SAR ADC Noise Cancellation Using Matched Comparator Inputs

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Solution Overview

Problem

Existing SAR-type analog-to-digital converters (ADCs) are affected by noise components, which degrade their performance and lead to incorrect digital signal data output.

Innovation Solution

The proposed ADC structure includes a digital-to-analog converter (DAC) that adds a noise component to both the analog input signal and the converted analog signal, ensuring that the same noise is applied to both inputs of the comparator, thereby canceling out the noise's influence on the comparison result.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If noise components are present in the ADC system, then the ADC can operate in realistic environments, but the measurement precision degrades and incorrect digital signal data is output

Engineering Contradiction:

Improveoperation in noisy environmentsVSAvoiddigital signal conversion accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent generates artificial noise components and adds them to both the analog input signal and the DAC output signal. By intentionally introducing controlled noise to both comparator inputs, the artificial noise cancels out the effect of environmental noise on the comparison result, thereby maintaining measurement precision in noisy environments

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent preemptively adds noise components to the signals before they enter the comparator. The noise is generated and applied in advance to both the analog input signal and the DAC output signal, creating a protective effect that counteracts the harmful influence of environmental noise on the ADC operation

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS20250150090A1Analog-to-digital converter and operation method thereof

Publication Date: 2025.05.08 SK KEYFOUNDRY INC

AI summary

An analog-to-digital converter (ADC) and an operation method thereof are provided. The ADC includes: a comparator which compares a signal input through a first input terminal and a signal input through a second input terminal, and outputs an output value according to the comparison result. A successive approximation register receives the output value of the comparator, sets digital signal values from a most significant bit to a least significant bit, and outputs the digital signal values. A digital-to-analog converter receives the digital signal values, and converts it into an analog signal based on a reference voltage Vref, and outputs it to the second input terminal. A noise component is added to the input signal and to the analog signal Vdac'.