SAR ADC Comparator Offset Calibration for Low-Noise Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-resolution successive approximation register analog-to-digital converters face performance limitations due to comparator noise and switch noise, which are not effectively addressed by existing technologies.
Innovation Solution
An analog-to-digital converter design that performs offset calibration using comparison circuits without a separate reference comparison circuit, allowing for sequential calibration of comparison results across multiple bits, reducing noise and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate reference comparison circuit is added for offset calibration, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the offset calibration function with the existing comparison circuits by reusing their structure and resources. The comparison circuits perform both their original comparison function and the offset calibration function, eliminating the need for a separate reference comparison circuit and reducing overall device complexity while maintaining calibration accuracy
Solution Approach 2:
The comparison circuits are designed to perform multiple functions: they conduct both the primary comparison operation and the offset calibration operation. This multi-functionality allows the same hardware resources to serve dual purposes, improving measurement precision through calibration without adding separate dedicated calibration circuits
2Measurement precision
If sequential calibration is performed across multiple operation periods, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent performs offset calibration in advance during dedicated operation periods before the main conversion process. By completing calibration beforehand, the system ensures accurate measurements without compromising conversion speed during actual operation, as the calibration results are stored and reused
Solution Approach 2:
The calibration process is organized into periodic operation periods where comparison circuits are sequentially activated for calibration purposes. This structured periodic approach allows systematic calibration of multiple circuits while managing time consumption through efficient scheduling and resource allocation
3Measurement precision
If multiple comparison circuits are used for high-resolution conversion, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent divides the high-resolution conversion task into multiple segments, each handled by a separate comparison circuit responsible for specific bit ranges. This segmentation allows the system to achieve high resolution through coordinated operation of multiple specialized circuits rather than requiring a single complex circuit, managing complexity through functional division
Solution Approach 2:
Each comparison circuit is equipped with self-calibration capability, allowing it to automatically adjust its own offset without external intervention. This self-service approach reduces the need for complex external calibration mechanisms and simplifies the overall system architecture while maintaining high measurement precision across all circuits
Data Source
AI summary
An analog-to-digital converter is provided. The analog-to-digital converter includes: a sample/hold circuit; a digital-to-analog converter; a plurality of comparison circuits; a control logic; and a digital register, wherein the plurality of comparison circuits include: a first comparison circuit configured to output a first comparison result signal in a first operation period; a second comparison circuit configured to, in a second operation period, calibrate an offset of a second comparison result signal based on a reference signal corresponding to the first comparison result signal among a plurality of reference signals and output the calibrated second comparison result signal; and a third comparison circuit configured to, in a third operation period, calibrate an offset of a third comparison result signal based on a reference signal corresponding to the calibrated second comparison result signal and output the calibrated third comparison result signal.