Sigma-delta analog-to-digital converter adopting two-step process and hardware multiplexing

Abstract

The invention relates to the field of digital-analog hybrid integrated circuit design. In order to reducing the conversion time required by a high-accuracy sigma-delta analog-to-digital converter without greatly increasing the area and the power consumption and without increasing the analog circuit accuracy and matching degree requirements at the same time. Thus, the invention adopts the following technical scheme that a sigma-delta analog-to-digital converter adopting two-step process and hardware multiplexing is disclosed, the sigma-delta analog-to-digital converter comprises a switched capacitor integrator, a 1.5-bit analog-to-digital converter, a 1.5-bit digital-to-analog converter, an adder, a multiplexer, a register and a counter; the multiplexer comprises a linked switch S1 and a linked switch S3, an input signal is outputted by the linked switch S1, the adder, the switched capacitor integrator, the 1.5-bit analog-to-digital converter, the linked switch S1, the counter and another adder successively. The sigma-delta analog-to-digital converter of the invention is mainly used in digital-analog hybrid integrated circuits.

Description

technical field [0001] The invention relates to the field of digital-analog hybrid integrated circuit design, in particular to the design and circuit realization of an analog-to-digital converter. Specifically, it relates to a sigma-delta analog-to-digital converter using two-step processing and hardware multiplexing. technical background [0002] Where a high-precision analog-to-digital converter is required, a sigma-delta analog-to-digital converter is usually used, which is an oversampling analog-to-digital converter. Its advantage is that it has lower requirements for circuit matching and analog circuit indicators, but because its sampling frequency is much higher than that of the Nyquist sampling rate analog-to-digital converter, it is slower, so the sigma-delta analog-to-digital converter Commonly used for low-speed (usually lower than audio) high-precision analog-to-digital conversion. To achieve 10-bit accuracy using a 1st-order sigma-delta ADC requires at least 2 ...

AI Technical Summary

Problems solved by technology

[0004] Circular ADC and pipeline ADC are faster ADCs, but their accuracy is limited because they depend on the matching degree of devices in integrated circuits. high demands

Because of the above limitations, they have encountered great difficulties in the realization of high precision, especially the precision above 12 bits

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