Allegro Microsystems, LLC

Zachary Richards

Andrea Foletto

Eric G Shoemaker

Methods and apparatus for determining and transmitting speed and/or direction information for a rotating target by a magnetic field sensor. A reference channel signal is generated for a target from at least one magnetic field sensing element and a virtual channel signal in quadrature with the reference channel signal is generated. A tangent signal is generated. A slope of an arctangent of the tangent signal is determined, wherein the slope corresponds to rotational speed of the target. The speed and/or direction of the target can be transmitted by a sensor IC.

High resolution magnetic field sensors

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.

Regulation of coefficients used in magnetic field sensor virtual signal generation

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 and a controller responsive to the at least two measured magnetic field signals. The controller is configured to generate an angle signal and to compare the angle signal to at least one angle signal threshold. The angle signal can be compared to a plurality of angle signal thresholds to generate a plurality of output transitions, each output transitions indicative of the angle signal crossing the corresponding angle signal threshold. The number of angle signal thresholds can be dependent upon a desired number of output transitions per pole-pair of the angle signal.

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 and a controller responsive to the at least two measured magnetic field signals. The controller 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. In embodiments, the virtual magnetic field signal has the second predetermined phase difference with respect to each of the at least two measured magnetic field signals.

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Epsom, NH, United States of America

Zachary Richards