Hi Al.
The basics to consider are: -
Gm= 10mA per Vsense ,, the Vsense is the voltage drop across the Rsense at 1Amp in your application.
So using a 0.1R sense resistor at 1Amp maximum load current will give:
Vsense voltage of, Vs= 0.1R * 1Amp = 0.1Vsense
You know that Gm= 10mA per Vsense:
So Iout = 10mA * 0.1Vsense = 1mA.
So with a 1K Rout, the Vout will be 1000R * 1mA = 1Volt
With a
2K, Vout = 2V, for 1Amp load current.
3K, Vout = 3V, for 1Amp load current
For a maximum out of [5Vsupply -1.2V] = 3.8V, the Rout could be 3.8K
Your problem is caused by the 1R sense resistor.
At 1Amp load current the Vsense is 1V,,, so using Iout = 10mA per Vsense gives an Iout of 10mA, which when flowing in a 3.k48 resistor will 'try' to give voltage of 3.48k * 10mA = 34.8V !!!
But the Vout can never be greater than 3.8V.
If you used a Rout= 348R you could get 3.48V
I would recommend a 0.1R sense resistor and a 2.55K Rout resistor [5Kpot] , this should make the scaling in the ADC easier.
Hope this is helpful.
Eric