Vin is the output of the voltage regulator, so we can't know for sure the voltage at Vin. But because of the configuration of the OpAmp (Voltage Follower), we can assure that Node A and Vin are at the same voltage.
Given that Node A is equal to Vin, the OpAmp will compensate for the voltage drop across the Shunt Resistor, thus Node B voltage will be Node A Voltage plus the voltage across the shunt resistor.
I've thought of a Differential amplifier between nodes A and B, to get to know the Voltage across the shunt, thus knowing the current flowing across the load and the shunt.
*Suppose 4 Resistor values are the same
With this configuration a microcontroller con sort out the shunt current with Ohm's Law. But the equation system I tried to solve was missing one variable.
It is possible to figure out the voltage and resistance of the load by knowing the current and voltage across the shunt?
If not, which would be the most part efficient way of sensing the voltage and current across the Load?