Invensense, Inc.

Brian Moss

Kieran P Harney

Adrianus Maria Lafort

Alain Valentin Guery

Dipak Sengupta

Dion Ivo De Roo

David Frank Bolognia

Microelectromechanical systems (MEMS) sensors and related bias voltage techniques are described. Exemplary MEMS sensors, such as exemplary MEMS acoustic sensors or microphones described herein can employ one or more bias voltage generators and single-ended or differential amplifier arrangements. Various embodiments are described that can effectively increase the bias voltage available to the sensor element without resorting to high breakdown voltage semiconductor processes. In addition, control of the one or more bias voltage generators in various operating modes is described, based on consideration of a number of factors.

Microelectromechanical systems (MEMS) microphone bias voltage

A microphone module has a substrate with an aperture to allow sound waves to pass through the substrate, a lid mounted to the substrate to define a first interior volume, a microphone mounted to the substrate within the first interior volume, and a housing coupled to the substrate and covering the aperture. The housing forms a second interior volume and includes an acoustic port configured to allow sound to enter the second interior volume. The module further includes a pipe extending from the acoustic port in the housing, and at least one exterior interface pad outside of the second interior volume. The pipe has an open end to receive sound waves and direct them toward the acoustic port in the housing. Moreover, the at least one exterior interface pad electrically couples to the microphone.

Microphone module with sound pipe

Improving noise rejection of a micro-electro-mechanical system (MEMS) microphone by utilizing a membrane sandwiched between oppositely biased backplates is presented herein. The MEMS microphone can comprise a diaphragm that converts an acoustic pressure into an electrical signal; a first backplate capacitively coupled to a first side of the diaphragm&#x2014;the first backplate biased at a first direct current (DC) voltage; a second backplate capacitively coupled to a second side of the diaphragm&#x2014;the second backplate biased at a second DC voltage; and an electronic amplifier that buffers the electrical signal to generate a buffered output signal representing the acoustic pressure.

Micro-electro-mechanical system microphone with dual backplates

A microphone system has a package with a top, a bottom, and four sides that at least in part form an interior chamber. One of the sides forms an inlet aperture for communicating the inlet chamber with the exterior environment. The system also has first and second microphone dies, in a stacked relationship, respectively having a first and second diaphragms. A circuit die, positioned in electrical communication with the first and second microphone dies, is configured to mitigate vibrational noise from the first microphone die using a signal produced by the second microphone die or vice versa. The first and second microphone dies are positioned so that the first and second diaphragms are substantially the same distance from the inlet aperture in the side.

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Brian Moss