Successive approximation type analog-to-digital converter of self-calibration bridge-connection capacitor structure

Abstract

The invention belongs to the technical field of analog-to-digital converters and particularly relates to a successive approximation type analog-to-digital converter of a self-calibration bridge-connection capacitor structure. The successive approximation type analog-to-digital converter of the self-calibration bridge-connection capacitor structure comprises a sample hold circuit, a comparer, a logic control circuit, a digital-to-analog converter and a calibrating circuit, wherein the capacitor-type digital-to-analog converter is of a redundant capacitor bridge-connection structure, and a redundant capacitor and an auxiliary capacitor are added in the bridge-connection structure; meanwhile, a calibrating algorithm is built in a calibration control unit and a calibration processing unit, and nonlinear characteristics caused by mismatch and parasitism of a manufacturing process in the bridge-connection capacitor structure are measured through the redundant capacitor bridge-connection structure in the calibration detection stage; in the normal analog-to-digital converting process, the calibration processing unit performs postprocessing on digital output of the analog-to-digital converter according to detected nonlinear information and outputs a calibrated digital signal.

Description

technical field [0001] The invention belongs to the technical field of analog-to-digital converters, and in particular relates to a successive approximation analog-to-digital converter. Background technique [0002] An analog-to-digital converter (ADC) is a device that converts continuous analog signal acquisition into discrete digital signals for digital analysis and processing. The successive approximation analog-to-digital converter (SAR ADC) uses the binary search method to continuously generate new analog voltages through the internal integrated digital-to-analog converter (DAC) to approximate the original input analog signal, and finally convert the integrated digital-to-analog The digital input corresponding to the device (DAC) is used as the output of the ADC. [0003] figure 1 Shown is a typical structure of a SAR ADC, and the SAR ADC 100 has a sample-and-hold circuit 110, a comparator 120, a logic control unit 130, and a digital-to-analog converter 140. The digi...

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Problems solved by technology

[0008] The purpose of the present invention is to solve the bridging non-linear problem of the bridging capacitor structure SAR ADC due to the limitations of semiconductor technology such as matching and parasitic, and propose a successive approximation analog-to-digital converter with a self-calibrating bridging capacitor structure

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