Abstract: In one aspect, bridge circuitry includes a first magnetoresistance (MR) element connected with a second MR element at a first node; a third MR element connected with the first MR element at a second node; a fourth MR element connected with the third MR element at a third node; a fifth MR element connected with a sixth MR element at a fourth node; a seventh MR element connected with the fifth MR element at a fifth node; and an eighth MR element connected with the seventh MR element at a sixth node; and a plurality of eight switches. Six of the plurality of eight switches are each connected to a corresponding one node.

Abstract: Magnetic-field sensors use magnetic closed-loops with magnetic-field sensing elements, e.g., magnetoresistance (MR) elements, and diagnostic circuitry operating in a separate frequency band than that used for magnetic field sensing. The MR elements can be used in a first stage of a high gain amplifier which provides a feedback signal to a feedback coil in a feedback configuration to provide a magnetic feedback field. The magnetic feedback field attenuates the sensed magnetic field so that the MR elements operate in a linear range. Magnetic stray field effects and any limited linearity of magnetic-field sensing elements can be masked by the loop gain of the closed loop. For a magnetic closed-loop, a negative feedback configuration can be used or a positive feedback configuration can be used with a loop-gain of less than one. The diagnostic signal traverses the closed-loop and provides information regarding correct or incorrect functioning of the loop components.

Abstract: A magnetic field sensor includes a first coil responsive to a first AC coil drive signal having a first frequency, a magnetic field sensing element responsive to a sensing element drive signal and configured to simultaneously detect a directly coupled magnetic field generated by the first coil and a reflected magnetic field generated by an eddy current induced in a conductive target by the first coil, the conductive target disposed proximate to the magnetic field sensing element, the magnetic field sensing element further configured to generate a magnetic field signal, a second coil responsive to a second AC coil drive signal having a second frequency that is the same as the first frequency and current sensing circuitry configured to measure a magnitude of the second AC coil drive signal that causes the magnetic field signal to be approximately zero.

Abstract: A magnetic field sensor can be are based upon three element vertical Hall element building blocks, e.g., three element or six element vertical Hall element arrangements, all arranged in a circle. In some embodiments, the circle of vertical Hall elements can be arranged as a CVH sensing element.

Abstract: A magnetic field sensor includes at least one coil responsive to an AC coil drive signal; at least one magnetic field sensing element responsive to a sensing element drive signal and configured to detect a directly coupled magnetic field generated by the at least one coil and to generate a magnetic field signal in response to the directly coupled magnetic field; a processor responsive to the magnetic field signal to compute a sensitivity value associated with detection of the directly coupled magnetic field and substantially independent of a reflected magnetic field reflected by a conductive target disposed proximate to the at least one magnetic field sensing element; and an output signal generator configured to generate an output signal of the magnetic field sensor indicative of the reflected magnetic field.

Abstract: Magnetic field closed loop sensors including offset reduction circuitry to reduce undesired baseband components attributable to offset associated with magnetoresistance elements are described. A superimposed signal including a main signal portion indicative of a parameter of a target and an offset reduced signal portion is coupled to feedback circuitry. The feedback circuitry generates a feedback signal to drive a feedback coil. Main processing circuitry is operative to extract the main signal portion from the superimposed signal and produce a sensor output signal based on the main signal portion. Example offset reduction circuitry can take the form of AC coupling circuitry or a ripple reduction loop.

Abstract: Methods and apparatus for linear inductive torque sensing that may include transmitting an AC magnetic field with a transmit coil toward a conductive target and receiving a field reflected by the conductive target with a receive coil, wherein the conductive target comprises first and second targets positioned with respect to each other and each shaped to linearly increase or decrease an amount of conductive area of the conductive target due to relative movement of the first and second targets which changes an amount of the field reflected by the conductive target. A signal from the receive coil can be processed to determine a relative position of the first and second targets corresponding to an amount of torque on an elongate member connected to the first and second targets. In other embodiments, a change in inductance of the transmit coil is measured to determine relative target position.

Abstract: A method is provided for use in a sensor, the method comprising: selecting a switching cycle for the sensor; transitioning the sensor into a state in which at least one component of the sensor is periodically turned on and off in accordance with the switching cycle; sampling an analog signal to generate a sampled signal, the analog signal being generated by at least one sensing element, the analog signal being sampled only during periods in which the at least one component of the sensor is turned on; and generating an output signal based, at least in part, on the sampled signal and outputting the output signal.

Abstract: In one aspect, a magnetic-field sensor includes main coil circuitry configured to generate a first magnetic field signal at a first frequency. A reflected signal is generated from a target caused by the first signal generated by the main coil circuitry. The magnetic field sensor also includes magnetoresistance circuitry configured to receive an error signal. The error signal is formed from a combination of the reflected signal and a second magnetic field signal. The magnetic-field sensor further includes analog circuitry configured to receive an output signal from the magnetoresistance circuitry, digital circuitry configured to receive an output signal from the analog circuitry, a mixer configured to receive a feedback signal from one of the digital circuitry or the analog circuitry, and secondary coil circuitry configured to receive a driver signal from the mixer causing the secondary coil circuitry to generate the second magnetic field signal at the first frequency.

Abstract: In one aspect, bridge circuitry includes a first magnetoresistance (MR) element; a second MR element connected in series with the first MR element at a first node; a third MR element; a fourth MR element connected in series with the third MR element at a second node; a first switch connected at one end to a supply voltage and connected at the other end to the third MR element; a second switch connected at one end to ground and connected at the other end to the fourth MR element; a third switch connected at one end to ground and connected at the other end to the third MR element and the first switch; and a fourth switch connected at one end to the supply voltage and the other end to the fourth MR element and the second switch. The first and second MR elements are in parallel with the third and fourth MR elements.

Abstract: Methods and apparatus for linear inductive torque sensing that may include transmitting an AC magnetic field with a transmit coil toward a conductive target and receiving a field reflected by the conductive target with a receive coil, wherein the conductive target comprises first and second targets positioned with respect to each other and each shaped to linearly increase or decrease an amount of conductive area of the conductive target due to relative movement of the first and second targets which changes an amount of the field reflected by the conductive target. A signal from the receive coil can be processed to determine a relative position of the first and second targets corresponding to an amount of torque on an elongate member connected to the first and second targets. In other embodiments, a change in inductance of the transmit coil is measured to determine relative target position.

Abstract: A magnetic field angle sensor includes a coil configured to generate a magnetic field that induces an eddy current in a rotatable target, a first magnetic field sensing structure positioned proximate to the coil and configured to detect a reflected magnetic field generated by the eddy current induced in the target, a second magnetic field sensing structure positioned proximate to the coil and configured to detect the reflected magnetic field generated by the eddy current induced in the target, wherein the first and second magnetic field sensing structures are configured to detect quadrature components of the reflected magnetic field, and a processing module configured to process the reflected magnetic field detected by the first and second magnetic field sensing structures for determining an angular position of the target.

Abstract: A sensor, comprising: a substrate having a reference crystal orientation and a plurality of vertical Hall element pairs that are formed on the substrate. Each vertical Hall element pair includes: (i) a respective first vertical Hall element that is oriented at a respective first angle relative to the reference crystal orientation of the substrate and (ii) a respective second vertical Hall element that is oriented at a respective second angle relative to the reference crystal orientation of the substrate. The substrate has a rectangular shape, and each of the vertical Hall element pairs is disposed in a different respective corner of the substrate.

Abstract: A magnetic field angle sensor includes a coil configured to generate a magnetic field that induces an eddy current in a rotatable target, a first magnetic field sensing structure positioned proximate to the coil and configured to detect a reflected magnetic field generated by the eddy current induced in the target, a second magnetic field sensing structure positioned proximate to the coil and configured to detect the reflected magnetic field generated by the eddy current induced in the target, wherein the first and second magnetic field sensing structures are configured to detect quadrature components of the reflected magnetic field, and a processing module configured to process the reflected magnetic field detected by the first and second magnetic field sensing structures for determining an angular position of the target.

Abstract: In one aspect, a magnetic-field sensor includes main coil circuitry configured to generate a first magnetic field signal at a first frequency. A reflected signal is generated from a target caused by the first signal generated by the main coil circuitry. The magnetic field sensor also includes magnetoresistance circuitry configured to receive an error signal. The error signal is formed from a combination of the reflected signal and a second magnetic field signal. The magnetic-field sensor further includes analog circuitry configured to receive an output signal from the magnetoresistance circuitry, digital circuitry configured to receive an output signal from the analog circuitry, a mixer configured to receive a feedback signal from one of the digital circuitry or the analog circuitry, and secondary coil circuitry configured to receive a driver signal from the mixer causing the secondary coil circuitry to generate the second magnetic field signal at the first frequency.

Abstract: In one aspect, a magnetic-field sensor includes main coil circuitry configured to generate a first magnetic field signal at a first frequency. A reflected signal is generated from a target caused by the first signal generated by the main coil circuitry. The magnetic field sensor also includes magnetoresistance circuitry configured to receive an error signal. The error signal is formed from a combination of the reflected signal and a second magnetic field signal. The magnetic-field sensor further includes analog circuitry configured to receive an output signal from the magnetoresistance circuitry, digital circuitry configured to receive an output signal from the analog circuitry, feedback circuitry configured to receive a feedback signal from one of the digital circuitry or the analog circuitry, and secondary coil circuitry configured to receive a driver signal from the feedback circuitry causing the secondary coil circuitry to generate the second magnetic field signal at the first frequency.

Abstract: An electronic circuit can have a first plurality of vertical Hall elements and a second plurality of vertical Hall elements all disposed on a substrate having a plurality of crystal unit cells, wherein the first plurality of vertical Hall elements have longitudinal axes disposed within five degrees of parallel to an edge of the crystal unit cells, and wherein the second plurality of vertical Hall elements have longitudinal axes disposed between eighty-five and ninety-five degrees relative to the longitudinal axes of the first plurality of vertical Hall elements.

Abstract: A magnetic field sensor includes: a substrate; a transmission coil formed on the substrate, the transmission coil being configured to generate a direct magnetic field; a sensing bridge that is formed on the substrate, the sensing bridge being configured to detect the direct magnetic field and a reflected magnetic field that is generated by a target, the reflected magnetic field being generated in response to eddy currents that are induced in the target by the direct magnetic field; a processing circuitry being configured to generate an output signal that is indicative of a position of the target, the output signal being generated by normalizing a first signal with respect to a second signal, the first signal being generated at least in part by using the sensing bridge, and the second signal being generated at least in part by using the sensing bridge, wherein the second signal is based on the detected direct magnetic field.

Abstract: A magnetic field sensor includes at least one coil responsive to an AC coil drive signal; at least one magnetic field sensing element responsive to a sensing element drive signal and configured to detect a directly coupled magnetic field generated by the at least one coil and to generate a magnetic field signal in response to the directly coupled magnetic field; a processor responsive to the magnetic field signal to compute a sensitivity value associated with detection of the directly coupled magnetic field and substantially independent of a reflected magnetic field reflected by a conductive target disposed proximate to the at least one magnetic field sensing element; and an output signal generator configured to generate an output signal of the magnetic field sensor indicative of the reflected magnetic field.

Abstract: An electronic circuit can have a first plurality of vertical Hall elements and a second plurality of vertical Hall elements all disposed on a substrate having a plurality of crystal unit cells, wherein the first plurality of vertical Hall elements have longitudinal axes disposed within five degrees of parallel to an edge of the crystal unit cells, and wherein the second plurality of vertical Hall elements have longitudinal axes disposed between eighty-five and ninety-five degrees relative to the longitudinal axes of the first plurality of vertical Hall elements.