Abstract: Systems and methods to detect when the external magnetic field becomes higher than the saturation field of AMR material are described. Approaches include saturation detection by combining sensors with different full-scale ranges, saturation detection using DC current and saturation detection by arranging sensitive axes at 45° offsets.

Abstract: Method and apparatus of integrating a three-axis magnetometer and a three-axis accelerometer to provide attitude and heading, calibrated magnetometer and accelerometer data, and angular rate, while removing sensor error sources over time and temperature and to compensate for hard and soft iron distortions of the Earth magnetic field. Filtered accelerometer data are corrected to account for various error sources. The magnetic heading is calculated from a horizontal magnetic field vector transformed from three dimensional Earth's magnetic field vector by using quasi-static roll and pitch angles from the filtered accelerometer data. A first Kalman filter estimates the state vector, based on the principle that the magnitude of local Earth's magnetic field vector is constant, to form hard and soft iron correction matrices.

Abstract: Packaged MEMS devices are described. One such device includes a substrate having an active surface with an integrated circuit. Two substrate pads are formed on the substrate; one pad is a closed ring pad. The device also includes a cap wafer with two wafer pads. One of these wafer pads is also a closed ring pad. A hermetic seal ring is formed by a first bonding between the two ring pads. The device has a gap between the substrate and the cap wafer. This gap may be filled with a pressurized gas. An electrical connection is formed by a second bonding between one substrate pad and one wafer pad. An electrical contact is disposed over the cap wafer. The device also includes an insulation layer between the electrical contact and the cap wafer. Methods of producing the packaged MEMS devices are also described.

Abstract: A three-axis magnetic sensor or magnetometer is provided. Two magnetic sensor Wheatstone bridges using barber pole AMR structures are fabricated on opposite sides of a bump structure formed on a substrate to provide surfaces that are at a predetermined angle with respect to the flat surface of the substrate. The bridge assembly is oriented along the Y axis and the bridges are interconnected such that Y and Z channel signals can be produced by processing of the bridge signals. The X channel signals are provided by an X axis sensor provided on the level surface of the substrate.

Abstract: A magnetometer with a set/reset coil having portions that cross portions of sensing strips at an angle in order to create a magnetic field in the sensing strip that is at an angle with respect to the easy axis of magnetization of the sensing strip. Each sensing strip may have a portion having a magnetic field created therein that is different from a magnetic field created in another portion of the same sensing strip. As a result, a lower set/reset coil current is needed to initialize the magnetometer.

Abstract: A multi-axis GMR or TGMR based magnetic field sensor system is disclosed. Preferably a three axis sensor system is provided for sensing magnetic flux along three mutually orthogonal axes, which can be used for magnetic compass or other magnetic field sensing applications. The sensing units are operative to sense X and Y axis magnetic flux signals in the device (XY) plane, while Z axis sensitivity is achieved by use of a continuous ring shaped or octagonal magnetic concentrator that is adapted to convert the Z axis magnetic flux signal into magnetic flux signals in the XY plane.

Abstract: A unitary sensor package having a magnetometer, accelerometer and gyroscope incorporated into a monolithic structure composed of one or more wafers or substrates. Pressure and/or other types of sensors can also be incorporated in the monolithic structure.

Abstract: An integrated calibration system and process for a three-axis (X, Y, Z) accelerometer estimates Z-axis bias, Z-axis bias drift and determines X, Y, and Z-axes error sources based on measurements taken when the accelerometer is static, i.e., sensing only the earth's gravitational acceleration. Optimal on-the-fly error estimates for the three-axis accelerometer are obtained so that the measurements provided by the three-axis accelerometer remain error-free.

Abstract: A Z-axis capacitive accelerometer includes a substrate, a capacitance sensing plate, a proof mass and at least one pair of spring beams. The capacitance sensing plate includes two symmetrical sense areas to create differential capacitive measurement. A decoupling structure separates the proof mass and the capacitance sensing plate and their rotational motions from each other. In the proposed Z axis capacitive accelerometer, the distance of the capacitance sensing plate relative to its rotation axis is considerably increased, thereby effectively enhancing the sensitivity when measuring the Z-axis acceleration.

Abstract: An interface within an electronic device coupled to a serial communications bus having one or more serial communications lines generates a reference voltage source within the electronic device from the logic signals carried on the serial communications line(s). The generated reference voltage source is used within the electronic device to decode the logic signals received from the serial communications line(s).

Abstract: A magnetometer with a set/reset coil having portions that cross portions of sensing strips at an angle in order to create a magnetic field in the sensing strip that is at an angle with respect to the easy axis of magnetization of the sensing strip. Each sensing strip may have a portion having a magnetic field created therein that is different from a magnetic field created in another portion of the same sensing strip. As a result, a lower set/reset coil current is needed to initialize the magnetometer.

Abstract: A device, system, and method for generating location and path-map data for displaying a location and path-map is disclosed.

Abstract: A magnetometer with only a SET operation for initiating a magnetic orientation within a magnetic field sensor based on anisotropic magnetoresistive (AMR) technology. Within the magnetometer, the relative orientations of the respective X, Y and Z axes detectors are maintained by a package in which all detectors are mounted on a single assembly with the Z axis sensor displaced and held orthogonal to the other two sensors by potting material. Shorting bars on respective barber pole structures are provided with a geometry that allows for closer placement of adjacent barber poles to one another. The barber pole structures are deposited in a nested orientation which provides for balanced resistance legs in a Wheatstone bridge construction.

Abstract: This invention uses surface tension to align a z-axis MEMS sensing device that is mounted onto a substrate or lead frame oriented in an xy-plane. According to the teachings of the present invention, the height of the z-axis sensing device is less than or substantially equal to its width (y-dimension) while the length of the device in the longitudinal direction (x-dimension) is greater than either of the y- or z-dimensions. As a result, instead of being thin and tall like a wall, which configuration is extremely difficult to align vertically, the elongate z-axis sensing device is mounted on a short z-axis, making it easier to align vertically.

Abstract: A monolithic tri-axis anisotropic magnetoresistive (AMR) sensor and the method of manufacturing of the AMR sensor are presented. In one embodiment, the monolithic tri-axis AMR sensor includes (a) a substrate, (b) a first horizontal direction sensor disposed on the substrate, (c) a second horizontal direction sensor disposed on the substrate, (d) a third horizontal direction sensor disposed on the substrate, and (e) a flux concentrator disposed on the third horizontal direction sensor, wherein the flux concentrator is in cooperation with the third horizontal direction sensor to realize a function of a Z-axis sensor, such that the Z-axis direction can be effectively measured. The integration of the tri-axis AMR sensor is therefore accomplished. In addition, the integrated tri-axis AMR sensor has low production cost and improved reliability.

Abstract: A multiple-axis accelerometer for use with a blood pressure monitor or a blood pressure measuring device (BPM) to determine an inclination associated with the point of fixture. The accelerometer is attached to a substrate that is structured and arranged in a vertical or substantially vertical plane. The accelerometer includes a first accelerometer portion that is adapted to generate a first output based on acceleration in a first direction in the vertical plane (Ax); and a second accelerometer portion that is adapted to generate a second output based on acceleration in a second direction, orthogonal to the first direction, in the vertical plane (Ay). The first and second outputs provide a measure of the inclination about an axis that is orthogonal or substantially orthogonal to the vertical plane. The measured inclination is a roll angle (?) is given by the formula: ?=arctan(Ay/Ax).

Abstract: A Z-axis capacitive accelerometer includes a substrate, a capacitance sensing plate, a proof mass and at least one pair of spring beams. The capacitance sensing plate includes two symmetrical sense areas to create differential capacitive measurement. A decoupling structure separates the proof mass and the capacitance sensing plate and their rotational motions from each other. In the proposed Z axis capacitive accelerometer, the distance of the capacitance sensing plate relative to its rotation axis is considerably increased, thereby effectively enhancing the sensitivity when measuring the Z-axis acceleration.

Abstract: An ion discharge gyroscope measures rotational motion and linear acceleration by generating symmetrical ion jet streams and measuring respective amounts of the jet streams impinging on detectors located so as to intercept the ion jet streams. The ion jet streams will be diverted by operation of the Coriolis effect and the differences in the amount of each ion jet stream impinging on the detectors is an indication of rotational motion and linear acceleration. In one embodiment, the ion jet streams are heated and the respective temperatures of the detectors are measured. In another embodiment, the amounts of current flowing through each detector, as contributed by the ion jet streams, are measured and used to determine rotation and acceleration.

Abstract: The use of magnetic field sensing to perform sophisticated command control and data input into a portable device is disclosed. A magnetic field sensor is embedded or fixedly attached to a portable device to measure changes in the magnetic field strength and/or direction accompanying movement, motion or tilt of the device in one-, two- or three-dimensions when the portable device is used to air-write or make gestures.

Abstract: A method and device for identifying leaks in or a leakage rate of an integrated circuit package. The method and device include integrating a micromachined-thermal-convection accelerometer in the integrated circuit package and evaluating the initial and subsequent sensitivities of the accelerometer. A change in sensitivity with time provides indicia of a leak and a measure of leakage rate.