I set up this circuit on a breadboad but it doesn't seen to work correctly. I used 1 ohm(5%) for the sense resestor and set the voltage using a divider down to 1v but there're 2 issues:
1- the voltage across the resistor is about .8 V and goes down after a little bit I guess because the mosfet on resistance increases with temperature.
2- The mosfet heats up so quickly (it's heat-sinked) although it has a very low on resistance of .025 ohm (irfz44n).
I tried to put a small series resistance with the the gate of the mosfet so it prevent ringing but still the same problem. I even put 10 kOHM resistor to make a schmitt trigger but also didn't work.
I'm using a 12 V, 1 A limited voltage source and LM358 for the OpAmp.