Abstract: A system is provided for driving a load such as a multi-phase motor. The system includes a motor driver that has a plurality of switches coupled to a motor to drive a current through each of a plurality of phase coils of the motor. A polarity detection circuit detects a polarity of the current in one or more of the phase coils of the motor to generate a polarity value that represents the detected current polarity. The polarity detection circuit can include at least one comparator that has a first input coupled to a node between two of the plurality of switches, a second input coupled to receive a threshold value, and an output from which the polarity value is provided. Further included is a controller that is configured to provide a plurality of pulse width modulated (PWM) output control signals to the plurality of switches to control the switches to drive the current through the plurality of phase coils of the motor.

Abstract: A magnetic field sensor includes a lead frame, a semiconductor die having a first surface in which a magnetic field sensing element is disposed and a second surface attached to the lead frame, and a non-conductive mold material enclosing the die and at least a portion of the lead frame. The sensor may include a ferromagnetic mold material secured to a portion of the non-conductive mold material. Features include a multi-sloped taper to an inner surface of a non-contiguous central region of the ferromagnetic mold material, a separately formed element disposed in the non-contiguous central region, one or more slots in the lead frame, a molded ferromagnetic suppression device spaced from the non-conductive mold material and enclosing a portion of a lead, a passive device spaced from the non-conductive mold material and coupled to a plurality of leads, and a ferromagnetic bead coupled to a lead.

Abstract: Methods for fabricating an integrated circuit having a plurality of gate dielectrics. The methods are provided to include: forming one or more isolation trenches and a first active region and a second active region in a substrate; depositing hard mask material on the substrate; removing a first portion of the hard mask material over the first active region; forming a first oxide layer having a first thickness over the first active region; removing a second portion of the hard mask material over the second active region; and forming a second oxide layer having a second thickness over the first and second active regions such that a thickness of oxide formed over the first active region comprises a sum of the thickness of the first oxide layer and the second oxide layer, and a thickness of oxide formed over the second active region comprises the second thickness.

Abstract: A magnetic field sensor comprises a substrate, a first coil supported by the substrate and configured to carry a first current in a first direction to generate a first magnetic field, and a second coil supported by the substrate and nested within the first coil to form a gap between the first and second coils, the second coil configured to carry a second current in a second, opposite direction to generate a second magnetic field. A plurality of magnetic field sensing elements is configured to detect the first and second magnetic fields. A switching network is coupled to the plurality of magnetic field sensing elements and configured to connect the plurality of magnetic field sensing elements to form a first bridge circuit having a first arrangement of the magnetic field sensing elements and a second bridge circuit having a second arrangement of the magnetic field sensing elements.

Abstract: Methods and apparatus for a sensor having non-ratiometric fault trip level setting. In embodiments, a sensor has a sensing element with a fixed gain. A signal processing module receives the fault trip level setting and maintains the fault trip level setting constant during changes in the supply voltage.

Abstract: A current sensor can include a lead frame. The lead frame can include a first lead and a second lead, wherein the first and second leads are coupled together at a first junction region of the lead frame, wherein the current sensor is operable to sense a magnetic field generated by a first current passing through the first junction region. The current sensor can further include a first die disposed proximate to the lead frame. The first die can include a first magnetic field sensing element disposed on a surface of the first die, a first circuit coupled to the first magnetic field sensing element for generating a first signal indicative of a first current, and a first node coupled to the first signal. The current sensor can further include a second die disposed proximate to the lead frame.

Abstract: An isolation circuit that isolates a driver circuit that is biased at a first common mode voltage from a detection circuit that is biased at a second common mode voltage using isolation capacitors. The detection circuit includes a transimpedance amplifier having improved susceptibility to transient common-mode input signals and improved insensitivity to parasitic capacitance on the isolation capacitor terminals. Included within the transimpedance amplifier are circuits for mirroring current to convert the input current from the isolation capacitors into a voltage value and to amplify that voltage value. The transimpedance amplifier outputs a differential voltage value that is held by a latch circuit so that a comparator in the detection circuit can process the differential voltage value and output a differential signal with fully restored logic levels.

Abstract: A current sensor can include a lead frame. The lead frame can include a first lead and a second lead, wherein the first and second leads are coupled together at a first junction region of the lead frame, wherein the current sensor is operable to sense a magnetic field generated by a first current passing through the first junction region. The current sensor can further include a first die disposed proximate to the lead frame. The first die can include a first magnetic field sensing element disposed on a surface of the first die, a first circuit coupled to the first magnetic field sensing element for generating a first signal indicative of a first current, and a first node coupled to the first signal. The current sensor can further include a second die disposed proximate to the lead frame.

Abstract: Methods and apparatus for sensing target position by generating a signal by energizing a shaped coil with an AC signal. A sensor receives a signal reflected by a target in response to the signal from the shaped coil, wherein the shaped coil has a first width, and wherein the sensor includes a first sensing element aligned with the shaped coil at the first width, wherein a ratio of the first width and a distance from the sensor to the target is about three-to-one. The received signal can be processed to determine position information of the target. In some embodiments, a shaped coil can have a trapezoidal shape and sensors aligned with the coil to select a sensor based upon target to sensor distance.

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.

Abstract: A magnetic field sensor includes a plurality of magnetic field sensing elements configured to generate at least two measured magnetic field signals indicative of a magnetic field affected by an object and having a first predetermined phase difference with respect to each other. A controller responsive to the measured magnetic field signals is configured to generate at least one virtual magnetic field signal having a second predetermined phase difference with respect to at least one of the measured magnetic field signals. The controller is configured to calculate a virtual tangent of the virtual magnetic field signal and at least one measured magnetic field signal and compute a second derivative of an arctangent extraction of the virtual tangent. Coefficients used to generate the virtual magnetic field signals are regulated in a feedback system in order to achieve a desired phase difference between a reference and a virtual magnetic field signal.

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 sensor includes an output circuit configured to generate a sensor output signal based on an input signal having a logic high or low level, as may be provided by a Schmitt trigger circuit. During normal operation, the output switches between a first percentage of the supply voltage for logic high and a second percentage of the supply voltage for logic low. To convey a failure at the output, an output signal is output as either ground or the supply voltage when a fault is detected. As such, a fault can be communicated any time the output voltage is not equal to the first percentage or the second percentage of the supply voltage.

Abstract: A magnetic field sensor includes a substrate first and second magnetic field sensing elements, comprising first and second magnetoresistance elements, respectively. The first and second magnetic field sensing elements are responsive to the magnet. At or more positions of the magnet relative to the first and second magnetic field sensing elements while the magnet is stopped moving, at least one of the first magnetic field sensing element or the second magnetic field sensing element is in saturation in response to the magnet.

Abstract: A current sensor is provided with one or more magnetic field sensing elements configured to generate a magnetic field signal indicative of a magnitude of a sensed magnetic field, wherein the sensed magnetic field is related to a magnitude and frequency of a current through a conductor. A signal path is responsive to the magnetic field signal and includes a compensator configured to apply a compensation factor to the magnetic field signal to generate a sensor output signal indicative of the magnitude of the current and substantially independent of a frequency of the current. The sensed magnetic field is related to the magnitude of the current by a coupling factor and the signal path is responsive to a characterization of the coupling factor over a range of frequencies of the current in order to determine the compensation factor to be applied.

Abstract: A magnetic field sensor includes a substrate, a first channel comprising a first magnetic field sensing element supported by the substrate and configured to generate a first magnetic field signal indicative of a first magnetic field experienced by the first magnetic field sensing element, a second channel comprising a second magnetic field sensing element supported by the substrate and configured to generate a second magnetic field signal indicative of a second magnetic field experienced by the second magnetic field sensing element, and at least one shield configured to reduce a bandwidth of the first magnetic field by a first amount and to reduce a bandwidth of the second magnetic field by a second amount. The shield is able to act as a magnetic anti-aliasing filter for the magnetic field sensing elements, which can then be chopped or sampled.

Abstract: A system includes a ring magnet having magnetic segments and configured to rotate about an axis of rotation, wherein adjacent segments have different magnetic polarities, The system can further include a substrate positioned so that a top surface of the substrate is substantially parallel to the axis of rotation and a center plane passing through the ring magnet and perpendicular to the axis of rotation of the ring magnet intersects the top surface at an intersection line. The system can further include four magnetic field sensing elements supported by the substrate and electrically coupled to form a first bridge circuit, wherein two of the four magnetic field sensing elements are positioned on one side of the intersection line and the other two of the four magnetic field sensing elements are positioned on the other side of the intersection line.

Abstract: A magnetic field sensor responsive to a movement of a target object can include a plurality of magnetoresistance elements arranged in a line and having a span according to y(1?1/x), where y is equal a full spatial period of the target object and where x is equal to a total quantity of magnetoresistance elements in the plurality of magnetoresistance elements. The plurality of magnetic field sensing elements is operable to generate a signal that is substantially not responsive to the movement of the target object but is responsive to stray external magnetic fields.

Abstract: A magnetic field sensor includes a first magnetic field sensing element first generating a first signal having a first axis of maximum sensitivity, a second magnetic field sensing element for generating a second signal and having a second axis of maximum sensitivity, one or more detectors for receiving an output of the first magnetic field sensing element or the second magnetic field sensing element, and a processor that receives an output of the one or more detectors and uses the output of the one or more detectors to calculate a first constant Kc and a second constant Ks and then uses Kc and Ks to compensate for an orthogonality error between the first axis of maximum sensitivity and second axis of maximum sensitivity. The detectors include peak detectors and/or zero-crossing detectors that compare the output of the first input signal or the second input signal with a threshold or zero.

Abstract: Apparatus and methods provide a current sensor system including a plurality of current sensors positioned proximate a plurality of conductors. Each conductor is configured to carry a current to be measured. Each current sensor comprises one or more magnetic field sensing elements configured to generate a respective magnetic field signal indicative of a detected magnetic field. The plurality of current sensors includes a first number of current sensors and the plurality of conductors includes a second number of conductors such that the first number is at least one more than the second number. A controller is coupled to receive the magnetic field signal from each of the current sensors and, for each magnetic field sensing element, is configured to characterize a magnetic coupling between the magnetic field sensing element and each of the plurality of conductors.