Operational amplifier

Abstract

The invention relates to a semiconductor integrated circuit, and provides an operational amplifier. The operational amplifier can receive and amplify a positive differential input voltage and a negative differential input voltage through an input stage circuit and output a first positive differential output voltage and a first negative differential output voltage; the operational amplifier respectively output a first driving voltage and a second driving voltage by using a control stage circuit according to the first positive differential output voltage and the first negative differential output voltage; based on the fact that an output stage circuit is coupled to the control stage circuit, the operational amplifier generates an output voltage according to the first driving voltage and the second driving voltage. and a first control voltage or a second control voltage are correspondingly generated by using a feedback stage circuit according to the first driving voltage or the second driving voltage, so the operational amplifier provided by the invention can adjust the state of the control stage circuit by using the control stage circuit according to the first control voltage or the second control voltage so as to stabilize the offset voltage of the operational amplifier. Therefore, the offset voltage can be stabilized while high gain is ensured.

Description

technical field [0001] The invention relates to the technical field of semiconductor integrated circuits, in particular to an operational amplifier. Background technique [0002] The operational amplifier is a high-gain voltage amplifier with differential input and single-ended output. With the development of electronic devices and semiconductor technology, operational amplifiers are used more and more widely. There are many types of operational amplifiers and are widely used in the electronics industry. When operational amplifiers have requirements for speed, the output terminal voltage needs to be established within a certain period of time. To the target value, that is, the slew rate at the output of the operational amplifier is required to be relatively large. [0003] At present, existing operational amplifier circuits such as rail-to-rail (rail to rail) input class AB output op amps, if there is a requirement for the slew rate, the usual method is to increase the curr...

AI Technical Summary

Problems solved by technology

If (1+Rf / Ri)*Vos2<-VS, then Vout≈-VS, while Vgs1 and Vgs2 remain high, close to +VS, so that the potential of node B is close to +VS, Mp2 remains in the linear region, and Vout cannot Return to the normal value. If the tail current source I1 has all flowed into the MOS transistor Mp5 at this time, no matter how the input signal Vi changes, the operational amplifier 100 cannot return to the correct state.

[0008] To sum up, in practical applications, starting at a larger closed-loop gain or input signal interference will be caused by (1+Rf / Ri)*Vi>+VS or (1+Rf / Ri)*Vi<-VS, cause the operational amplifier 100 to overload and not recover, so this problem needs to be solved

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