The pictures below are enhanced output impedance current mirror and a general negative feedback model. The current mirror has a negative feedback loop. However, I can't determine where is the input that is corresponding to the "input" signal in the general feedback model.
What is the input signal of the feedback network here? The output signal is Iout, and the input is not clear to me.
PS: I would like to talk more about my purpose of this post now. I want to make it clear what feedback configuration the circuit is (voltage-voltage, current-voltage, voltage-current or current-current) and then I can apply the feedback theorem to calculate output impedance of this circuit.
Rout = gm1*ro1*ro2*(1+A) where A is the loop gain and the output impedance of the network without feedback is gm1*ro1*ro2.