Analog Devices,inc.

Jianglong Zhang

Baoxing Chen

Xin Zhang

Alan J O'Donnell

Kuang L Yang

Jinbo Kuang

Kemiao Jia

Paul Vincent Errico

Christopher Hyde

Paul Errico

Sensing devices are described. A sensing device includes an inertial sensor, a read-out circuit configured to determine first data indicative of an acceleration of the structure using an output of the inertial sensor, an energy harvester configured to capture energy, and a power management unit. The power management unit comprises a plurality of energy storage components coupled to the energy harvester and a plurality of switches coupled to respective energy storage components of the plurality of energy storage components. The power management unit monitors energy levels stored in the energy storage components, selectively charges the plurality of energy storage components by selectively activating the plurality of switches, and provides power to one or more of the inertial sensor and the read-out circuit based on the monitored energy levels.

3-axis angular accelerometer

A three-axis accelerometer includes a single, integrated mass including at least one lateral (x-y) proof mass and at least one vertical (z) proof mass. The vertical proof mass is arranged as a teeter-totter mass, which is located within the lateral proof mass. The vertical proof mass is mechanically coupled to the lateral proof mass with one or more torsional springs, and the lateral proof mass is mechanically coupled to one or more anchors with one or more lateral springs. The at least one vertical proof mass may be symmetrically positioned about one or more axes of the three-axis accelerometer, so that the 3-axis accelerometer has in-plane symmetry. The three-axis accelerometer may be less susceptible for mechanical cross-talk or noise and may provide a smaller packaged solution for sensing acceleration in three directions.

3-axis accelerometer

Disclosed herein are aspects of a multiple-mass, multi-axis microelectromechanical systems (MEMS) accelerometer sensor device with a fully differential sensing design that applies differential drive signals to movable proof masses and senses differential motion signals at sense fingers coupled to a substrate. In some embodiments, capacitance signals from different sense fingers are combined together at a sensing signal node disposed on the substrate supporting the proof masses. In some embodiments, a split shield may be provided, with a first shield underneath a proof mass coupled to the same drive signal applied to the proof mass and a second shield electrically isolated from the first shield provided underneath the sense fingers and biased with a constant voltage to provide shielding for the sense fingers.

Fully differential accelerometer

Angular accelerometers are described, as are systems employing such accelerometers. The angular accelerometers may include a proof mass and rotational acceleration detection beams directed toward the center of the proof mass. The angular accelerometers may include sensing capabilities for angular acceleration about three orthogonal axes. The sensing regions for angular acceleration about one of the three axes may be positioned radially closer to the center of the proof mass than the sensing regions for angular acceleration about the other two axes. The proof mass may be connected to the substrate though one or more anchors.

A microelectromechanical systems (MEMS) sensor device with a compound folded tether is disclosed. The compound folded tether connects a movable proof mass to a substrate, and includes folds composed of multiple short segments aligned with each other to form a longer composite segment having multiple breaks along its length. The use of multiple short segments to create a longer composite segment of the folded tether provides the tether with increased stiffness without altering the fundamental resonance frequency of the tether. The increased stiffness can beneficially lower the occurrence of stiction. Moreover, such a tether configuration provides larger separation between the tether's fundamental resonance frequency and higher order resonant mode frequencies, meaning that the higher order modes may be suppressed in typical operation of the MEMS sensor device.

Folded tether structure for MEMS sensor devices

A two-axis microelectromechanical systems (MEMS) gyroscope having four proof masses disposed in respective quadrants of a plane is described. The quad proof mass gyroscope may comprise an inner coupler passing between a first and a third proof mass and between a second and a fourth proof mass, and coupling the four proof masses with one another. The quad proof mass gyroscope may further comprising a first outer coupler coupling the first and the second proof masses and a second outer coupler coupling the third and the fourth proof masses. The outer couplers may have masses configured to balance the center of masses of the four proof masses, and may have elastic constants matching the elastic constant of the inner coupler. The quad gyroscope may further comprise a plurality of sense capacitors configured to sense angular rates.

Quad proof mass MEMS gyroscope with outer couplers and related methods

A teeter-totter type accelerometer includes one or more platforms configured so as to move in proportion to deformation of the substrate and/or anchor(s). The platform(s) may be in a fixed position relative to the substrate, e.g., by being fixedly attached to the anchor(s) or by being fixedly attached to the substrate, or the platform(s) may be movable relative to the substrate, e.g., by being tethered to the anchor(s) so as to allow the platform(s) to pivot relative to the anchor(s). Electrodes are placed on the substrate underlying the platform(s) for sensing position of the platform(s) relative to the underlying substrate. The teeter-totter proof mass is configured such that it can rotate relative to the platform(s), e.g., by being tethered to the platform(s) or by being tethered to one or more anchors separate from the platform(s). The output of the accelerometer is adjusted based on signals from these platform-sensing electrodes in order to reduce or eliminate offset drift.

Z axis accelerometer design with offset compensation

A balanced teeter-totter accelerometer has a mass suspended above a substrate, the mass having an axis of rotation that is parallel to the substrate and substantially geometrically centered with respect to the shape of the mass. A physical acceleration in a direction perpendicular to the substrate causes the mass to rotate about the axis of rotation. The rotation is sensed by measuring a change in capacitance of electrodes on the substrate. The accelerometer may be calibrated using the same sensing electrodes.

Teeter totter accelerometer with unbalanced mass

A MEMS device includes a substrate, a mass having a first and second set of elongated mass fingers extending from the mass, and a support structure supporting the mass on the substrate. The support structure may include at least one anchor and a plurality of springs that allow movement of the mass relative to the substrate. The MEMS device may also include a first set of sensing fingers for sensing movement of the first set of mass fingers relative to the first set of sensing fingers, and a second set of sensing figures for sensing movement of the second set of mass fingers relative to the second set of sensing fingers. The first and second sets of sensing fingers may have different size finger gaps between the sensing fingers and the respective mass fingers.

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Vienna, VA, United States of America

Jianglong Zhang