Microphone ADC Common-Mode Sensing for Configuration Adaptation
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Solution Overview
Problem
Analog-to-digital converters (ADCs) are limited by the need to match specific microphone configurations, restricting their usability with different microphones and increasing device complexity and cost due to requirements for various coupling configurations and processing methods.
Innovation Solution
An ADC is configured to automatically detect the microphone configuration and adjust its operation accordingly, using two processing paths to process differential input signals and common mode signals, allowing a single ADC to work with various microphone topologies without the need for redesign or replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an ADC is designed to match a specific microphone configuration, then the ADC can process signals correctly for that configuration, but the ADC cannot be used with different microphone configurations, increasing device complexity and cost
Solution Approach 1:
The patent implements a universal ADC interface that can handle multiple microphone configurations (AC-coupled fully-differential, AC-coupled pseudo-differential, DC-coupled fully-differential, and DC-coupled pseudo-differential) through a single standardized interface. The system uses detection circuits to identify the microphone type and automatically configures the processing paths accordingly, eliminating the need for multiple specialized ADC designs and reducing device complexity while maintaining signal processing correctness across all configurations
2Adaptability or versatility
If different coupling configurations are implemented to support various microphone types, then the ADC can work with different microphones, but the device complexity and cost increase due to multiple processing methods
Solution Approach 1:
The patent divides the signal processing into separate detection and processing segments. A detection circuit first identifies the microphone configuration type, then the system activates only the relevant processing path for that specific configuration. This segmentation allows the system to support multiple microphone types while keeping the active processing path simple and optimized for the detected configuration, reducing overall device complexity
Solution Approach 2:
The system dynamically configures its processing paths based on the detected microphone type. Rather than having fixed, static processing circuits for each configuration, the system uses switches and control logic to dynamically activate the appropriate processing path, allowing a single ADC to adapt its behavior to match the connected microphone configuration, thereby reducing the need for multiple dedicated circuits
Data Source
Figure 1A~1D
Figure 1E~1G
Figure 2
AI summary
An analog-to-digital converter (ADC) may include capability to sense and/or compensate for undesired effects when receiving input from a microphone. For example, a sense node may be provided between differential inputs, and that sense node separated from the differential inputs by two or more switches. The sense node may allow for a measurement of an average voltage of the differential inputs. The average voltage may be obtained activating the switches to sample the sampling capacitors coupled to the differential inputs. That average voltage may be used as common mode (CM) data. A controller may receive the CM data, along with differential mode (DM) data, and use the CM and DM data to determine undesired effects, such as DC or AC mismatch at the microphone interface. The controller may then generate a signal for applying compensation to the differential inputs to reduce or eliminate the undesired effects.