Comparator offset calibration device and calibration method based on majority voting

Abstract

The invention discloses a comparator offset calibration device based on majority voting. The comparator offset calibration device comprises an input signal detection module, a clock frequency divisionmodule, a majority voting circuit, a shift counting circuit and a resistor string analog-to-digital conversion module. The method comprises: detecting whether two input signals are the same or not through a two-input exclusive-OR gate, and using an output signal is as a clock signal of the majority voting circuit; generating a control signal according to a result obtained by voting, and controlling an output code of a shift counter to move leftwards or rightwards; and by an output code of the shift counter, controling the resistor string analog-to-digital conversion circuit, so that the VCALPand the VCALN are respectively reduced by one step length and increased by one step length. According to the invention, a calibration error caused by noise during offset calibration can be effectively reduced by adopting the three-out-of-five majority voting circuit, so that the calibration accuracy is greatly improved.

Description

technical field [0001] The invention relates to the technical field of successive approximation analog-to-digital converters, in particular to a comparator offset calibration device and calibration method based on majority voting. Background technique [0002] Successive approximation analog-to-digital converter (SAR ADC) is a kind of analog-to-digital converter that is widely used at present. It has the advantages of low power consumption and simple structure, and it shows more and more obvious advantages in the case of shrinking process size. , suitable for various mobile devices and communication devices with low power consumption requirements. [0003] For some SAR ADCs that need to use multiple comparators to quantify the input signal, the offset between different comparators is one of the determining factors that cause nonlinear errors in the output results, so the calibration of the comparator offset is necessary. It is a more popular calibration method to provide a...

AI Technical Summary

Problems solved by technology

However, due to the influence of noise in addition to the offset mismatch between comparators in the actual circuit, we cannot judge how much of the error in the quantization result of the comparator is caused by the offset, even if there is no offset. Such an offset calibration circuit may also produce wrong offset calibration due to the influence of noise, which limits the accuracy of the circuit calibration

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