Abstract: A magnetoresistive mixer, comprising a spiral coil, a bridge-type magnetoresistive sensor and a magnetic shielding layer, wherein the spiral coil is located between the bridge-type magnetoresistive sensor and the magnetic shielding layer. Four tunnel magnetoresistive sensor units forming the bridge-type magnetoresistive sensor respectively contain N array-type magnetic tunnel junction rows. The magnetic tunnel junction rows are connected in series, parallel, or combination of series and parallel connections to form two port structures.

Abstract: A magnetoresistive current limiter, comprising a substrate, a magnetoresistive sensor layer, a first insulating layer, a coil, a second insulating layer, a magnetic shield layer, and an input electrode and output electrode. The coil is located between the magnetic shield layer and the magnetoresistive sensor layer. The first and second insulating layers are isolated from the magnetoresistive sensor layer and the coil, and from the coil and the magnetic shield layer, respectively; the magnetoresistive sensor layer and the coil are connected in series, and are connected to the input electrode and the output electrode.

Abstract: A liquid level sensor system is disclosed for remotely monitoring the liquid level in a tank. The system comprises a first fixed portion with a first liquid level response unit, and a second fixed portion with a second liquid level response unit. A guide tube is inserted into the tank and attached to the bottom of the first fixed portion. The guide tube is provided with a multitude of ports, such that the liquid level in the guide tube is flush with the liquid level in the tank. The first liquid level response unit comprises a float floating up and down with the variation of the liquid level in the guide tube, a rotating shaft rotating around a relatively fixed axis of rotation in the up and down floating process of the float, and a permanent magnet. The second fixed portion is attached to the top of the first fixed portion. The second liquid level response unit comprises a PCB, a magnetoresistive angle sensor chip, and a control circuit electrically connected to the magnetoresistive angle sensor chip.

Abstract: A three-axis digital compass comprising two X-axis magnetic sensors, two Y-axis magnetic sensors, a flux concentrator, a signal sampling unit, a signal processing unit, and a signal output unit is disclosed. The X-axis and Y-axis magnetic sensors are arranged along a periphery of the flux concentrator. An external magnetic field is distorted when passing through the flux concentrator. An Z axis component of the external magnetic field is converted into X-axis or Y-axis magnetic field components when passing through the flux concentrator, and the so converted components of the external magnetic field act on the X-axis and Y-axis magnetic sensitive sensors. An output signal of the X-axis and Y-axis magnetic sensitive sensors is sent to the signal processing unit through the signal sampling unit, and it is used to calculate the three orthogonal components of the external magnetic field. These calculated external magnetic field components are output in a digital format through the signal output unit.

Abstract: A single-chip magnetic field sensor bridge, comprising a substrate, a reference arm, a sensing arm, shielding structures, and wire bond pads is disclosed. The reference arm and the sense arm respectively comprise at least two rows/columns of reference element strings and sense element strings formed by electrically connecting one or more identical magnetoresistive sensing elements. The reference element strings and the sense element strings are alternately arranged. The magnetoresistive sensing elements are AMR, GMR or TMR sensing elements. The reference element strings are provided with shielding structures thereon, and the sensing element strings are located in gaps between two adjacent shielding structures. The shielding structures are arrays of elongated strips composed of permalloy or another soft ferromagnetic material. The sensors can be implemented as one of three different bridge structures, called a quasi-bridge, a half-bridge, or a full-bridge.

Abstract: A magnetoresistive sensor bridge utilizing magnetic tunnel junctions is disclosed. The magnetoresistive sensor bridge is composed of one or more magnetic tunnel junction sensor chips to provide a half-bridge or full bridge sensor in a standard semiconductor package. The sensor chips may be arranged such that the pinned layers of the different chips are mutually antiparallel to each other in order to form a push-pull bridge structure. The sensor chips are then interconnected using wire bonding. The chips can be wire-bonded to various standard semiconductor leadframes and packaged in inexpensive standard semiconductor packages. The bridge design may be push-pull or referenced. In the referenced case, the on-chip reference resistors may be implemented without magnetic shielding.

Abstract: An electronic water meter capable of implementing precision metering. The electronic water meter comprises a machine frame, multiple counter units, and multiple shielding plates. The counter units comprise numerical character wheels, magnets, magnetic angular displacement sensors, and digital circuits. The magnetic angular displacement sensors are electrically connected to the digital circuits, sense components of magnetic fields at respective positions thereof on the basis of angular position changes of magnetic field vectors of the counter units, and transmit a corresponding electric signal to the digital circuits. The digital circuits perform a calculation processing on the basis of the electrical signal outputted by the magnetic angular displacement sensors and output a digital signal corresponding to the angular positions of the numerical character wheels.

Abstract: The present invention discloses a design and manufacturing method for a single-chip magnetic sensor bridge. The sensor bridge comprises four magnetoresistive elements. The magnetization of the pinned layer of each of the four magnetoresistive elements is set in the same direction, but the magnetization directions of the free layers of the magnetoresistive elements on adjacent arms of the bridge are set at different angles with respect to the pinned layer magnetization direction. The absolute values of the angles of the magnetization directions of the free layers of all four magnetoresistive elements are the same with respect with their pinning layers. The disclosed magnetic biasing scheme enables the integration of a push-pull Wheatstone bridge magnetic field sensor on a single chip with better performance, lower cost, and easier manufacturability than conventional magnetoresistive sensor designs.

Abstract: A magnetoresistive sensor bridge utilizing magnetic tunnel junctions is disclosed. The magnetoresistive sensor bridge is composed of one or more magnetic tunnel junction sensor chips to provide a half-bridge or full bridge sensor in a standard semiconductor package. The sensor chips may be arranged such that the pinned layers of the different chips are mutually anti-parallel to each other in order to form a push-pull bridge structure. The sensor chips are then interconnected using wire bonding. The chips can be wire-bonded to various standard semiconductor leadframes and packaged in inexpensive standard semiconductor packages. The bridge design may be push-pull or referenced. In the referenced case, the on-chip reference resistors may be implemented without magnetic shielding.

Abstract: Provided is a magnetic absolute rotary encoder, comprising a rotation shaft, multiple rotating wheels that can rotate along the rotation shaft, multiple encoding units that correspond to the multiple rotating wheels one-to-one, and one or more permanent magnet assemblies that provide the magnetic bias to the multiple encoding units. Each encoding unit comprises a magnetically permeable encoder disc, the structure thereof enabling the magnetic permeability thereof to be different according to the different positions of the rotation shaft, and comprises multiple sensor units that comprise multiple magnetic sensors. The sensor units are used to sense the magnetic permeability of the magnetically permeable encoder disc and to output the sensor signals that characterize the relative position of the magnetically permeable encoder disc.

Abstract: A multi-turn absolute magnetic encoder, comprising (M+1) counting units, a single-turn signal processing unit, and a multi-turn signal processing unit. Each counting unit comprises counting wheels with a cylindrical ring permanent magnet fixed thereon, and a tunneling magnetoresistive angular displacement sensor. The magnetoresistive angular displacement sensor is located within a region in a detection plane of the permanent magnet at within a specific radius range from the axis of the cylindrical ring permanent magnet, within the detection plane the angle of a component of a magnetic field generated by the permanent magnet is linearly proportional to the rotation angle of the cylindrical ring permanent magnet.

Abstract: A thin film magnetoresistive sensor for detecting a magnetic field components perpendicular and parallel to the plane of the sensor substrate is disclosed. The sensing element comprises a free layer, a reference layer, and a spacer layer between the free layer and the reference layer. The easy-axis magnetization, which is inherent to the material of the free layer, is arranged to be perpendicular to the plane of the sensor substrate. The magnetization direction of the reference layer is confined to a direction parallel to the substrate plane. The reference layer consists of a ferromagnetic layer exchange coupled to an antiferromagnetic layer, or consists of a ferromagnetic layer having a higher coercive force than that of the free layer. The spacer layer is composed of an insulating material or a conductive material. The magnetoresistive sensor further includes an array of aforementioned sensing elements coupled to an electronic device in order to provide three-axis sensing.

Abstract: A magnetic angle encoder comprising counting wheels, with columnar ring-shaped permanent magnets coaxially mounted to the counting wheels, tunneling magnetoresistive angular displacement sensors, and a digital processing circuit. In the magnetic angle encoder, the tunneling magnetoresistive angular displacement sensors are located in a region within detection planes of the permanent magnets with an axial distance and a specific radial distance from the permanent magnets. Within this specific radius range, the rotating magnetic field angle (?) of the component of the magnetic field generated by the permanent magnets in the detection planes varies linearly with the rotation phase angle (?) of the permanent magnets. An electronic water meter is also disclosed, and it comprises a plurality of counting units and a digital processing circuit. The counting units contain counting wheels, permanent magnets, and tunneling magnetoresistive angular displacement sensors.

Abstract: A digital liquid-level sensor comprises a non-magnetic conduit, a floater provided outside the non-magnetic conduit and capable of axially moving along the non-magnetic conduit, and a permanent magnet fixed on the floater. The non-magnetic conduit further comprises a switch unit and an encoding unit. The switch unit comprises at least one tunneling magnetoresistance switch which is turned on or turned off under the effect of the magnetic field produced by the permanent magnet; and the encoding unit comprises at least one encoder, of which an input end receives an on/off signal from the tunneling magnetoresistance switch and outputs a digital signal indicating the position of the floater. The digital liquid-level sensor is of a small size; has low cost, low power consumption, high reliability, high sensitivity, high solution, long service life, and a good anti-interference capability; and can directly output the digital signal.

Abstract: The present invention relates to a permanent magnet suitable for a magnetic angle encoder. The permanent magnet has an annular cylindrical structure and comprises a first permanent magnet unit and a second permanent magnet unit. The first permanent magnet unit and the second permanent magnet unit are geometrically symmetrical with respect to a diametral cross section. The magnetisation intensity of the first permanent magnet unit and the magnetisation intensity of the second permanent magnet unit are parallel to the axial direction of the annular cylinder and are in opposite directions, or the magnetisation intensity of the first permanent magnet unit and the magnetisation intensity of the second permanent magnet unit are perpendicular to the diametral cross section and are parallel to one another and in the same direction.

Abstract: A magnetic currency verification head may include a magnetoresistive sensor chip, and a magnetic bias unit disposed on the side of the magnetoresistive sensor chip away from the detection surface of the magnetic currency verification head, and separated from the magnetoresistive sensor chip; the magnetoresistive sensor chip comprises a gradiometric bridge circuit that includes magnetic sensor elements; the sensitive direction of the magnetic sensor elements is parallel to the detection surface of the magnetic currency verification head; and the magnetic bias unit has a recessed magnetic structure configured such that the magnetic field generated by the magnetic bias unit only has a small magnetic field component in the direction parallel to the detection surface, thereby enabling the magnetic sensor elements to operate in their linear range. As a result, the magnetic currency verification head has high sensitivity and signal-to-noise ratio.

Abstract: A single-package bridge-type magnetic-field angle sensor comprising one or more pairs of magnetic tunnel junction sensor chips rotated relative to each other by 90 degrees in order to detect two magnetic field components in orthogonal directions respectively is disclosed. The magnetic-field angle sensor may comprise a pair of MTJ full-bridges or half-bridges interconnected with a semiconductor package lead. The magnetic-field angle sensor can be packaged into various low-cost standard semiconductor packages.

Abstract: A thin film magnetoresistive sensor for detecting a magnetic field components perpendicular and parallel to the plane of the sensor substrate is disclosed. The sensing element comprises a free layer, a reference layer, and a spacer layer between the free layer and the reference layer. The easy-axis magnetization inherent to the material of the free layer is arranged to be perpendicular to the plane of the sensor substrate. The magnetization direction of the reference layer is confined to a direction parallel to the substrate plane. The reference layer consists of a ferromagnetic layer exchange coupled to an antiferromagnetic layer, or consists of a ferromagnetic layer having a higher coercive force than that of the free layer. The spacer layer is composed of an insulating material or a conductive material. The magnetoresistive sensor further includes an array of aforementioned sensing elements coupled to an electronic device to provide three-axis sensing.

Abstract: The present invention discloses a design and manufacturing method for a single-chip magnetic sensor bridge. The sensor bridge comprises four magnetoresistive elements. The magnetization of the pinned layer of each of the four magnetoresistive elements is set in the same direction, but the magnetization directions of the free layers of the magnetoresistive elements on adjacent arms of the bridge are set at different angles with respect to the pinned layer magnetization direction. The absolute values of the angles of the magnetization directions of the free layers of all four magnetoresistive elements are the same with respect with their pinning layers. The disclosed magnetic biasing scheme enables the integration of a push-pull Wheatstone bridge magnetic field sensor on a single chip with better performance, lower cost, and easier manufacturability than conventional magnetoresistive sensor designs.

Abstract: The present invention discloses a magnetoresistive gear tooth sensor, which includes a magnetoresistive sensor chip and a permanent magnet. The magnetic sensor chip is comprised of at least one magnetoresistive sensor bridge, and each arm of the sensor bridge has at least one MTJ element group. The magnetoresistive gear tooth sensor has good temperature stability, high sensitivity, low power consumption, good linearity, wide linear range, and a simple structure. Additionally, the magnetoresistive gear tooth sensor has a concave soft ferromagnetic flux concentrator, which can be used to reduce the component of the magnetic field generated by the permanent magnet along the sensing direction of the MTJ sensor elements, enabling a wide linear range. Because it is arranged as a gradiometer, the magnetoresistive gear tooth sensor bridge is not affected by stray magnetic field; it is only affected by the gradient magnetic field generated by gear teeth in response to the permanent magnet bias.