SAR ADC Dynamic Comparator Threshold for DAC Mismatch Accuracy
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Solution Overview
Problem
Existing successive approximation register analog-to-digital converters face limitations in accuracy and efficiency due to exclusive compensation methods for digital-to-analog converters, leading to reduced performance in analog-to-digital conversion.
Innovation Solution
An advanced successive approximation register analog-to-digital converter is developed, incorporating a comparator with a threshold voltage determining unit that dynamically sets the threshold voltage based on input or output signals, and a sample-and-hold unit, allowing for iterative adjustments to compensate for digital-to-analog converter mismatches, thereby enhancing accuracy and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If exclusive compensation is performed with respect to the digital-to-analog converter using a switch capacitor array, then the device complexity is reduced, but the measurement precision and conversion accuracy deteriorate
Solution Approach 1:
The patent merges the compensation function into the comparator unit itself, combining the threshold voltage determining unit with the comparator to form an integrated compensation mechanism. This integration allows simultaneous compensation for both digital-to-analog converter mismatches and comparator offset errors, resolving the contradiction by achieving high precision without proportionally increasing device complexity through separate compensation circuits.
Solution Approach 2:
The comparator unit is designed to perform multiple functions: it not only compares voltages but also dynamically determines and adjusts its own threshold voltage to compensate for mismatches. This multi-functionality allows the same hardware component to address multiple sources of error, improving measurement precision without adding dedicated compensation hardware for each error source.
2Device complexity
If a static threshold voltage is used in the comparator, then the device complexity is minimized, but the conversion efficiency and accuracy deteriorate due to inability to adapt to signal variations
Solution Approach 1:
The threshold voltage is transformed from a static parameter to a dynamic one that automatically adjusts based on the input signal characteristics. The threshold voltage determining unit continuously adapts the threshold level during the conversion process, enabling the comparator to maintain optimal performance across varying signal conditions without requiring complex external control mechanisms.
Solution Approach 2:
The comparator unit performs self-adjustment by dynamically determining its own threshold voltage based on the signal being processed. This self-service capability eliminates the need for external threshold control circuits, maintaining device simplicity while achieving adaptive efficiency through autonomous threshold optimization during conversion operations.
3Area of stationary object
If the digital-to-analog converter size is reduced to improve integration, then the area is saved, but the settling time increases and accuracy deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the comparator's dynamic threshold adjustment compensates for the reduced precision caused by smaller digital-to-analog converter capacitors. The feedback loop continuously monitors conversion results and adjusts the threshold voltage accordingly, allowing the system to maintain high accuracy despite the reduced physical size of the converter components.
Data Source
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AI summary
An advanced successive approximation register analog-to-digital converter (10) is provided. Said advanced successive approximation register analog-to-digital converter (10) comprises a digital-to-analog converter (11), a successive approximation register (12), a comparator (13), and a threshold voltage determining unit (14). In this context, the threshold voltage determining unit (14) is configured to dynamically determine the respective threshold voltage of the comparator (13) on the basis of the respective input signal of the digital-to-analog converter (11) or the respective output signal of the comparator (13).