The present disclosure relates to a system comprising: a MEMS capacitive transducer comprising a first electrode and a second electrode; integrator circuitry; and test circuitry. The MEMS capacitive transducer forms part of a negative feedback path of the integrator circuitry, and the test circuitry is operable to selectively apply one or more current sources to an input of the integrator circuitry based on a signal at an output of the integrator so as to generate a periodic signal at the output of the integrator circuitry. A frequency of the periodic signal is at least partially dependent upon a capacitance of the MEMS capacitive transducer. The system is further operative to determine a parameter indicative of the frequency of the periodic signal and to estimate the capacitance of the MEMS capacitive transducer based on the parameter indicative of the frequency of the periodic signal.

A microelectromechanical membrane transducer includes: a supporting structure; a cavity formed in the supporting structure; a membrane coupled to the supporting structure so as to cover the cavity on one side; a cantilever damper, which is fixed to the supporting structure around the perimeter of the membrane and extends towards the inside of the membrane at a distance from the membrane; and a damper piezoelectric actuator set on the cantilever damper and configured so as to bend the cantilever damper towards the membrane in response to an electrical actuation signal.

A package structure includes a first substrate and a first device disposed on the first substrate. The first device includes at least one anchor structure, a film structure anchored by the anchor structure and an actuator configured to control the film structure to form a first vent temporarily. The film structure partitions a space into a first volume to be connected to an ear canal and a second volume connected to an ambient of a wearable sound device. The ear canal and the ambient are connected via the first vent when the first vent is opened. The first vent is opened by controlling a first membrane portion and a second membrane portion of the film structure, such that a difference between a first displacement of the first membrane portion and a second displacement of the second membrane portion is larger than a thickness of the film structure.

This application relates to transducer apparatus (300, 400), especially for MEMS capacitive transducers. The apparatus has a voltage bias generator (102) for receiving a supply voltage (V.sub.DD) and generating a bias voltage (V.sub.B) for biasing a capacitive transducer (101). A voltage supply path extends between a supply voltage input terminal (309a) and the voltage bias generator (102). A programmable trim circuit (207), in use, controls the bias voltage generated by the voltage bias generator. A first filter (301) is configured to applying filtering to the voltage supply path. A programming contact pad (308) is configured to form an external contact of the transducer apparatus when packaged and is electrically coupled to the programmable trim circuit via a signal path that does not include the first filter.

The disclosure provides a system, comprising: a MEMS capacitive transducer, comprising one or more first capacitive plates coupled to a first node and one or more second capacitive plates coupled to a second node; biasing circuitry coupled to the first node, operable to provide a biasing voltage to the one or more first capacitive plates; and test circuitry coupled to the second node, operable to: selectively apply one or more current sources to the second node, so as to charge and discharge the MEMS capacitive transducer and so vary a signal based on a voltage at said second node between an upper value and a lower value; determine a parameter that is indicative of a time period of the variation of the signal; and determine a capacitance of the MEMS capacitive transducer based on the parameter that is indicative of the time period.

A triple-membrane MEMS device includes a first membrane, a second membrane and a third membrane spaced apart from one another, wherein the second membrane is between the first membrane and the third membrane, a sealed low pressure chamber between the first membrane and the third membrane, a first stator and a second stator in the sealed low pressure chamber, and a signal processing circuit configured to read-out output signals of the triple-membrane MEMS device.

Impedance paths for integrated circuits having microelectromechanical systems (MEMS) switches that allow for electrical charge to bleed from circuit nodes to fixed electric potentials (e.g., ground) are described. Such paths are referred to herein as charge bleed circuits. The circuit nodes may be circuit locations where electrical charge may accumulate because there is no other path for the electrical charge to dissipate. In some embodiments, a charge bleed circuit includes a switchable device (e.g., a MEMS switch, a solid-state device switch, or a circuit including various solid-state device switches that, collectively, implement a device that can be switched on and off) that connects and disconnects the impedance path from a circuit node. This may allow the device to perform different types of measurements at desired performance levels.

An application specific integrated circuit (ASIC) chip is provided. Stress in various directions can be measured by disposing symmetrical four-corner+middle delay chain combinations in three dimensions inside the ASIC chip. Two sensors using the ASIC chip are further provided. In one sensor, a micro-electromechanical system (MEMS) chip is stacked with the ASIC chip. In the other sensor, the MEMS chip and the ASIC chip are symmetrically arranged. After being stacked and symmetrically arranged, the MEMS chip and the ASIC chip have highly consistent stress concentration characteristics, which can calibrate stress in various directions and effectively improve accuracy and temperature stability of the MEMS chip. In addition, an electric toothbrush using the ASIC chip is further provided, which can effectively improve consistency, stability, reliability, sensitivity, and linearity of stress detection, and can more accurately compensate for a temperature drift.

The present disclosure relates generally to digital microphone and other sensor assemblies including a transducer and a delta-sigma analog-to-digital converter (ADC) with digital-to-analog converter (DAC) element mismatch shaping and more particularly to sensor assemblies and electrical circuits therefor including a dynamic element matching (DELM) entity configured to select DAC elements based on data weighted averaging (DWA) and a randomized non-negative shift.

A microelectromechanical systems (MEMS) switching circuit and related apparatus is provided. In examples discussed herein, the MEMS switching circuit is configured to toggle (open or close) a number of MEMS switches without causing hot switching in any of the MEMS switches. More specifically, the MEMS switching circuit determines a switching sequence for toggling the MEMS switches such that each MEMS switch is only opened or closed under a very low current (e.g., <0.1 mA) or a very low voltage (e.g., <0.1 V). By operating the MEMS switches based on the determined switching sequence, it may be possible to protect the MEMS switches from hot switching damage, thus making it possible to employ the MEMS switches in an apparatus (e.g., a wireless communication device) to replace conventional switches for improved power amplifier efficiency and radio frequency (RF) performance.