Stmicroelectronics S.r.l.

Maxim Integrated Products, Inc.

Hanking Electronics, Ltd.

Luciano Prandi

Carlo Caminada

Ernesto Lasalandra

Gabriele Cazzaniga

Alessandra Maria Rizzo Piazza Roncoroni

Federico Forte

Luca Coronato

Paolo Invernizzi

Andrea Donadel

Arber Cauli

Paolo Angelini

Tommaso Ungaretti

Manuel Santoro

Demetre Kondylis

Andrea Visconti

Barbara Simoni

Carlo Alberto Romani

Carolo Caminada

Gabrielle Cazzaniga

A demodulator is provided for demodulating an amplitude-modulated input signal defined by a carrier signal having a carrier frequency modulated by a modulating signal, the demodulator including an amplifier stage having a gain and structured to receive the amplitude-modulated input signal, and a gain control stage coupled to the amplifier stage and configured to vary the gain of the amplifier stage according to the carrier frequency of the carrier signal.

Fully differential demodulator with variable gain, and method for demodulating a signal

The invention relates to a sensor system, and more particularly, to systems, devices and methods of processing a sensing signal from a sensor to generate amplitude and phase controls for driving this sensor in a controlled manner and enabling synchronized operation of the sensor system. A signal processor in the sensor system comprises a sensor readout circuit, an amplitude controller and a phase controller. A subset of functional blocks in the signal processor may alternate between active and inactive power saving durations. During the active power saving durations, the subset of functional blocks are powered off or functionally disabled to conserve power consumption. The amplitude and phase controls are latched for the purposes of properly maintaining the driving signal and the system clock. During the subsequent inactive power saving durations, the subset of functional blocks return to normal operation to refresh the amplitude and phase controls.

Spot mode functionality for power saving in a sensor system

The present invention concerns an MEMS sensor and a method for compensation of a quadrature error on an MEMS sensor, which is intended for detection of movements of a substrate, especially accelerations and/or rotation rates. At least one mass arranged on the substrate and mounted to move relative to it is driven by means of drive electrodes. The mass/es execute a movement deviating from the prescribed movement due to a quadrature error. A deflection of the mass/es occurring due to Coriolis force and quadrature error is detected with detection electrodes. It is proposed according to the invention that a capacitance change be detected as a function of drive movement of the mass/es by means of compensation electrodes. A compensation charge dependent on the quadrature error of the MEMS sensor is generated on the compensation electrodes. For compensation, the distorted or incorrect charge generated by the quadrature error in the detection electrodes is compensated with the compensation charge.

Method and system for quadrature error compensation

Various embodiments of the invention allow to cancel demodulation phase error. In certain embodiments, cancellation is accomplished by determining the phase delay of a drive front end signal that is in phase with an undesired signal and digitally adjusting the demodulation signal with a calibrated signal. The phase delay may be adaptively compensated during regular circuit operation, only at predetermined times, or during a factory calibration.

Adaptive phase delay adjustment for MEMS sensors

Various embodiments of the invention reduce stiction in a wide range of MEMS devices and increase device reliability without negatively impacting performance. In certain embodiments, stiction recover is accomplished by applying electrostatic forces to electrodes via optimized voltage signals that generate a restoring force that aids in overcoming stiction forces between electrodes. The voltage signals used within a stiction recovery procedure may be static or a dynamic, and may be applied directly to existing electrodes within a MEMS device, thereby, eliminating the need for additional components. In some embodiments, the voltage is estimated or calibrated and swept through a range of frequencies that contains one or more resonant frequencies of the mechanical structure that comprises the parts to be detached.

Recovery system and methods for MEMS devices

Various embodiments of the invention provide for improved performance by reducing a quadrature error signal. In certain embodiments, this is accomplished by using a mixed-signal architecture comprising analog and digital circuit components in a closed-loop configuration that generates from a detected quadrature error signal a calibration quadrature signal that is then compensated at a virtual ground of an analog front end circuit. Some embodiments allow for pre-calibration for quadrature error and/or adaptive compensation of unwanted drift effects of the quadrature error, including temperature drifts.

Systems and methods to reduce quadrature error in sensors

Various embodiments of the invention provide for cancellation of unwanted signals in switched-capacitor circuits. In certain embodiments cancellation this is accomplished by performing a multi-phase CDS technique. The technique comprises resetting capacitive elements in the feedback path of an operational amplifier during a reset interval, maintaining a decoupled condition during a sampling interval in which the unwanted signals are sampled, and cancelling unwanted signals in a sensing interval.

Switched-capacitor network with input-output common mode decoupling

The invention relates to a controller, and more particularly, to systems, devices and methods of processing multiple sensor signals of a gyroscope. The signal processor includes: a front end amplifier for converting a signal into a voltage variation signal; at least one analog-to-digital converter coupled to the front end amplifier and operative to convert an analog signal into a digital signal; and at least one demodulator coupled to the analog-to-digital converter and operative to demodulate the digital signal to thereby extract an envelope signal therefrom.

Innovative angular sensor read-out multi-axes digital front-end chain

A gyroscope includes a body, a driving mass, which is mobile according to a driving axis, and a sensing mass, which is driven by the driving mass and is mobile according to a sensing axis, in response to rotations of the body. A driving device forms a microelectromechanical control loop with the body and the driving mass and maintains the driving mass in oscillation with a driving frequency. The driving device comprises a frequency detector, which supplies a clock signal at the frequency of oscillation of the driving mass, and a synchronization stage, which applies a calibrated phase shift to the clock signal so as to compensate a phase shift caused by components of the loop that are set between the driving mass and the control node.

Microelectromechanical gyroscope with calibrated synchronization of actuation and method for actuating a microelectromechanical gyroscope

A microelectromechanical gyroscope that includes a first mass oscillatable according to a first axis; an inertial sensor, including a second mass, drawn along by the first mass and constrained so as to oscillate according to a second axis, in response to a rotation of the gyroscope; a driving device coupled to the first mass so as to form a feedback control loop and configured to maintain the first mass in oscillation at a resonance frequency; and an open-loop reading device coupled to the inertial sensor for detecting displacements of the second mass according to the second axis. The driving device includes a read signal generator for supplying to the inertial sensor at least one read signal having the form of a square-wave signal of amplitude that sinusoidally varies with the resonance frequency.

Microelectromechanical gyroscope with open loop reading device and control method

A microelectromechanical gyroscope having a supporting structure; a mass capacitively coupled to the supporting structure and movable with a first degree of freedom and a second degree of freedom, in response to rotations of the supporting structure about an axis; driving components, for keeping the mass in oscillation according to the first degree of freedom; a read interface for detecting transduction signals indicating the capacitive coupling between the mass and the supporting structure; and capacitive compensation modules for modifying the capacitive coupling between the mass and the supporting structure. Calibration components detect systematic errors from the transduction signals and modify the capacitive compensation modules as a function of the transduction signals so as to attenuate the systematic errors.

Microelectromechanical gyroscope with self-calibration function and method of calibrating a microelectromechanical gyroscope

A band-pass filter made up by an operational amplifier and by an input circuit. The input circuit is formed by a capacitive filtering element, connected to the input of the operational amplifier; a coupling switch, coupled between an input node and the capacitive filtering element; a capacitive sampling element, coupled between the input of the filter and the input node; and a sampling switch, coupled between the input node and a reference-potential line. The coupling switch and the input sampling switch close in phase opposition according to a succession of undesired components sampling and sensing steps, so that the capacitive sampling element forms a sampler for sampling the undesired component in the undesired components sampling step, in the absence of the component of interest, and forms a subtractor of the undesired components from the input signal in the sensing step.

Switched-capacitor band-pass filter of a discrete-time type, in particular for cancelling offset and low-frequency noise of switched-capacitor stages

A method of protection from noise of a digital signal generated by a comparator, including the steps of generating an output signal that switches from a first logic state to a second logic state at a first switching of logic state of the digital signal; detecting a change from the first logic state to the second logic state of the output signal; and inhibiting further switchings of the output signal for a first time interval after the change from the first logic state to the second logic state.

Digital noise protection circuit and method

Disclosed are a MEMS sensor and methods to compensate a quadrature error on the sensor. The sensor detects movements of a substrate, especially accelerations and rotation rates. At least one mass arranged on the substrate and mounted to move relative to it is driven by drive electrodes. The mass executes a movement deviating from the prescribed movement due to a quadrature error. A deflection of the mass occurring due to Coriolis force and quadrature error is detected with detection electrodes. A capacitance change is detected as a function of drive movement of the mass by using compensation electrodes. A compensation charge dependent on the quadrature error of the MEMS sensor is generated on the compensation electrodes. For compensation, the distorted or incorrect charge generated by the quadrature error in the detection electrodes is compensated with the compensation charge.

A microelectromechanical gyroscope having a microstructure that includes a first mass and a second mass, wherein the first mass is oscillatable according to a first axis and the second mass is constrained to the first mass so as to be drawn along by the first mass according to the first axis and to oscillate according to a second axis, in response to a rotation of the microstructure, a driving device coupled to the microstructure to maintain the first mass in oscillation at the driving frequency, and a reading device that detects displacements of the second mass according to the second axis. The gyroscope is provided with a self-test actuation system coupled to the second mass for applying an electrostatic force at the driving frequency so as to move the second mass according to the second axis.

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Bellinzago Novarese, Italy

Luciano Prandi