Several COS’s have been proposed in literature to improve
the parameters like CMRR. [11] fixed the potential
at the source of COA transistors by two auxiliary differential
amplifier to improve CMRR. But these structures
suffer from high power dissipation and high supply voltage.
[14] used the same method to achieved high CMRR
while it could decrease supply voltages to some extent.
[10] used CMFF technique to improve CMRR, but suffer
from stability and high supply voltage problem