Abstract: The present invention discloses a direct read metering device, comprising a digital counting wheel connected with a rotary shaft, a micro-controller—a ring magnet coaxially installed on the digital counting wheel, and a tunneling magnetoresistive angular displacement sensor installed radially displaced from the central axis of the annular magnet; the tunneling magneto-resistive angular displacement sensor and the ring magnet are separated by a certain distance in the direction parallel to the central axis of the ring magnet; the micro-controller is connected to the tunneling magnetoresistive angular displacement sensor and used to convert the output of the tunneling magnetoresistive angular displacement sensor into a readable number.

Abstract: The present invention discloses a single-chip referenced full-bridge magnetoresistive magnetic-field sensor. The single-chip sensor is a Wheatstone bridge arrangement of magnetoresistive sensing elements and reference elements. The sensing elements and reference elements are formed from either magnetic tunnel junctions or giant magnetoresistive materials. The sensitivity of the reference and sensor elements is controlled through one or a combination of magnetic bias, exchange bias, shielding, or shape anisotropy. Moreover, the bridge output is tuned by setting the ratio of the reference and sensor arm resistance values to a predetermined ratio that optimizes the bridge output for offset and symmetry. The single-chip referenced-bridge magnetic field sensor of the present invention exhibits excellent temperature stability, low offset voltage, and excellent voltage symmetry.

Abstract: The present invention discloses a design for a single-chip dual-axis magnetic field sensor, based on magnetic tunnel junction (MTJ) elements and permanent magnets integrated on a semiconductor substrate to produce two types of sensor bridges that detect orthogonal magnetic field components. The orthogonal magnetic field component detection capability results from the different types of sensor bridges that can be produced by varying the shape of the MTJ elements and the bias fields that can be created by permanent magnets. Because the permanent magnets can create orthogonal bias fields on the different sensor bridges, it is possible to use a single pinned layer to set direction for both sensor bridges. This is advantageous because it permits the two-axis sensor to be fabricated on a single semiconductor chip without the need for specialized processing technology such as local heating, or deposition of multiple magnetoresistive films with different pinned layers setting directions.

Abstract: The present invention discloses a design of a single-chip push-pull bridge sensor, composed of magnetoresistive elements, utilizing on-chip permanent magnets. The permanent magnets are oriented to preset magnetization directions of free layers of adjacent sensor bridge arms so that they point to different directions with respect the same sensing direction, enabling push-pull operation. The push-pull bridge sensor of the present invention is integrated on a single chip. Additionally, an on-chip coil is disclosed to reset or calibrate the magnetization directions of the free layers of the magnetoresistive elements.

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.