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: A magnetic field sensor includes at least one coil responsive to an AC coil drive signal; at least two spaced apart magnetic field sensing elements responsive to a sensing element drive signal and positioned proximate to the at least one coil; and a circuit coupled to the at least two magnetic field sensing elements to generate an output signal of the magnetic field sensor indicative of a difference between a distance of a conductive target with respect to each of the at least two spaced apart magnetic field sensing elements.

Abstract: A pressure sensor includes a chamber comprising a conductive portion and a deformable portion coupled to the conductive portion and susceptible to deformation in response to a pressure differential between an interior of the chamber and an exterior of the chamber; at least one coil responsive to an AC coil drive signal; at least one magnetic field sensing element disposed proximate to the at least one coil and to the conductive portion of the chamber and configured to generate a magnetic field signal in response to a reflected magnetic field generated by the at least one coil and reflected by the conductive portion; and a circuit coupled to the at least one magnetic field sensing element to generate an output signal of the pressure sensor indicative of the pressure differential between the interior of the chamber and the exterior of the chamber in response to the magnetic field signal.

Abstract: A magnetic field sensing system may include a first magnetic field sensing element; a second magnetic field sensing element; means for generating a first magnetic field having a first non-zero frequency; means for generating a second magnetic field having a second frequency; a conductive target positioned to generate a reflected magnetic field in response to the first magnetic field; means for producing a first signal representing the first magnetic field and the reflected magnetic field during a first alternating time period; means for producing a second signal representing the second magnetic field during a second alternating time period; means for calculating an error value as a function of the first and second signals, wherein the error value is based, at least in part, on the second signal during the first time period; and means for applying the error value to the first signal during the first alternating time period.

Abstract: An apparatus comprises a conductive material having varying thickness along its length, the varying thickness providing varying response along a length of the conductive material to a magnetic field having a non-zero frequency; wherein the magnetic field produces an eddy current in the conductive material which generates a reflected magnetic field, wherein the varying response causes the reflected magnetic field to vary in strength along the length of the conductive material. The apparatus may include one or more reference portions of conductive material.

Abstract: Methods and apparatus embodiments to communicate data via a digital isolator by receiving an input data stream having first and second states, generating a first pulse train for the first state and a second pulse train for the second state. The first and second pulse types are transmitted across a voltage barrier of a digital signal isolator and received by a receive channel. The first and second pulse trains are processed to recover the input data stream in an output data stream. Data/System integrity functionality can identify fault conditions from an alteration of transmitted pulses.

Abstract: A magnetoresistance (MR) element includes a first stack portion comprising a first plurality of layers including a first spacer layer having a first thickness and a first material selected to result in the first stack portion having a first sensitivity to the applied magnetic field. The MR element also has a second stack portion comprising a second plurality of layers, including a second spacer layer having a second thickness to result in the second stack portion having a second sensitivity to the applied magnetic field. The first thickness may be different than the second thickness resulting in the first sensitivity being different than the second sensitivity.

Abstract: A magnetoresistance element deposited upon a substrate includes a first stack portion having opposing first and second surfaces and including a first plurality of layers. The first stack portion has a first substantially linear response corresponding to an applied magnetic field over a first magnetic field strength range. The magnetoresistance element also includes a second stack portion having opposing first and second surfaces and including a second plurality of layers. The first surface of the second stack portion is disposed over the second surface of the first stack portion and the second stack portion has a second substantially linear response that is different than the first substantially linear response. The second substantially linear response corresponds to the applied magnetic field over a second magnetic field strength range.

Abstract: A gate-less electrostatic discharge (ESD) protection device is provided that can be formed in various complementary metal-oxide-semiconductor (CMOS) systems. The gate-less ESD event protection device includes a substrate, a first doped region formed in the substrate, a second doped region extending into the first doped region, a third doped region extending into the first doped region, a first node formed over a portion of the second doped region and coupled to a source terminal and a second node formed over the third doped region and coupled to a drain terminal. The gate-less ESD protection devices can be formed such that no gate electrode is formed and the gate-less ESD protection device does not include a gate terminal. Thus, an operating voltage range of the gate-less ESD protection device is not limited by gate oxide degradation.

Abstract: A magnetic field sensor for sensing external magnetic fields on multiple axes comprises a coil structure and a gain equalization circuit. The coil structure generates reference fields on magnetic field sensing elements in each axis. The gain equalization circuit measures and compares reference fields to generate gain-equalized output signals responsive to the external magnetic fields.

Abstract: A structure having collocated magnetic field sensing elements can be used to simultaneously determine magnetic field and mechanical stress. A primary magnetic field sensing element generates a primary signal responsive to a magnetic field and a secondary magnetic field sensing element generates a secondary signal responsive to mechanical stress. A system includes a stress compensation module to receive the primary and signals, and to compensate for mechanical stress in the primary signal.

Abstract: A joystick assembly for use with a device including a joystick surface and a first magnet having north and south magnetic poles includes a second magnet having north and south magnetic poles and a movable elongated shaft having first and second opposing ends arranged along a major axis of the shaft. The first end of the shaft is coupled to the second magnet such that movement of the shaft results in movement of the second magnet relative to the first magnet such that a line between centers of the north and south magnetic poles of the second magnet is movable relative to a line between the north and south magnetic poles of the first magnet. An attraction of the second magnet to the first magnet results in a restoring force upon the shaft, and the shaft and the second magnet are removable from the joystick surface.

Abstract: In one aspect, an integrated circuit (IC) includes an output port enabling measurement of a performance characteristic of the IC at a first temperature. The performance characteristic of the IC is a minimum value at the first temperature with respect to any other temperature. The first temperature may be room temperature.

Abstract: In one aspect, a magnetic field sensor includes a chopper stabilized amplifier and a plurality of Hall-type elements in parallel and connected to the chopper stabilized amplifier. In another aspect, a magnetic field sensor includes a chopper stabilized amplifier and a plurality of Hall quad elements in parallel and connected to the chopper stabilized amplifier. In a further aspect, a current sensor has a bandwidth of 1 MHz and includes a chopper stabilized amplifier and a plurality of Hall quad elements, fabricated in silicon, in parallel and connected to the chopper stabilized amplifier.

Abstract: A magnetic field sensor has an error correction signal generator circuit to inject an error correction signal into a primary signal channel to cancel an error signal component in the primary signal channel.

Abstract: Methods and apparatus for detecting a magnetic field include a semiconductor substrate, a coil configured to provide a changing magnetic field in response to a changing current in the coil; and a magnetic field sensing element supported by the substrate. The coil receives the changing current and, in response, generates a changing magnetic field. The magnetic field sensing element detects the presence of a magnetic target by detecting changes to the magnetic field caused by the target and comparing them to an expected value.

Abstract: A magnetic field sensor includes a plurality of magnetoresistance elements, each having at least one characteristic selected to provide a respective, different response to an applied magnetic field, wherein each of the plurality of magnetoresistance elements is coupled in parallel. Illustrative characteristics selected to provide the respective responses include dimensions and/or construction parameters such as materials, layer thickness and order, and spatial relationship of the magnetoresistance element to the applied magnetic field. A method includes providing each of a plurality of magnetoresistance elements with at least one characteristic selected to provide a respective, different response to an applied magnetic field, wherein each of the plurality of magnetoresistance elements is coupled in parallel.

Abstract: A current sensor includes a ferromagnetic core having a substantially central opening for receiving a current conductor and a gap. A detector of the current sensor includes at least one first magnetic field sensing element disposed in a first gap portion and configured to generate a respective first magnetic field signal in response to a first magnetic field having a first angle with respect to the at least one first magnetic field sensing element. The detector also includes at least one second magnetic field sensing element disposed in a second gap portion and configured to generate a respective second magnetic field signal in response to a second magnetic field having a second angle with respect to the at least one second magnetic field sensing element. The first and second magnetic fields are substantially equal in magnitude and the first and second angles are substantially opposite in polarity.

Abstract: Methods and apparatus for determining a position of a rotor in a three-phase motor by determining first and second ones of sectors in which a first one of the magnetic poles of the rotor may be positioned by respectively driving phase pairs complementary signals and examining a voltage of a floating one of the phases. Embodiments can include applying torque to the motor by driving at least one phase pair with respective signals aligned in phase and unequal duty cycles to move the rotor a given amount from the rotor position in the first or second ones of the sectors for determining the position of the rotor.

Abstract: Systems and methods described herein are directed towards differential current sensing a current sensor having two or more magnetic field sensing elements that are oriented to sense a magnetic field generated by a current through an external conductor in the same direction. The current sensor can be positioned such that at least one first magnetic field sensing element is vertically aligned with the external conductor and at least one second magnetic field sensing element is not vertically aligned with the external conductor. The magnetic field sensing elements may be spaced from each to measure a gradient field and can generate a magnetic field signal indicative of a distance between the respective magnetic field sensing element and the current carrying external conductor. A difference between the magnetic field signals can be determined that is indicative of the current through the external conductor.