Multipath Digital Microphones With Adaptive ADC Range Switching
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Solution Overview
Problem
Conventional digital microphones face challenges in achieving high dynamic range (DR) while maintaining low power consumption, which is essential for small, mobile, and feature-rich consumer devices.
Innovation Solution
The development of adaptive analog-to-digital converter (ADC) range multipath digital microphones, which employ a plurality of digital audio filters and adaptive ADCs to adjust gain based on sound pressure level thresholds, minimizing power consumption while maintaining high DR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional digital microphones use high DR ADC or automatic gain control amplifier to improve dynamic range, then dynamic range is improved, but power consumption increases excessively
Solution Approach 1:
The patent divides the audio signal processing into multiple parallel paths, each with its own ADC operating at different gain levels. Instead of using a single high-DR ADC that consumes excessive power, the system segments the DR requirement across multiple lower-power ADCs, where each handles a specific portion of the dynamic range through adaptive gain control.
Solution Approach 2:
The patent implements dynamic gain adjustment in the multipath architecture where ADCs can adaptively change their gain levels based on the input signal characteristics. This dynamic adaptation allows the system to maintain high effective dynamic range while consuming less power by adjusting ADC operating points in real-time rather than using a fixed high-DR configuration.
2Use of energy by stationary object
If conventional digital microphones reduce power consumption to meet mobile device requirements, then power efficiency is improved, but dynamic range performance deteriorates
Solution Approach 1:
The patent merges multiple parallel signal paths, each with its own ADC operating at different gain levels, into a unified output. By combining the outputs of these lower-power ADCs through adaptive mixing and gain control, the system achieves the dynamic range performance of a high-DR ADC while maintaining lower overall power consumption.
Solution Approach 2:
The patent changes the operating parameters (gain levels) of multiple ADCs dynamically based on the input signal conditions. By adjusting the gain parameters of individual ADCs in the multipath architecture, the system can maintain optimal dynamic range performance across varying signal levels while keeping each ADC operating at lower power consumption levels.
3Measurement precision
If automatic gain control amplifier is used to lower ADC DR requirements, then ADC DR requirements are reduced, but troublesome artifacts are introduced
Solution Approach 1:
The patent replaces the conventional automatic gain control amplifier approach with a digital signal processing-based multipath combining algorithm. Instead of using analog AGC circuitry that introduces artifacts, the system uses digital adaptive mixing and gain control in the multipath architecture, which maintains signal fidelity while achieving the same effect of reducing ADC DR requirements.
4Measurement precision
If multipath approach with combining algorithm is used, then ADC DR requirements are reduced, but instantaneous saturation effects occur
Solution Approach 1:
The patent applies preliminary gain control and signal conditioning in each parallel path before the ADCs to prevent instantaneous saturation. By pre-adjusting the signal levels and applying protective gain control measures in advance in each path, the system avoids saturation effects that would otherwise occur during the combining process, while still maintaining reduced ADC DR requirements.
Data Source
AI summary
Exemplary multipath digital microphone described herein can comprise exemplary embodiments of adaptive ADC range multipath digital microphones, which allow low power to be achieved for amplifiers or gain stages, as well as for exemplary adaptive ADCs in exemplary multipath digital microphone arrangements described herein, while still providing a high DR digital microphone systems. Further non-limiting embodiments can comprise an exemplary glitch removal component configured to minimize audible artifacts associated with the change in the gain of the exemplary adaptive ADCs.