Abstract: A MEMS microphone having a backplate, a spring, and a membrane. In one embodiment, the membrane is supported in an approximate center of the membrane via a support. The support is connected to the approximate center of the membrane and an approximate center of the backplate. The membrane is connected to a spring that provides an electrical connection. The membrane may be electrically biased via the electrical connection. One or more overtravel stops are fixed to the backplate and pass through an aperture of the membrane. The overtravel stops are configured to prevent movement of the membrane in a radial direction opposite to the backplate. The membrane includes a stress gradient, a corrugation, or another structure that sets or determines a stiffness of the membrane.

Abstract: A system and a method are provided for testing a MEMS microphone during manufacture by using a film to obstruct the acoustic ports of the microphone. The microphone testing is performed while the microphones are still in an array and mounted on a film frame. By performing the testing while the acoustic ports of the microphone are covered with film, unwanted, external noise is attenuated.

Abstract: Systems for controlling parameters of a MEMS microphone. In one embodiment, the microphone system includes a MEMS microphone and a controller. The MEMS microphone includes a movable electrode, a stationary electrode, and a driven electrode. The movable electrode is configured such that acoustic pressure acting on the movable electrode causes movement of the movable electrode. The stationary electrode and the driven electrode are positioned on a first side of the movable electrode. The driven electrode is configured to alter a parameter of the MEMS microphone based on a control signal. The controller is coupled to the stationary electrode and the driven electrode. The controller is configured to determine a voltage difference between the movable electrode and the stationary electrode. The controller is also configured to generate the control signal based on the voltage difference.

Abstract: MEMS microphones and MEMS devices. In one embodiment, the MEMS microphone includes a membrane and a layer. The membrane is coupled to a support. The layer includes a backplate and an overtravel stop. The backplate is coupled to the support. The overtravel stop is coupled to the membrane and is physically separated from the backplate by a gap in a radial direction. The overtravel stop has a first end that is oriented proximal to the membrane and a second end that is oriented distal to the membrane. The second end flares outward to restrict movement of the membrane in the radial direction by contacting the backplate.

Abstract: Systems for controlling parameters of a MEMS microphone. In one embodiment, the microphone system includes a MEMS microphone and a controller. The MEMS microphone includes a movable electrode, a stationary electrode, and a driven electrode. The movable electrode is configured such that acoustic pressure acting on the movable electrode causes movement of the movable electrode. The stationary electrode and the driven electrode are positioned on a first side of the movable electrode. The driven electrode is configured to alter a parameter of the MEMS microphone based on a control signal. The controller is coupled to the stationary electrode and the driven electrode. The controller is configured to determine a voltage difference between the movable electrode and the stationary electrode. The controller is also configured to generate the control signal based on the voltage difference.

Abstract: A MEMS microphone having a backplate, a spring, and a membrane. In one embodiment, the membrane is supported in an approximate center of the membrane via a support. The support is connected to the approximate center of the membrane and an approximate center of the backplate. The membrane is connected to a spring that provides an electrical connection. The membrane may be electrically biased via the electrical connection. One or more overtravel stops are fixed to the backplate and pass through an aperture of the membrane. The overtravel stops are configured to prevent movement of the membrane in a radial direction opposite to the backplate. The membrane includes a stress gradient, a corrugation, or another structure that sets or determines a stiffness of the membrane.

Abstract: Systems and methods for controlling parameters of a MEMS microphone. The microphone system includes a MEMS microphone and a controller. The MEMS microphone includes a movable electrode, a stationary electrode, and a driven electrode. The movable electrode has a first side and a second side that is opposite the first side. The movable electrode is configured such that acoustic pressures acting on the first side and the second of the movable electrode cause movement of the movable electrode. The stationary electrode is positioned on the first side of the movable electrode. The driven electrode is configured to receive a control signal and alter a parameter of the MEMS microphone based on the control signal. The controller is configured to determine a voltage difference between the movable electrode and the stationary electrode. The controller is also configured to generate the control signal based on the voltage difference.

Abstract: A MEMS microphone including a plurality of overtravel stops (OTS) connected to a perimeter of a membrane of the MEMS microphone. The OTS are released from a backplate layer during manufacturing and are configured to contact the backplate to restrict movement of the OTS and thus restrict movement of the membrane of the MEMS microphone. Embodiments of the invention provide, in particular, an overtravel stop that limits movement of the membrane in a radial direction.

Abstract: In one embodiment, the invention is a microphone system for adjusting the final output sensitivity of a microphone. The system includes transducers that output transducer signals. The system also includes bias circuits providing bias signals to the transducers, as well as amplifiers to receive the transducer signals and output amplified signals. The amplified signals are summed by a summer, which outputs a summed signal. A controller receives the summed signal, and is configured to obtain a desired microphone output characteristic and calculate adjustment amounts based on the characteristic. The controller modifies signals from the transducers based on the adjustment amounts. The controller then outputs a microphone signal based on the summed signal. In another embodiment, the invention provides a method for adjusting the final output sensitivity of a microphone.

Abstract: A MEMS microphone including a plurality of overtravel stops (OTS) connected to a perimeter of a membrane of the MEMS microphone. The OTS are released from a backplate layer during manufacturing and are configured to contact the backplate to restrict movement of the OTS and thus restrict movement of the membrane of the MEMS microphone. Embodiments of the invention provide, in particular, an overtravel stop that limits movement of the membrane in a radial direction.

Abstract: A system and a method are provided for testing a MEMS microphone during manufacture by using a film to obstruct the acoustic ports of the microphone. The microphone testing is performed while the microphones are still in an array and mounted on a film frame. By performing the testing while the acoustic ports of the microphone are covered with film, unwanted, external noise is attenuated.

Abstract: In one embodiment, the invention is a microphone system with an internal test circuit. The system includes a microphone having a housing with an acoustic port, a first transducer, a second transducer, a controller, and a current source. The system also includes an acoustic assembly with a cover and an acoustic pressure source positioned in the cover. When the acoustic assembly is positioned over the acoustic port, an acoustic chamber is formed, and a signal can be applied to the acoustic pressure source such that a first set of measurements can be taken. The acoustic assembly can be removed and replaced with an acoustic cover to take a second set of measurements. Based on the first and second measurements, sensitivities of the first and second transducers can be determined. In another embodiment, the invention provides a method for calibrating the sensitivity of a microphone.

Abstract: A method of testing a MEMS pressure sensor device such as, for example, a MEMS microphone package. The MEMS pressure sensor device includes a pressure sensor positioned within a housing and a pressure input port to direct acoustic pressure from outside the housing towards the pressure sensor. An acoustic pressure source is activated and acoustic pressure from the acoustic pressure source is directed to the pressure input port and to an exterior location of the housing other than the pressure input port. Based on the output signal of the pressure sensor, it is determined whether any defects exist that allow acoustic pressure to reach the pressure sensor through the exterior of the housing at locations other than the pressure input port.

Abstract: A system and a method are provided for testing a MEMS microphone during manufacture by using a film to obstruct the acoustic ports of the microphone. The microphone testing is performed while the microphones are still in an array and mounted on a film frame. By performing the testing while the acoustic ports of the microphone are covered with film, unwanted, external noise is attenuated.

Abstract: Methods and systems are taught for testing microphone packages—including measuring non-acoustic noise for the package. A package positioner holds a microphone package such that an acoustic input port of the microphone package is aligned with a plug. An actuator moves the plug relative to the microphone package between a first position—where the plug does not obstruct the acoustic input port of the microphone package—and a second position—where the plug obstructs the acoustic input port and restricts acoustic pressures from entering the microphone package through the acoustic input port. A controller monitors an output of the microphone package and identifies the output as indicative of isolated non-acoustic noise when the plug is in the second position.

Abstract: A microphone test fixture. The test fixture includes a test chamber, an acoustic source, a reference microphone, and an acoustic resistor. The acoustic source is configured to produce sound waves in the test chamber. The reference microphone is positioned to receive the sound waves in the test chamber. The acoustic resistor forms a contiguous space with the test chamber, and is sized to prevent resonances and echoes of the sound waves for a fixed high frequency limit.

Abstract: Systems and methods for controlling parameters of a MEMS microphone. The microphone system includes a MEMS microphone and a controller. The MEMS microphone includes a movable electrode, a stationary electrode, and a driven electrode. The movable electrode has a first side and a second side that is opposite the first side. The movable electrode is configured such that acoustic pressures acting on the first side and the second of the movable electrode cause movement of the movable electrode. The stationary electrode is positioned on the first side of the movable electrode. The driven electrode is configured to receive a control signal and alter a parameter of the MEMS microphone based on the control signal. The controller is configured to determine a voltage difference between the movable electrode and the stationary electrode. The controller is also configured to generate the control signal based on the voltage difference.

Abstract: A MEMS microphone. The MEMS microphone includes a substrate, a transducer support that includes or supports a transducer, a housing, and an acoustic channel. The transducer support resides on the substrate. The housing surrounds the transducer support and includes an acoustic aperture. The acoustic channel couples the acoustic aperture to the transducer, and isolates the transducer from an interior area of the MEMS microphone.

Abstract: In one embodiment, the invention is a microphone system with an internal test circuit. The system includes a microphone having a housing with an acoustic port, a first transducer, a second transducer, a controller, and a current source. The system also includes an acoustic assembly with a cover and an acoustic pressure source positioned in the cover. When the acoustic assembly is positioned over the acoustic port, an acoustic chamber is formed, and a signal can be applied to the acoustic pressure source such that a first set of measurements can be taken. The acoustic assembly can be removed and replaced with an acoustic cover to take a second set of measurements. Based on the first and second measurements, sensitivities of the first and second transducers can be determined. In another embodiment, the invention provides a method for calibrating the sensitivity of a microphone.

Abstract: A MEMS microphone. The MEMS microphone includes a back plate, a membrane, a support structure, a substrate, and an overtravel stop. The membrane is coupled to the back plate. The support structure includes a support structure opening and a first side of the support structure is coupled to a second side of the back plate. The substrate includes a substrate opening and a first side of the substrate is coupled to a second side of the support structure. The overtravel stop limits a movement of the membrane away from the back plate and includes at least one of an overtravel stop structure coupled to the substrate, an overtravel stop structure formed as part of a carrier chip, and an overtravel stop structure formed as part of the support structure in the support structure opening.