In my texbook [Analog VLSI: Circuits and Principles] there are two circuits that function as a current mirror. The first uses two nfets with a shared gate, and the drain of the first nfet (M1) is tied to the common gate. The current through M1 is then mirrored through M2.
The book also shows a Winner Take All circuit that uses a current mirror where the gate of M2 is tied to the drain of M1. And the gate of M1 is tied to the source of M2.
The book states "We should remember that Vg is determined by the gate charge, which cannot be directly influenced by the input current due to the infinite impedance between channel and gate." For the second current mirror design, how is the current getting mirrored to M2 if the gate can not be directly set by the input current in M1?