Rail-to-rail input and output operational amplifier based on bipolar process

Abstract

The invention provides a single-power-supply, low-power-consumption and rail-to-rail input and output operational amplifier based on a bipolar process, which belongs to the technical field of analog integrated circuits and particularly comprises a biasing circuit, an input stage, a gain stage, an output stage and a frequency compensation network. The bias circuit adopts a bipolar peak current source to provide microampere bias current; the input stage adopts a complementary differential pair structure to realize rail-to-rail common-mode input, and realizes constant transconductance of the input stage by using a cross conduction method; wherein the gain stage and the input stage form a folding cascode structure, and a signal from the input stage passes through the source follower to serve as an input signal of a gain stage differential pair; the output stage adopts AB type rail-to-rail output so as to provide expansible output current sink (sinking current) and output current source (sourcing current) capabilities; the frequency compensation network provides sufficient phase margin for the operational amplifier, and stable unit gain bandwidth is realized.

Description

technical field [0001] The invention relates to the technical field of analog integrated circuits, in particular to a rail-to-rail input and output operational amplifier based on bipolar technology. Background technique [0002] In recent years, with the development of deep submicron and ultra-deep submicron technology, the size of CMOS devices has been continuously reduced, and the principle of proportional reduction of MOSFETs has made the operating voltage of integrated circuits lower and lower. The problem is that the maximum signal amplitude that the operational amplifier can handle becomes smaller, resulting in a reduced signal-to-noise ratio, which increases the influence of noise on the circuit and deteriorates the accuracy of the operational amplifier. Rail-to-rail operational amplifiers can increase the input and output range without increasing the impact of noise on the operational amplifier while reducing the supply voltage. In addition, the advantages of low no...

AI Technical Summary

Problems solved by technology

[0002] In recent years, with the development of deep submicron and ultra-deep submicron technology, the size of CMOS devices has been continuously reduced, and the principle of proportional reduction of MOSFETs has made the operating voltage of integrated circuits lower and lower. The problem is that the maximum signal amplitude that the operational amplifier can handle becomes smaller, resulting in a decrease in the signal-to-noise ratio, increasing the influence of noise on the circuit, and deteriorating the accuracy of the operational amplifier.

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