A control circuit includes: a voltage output circuit control unit that controls a voltage output circuit so as to apply a voltage, which corresponds to an output control signal and is to cause an electrostatic transducer to generate vibration, sound, or pressure, between both ends of the electrostatic transducer in a case where a detection control signal is at a first level, and that stops the voltage output circuit in a case where the detection control signal is at a second level; a pulse signal output unit that outputs a pulse signal, which is to cause the electrostatic transducer to detect vibration, sound, or pressure, to a terminal on a high potential side of the electrostatic transducer via a diode; and a voltage clamp unit that outputs a clamp voltage acquired by clamping of a voltage between the terminals of the electrostatic transducer to a predetermined voltage or lower.

Aspects of the subject technology relate to electronic devices having speakers such as microelectromechanical systems (MEMS) speakers. A MEMS speaker can include an electrostatically driven, corrugated MEMS structure to move air without a magnet, coil, or traditional speaker membrane, and thus provide a low-power, compact speaker with a large acoustically active area in a small volume. Neighboring folds in the corrugated MEMS structure may form pairs of MEMS electrodes that can be pushed together and/or pulled apart to deform the MEMS structure in a breathing motion that generates pressure differentials on opposing sides of the corrugated MEMS structure to generate sound. Additional modes of operation are described.

Aspects of the subject technology relate to electronic devices having speakers such as microelectromechanical systems (MEMS) speakers. A MEMS speaker can include an electrostatically driven, corrugated MEMS structure to move air without a magnet, coil, or traditional speaker membrane, and thus provide a low-power, compact speaker with a large acoustically active area in a small volume. Neighboring folds in the corrugated MEMS structure may form pairs of MEMS electrodes that can be pushed together and/or pulled apart to deform the MEMS structure in a breathing motion that generates pressure differentials on opposing sides of the corrugated MEMS structure to generate sound. Additional modes of operation are described.

An in-ear receiver can be used in a headset and/or hearing aid and includes a housing in which at least one ear canal section is configured to be inserted into an ear canal of a wearer when the in-ear receiver is used as intended. The housing defines at least one outer contour that is configured with at least in one section adapted to the ear canal of the wearer. The in-ear receiver includes a sound transducer arranged in the housing, and at least one resonant cavity, which is formed in the housing and is divided by the sound transducer into a front volume and a rear volume. The sound transducer is a MEMS sound transducer, and the front volume and/or the rear volume have/has an inner contour adapted to the ear canal.

A crossover circuit, disposed within a sound producing device including a first sound producing cell driven by a first driving signal and a second sound producing cell driven by a second driving signal, includes a first filter receiving an input signal at an input terminal of the first filter, a first subtraction circuit, and a second filter coupled between the output terminal of the first filter and the second input terminal of the first subtraction circuit. A first input terminal of the first subtraction circuit is coupled to the input terminal of the first filter; a second input terminal of the first subtraction circuit is coupled to an output terminal of the first filter. The crossover circuit produces the first driving signal and the second driving signal according to a first output signal of the first subtraction circuit and a second output signal of the first filter respectively.

A method for manufacturing an opening structure is provided. The method may include: forming a patterned mask over a first side of a carrier; forming material over the first side of the carrier covering at least a portion of the carrier; forming a first opening in the carrier from a second side of the carrier opposite the first side of the carrier to at least partially expose a surface of the patterned mask; and forming a second opening in the material from the second side of the carrier using the patterned mask as a mask.

Ultrasonic transducers that are capable of generating increased levels of ultrasound, as well as receiving ultrasonic waves with increased sensitivity. The ultrasonic transducers include a back cover, a protective front cover, a backplate, and a vibrator film layer disposed between the backplate and the protective front cover. The backplate includes a plurality of grooves formed on a surface thereof facing the vibrator film layer. Each groove includes upper edges having cross-sectional contours that gradually tend toward the deepest part of the groove to allow a larger area of the backplate to be closer to the vibrator film layer, thereby increasing the resulting electric field, and, consequently, increasing the output power and sensitivity of the ultrasonic transducer.

Ultrasonic transducers that are capable of generating increased levels of ultrasound, as well as receiving ultrasonic waves with increased sensitivity. The ultrasonic transducers include a back cover, a protective front cover, a backplate, and a vibrator film layer disposed between the backplate and the protective front cover. The backplate includes a plurality of grooves formed on a surface thereof facing the vibrator film layer. Each groove includes upper edges having cross-sectional contours that gradually tend toward the deepest part of the groove to allow a larger area of the backplate to be closer to the vibrator film layer, thereby increasing the resulting electric field, and, consequently, increasing the output power and sensitivity of the ultrasonic transducer.

The MEMS actuator is formed by a body, which surrounds a cavity and by a deformable structure, which is suspended on the cavity and is formed by a movable portion and by a plurality of deformable elements. The deformable elements are arranged consecutively to each other, connect the movable portion to the body and are each subject to a deformation. The MEMS actuator further comprises at least one plurality of actuation structures, which are supported by the deformable elements and are configured to cause a translation of the movable portion greater than the deformation of each deformable element. The actuation structures each have a respective first piezoelectric region.

The MEMS actuator is formed by a body, which surrounds a cavity and by a deformable structure, which is suspended on the cavity and is formed by a movable portion and by a plurality of deformable elements. The deformable elements are arranged consecutively to each other, connect the movable portion to the body and are each subject to a deformation. The MEMS actuator further comprises at least one plurality of actuation structures, which are supported by the deformable elements and are configured to cause a translation of the movable portion greater than the deformation of each deformable element. The actuation structures each have a respective first piezoelectric region.