wjxcom
Full Member level 5

Hi, all: this circuit is a full differential OPA whose CMFB is controlled by switchs and capacitance. but there has a question: what is the role of the switch M19 and M22? I think the role of the switch of M20 and M21 is clear. But why there have M19 and M22? I do not know how to analyse the circuit.
Help me. please!!
Help me. please!!