Hybrid Delta-Sigma SAR ADC for High Resolution at Lower Conversion Time
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Solution Overview
Problem
Existing analog to digital converters face challenges in achieving high resolution without incurring substantial conversion time or noise, with delta-sigma converters requiring excessive samples for high resolution and SAR converters providing quick but often inaccurate results.
Innovation Solution
A hybrid approach combining delta-sigma and SAR based analog to digital converters, where the delta-sigma converter provides the most significant bits and the SAR converter handles the residue to produce a combined result, allowing for high resolution with reduced conversion time and maintained noise performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If delta-sigma modulation technique is used to achieve high resolution, then measurement precision is improved, but loss of time increases exponentially
Solution Approach 1:
The patent divides the conversion process into two distinct stages: a first conversion stage that produces an initial digital output, and a second conversion stage that processes the residue from the first stage to generate additional bits. This segmentation allows the system to achieve high resolution without requiring all conversions to follow the time-consuming delta-sigma approach throughout, thereby reducing total conversion time while maintaining measurement precision.
Solution Approach 2:
The patent dynamically switches between different conversion techniques based on the stage of conversion. The first conversion stage uses one technique (delta-sigma or SAR) to establish the most significant bits, then the system transitions to a second stage using a different technique to refine the result. This dynamic adaptation allows optimization of both speed and precision at different phases of the conversion process.
2Measurement precision
If delta-sigma modulation technique is used to achieve high resolution, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent employs a unified converter structure capable of operating in multiple modes or stages. The same hardware infrastructure supports both the first conversion stage and the second conversion stage, with the ability to switch between different conversion techniques (delta-sigma and SAR) without requiring completely separate dedicated circuits for each. This multi-functionality reduces overall device complexity compared to having separate specialized converters for each stage.
Solution Approach 2:
The patent merges the functionality of multiple conversion techniques into a single integrated converter system. By combining the first conversion stage and second conversion stage into one unified device that can execute different conversion algorithms in sequence, the patent reduces the complexity that would arise from implementing separate standalone converters for each conversion type.
3Loss of time
If SAR based converter is used for quick conversion, then loss of time is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent segments the precision requirements into two parts: the first conversion stage handles the most significant bits where speed is prioritized, and the second conversion stage handles the less significant bits where additional precision is refined. This segmentation allows the system to use faster conversion techniques for the bulk of the conversion while still achieving high overall precision through the subsequent refinement stage.
Solution Approach 2:
The patent dynamically adjusts the conversion approach by using a first conversion technique for the initial digital output and then switching to a second conversion technique for residue processing. This dynamic transition allows the system to leverage the speed advantages of SAR-like approaches in the first stage while maintaining precision through the second stage, effectively combining the strengths of different methods.
Data Source
AI summary
Various systems and methods for capturing data are disclosed. For example, some embodiments of the present invention provide methods for performing a first analog to digital conversion using a delta-sigma based analog to digital converter, and performing a second analog to digital conversion using a SAR based analog to digital converter. The delta-sigma converter provides a first portion of a conversion result, and the SAR based analog to digital converter provides a second portion of the conversion result. The methods further include combining the first portion of the conversion result with the second portion of the conversion result to produce a combined conversion result.