Abstract:
A differential piezoelectric actuator-system includes an inductor and driver-circuit having switches for transferring energy between first and second actuators and the inductor, and between a voltage-supply node and the inductor. Control circuitry determines whether a next phase in which to operate the driver-circuit is a first charging-phase or a first recovery-phase. The first charging-phase includes operating the switches in: a first sub-phase to transfer energy from the first actuator to the inductor; a second sub-phase to transfer energy from the voltage supply node to the inductor; and a third sub-phase to transfer energy from the inductor to the second actuator. The first recovery-phase includes operating the switches in: a first sub-phase to transfer energy from the first actuator to the inductor; a second sub-phase to transfer energy from the inductor to the voltage supply node; and a third sub-phase to transfer energy from the inductor to the second actuator.
Abstract:
The present disclosure is directed to a dual-mode control circuit for a microelectromechanical system (MEMS) gyroscope. A control circuit is coupled to a Lissajous frequency modulated (LFM) gyroscope to control amplitude of oscillation of a mass along two directions. The amplitude of oscillation is controlled by an automatic gain control (AGC) loop which allows the same amplitude of oscillation in both directions. An AGC is implemented with a combination of proportional control (P-type) and integral control (I-type) paths that maintain the correct Lissajous pattern of the oscillation of the mass. The AGC may include a dual-mode stage which is able to switch between a P-type control path and an I-type control path based on the operation of the LFM gyroscope. A fast start-up phase may be controlled by the P-type control path while the I-type path is pre-charged to be ready to use in a steady state condition.
Abstract:
A differential piezoelectric actuator-system includes an inductor and driver-circuit having switches for transferring energy between first and second actuators and the inductor, and between a voltage-supply node and the inductor. Control circuitry determines whether a next phase in which to operate the driver-circuit is a first charging-phase or a first recovery-phase. The first charging-phase includes operating the switches in: a first sub-phase to transfer energy from the first actuator to the inductor; a second sub-phase to transfer energy from the voltage supply node to the inductor; and a third sub-phase to transfer energy from the inductor to the second actuator. The first recovery-phase includes operating the switches in: a first sub-phase to transfer energy from the first actuator to the inductor; a second sub-phase to transfer energy from the inductor to the second actuator; and a third sub-phase to transfer energy from the inductor to the voltage supply node.
Abstract:
Disclosed herein is a control system for a projection system, including a first subtractor receiving an input drive signal and a feedback signal and generating a first difference signal therefrom, the feedback signal being indicative of position of a quasi static micromirror of the projection system. A type-2 compensator receives the first difference signal and generates therefrom a first output signal. A derivative based controller receives the feedback signal and generates therefrom a second output signal. A second subtractor receives the first and second output signals and generates a second difference signal therefrom. The second difference signal serves to control a mirror driver of the projection system. A higher order resonance equalization circuit receives a pre-output signal from an analog front end of the projection system that is indicative of position of the quasi static micromirror, and generates the feedback signal therefrom.
Abstract:
The invention relates to an inertial sensor (1) comprising a substrate extending along a drive excitation direction (x) and a detection direction (y) normal to each other, the device plane being perpendicular to a rotation direction (z), a first drive frame (110) and a second drive frame (120), a first sense frame (210), a second sense frame (220), a sense lever (1000) pivotably mounted around a rotation axis (1001), a sensing system comprising a strain gauge (1600) mechanically stressed by the sense lever it is rotating around the rotation axis. The sense lever includes a central portion (1500), a first arm (1100) and a second arm (1200), the central portion having a dimension along the detection direction called central width, the arms having a dimension along the detection direction called arm width, the central width being at least twice greater than the arm width.
Abstract:
An inertial sensor including a substrate, sense frames, drive frames configured to put into motion the sense frames, and a sense lever pivotably mounted around a rotation axis. The sense frames, drive frames and sense lever are connected to each other in such a way that when the inertial sensor is subjected to a rotational movement around the rotation axis, the first sense frame, the second sense frame and the sense lever respectively feature a first tilt θ1 a second tilt θ2 and a lever tilt θs relatively to the device plane, and both θ1/θs and θ2/θs are lower than 0.1. The inertial sensor features strain gauges that get stressed when the lever rotates due to the motion of the sense frames.
Abstract:
Piezoresistive detection resonant device comprising a substrate, a mobile par configured to move with respect the substrate, suspension elements suspending the mobile part to the substrate, a piezoresistive detection device to detect the motions of the mobile part, said piezoresistive detection device comprising at least one strain gauge, wherein the piezoresistive detection resonant device also comprises a folded spring with at least two spring arms, connected to the mobile part and configured to be deformed by the motion of the mobile part, the at least one gauge being suspended between the substrate and the folded spring in such manner that the deformation of the gauge is reduced compared to the motion of the mobile part.
Abstract:
A monolithically-integrated current-feedback instrumentation amplifier includes two differential pairs of transistors. A drain terminal of transistor is directly connected to a drain terminal of transistor and to a differential voltage amplifier, and is connected to a ground terminal by means of a first sink resistor. A drain terminal of transistor is directly connected to a drain terminal of transistor and to the differential voltage amplifier, and is connected to a ground terminal by means of a second sink resistor. An output terminal of the differential voltage amplifier is connected to a resistive voltage divider. Source terminals of the transistors are directly connected together and to a first bias current source without a degeneration resistor, and source terminals of the transistors are directly connected together and to a second bias current source without a degeneration resistor. A sensing system comprising a piezoresistive N&MEMS sensor and a monolithically-integrated differential readout circuit comprising the amplifier are also provided.
Abstract:
An inertial sensor including a substrate, a first pair of proof masses sensitive to rotation movements occurring around a first direction and a third direction, a second pair of proof masses sensitive to rotation movements occurring around a second direction and the third direction, an excitation device, four frames, a rotatable frame and a sensing system connected to the rotatable frame. This inertial sensor is characterized in that the excitation device is configured to force the first pair of proof masses and the second pair of proof masses into a motion going towards and away from the sensing system, and wherein the readout of the rotation movements occurring in each of the three directions is achieved with piezoelectric gauges.
Abstract:
A MEMS triaxial magnetic sensor device includes a sensing structure having: a substrate; an outer frame, which internally defines a window and is elastically coupled to first anchorages fixed with respect to the substrate by first elastic elements; a mobile structure arranged in the window, suspended above the substrate, which is elastically coupled to the outer frame by second elastic elements and carries a conductive path for flow of an electric current; and an elastic arrangement operatively coupled to the mobile structure. The mobile structure performs, due to the first and second elastic elements and the arrangement of elastic elements, first, second, and third sensing movements in response to Lorentz forces from first, second, and third magnetic-field components, respectively. The first, second, and third sensing movements are distinct and decoupled from one another.