Thank you. I got confused because I have the habit of writng absolute values, I should have seen that it was a PMOS.
I have attached the bias block as well.
My confusion about the bias voltages was because the required Vb1, Vb2, Vb3, Vb4, Vb5, Vb6 in the opamp was not
matching the Vb1, Vb2, Vb3, Vb4, Vb5, Vb6 generated from the bias block.
For example, Vb3 (opamp) = Vov(Q1C) + Vth (Q1C) + Vov(Q5) ----- (1)
Vb3 (bias block) = Vov (Q25) + Vth (Q25) ----- (2)
I was confused that the Vb3 generated in bias block is one Vov short.
But now I understand that since the currents are different, both (1) and (2) work out to approxiamately same numerically. Is this analysis correct?
Then I want to understand on what criteria should the biasing scheme be chosen ? I can choose any biasing scheme as long as current mirroring happens
and absolute voltages required are approxiamately the same both in the bias block and the opamp ? Is this correct ?
Thank you for your time.