Digital Microphone SA Quantizer Code Reuse for Lower Power
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Solution Overview
Problem
Digital microphone and sensor assemblies with successive-approximation (SA) quantizers face high power consumption due to the continuous generation of new digital codes, especially in applications with narrow frequency bands where code repetition is frequent.
Innovation Solution
The SA quantizer is configured to reuse digital codes generated in previous sample periods when the difference between the current sample and the previous analog output is less than a certain threshold, thereby bypassing the search for a new digital code and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the SA quantizer continuously generates new digital codes for each sampled input signal, then the digital code accuracy is maintained, but the power consumption increases significantly
Solution Approach 1:
The patent applies partial action by performing the full successive-approximation search only when necessary (when code change is detected in the compressed domain) rather than for every sample. The quantizer performs partial processing by working in the compressed domain using exponent and mantissa values, generating full digital codes only when the reuse condition is not met, thereby reducing overall power consumption while maintaining accuracy when needed
Solution Approach 2:
The patent uses copying by working with compressed representations (exponent and mantissa values) of the input signal rather than full digital codes. The compressed domain values serve as copies that consume less power to process, and full digital codes are generated only when necessary based on comparison of these compressed representations
2Measurement precision
If the SA quantizer performs successive-approximation search for every sample, then the digital code generation accuracy is ensured, but the processing time increases
Solution Approach 1:
The patent applies partial action by performing the computationally intensive successive-approximation search only when necessary (when code change is detected) rather than for every sample. The system performs partial processing in the compressed domain first, then proceeds to full code generation only when the reuse condition is not met, thereby reducing processing time while maintaining accuracy when needed
3Measurement precision
If the quantizer elements (SC-DAC, comparator, SA logic) operate continuously, then the signal processing accuracy is maintained, but the power consumption increases
Solution Approach 1:
The patent applies periodic action by operating the quantizer elements (SC-DAC, comparator, SA logic) only periodically when code changes are detected, rather than continuously for every sample. The system uses periodic full code generation based on compressed domain comparisons, allowing these power-consuming elements to remain inactive during periods where the output code remains the same, thereby reducing overall power consumption while maintaining signal processing accuracy when needed
Data Source
AI summary
The present disclosure relates generally to digital microphone and other sensor assemblies including a transduction element and a successive-approximation (SA) quantizer configured to reuse a digital code generated for a prior sample period for a current sample period when a reuse condition is satisfied. The SA quantizer does not regenerate a new digital code for the current sample period when the digital code generated for the prior sample period is used thereby reducing power consumption.