Novel high-precision capacitor self-calibration analog-to-digital converter of successive approximation type

Abstract

The invention discloses a novel high-precision capacitor self-calibration analog-to-digital converter of a successive approximation type, and the converter is characterized in that the converter comprises a plurality of adjustment capacitor arrays, a calibration storage unit, a successive approximation control logic unit, and a calibration control logic unit; each to-be-adjusted sampling capacitor Ci is connected with one adjustment capacitor array; each adjustment capacitor array comprises a compensation capacitor and a residual capacitor; the upper electrode plate of each compensation capacitor and the upper electrode plate of each residual capacitor are respectively connected with a common end of the upper electrode plate of the corresponding sampling capacitor; the lower electrode plate of each compensation capacitor and the lower electrode plate of the sampling capacitor Ci; the lower electrode plate of each residual capacitor is connected with the lower electrode plate of the sampling capacitor Ci+1; the output end of a comparator is connected with the calibration storage unit through a gating switch and the calibration control logic unit; the calibration storage unit is connected with the switching control end of each compensation capacitor and the switching control end of each residual capacitor; the output end of the comparator is connected with the switching control end of the lower electrode plate of each sampling capacitor through the gating switch and the successive approximation control logic unit.

Description

technical field [0001] The invention belongs to the technical field of microelectronics, and is a novel high-precision successive approximation analog-to-digital converter (SAR ADC) based on capacitance self-calibration technology. Background technique [0002] With the development of information technology, many portable instruments and electronic products require an analog-to-digital converter (ADC) with high precision and low power consumption. At the same time, the ADC is required to be small in size, high in reliability and good in stability. As a key module of the interface circuit between analog system and digital system, ADC is widely used in radar, communication, measurement and control, medical treatment, instrumentation, image and audio and other fields. Its function is to convert the external analog quantity into the corresponding numerical code, and only through the ADC can the acquisition and processing of the external signal be completed. At the same time, th...

AI Technical Summary

Problems solved by technology

Digital calibration technology is to describe the influence of mismatch error in the circuit in the digital field, and correct the output code in the digital field, but the accuracy of calibrating the digital output code with this method depends on the accuracy of the calibration parameters, and currently Digital calibration technology generally has the problem of inaccurate calibration parameters

Analog calibration technology uses lasers to correct chip components or adjust related quantities to normal values ​​in the analog field. The cost of laser correction technology is high and it is easily affected by mechanical stress during packaging.

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