Differential amplifier, calibration circuit and calibration method applied to two-stage analog-to-digital converter

Abstract

The invention discloses a differential amplifier for a two-stage analog-to-digital converter, a calibration circuit and a calibration method. The differential amplifier comprises a first group of input geminate transistors, a second group of current mirrors, a third group of current mirrors, a current source, a first output resistor and a second output resistor, the first group of input geminate transistors comprises a first mos transistor and a second mos transistor; according to the differential amplifier, an open-loop structure is adopted, differential input voltage can be rapidly amplified, and an accurate and stable voltage value can be obtained within a short time. The gain of the amplifier is determined by the resistance ratio, and the gain of the amplifier can be accurately adjusted by adjusting the resistance ratio, so that the amplifier is suitable for different circuit requirements.

Description

technical field [0001] The invention relates to the technical field of integrated circuits, in particular to a differential amplifier for a two-stage analog-to-digital converter, a calibration circuit and a calibration method. Background technique [0002] In recent years, emerging information technologies such as big data, artificial intelligence, and the Internet of Things have developed rapidly, which has brought profound impacts on the economy and society. The development of these technologies is inseparable from the acquisition, quantification and processing of large amounts of data. Data quantification is an essential part of the whole process of data processing, which determines the quantity and quality of the entire data circulation. Data quantization is to convert an analog signal into a digital signal; a circuit that converts an analog signal to a digital signal is called an analog-to-digital converter. There are many types of analog-to-digital converters, includ...

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Problems solved by technology

Third, the speed of amplifiers based on negative feedback is often relatively slow. On the one hand, the bandwidth of the operational amplifier needs to be very wide. On the other hand, it takes a long time to obtain stable results.

Also, the amplification factor of an amplifier based on negative feedback is limited by the open-loop gain of the op amp

In addition, the high-precision high-gain operational amplifier circuit is complex and large-scale, often occupying a large area and high cost

When applied to amplify the residual voltage of an analog-to-digital converter, a fully differential operational amplifier circuit connected in a negative feedback manner is difficult to integrate on-chip

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