Differential Silicon Microphone Signal-to-Noise Ratio
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Solution Overview
Problem
Existing silicon-based microphones have a limited signal-to-noise ratio, which affects the quality of audio output due to inadequate interference rejection and noise reduction.
Innovation Solution
A silicon-based microphone device with at least two differential silicon-based microphone chips, where the first and second microphone structures are electrically connected, forming a sound cavity with sound inlet holes, and a control chip for differential signal processing to enhance the signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single silicon-based microphone chip is used, then the device structure is simple, but the signal-to-noise ratio is low due to inadequate noise rejection
Solution Approach 1:
The patent divides a single microphone chip into two separate microphone structures (first and second microphone structures) on the same chip. Each structure has its own diaphragm and back cavity, allowing independent sound signal acquisition. This segmentation enables differential processing to reject common-mode noise while maintaining the integrated chip architecture.
Solution Approach 2:
The patent combines two microphone structures onto a single silicon-based chip substrate, integrating multiple functional elements (diaphragms, back cavities, electrode structures) into one unified device. This merging achieves noise rejection through differential signaling while avoiding the complexity of multiple separate chips and their associated alignment and sealing requirements.
2Reliability
If traditional electret microphones are used, then the manufacturing is simple, but the audio quality and noise performance are insufficient
Solution Approach 1:
The patent replaces traditional electret microphone mechanisms (which rely on charged particles and mechanical diaphragms) with a silicon-based MEMS structure using capacitive sensing. The silicon chip incorporates precisely fabricated diaphragms, back cavities, and electrode structures that convert sound pressure into electrical signals through capacitance changes, offering superior noise performance and audio quality while maintaining manufacturability through semiconductor fabrication processes.
3Measurement precision
If the microphone chip is fully sealed, then external noise interference is reduced, but sound signal acquisition is blocked
Solution Approach 1:
The patent segments the acoustic environment by creating separate sound inlet paths for each microphone structure. Each structure has its own back cavity that is isolated from the other, allowing sound signals to reach each diaphragm independently while maintaining acoustic isolation between the two sensing paths. This enables differential noise rejection without compromising sound signal acquisition.
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
The arrangement increases the sound signal amplitude while reducing common-mode noise, thereby improving the tone quality and signal-to-noise ratio, leading to better acoustic performance.
Implementation Method 1
a silicon-based microphone chip in the microphone generates a vibration due to a sound wave acquired therefrom, and the vibration brings about a variation in capacitance that may form an electrical signal, thereby converting the sound wave into an electrical signal to be output
Data Source
AI summary
Provided are a silicon-based microphone device and an electronic device. The silicon-based microphone device comprises a circuit board, a shielding housing and at least two differential silicon-based microphone chips, wherein at least two sound inlet holes are provided on the circuit board, the shielding housing covers one side of the circuit board and forms a sound cavity with the circuit board, the silicon-based microphone chips are all located inside the sound cavity, the differential silicon-based microphone chips are respectively disposed at the sound inlet holes, and a back cavity of each differential silicon-based microphone chip is communicated with the sound inlet hole at the corresponding position, each of the differential silicon-based microphone chips comprises a first microphone structure and a second microphone structure, all of the first microphone structures are electrically connected, and all of the second microphone structures are electrically connected.