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US 2020/0052668 A1Published application
Capacitive mems microphone with active compression
AssigneeChaoyang Semiconductor Jiangyin Technology Co., Ltd.
InventorHassan Ihs
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Abstract
A digital microphone compresses a large voltage swing signal from a MEMS capacitor to a signal suitable for processing by integrated circuitry. The compression may be performed in an analog domain by selectively coupling adjustment capacitors in parallel to the MEMS capacitor. The digital microphone may decompress the signal in the digital domain using a decompression technique substantially an inverse of the compression performed in the analog domain.
Claims14
A digital microphone, comprising:
- a microelectromechanical system (MEMS) capacitor;
- a plurality of adjustment capacitors selectively coupleable in parallel to the MEMS capacitor, the adjustment capacitors selectively coupleable to the MEMS capacitor to achieve a compression in the form of x/(1+N|x|) of a voltage output of the MEMS capacitor, N being a compression index number greater than 1;
- and
- a processing chain coupled to one side of the MEMS capacitor, the processing chain including, in sequence, a preamplifier, an analog-to-digital converter (ADC), and a decompression module, the decompression module being configured to perform a decompression substantially an inverse of the compression in the form of x/(1+N|x|).
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A method for processing signals for a digital microphone, comprising:
- selectively coupling a plurality of adjustment capacitors in parallel with a microelectromechanical system (MEMS) capacitor serving as a sensor for a digital microphone, so as to perform a first compression technique on a signal generated by the MEMS capacitor;
- amplifying the signal from the MEMS capacitor, to provide an amplified signal;
- digitizing the amplified signal, to prove a digital signal;
- and
- performing a digital operation on the digital signal, the digital operation being an inverse of the first compression technique.
2 more elements
Dependencies are inferred from the claim text.