SAR ADC Filtering Control to Cut Circuit Area
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Solution Overview
Problem
Conventional A/D converters require additional filters to achieve desirable signal conversion performance, increasing circuit area and manufacturing costs.
Innovation Solution
A successive approximation A/D converter with a filtering control circuit that adjusts the sampled analog voltage based on previous digital voltage conversions, effectively filtering the signal without the need for an additional filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an additional filter is used to filter the analog signal before A/D conversion, then the signal conversion performance is improved, but the circuit area and manufacturing cost increase
Solution Approach 1:
The patent merges the filtering function with the A/D converter by using the sample circuit to perform both sampling and filtering operations. The sample circuit adjusts the sampled analog voltage based on previous conversion results, effectively combining what were previously separate functions (filtering and conversion) into a single integrated circuit, thereby improving signal performance without increasing circuit area
Solution Approach 2:
The sample circuit is designed to perform multiple functions: it not only samples the analog signal but also performs filtering by adjusting the sampled voltage based on previous conversion results. This multi-functional design eliminates the need for a separate filter component, reducing circuit area while maintaining signal conversion performance
2Measurement precision
If an additional filter is used to filter the analog signal before A/D conversion, then the signal conversion performance is improved, but the manufacturing cost increases
Solution Approach 1:
The patent merges the filtering function with the A/D converter by using the sample circuit to perform both sampling and filtering operations. The sample circuit adjusts the sampled analog voltage based on previous conversion results, effectively combining what were previously separate functions (filtering and conversion) into a single integrated circuit, thereby improving signal performance without increasing circuit area
Solution Approach 2:
The sample circuit is designed to perform multiple functions: it not only samples the analog signal but also performs filtering by adjusting the sampled voltage based on previous conversion results. This multi-functional design eliminates the need for a separate filter component, reducing circuit area while maintaining signal conversion performance
3Measurement precision
If a digital filter is used after A/D conversion, then the signal conversion performance is improved, but the circuit area increases
Solution Approach 1:
The patent performs filtering action preliminarily during the sampling stage rather than after conversion. The sample circuit adjusts the analog voltage before conversion based on previous results, effectively performing the filtering function in advance. This eliminates the need for a separate digital filter stage, reducing circuit area while achieving the desired signal performance
Data Source
AI summary
A successive approximation analog to digital converter and a conversion method thereof are provided. The successive approximation analog to digital converter includes a sample circuit, a conversion circuit, and a filtering control circuit. The sample circuit is configured to sample an analog voltage from an analog signal. The conversion circuit is configured to convert the analog voltage into a digital voltage. The filtering control circuit is configured to transmit a filtering control signal to the sample circuit according to the digital voltage. The sample circuit further samples a next analog voltage from the analog signal and adjusts the next analog voltage into an adjusted analog voltage according to the filtering control signal. The conversion circuit further converts the adjusted analog voltage into a next digital voltage, wherein the next digital voltage is a filtered digital voltage.