Operational amplifier with low supply voltage and high common-mode rejection ratio

Abstract

The invention discloses an operational amplifier with low supply voltage and high common-mode rejection ratio. The operational amplifier comprises a main transconductance level circuit, a secondary transconductance level circuit, a first-level load circuit and a second-level amplification circuit, wherein the main transconductance level circuit comprises a fifth P-type metal oxide transistor, a sixth P-type metal oxide transistor, a seventh P-type metal oxide transistor, a fourth N-type metal oxide transistor and a fifth N-type metal oxide transistor; the secondary transconductance level circuit comprises a second P-type metal oxide transistor, a third P-type metal oxide transistor, a fourth P-type metal oxide transistor, a second N-type metal oxide transistor and a third N-type metal oxide transistor; and the second-level amplification circuit comprises a first P-type metal oxide transistor, a first N-type metal oxide transistor, a first capacitor and a first resistor. The operational amplifier disclosed by the invention can ensure the characteristics of high common-mode rejection ratio and high power supply rejection ratio under low supply voltage.

Description

technical field [0001] The invention relates to an operational amplifier, which has the characteristics of high common-mode rejection ratio and high power supply rejection ratio, and can work reliably under low power supply voltage (such as 0.6V). Background technique [0002] Operational amplifiers are an important functional block in many analog and mixed-signal systems. A large number of operational amplifiers with varying degrees of complexity are used to implement various functions: from DC bias generation to high-speed amplification or filtering. With each generation of CMOS technology, due to the reduction of supply voltage, the design of operational amplifiers continues to pose complex issues. In recent years, more and more silicon solar cells have been applied to circuit systems, while a single silicon solar cell only provides a power supply voltage of 0.6 volts. Designing an analog circuit that can work at a power supply voltage of 0.6V will expand the power supply...

AI Technical Summary

Problems solved by technology

If the tail current source transistor is biased in the linear region, the tail current is not constant, and the output impedance is greatly reduced, which seriously affects the common-mode rejection ratio and power supply rejection ratio of the operational amplifier.

So there are many challenges in designing op amps with high common mode rejection ratio and high power supply rejection ratio at low supply voltage

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