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US 2020/0053496 A1Published application
Capacitive mems microphone with built-in self-test
AssigneeChaoyang Semiconductor Jiangyin Technology Co., Ltd.
InventorHassan Ihs
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Abstract
A digital microphone includes built-in self-test features. The features may include capability to apply different bias voltages to a MEMS capacitor sensor of the digital microphone, simulating application of different sound pressures to the digital microphone. The features may also include a digital oscillator, for applying a test signal to an analog front end of the microphone.
Claims13
A method of testing a digital microphone, comprising:
- applying, at different times, a plurality of different bias voltages to a MEMS capacitor of the digital microphone, the MEMS capacitor serving as a sensor for the digital microphone;
- measuring outputs of an analog front end of the digital microphone resulting from the application of the plurality of different bias voltages to the MEMS capacitor.
A digital microphone with built-in self-test, comprising:
- a MEMS capacitor, the MEMS capacitor serving as a sensor for the digital microphone;
- at least one charge pump configured to provide a plurality of different bias voltages to the MEMS capacitor;
- a processing chain comprised of a preamplifier, an analog-to-digital converter (ADC), and a one bit sigma delta block, in series;
- and
- a multiplexer configured to pass a signal from the MEMS capacitor to the preamplifier in a first mode and to pass a signal from the sigma delta block in a second mode.
2 more elements
Dependencies are inferred from the claim text.