Allegro Microsystems, LLC

Eric G Shoemaker

Andrea Foletto

Paul A David

Ravi Vig

Andreas P Friedrich

P Karl Scheller

William P Taylor

Michael C Doogue

Devon Fernandez

Eric Burdette

Michael Morris

Peter Cisar

Jay M Towne

Christine M Graham

Marie-Adelaide Lo

Gerardo A Monreal

Glenn A Forrest

Jeffrey Eagen

James M Bailey

Manuel Rivas

Daniel S Dwyer

Jeff Eagen

Zachary Richards

Dominik Weiland

Timothy Sitorus

Geraldo A Monreal

A magnetic field sensor includes a lead frame, a passive component, semiconductor die supporting a magnetic field sensing element and attached to the lead frame, a non-conductive mold material enclosing the die and at least a portion of the lead frame, and a ferromagnetic mold material secured to a portion of the non-conductive mold material. The lead frame has a recessed region and the passive component is positioned in the recessed region. The ferromagnetic mold material may comprise a soft ferromagnetic material to form a concentrator or a hard ferromagnetic material to form a bias magnet.

Magnetic field sensor integrated circuit with integral ferromagnetic material

A magnetic field sensor includes one or more magnetic field sensing elements configured to generate a magnetic field signal responsive to a magnetic field and a detector coupled to receive an interpolated threshold and a signal representative of the magnetic field signal, wherein the detector is configured to compare the interpolated threshold with the signal representative of the magnetic field signal to generate a detector output signal. A memory is configured to store a first threshold value indicative of a threshold value at a first temperature and a second threshold value indicative of a threshold value at a second temperature lower than the first temperature and a threshold module coupled to the memory and configured to generate the interpolated threshold based on the stored first and second threshold values.

Magnetic field sensor having a temperature compensated threshold on power up

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.

Arrangements for magnetic field sensors that act as movement detectors

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.

Magnetic field sensors having virtual signals

A sensor integrated circuit includes an energy storage device having a first terminal coupled to a functional circuit and a blocking circuit coupled between a power supply pin and the first terminal of the energy storage device. The blocking circuit permits the energy storage device to store energy from an external power supply coupled to the power pin. The first terminal of the energy storage device is inaccessible from outside of the sensor IC. Additional features of the sensor IC can include a high regulator, a low regulator, and a low power circuit.

Apparatus and methods for extending sensor integrated circuit operation through a power disturbance

A magnetic field sensor can sense a movement of an object along a path. A movement line is tangent to the path. The magnetic field sensor can include a semiconductor substrate. The semiconductor substrate can have first and second orthogonal axes orthogonal to each other on the first surface of the substrate. A projection of the movement line onto a surface of the semiconductor substrate is only substantially parallel to the first orthogonal axis. The magnetic field sensor can also include first, second, third, and fourth magnetic field sensing elements disposed on the substrate. The first and second magnetic field sensing elements have maximum response axes parallel to the first orthogonal axis and the second and fourth magnetic field sensing elements have maximum response axes parallel to the second orthogonal axis. Signals generated by the second and fourth magnetic field sensing elements can be used as reference signals.

Arrangements for magnetic field sensors to cancel offset variations

A magnetic field sensor includes a lead frame, a semiconductor die supporting a magnetic field sensing element, a non-conductive mold material enclosing the die and a portion of the lead frame, a ferromagnetic mold material secured to the non-conductive mold material and a securing mechanism to securely engage the mold materials. The ferromagnetic mold material may comprise a soft ferromagnetic material to form a concentrator or a hard ferromagnetic material to form a bias magnet. The ferromagnetic mold material may be tapered and includes a non-contiguous central region, as may be an aperture or may contain the non-conductive mold material or an overmold material. Further embodiments include die up, lead on chip, and flip-chip arrangements, wafer level techniques to form the concentrator or bias magnet, integrated components, such as capacitors, on the lead frame, and a bias magnet with one or more channels to facilitate overmolding.

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 magnetic field sensor includes a magnetic field sensing element configured to generate a magnetic field signal; a measured threshold module configured to generate a measured threshold signal in accordance with positive peaks and negative peaks of the magnetic field signal; a memory device coupled to receive and configured to store, at each one of a plurality of storage times, a respective value of the measured threshold signal; a threshold module coupled to receive from the memory device, at a calculation time, a stored value of the measured threshold signal and configured to generate a calculated threshold value; and a comparison circuit coupled to receive the calculated threshold value and to receive the magnetic field signal. The comparison circuit is configured to compare the calculated threshold value with the magnetic field signal to generate an output signal. A corresponding method is associated with the magnetic field sensor.

Magnetic field sensor and associated method that can establish a measured threshold value and that can store the measured threshold value in a memory device

A magnetic field sensor and associated method provide an output signal with first and second different pulses with first and second different pulse widths indicative of first and second different directions of rotation of a moving target. The magnetic field sensor also includes third pulses with an identifiable encoding to indicate when a signature region in the moving target proximate to the magnetic field sensor passes by the magnetic field sensor. The third pulses each comprise respective state transitions and each comprise respective pulse widths with respective fixed predetermined time durations.

Systems and methods for providing signal encoding representative of a signature region in a target

A magnetic field sensor includes a comparator coupled to receive a calculated threshold value based upon a temperature signal, a stored value of a temperature coefficient signal, and a stored value of a measure threshold signal, and also coupled to receive a signal representative of a magnetic field signal. The comparator is configured to compare the calculated threshold value with the signal representative of the magnetic field signal to generate an output signal. A corresponding method is associated with the magnetic field sensor.

A circuit includes a current source having at least first terminal and a second, control terminal. The current source is configured to receive a current control signal at the control terminal and in response thereto generates a first current signal at the first terminal. The current control signal controls a current level of the first current signal. The circuit also includes at least one sensing element responsive to one or more sense parameters and having an input adapted to couple to the first terminal of said current source. The sensing element is configured to receive one or more current signals comprising at least the first current signal and in response thereto generates a sensed output signal at an output thereof. A corresponding method for operating the circuit is also provided.

Circuits and methods for modulating current in circuits comprising sensing elements

A magnetic field sensor uses an angle sensor to measure and angle of rotation of a target object to which a magnet is attached. The angle sensor in combination with electronics can generate an angle sensor output signal related to a direction of a magnetic field of the magnet. The angle sensor output signal can be compared to thresholds to generate a magnetic field sensor output signal the same as a known true power on state (TPOS) sensor output signal. A corresponding method is also described.

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Windham, NH, United States of America

Eric G Shoemaker