Allegro Microsystems, LLC

Christine M Graham

P Karl Scheller

Daniel S Dwyer

Paul A David

Eric G Shoemaker

Eric Burdette

Ravi Vig

Devon Fernandez

Gerardo A Monreal

Glenn A Forrest

Mark J Donovan

Manuel Rivas

James M Bailey

Jeff Eagen

Seth Prentice

Karl P Scheller

Geraldo A Monreal

An apparatus and a method provide an output signal indicative of a speed of rotation and/or a direction of movement of a ferromagnetic object having ferromagnetic features and capable of moving. A variety of signal formats of the output signal are described, each of which have pulses at a rate faster than the ferromagnetic features pass by the magnetic field sensor.

Magnetic field sensors and output signal formats for a magnetic field sensor

An integrated magnetic field sensor includes a magnetic field sensing circuit and a power driving circuit disposed upon or within a common substrate. A method of powering on and off a load uses the above integrated magnetic field sensor.

Integrated magnetic field sensor and method of powering on and off a load

A method of performing a self-test associated with a magnetic field sensor includes generating a proximity signal responsive to a proximity of a sensed object with one or more magnetic field sensing elements, and identifying one or more characteristic values associated with the proximity signal while the proximity signal is responding to the proximity signal, The method also includes categorizing the one or more characteristic values into three or more potential categories, including three or more categories, wherein the plurality of potential categories is representative of a plurality of discrete self-test states of the proximity signal that could occur while the proximity signal is responding to the proximity of the sensed object. The method also includes communicating at least one of the plurality of potential categories into which at least one of the one or more characteristic values was categorized. A magnetic field senor implements the above method.

Magnetic field sensors and related techniques that can communicate at least one of three or more potential categories in which one or more characteristic values of a proximity signal responsive to a proximity of a sensed object are categorized

Magnetic field sensors and related techniques can identify passing conditions, failing conditions, and marginal conditions of a sensed object. A magnetic field sensor used in the techniques can have a substrate and can have one or more magnetic field sensing elements disposed on the substrate that are configured to generate a proximity signal responsive to a proximity of the sensed object. The magnetic field sensor can have a self-test module disposed on the substrate, coupled to receive the proximity signal, configured to sample the proximity signal, by analog sampling or digitally converting, to generate a plurality of analog samples or a plurality of digital samples, respectively, each digital sample comprising a plurality of digital bits, configured to select samples from among the plurality of analog or digital samples, and configured to communicate the selected samples to outside of the magnetic field sensor.

Magnetic field sensors and related techniques provide a self-test by communicating selected analog or digital samples of a proximity signal

Magnetic field sensor and related techniques can identify passing conditions, failing conditions, and marginal conditions of a sensed object. The magnetic field sensor and techniques can use one or more peak values of a proximity signal representative of proximity of the sensed object, can generate one or more difference values representative of difference between the peak values of the proximity signal and threshold values of a threshold signal proportional to the peak values, can categorize the one or more difference values into a plurality of potential categories, wherein at least one of the plurality of potential categories is representative of a respective passing self-test and wherein another at least one of the plurality of potential categories is representative of a respective marginally passing self-test, can assign category values to the plurality of potential categories, and can communicate at least one of the plurality of category values.

Magnetic field sensors and related techniques that can provide a self-test using signals and related thresholds

A magnetic field sensor can provide an output signal indicative of a passing condition or a failing condition of the magnetic field sensor. The output signal has one of a variety of output signal formats.

Magnetic field sensors and related techniques that can provide self-test information in a formatted output signal

A circuit to detect a movement of an object includes a magnetic field sensing element for generating a magnetic field signal proportional to a magnetic field associated with the object and a motion detector to generate a motion signal indicative of the movement of the object. The motion detector includes a peak identifying circuit to provide a peak signal and a peak sample selection module that selects a sample associated with one or more prior cycles of a magnetic field signal to generate a selected peak signal. The motion detector further includes a threshold generator to generate a threshold signal as a function of the selected peak signal and a comparator to compare the threshold signal with the magnetic field signal to generate the motion signal. Peak samples from prior magnetic field signal cycles may be averaged for use to establish the threshold signal. A method associated with the circuit is also described.

Circuits and methods for generating a threshold signal used in a magnetic field sensor based on a peak signal associated with a prior cycle of a magnetic field signal

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Bow, NH, United States of America

Christine M Graham