Gain Enhanced Op Amp for Sigma Delta Modulator

Abstract

The invention relates to large-scale integrated circuits, and aims to improve direct current gain of an amplifier, simultaneously increase gain bandwidth product of the amplifier and finally realize increase of direct current gain and bandwidth of the amplifier under the condition of same chip area. Therefore, the technical scheme of the invention is a gain-boosted operational amplifier applicable to a sigma-delta modulator. The gain-boosted operational amplifier applicable to the sigma-delta modulator is composed of a Recycling folded cascade amplification stage, an output resistance boosting loop, a transconductance boosting loop and a common-mode feedback stage; differential mode signals Vin- and Vin+ are input through the Recycling folded cascade amplification stage, then, the signals are subjected to the cross positive feedback effect of the output resistance boosting loop stage and the transconductance boosting loop stage and further subjected to current multiplication of a cascade current mirror, and finally, the signals are output to output ends Vout- and Vout+. The gain-boosted operational amplifier applicable to the sigma-delta modulator is mainly applied to design and manufacturing of the large-scale integrated circuits.

Description

technical field [0001] The invention relates to a large-scale integrated circuit, low voltage and low power consumption, a sigma_delta modulator, and an operational amplifier, in particular, a gain-enhanced operational amplifier suitable for the sigma delta modulator. Background technique [0002] Low-voltage, low-power, high-gain operational amplifiers have always been an active area of ​​research in low-power analog circuits. Many high-gain operational amplifiers (such as multi-stage operational amplifiers) increase the gain of the amplifier by increasing the number of gain stages laterally. Although this increases the low-frequency gain, it reduces the stability of the amplifier and requires additional capacitors to improve stability. This increases the area of ​​the chip, so these are not conducive to the development of high integration of low-power amplifiers. At the same time, more large capacitors will reduce the unity gain bandwidth product of the amplifier, which r...

AI Technical Summary

Problems solved by technology

Many high-gain operational amplifiers (such as multi-stage operational amplifiers) increase the gain of the amplifier by increasing the number of gain stages laterally. Although this increases the low-frequency gain, it reduces the stability of the amplifier and requires additional capacitors to improve stability. This increases the area of ​​the chip, so these are not conducive to the development of high integration of low-power amplifiers

At the same time, more large capacitors will reduce the unity gain bandwidth product of the amplifier, which reduces the speed of the amplifier and is not conducive to the high-speed development of the amplifier.

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