Knowles Electronics, LLC

The disclosure relates to a transducer assembly like a microphone including a bias circuit having a charge pump and a filter circuit coupled to a transducer. The filter circuit includes a voltage-controlled resistor located between an output of the charge pump and the transducer, and a capacitor coupled to the voltage-controlled resistor opposite the charge pump, wherein the bias circuit is configured with a larger bandwidth for faster settling during transient operation than during steady-state operation.

A microphone assembly can include a microelectromechanical systems (MEMS) transducer comprising a transducer substrate, a diaphragm oriented substantially parallel to the transducer substrate and spaced apart from the transducer substrate to form a gap, and a counter electrode coupled to the transducer substrate, the counter electrode positioned between the diaphragm and the transducer substrate. The MEMS transducer can generate a signal representative of a change in capacitance between the counter electrode and the diaphragm. A back volume of the MEMS transducer can be an enclosed volume positioned between the transducer substrate and the diaphragm. The microphone assembly can include an integrated circuit that receives the signal, wherein every point within the back volume is less than a thermal boundary layer thickness from a nearest solid surface at an upper limit of an audio frequency band that the integrated circuit is monitoring.

A digital microphone or other sensor assembly includes a transducer and an electrical circuit including a slew-rate controlled output buffer configured to reduce propagation delay and maintain output rise and fall time independent of PVT variation and load capacitance. In some embodiments, the portions of the output buffer are selectably disabled to reduce power consumption without adversely substantially increasing propagation delay.

A microphone device, an interface circuit and method are provided for managing a potential difference in sensitivity to a detected environmental stimulus associated with a sensor arrangement, where multiple electrical signals forming a differential signal can be produced, and the multiple electrical signals can be better balanced. Such an interface circuit, which can be used within a microphone device includes a bias voltage generator having one or more bias output voltage terminals, where a respective one of one or more DC bias voltages is produced at each of the bias output voltage terminals, for being coupled to a pair of transduction elements of a sensor. The interface circuit further includes an amplifier circuit having a first input terminal coupled to a first one of the pair of output terminals of the sensor and having a second input terminal coupled to a second one of the pair of output terminals of the sensor, the amplifier circuit producing a differential output signal. The interface circuit still further includes a compensation circuit coupled to the amplifier circuit for producing a balance signal based on an output signal being produced by the amplifier circuit, wherein the balance signal compensates for any difference in amplitude in the first and second electrical signals that are received by the amplifier circuit from the sensor.

The present disclosure relates to microphone devices. One microphone assembly includes a transducer and a housing. The microphone assembly includes an integrated circuit coupled to the transducer. The housing includes a port, a base, and a cover. The cover includes an inner wall and an outer wall. The inner wall and outer wall can be coupled to the base. The inner wall and the base are mechanically coupled and define an enclosed volume. The transducer is disposed in the enclosed volume.

The disclosure relates to a transducer assembly like a microphone including a bias circuit having a charge pump and a filter circuit coupled to a transducer. The filter circuit includes a voltage-controlled resistor located between an output of the charge pump and the transducer, and a capacitor coupled to the voltage-controlled resistor opposite the charge pump, wherein the bias circuit is configured with a larger bandwidth for faster settling during transient operation than during steady-state operation.

A microphone assembly can include a microelectromechanical systems (MEMS) transducer comprising a transducer substrate, a diaphragm oriented substantially parallel to the transducer substrate and spaced apart from the transducer substrate to form a gap, and a counter electrode coupled to the transducer substrate, the counter electrode positioned between the diaphragm and the transducer substrate. The MEMS transducer can generate a signal representative of a change in capacitance between the counter electrode and the diaphragm. A back volume of the MEMS transducer can be an enclosed volume positioned between the transducer substrate and the diaphragm. The microphone assembly can include an integrated circuit that receives the signal, wherein every point within the back volume is less than a thermal boundary layer thickness from a nearest solid surface at an upper limit of an audio frequency band that the integrated circuit is monitoring.

A microelectromechanical systems (MEMS) diaphragm assembly comprises a first diaphragm and a second diaphragm. A plurality of pillars connects the first and second diaphragms, wherein the plurality of pillars has a higher distribution density at a geometric center of the MEMS diaphragm assembly than at an outer periphery thereof.

The disclosure describes devices and methods of providing a DC bias voltage in a microphone assembly. Particularly, one implementation of such a device may be implemented on an integrated circuit that includes a direct current (DC) bias circuit. The DC bias circuit may be coupled to a transducer and configured to supply a DC bias signal to the transducer. The DC bias circuit includes a multi-stage charge pump and a low pass filter (LUFF) circuit. The multi-stage charge pump includes transistors that are fabricated with deep trench isolation (DTI).

A MEMS transducer includes a transducer substrate, a counter electrode, and a diaphragm. The counter electrode is coupled to the transducer substrate. The diaphragm is oriented substantially parallel to the counter electrode and is spaced apart from the counter electrode to form a gap. A back volume of the MEMS transducer is an enclosed volume positioned between the counter electrode and the diaphragm. A height of the gap between the counter electrode and the diaphragm is less than two times the thermal boundary layer thickness within the back volume at an upper limit of the audio frequency band of the MEMS transducer.