Common-mode feedback circuit and operational amplifier

The invention discloses a common-mode feedback circuit and an operational amplifier. The common-mode feedback circuit comprises a common-mode detection module, an error amplifier module and a current feedback module. Wherein the input end of the common-mode detection module is connected with the output end of the Class AB fully differential operational amplifier; one input end of the error amplifier module is connected with the output end of the common-mode detection module, and the error amplifier module comprises a first sub-circuit structure and a second sub-circuit structure which are crossed and symmetrical, and an intermediate resistor connected with the first sub-circuit structure and the second sub-circuit structure; the first sub-circuit structure and the second sub-circuit structure respectively comprise common collector-common emitter transistors which are symmetrical up and down; the input end of the current feedback module is connected with the output end of the error amplifier module. Current on