Double-Sampled Sigma-Delta Modulator Feedback Reset Sequencing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Double-sampled sigma-delta modulators (SDM) face performance degradation due to mismatched feedback elements, leading to increased in-band noise floor and reduced signal-to-noise ratio (SNR) caused by non-idealities in electronic components and lack of proper reset mechanisms.
Innovation Solution
Implementing a method where three feedback elements are selected sequentially across clock half-cycles, with each element being reset before reuse, using a logic block and memory to manage selection based on identifiers and counters to ensure integrity of sampled data and mitigate mismatch effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If redundant feedback elements are reused without reset in a double-sampled SDM, then device complexity is reduced, but manufacturing precision deteriorates due to charge carryover and sample contamination
Solution Approach 1:
The patent applies preliminary action by resetting the selected feedback element before it is reused in a subsequent half-cycle. The reset operation clears any stored charge or memory from the previous sample, ensuring that the feedback element starts fresh for the next sampling event. This prevents charge carryover and sample contamination while maintaining the benefit of reusing redundant feedback elements.
2Device complexity
If traditional SDM uses finite gain op-amp without explicit reset, then device complexity is reduced, but reliability deteriorates due to non-idealities and instability
Solution Approach 1:
The patent applies preliminary action by performing a reset operation on the feedback element before its reuse. This reset clears any accumulated charge or memory effects from the operational amplifier, eliminating the instability caused by finite gain and non-idealities. The reset ensures that each sampling event starts with a clean state, improving reliability without significantly increasing device complexity.
3Ease of operation
If feedback elements are selected without restriction, then ease of operation is improved, but measurement precision deteriorates due to mismatch modulation
Solution Approach 1:
The patent applies preliminary action by resetting the selected feedback element before reuse. This ensures that when the same feedback element is selected again, it starts with a clean state rather than carrying over charge from previous operations. The reset operation eliminates the modulation of mismatch with high-frequency quantizer output, preventing in-band error components and improving measurement precision.
Data Source
AI summary
In an apparatus and method for improving performance of a third order, double-sampled, sigma-delta modulator (SDM), a first one of three feedback elements included in a feedback loop of the SDM is selected to complete the feedback loop during a first half-cycle of the clock used for the double-sampling. The first one is restricted from being reselected during a subsequent half-cycle of the clock until the first one is reset. A second one of the three feedback elements is selected during a second half-cycle of the clock that is consecutive to the first half-cycle, the second one being different than the first one. A third one of the three feedback elements is selected during a third half-cycle of the clock that is consecutive to the second half-cycle, the third one being different than the second one.