Making the bias an ideal current in a nmos source follower

[iainPOT_007]

good day..please refer attached circuit..
it is a source follower with NMOS as current source..
is there anything i have to add to the circuit
for the bias to be IDEAL CURRENT?

 

[Azmi]

nmos source follower

just add current mirror connected to M2.

 

[Raviprasad_K]

Re: nmos source follower

Hi,

You can add cascoding which would increase the output impedance of the current source

 

[patricky]

nmos source follower

Like above, cascode would be good, but a regulated cascode would boost output impedance even further. Using larger and lower threshold voltage devices would provide more headroom at the output.

 

[checkmate]

Re: nmos source follower

The thing you must understand is that M2 can never be an ideal current source, unless you replace it with one, which like all other ideal stuffs, dont exist in real life.

Real current sources have finite output impedance and minimum limits on vout.