How to design the MOS biasing circuit in analog IC?

[ee-fresh]

MOS biasing circuit

I am working on a IC design project for this semester. The text books mention very little about how to design the biasing cirucit in analog IC. Razavi's book always draws a current source I_s or I_ref. Some other books say the biasing circuit is there automatically... How should I do? Thank you very much.

 

[richloo]

MOS biasing circuit

u can refer to a book Analog Integrated Circuit Design by Daved Johns & Ken Martin. In chapter 5 & 6 have depth explaination on biasing circuit for opamp.
one of the circuit i have posted at