Abstract: A sensor is provided to include: a sampling clock circuit generating a sample clock signal with a predetermined sample clock period; a system clock circuit generating a system clock signal with a predetermined system clock period, wherein a value of the system clock period is less than a value of the sample clock period; a sensor circuit generating, during each sample clock period, a sensor signal representing a position of an object; a sampling circuit receiving the sensor signal and generate sample signal value in response; an interpolation circuit determining a first difference between a current sample signal and a previous sample signal, determining a second difference between a switchpoint threshold value and the previous sample signal, and determining a delay count based upon a ratio of the first difference and the second difference; and a switchpoint signal circuit generating a switchpoint signal based upon the delay count.

Abstract: A magnetoresistance element (e.g. a spin valve) for detecting a changing magnetic field includes a pinning layer, pinned layer adjacent to the pinning layer, a spacer layer adjacent to the pinned layer, and a free layer adjacent to the spacer layer and arranged so that the spacer layer is between the pinned layer and the free layer. The pinned layer has a bias with a bias direction configured to reduce an effect of a static field on the detection of the changing magnetic field.

Abstract: Magnetic field sensors can sense speed of movement and direction of movement of a ferromagnetic object. The magnetic field sensors employ both planar Hall effect elements and vertical Hall effect elements to generate two-state signals in two different signal paths with relative phases that are ninety degrees apart, the ninety degrees having sufficient margin to aid in detection of the direction of motion. Other magnetic field sensors use at least four vertical Hall effect elements to identify a speed of rotation and a direction of rotation of a moving ferromagnetic object.

Abstract: A data storage circuit for storing data from volatile memory to non-volatile memory is powered by a low power charge pump circuit that is independent of the power for the volatile memory and that is activated upon power loss. The low power charge pump circuit includes an amplifier, a voltage-controlled oscillator, a charge pump core, and a voltage divider. The amplifier outputs a current according to a voltage difference between a reference input voltage and a feedback voltage output from the voltage divider. The current is converted to a voltage that controls the oscillator, which outputs a series of pulses to power the charge pump core. The charge pump core in turn provides the output voltage, which may be used to power an attached load. The attached load may be a programming port for an EEPROM.

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: A monitor circuit for monitoring a level of a first and second regulated source may monitor a voltage level of regulated voltages or a current level of regulated currents. In an embodiment, the monitor circuit includes circuitry responsive to a first regulated voltage and to a second regulated voltage. A first circuit responsive to the first regulated voltage and to the second regulated voltage generates a first error signal indicative of at least one of an overvoltage condition of the first regulated voltage and an undervoltage condition of the second regulated voltage. A second circuit responsive to the first regulated voltage and to the second regulated voltage generates a second error signal indicative of at least one of an undervoltage condition of the first regulated voltage and an overvoltage condition of the second regulated voltage. A method for monitoring the levels of first and second regulated sources is also provided.

Abstract: Methods and apparatus for s sensor having magnetic field sensing elements coupled in a differential bridge and a signal processor configured to receive signals from the bridge to determine a distance from the magnetic field sensing elements to a magnet from flux line divergence of magnetic flux generated by the magnet.

Abstract: A magnetoresistance element assembly has two stacks of material layers with respective reference layers and respective bias layers that have relative magnetic directions that are not perpendicular to each other. Bias layers in the two stacks have bias magnetic directions that oppose each other. Linear range is increased.

Abstract: Methods and apparatus for sensor including a die, a leadframe having opposed first and second surfaces, the leadframe supporting the die on the first surface, lead fingers to provide electrical connections to the leadframe and to the die; and a component electrically coupled to the leadframe and to a first one of the lead fingers such that the component is an integrated part of the IC package. The leadframe may have a cutout region in which the component is positioned.

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 method of detecting a vibration comprises determining a vibration flag has been set during a running mode of the magnetic field sensor, remaining in the running mode until a predetermined number of vibration flags have been set, and entering a recalibration mode when the predetermined number of vibration flags have been set. A counter can be implemented for each of the plurality of vibration flags to determine if the predetermined number of vibration flags have been set.

Abstract: A method of detecting a vibration comprises determining a vibration flag has been set during a running mode, entering a vibration mode, providing direction information for a target object during the vibration mode of the magnetic field sensor, holding onto positive peak values and negative peak values of the magnetic field signal during the vibration mode of the magnetic field sensor, and returning to the running mode after receiving at least two clock cycles of the magnetic field signal with no further vibration flags set.

Abstract: A magnetic field sensor for detecting motion of an object includes one or more magnetic field sensing elements configured to generate a magnetic field signal in response to a magnetic field associated with the object. A motion detector responsive to the magnetic field signal and to a threshold signal is configured to generate a detector output signal having edges occurring in response to a comparison of the magnetic field signal and the threshold signal. A speed detector responsive to the detector output signal generates a speed signal indicative of a speed of motion of the object. A delay processor is responsive to the speed signal and configured to determine a delay for the detector output signal based on the speed of motion of the object.

Abstract: A magnetic switch sensor is provided having a magnetic field sensing element configured to generate a magnetic field signal in response to a magnetic field indicative of a distance or angle between the magnetic field sensing element and a target, a first circuit coupled to receive the magnetic field signal and having an output to provide a comparison signal, and a debounce circuit coupled to receive the comparison signal and having an output to provide a debounced signal. The sensor can include a second circuit having an input coupled to receive the debounced signal and an output at which is provided a toggle signal that transitions between first and second levels every other time the magnetic field signal crosses a threshold level.

Abstract: A magnetic field sensor that detects an angle of a target includes a first channel having first and second magnetic field sensing elements that are orthogonal with respect to each other and produce first and second magnetic field signals, and a second channel having third and fourth magnetic field sensing elements that are orthogonal with respect to each other and produce third and fourth magnetic field signals. The third sensing element is positioned at an angle (e.g., 45-degrees) with respect to the first sensing element. The magnetic field sensor includes a low power mode circuit that uses comparators to compare the first, second, third, and fourth magnetic field signals to a first, second, third, and fourth threshold, respectively. A processor is configured to use an output of the low power mode circuit to determine the angle of the target.

Abstract: A driver circuit includes a power terminal, a reference terminal, and a bridge circuit. The bridge circuit comprises a first switch coupled to the power terminal, a second switch coupled in series between the first switch and the reference terminal to form a first output terminal between the first and second switches, a third switch coupled to the power terminal, and a fourth switch coupled in series between the third switch and the reference terminal to form a second output terminal between the third and fourth switches. The second and fourth switches are PNP BJT devices.

Abstract: A magnetic field sensor for sensing a movement of a target object an include a substrate having a major planar surface and three or more magnetic field sensing elements disposed upon the major planar surface of the substrate. The three or more magnetic field sensing elements can have respective major response axes, each major response axis parallel to the major planar surface of the substrate. The three or more magnetic field sensing elements comprise first and third magnetic field sensing elements and a second magnetic field sensing element disposed between the first and third magnetic field sensing elements. A first spacing between the first and second magnetic field sensing elements is less than a second spacing between the second and third magnetic field sensing elements. No other magnetic field sensing elements are disposed between the first and third magnetoresistance elements.

Abstract: A magnetic field sensor including at least one magnetoresistance element configured to generate a magnetic field signal indicative of a magnetic field associated with a target having features and spaced from the at least one magnetoresistance element by an airgap. The sensor includes a detector responsive to the magnetic field signal and to a threshold level to generate a sensor output signal containing transitions, each transition associated with a feature of the target and occurring in response to the magnetic field signal crossing the threshold level. The sensor includes a threshold generator configured to generate the threshold level having a rising threshold level limit and a falling threshold level limit.

Abstract: A filter circuit includes a filter having an input and an output at which an output of the filter is provided, a step detector coupled to receive an input signal at the input of the filter and configured to detect a predetermined step in the input signal and to assert a bypass signal in response to detection of the predetermined step. A logic circuit is responsive to the bypass signal and configured to cause the input signal to be coupled to the output of the filter without filtering when the bypass signal is asserted.

Abstract: Systems and methods for computing an average supply current to a motor include a current sensor that is configured to sense a current through the motor. A converter is configured to sample the output of the current sensor at times that are established by a trigger signal and convert the samples into digital current values. A trigger signal generator generates the trigger signal based on one or more pulse width modulated (PWM) motor control signals within a PWM cycle. An average supply current value that indicates the average supply current to the motor is computed by a controller using the digital current values received from the converter.