Folded-cascode with common mode feedback, the upper MOSFEs work as the feedback transistor. The reference current source provides the mirror voltage for the current source on the folded-cascode topology. The tail current source for the input stage shall be double-width utilized MOSFETs, I utilize double width for simplicity. Attention! The circuit can not start up without hand adjusting, we need to turn off the mirror MOSFETs by adjusting the biasing voltage to start the circuit
Another simple start up method: adjust the VDD from 90 mV to 3.3V
