Delta-Sigma ADC Capacitor Swapping for Mismatch Suppression
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Solution Overview
Problem
Circuit mismatch issues in delta-sigma modulation-based analog-to-digital converters pose challenges in achieving accurate signal conversion due to nonlinearity and power supply noise, which existing designs struggle to effectively address.
Innovation Solution
The proposed analog-to-digital converter incorporates a modulation unit with a swapping design of input and integration capacitors, operational amplifiers, and feedback control circuits, where capacitors and feedback amounts are coupled in a swapping manner to switch between positive and negative paths, effectively mitigating circuit mismatch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a differential pair architecture is used for delta-sigma modulation, then power supply noise suppression and circuit nonlinearity reduction are improved, but circuit mismatch problems arise that affect signal conversion accuracy
Solution Approach 1:
The patent merges the differential pair architecture with a swapping mechanism that periodically exchanges the positions of capacitors and feedback paths. This combination allows the circuit to maintain the noise suppression benefits of differential architecture while compensating for mismatch errors through temporal averaging of swapped configurations.
Solution Approach 2:
The patent implements periodic swapping of capacitor positions and feedback paths at a frequency higher than the signal bandwidth. This periodic action causes mismatch errors to oscillate and average out over time, effectively reducing their impact on signal conversion accuracy while maintaining continuous operation.
2Measurement precision
If circuit mismatch is reduced through matching circuit design, then signal conversion accuracy is improved, but circuit complexity increases
Solution Approach 1:
The patent introduces dynamic swapping of capacitor positions and feedback paths, transforming a static mismatch problem into a dynamic one. Instead of requiring perfectly matched components, the system uses controlled temporal variation to average out mismatches, reducing the need for complex precision matching circuits.
Solution Approach 2:
The patent employs feedback paths that are swapped along with the capacitors. The feedback mechanism, combined with the swapping action, allows the system to self-correct for mismatch errors by comparing and averaging results from different configurational states, reducing the need for complex preliminary matching.
3Measurement precision
If swapping design is implemented for capacitors and feedback paths, then circuit mismatch is minimized and signal conversion accuracy is improved, but device complexity increases
Solution Approach 1:
The patent segments the modulation unit into distinct swappable components (capacitors and feedback paths) that can be independently controlled and exchanged. This segmentation allows the swapping mechanism to be implemented in a modular fashion, managing complexity through structured organization of interchangeable elements.
Data Source
AI summary
An analog-to-digital converter with delta-sigma modulation and the modulation unit thereof are disclosed, wherein, for each modulation unit, a pair of input capacitors, a pair of integration capacitors and a differential feedback are operated in a swapping manner for the positive path and the negative path, such that circuit mismatch problems are effectively removed.