Capacitance-to-digital converter for eliminating parasitic based on SAR logic

Abstract

The invention discloses a capacitance-to-digital converter for eliminating parasitic based on SAR logic, belongs to a new generation information technology, and aims to solve the problem that the overall performance of a capacitance-to-digital converter in the prior art is insufficient. Cycle-by-cycle compensation is conducted through a parasitic compensation current source array, and the parasitic capacitance influence of a measurement channel can be eliminated. By realizing the conversion from capacitance change to continuous time, the limitation of the traditional C / V structure is overcome,and the capacitance detection range is improved. A two-stage TDC quantization structure is adopted, the contradiction between the capacitance detection range and the detection precision is overcome,and high-dynamic-range and high-precision capacitance detection is achieved. Except a front-end CT conversion circuit, other circuits are all digital circuits, and the area and the power consumption are optimized. Therefore, the method can be widely applied to capacitance detection and sensing in a complex environment, and is suitable for highly integrated sensing circuits.

Description

Technical field[0001]The invention relates to a capacitance-to-digital converter, in particular to a capacitance-to-digital converter based on SAR logic to eliminate parasitics.Background technique[0002]The capacitance-to-digital converter has the advantages of small size, light weight, low power consumption, and so on. With the increasing development of capacitance-to-digital converters, its measurement accuracy, reliability and other aspects have been continuously improved, and it has been widely used in biomedical and short-range sensing, as well as on touch screens. As the detection environment becomes more complex and requires faster conversion speeds, capacitance-to-digital converters need to have high resolution, high parasitic tolerance, high linearity, and environmental interference resistance.[0003]In the monolithic integrated system, the traditional capacitance-to-digital conversion scheme uses a charge amplifier to convert the capacitance value into a voltage value by ch...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a capacitance-to-digital converter based on SAR logic to eliminate parasitics, to overcome the linearity and dynamic range limitation of traditional ADC capacitance-to-digital converters, and to eliminate the impact of high parasitic capacitance on capacitance detection accuracy through SAR logic , to improve the anti-interference ability of the capacitance-to-digital converter

Images