Speaker as Microphone for Power Reduction in Mobile Devices
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Solution Overview
Problem
Capacitive microphones in mobile devices consume significant power, limit audio performance, especially for high-volume sounds, and increase device cost when dual microphones are used to address these issues.
Innovation Solution
A mobile device design that utilizes a speaker as a microphone, with a controller processing signals from both speakers to determine sound characteristics and select the appropriate speaker for sound reception or emission based on volume and frequency, allowing for efficient power use and improved audio performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If capacitive microphones are used for voice activation in sleep mode, then voice command detection is enabled, but power consumption increases significantly
Solution Approach 1:
The speaker is designed to perform multiple functions: it can generate sound for audio output and also function as a microphone for voice input. By using the same component for both transmission and reception, the patent eliminates the need for separate microphone hardware during sleep mode, thereby reducing power consumption while maintaining voice command detection capability
Solution Approach 2:
The patent combines the speaker and microphone functions into a single component. The speaker assembly includes both a speaker driver for sound generation and a microphone element for sound reception, allowing the device to use one component for both audio output and voice activation input during low-power states
2Measurement precision
If capacitive microphones are used for high-volume sound recording, then audio performance is limited, but amplifier circuitry increases power consumption and cost
Solution Approach 1:
The speaker assembly is designed to handle both low-volume and high-volume sound scenarios. The same speaker component can function as a microphone across a wide dynamic range, eliminating the need for separate amplifier circuitry and bias electronics that would increase power consumption and cost
Solution Approach 2:
The patent changes the operational parameters of the speaker when used as a microphone, allowing it to detect sounds across a wide volume range including high-volume sounds like rock concerts. The speaker's mechanical design allows it to respond to both subtle and intense acoustic signals without requiring additional amplification stages
3Measurement precision
If dual capacitive microphones are included for low and high-volume sounds, then audio performance is improved, but device cost increases
Solution Approach 1:
The speaker assembly serves as both a speaker and a microphone, eliminating the need for separate microphone components. This multi-functional design reduces the total number of parts required in the device while maintaining the capability to handle both low-volume and high-volume sound scenarios
Solution Approach 2:
The patent merges the speaker and microphone functions into a single integrated assembly. By combining these functions, the device avoids the cost and complexity of including dual microphones or other additional audio components
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces power consumption, enhances audio performance by utilizing speakers as microphones for high-volume sounds, and selectively optimizes speakers for transmission or reception, thereby extending battery life and reducing component costs.
Implementation Method 1
a signal induced at least in part by sound incident on the speaker other than sound generated by the speaker
Data Source
AI summary
In accordance with methods and systems of the present disclosure, a mobile device may include an enclosure adapted such that the enclosure is readily transported by a user of the mobile device, a speaker associated with the enclosure for generating sound, and a controller within the enclosure, communicatively coupled to the speaker. The controller may be configured to receive a signal from the speaker, the signal induced at least in part by sound incident on the speaker other than sound generated by the speaker and process the signal.