Allegro Microsystems, LLC

Mathew Drouin

Devon Fernandez

William P Taylor

Jay M Towne

Alejandro Gabriel Milesi

Andreas P Friedrich

Andrea Foletto

P Karl Scheller

Glenn A Forrest

Michael Morris

Jeff Eagen

Jonathan Zimmermann

An interface circuit for a position sensor system including an oscillator generating an oscillation signal having a carrier frequency and a primary phase, a primary coil responsive to the oscillation signal, and a secondary coil electromagnetically coupled to the primary coil by a target and configured to generate a secondary signal having the carrier frequency and a secondary phase provides phase compensation. The interface circuit includes a sampling and conversion circuit configured to sample the secondary signal during sample periods and convert the secondary signal into a digital signal, a demodulator coupled to receive the digital signal and configured to demodulate the digital signal in order to generate a position signal indicative of a position of the target, a phase detector coupled to receive the position signal and configured to detect an alignment of the secondary phase with respect to the sample periods and generate a phase detector output signal indicative of whether the secondary phase is aligned with the sample periods, and a delay circuit responsive to the phase detector output signal and configured to apply a delay to the sampling and conversion circuit if the phase detector output signal indicates that the secondary phase is not aligned with the sample periods.

Phase compensation for an inductive position sensor

Electronic circuits used in magnetic field sensors use transistors for passing a current through the transistors and also through a magnetoresistance element.

Magnetic field sensor and electronic circuit that pass amplifier current through a magnetoresistance element

An integrated circuit including a first multiplexor configured to receive one of a plurality of diagnostic signals from circuitry under test (DUT), the first multiplexor responsive to diagnostic signals provided thereto and configured to selectively output one of the diagnostic signals in response to a control signal, a second multiplexor configured to receive one of a plurality of reference signals from one of a plurality of nodes on a reference circuit, the second multiplexor configured to selectively output one of the diagnostic signals in response to a control signal, and a comparator configured to compare the diagnostic signal elicited from the first multiplexor with the reference signal elicited from the second multiplexor, the comparator further configured to output the result of the comparison between the diagnostic signal and the reference signal.

Systems for diagnostic circuit testing

A magnetic field sensor for detecting motion of an object includes threshold generation circuitry and processing. Magnetic field sensing elements are 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 threshold generator responsive to the speed signal generates the threshold signal having a level that varies in response to the speed signal.

Methods and apparatus for generating a threshold signal in a magnetic field sensor

In an embodiment, a circuit is configured to produce a magnetic field signal having a frequency spectrum. The circuit may also produce a temperature signal. A modulation circuit may modulate the temperature signal with a frequency outside the frequency spectrum of the magnetic field signal. The modulated signal and the magnetic field signal may be combined to produce a combined signal. A separation circuit may be configured to separate component signals from the combined signal. The separation circuit may include a first filter, which, when applied to the combined signal, produces a filtered signal; a modulation circuit configured to shift the data representing the temperature signal to a baseband frequency; and a second filter configured to separate the data representing the temperature signal from the combined signal.

Systems and methods for processing temperature data or other signals

Presented herein is a magnetic field sensor architecture that uses outputs of a peak detector and threshold detector operating in parallel to detect magnetic anomalies that may be associated with the target being sensed, e.g., a rotational ferromagnetic object such as a toothed gear, and use such detection to prevent sensor malfunction. The sensor includes an edge detection circuit and an error detection circuit. In one embodiment, the edge detection circuit includes circuits to detect edges (or transitions) of the threshold and peak detector output signals and the error detection circuit includes circuits, responsive to the edge detection circuit, to indicate an error when a 'missed transition' occurs or a peak-to-peak value of an input signal as detected by the peak detector for a current cycle differs from an expected peak-to-peak value by a predetermined amount.

Gear tooth sensor with peak and threshold detectors

A switching device for driving a load is provided. The switching device comprises a control terminal and has a conduction threshold which, when crossed by a control signal coupled to the control terminal, causes the switching device to conduct. A control circuit for generating the control signal is also provided. The control circuit is configured to generate a control signal having a first slew rate prior to the control signal crossing the conduction threshold and a second slew rate after the control signal has crossed the conduction threshold. The first slew rate may be faster than the second slew rate.

Output driver having improved switching delay and associated methods

A proximity detector employs a first peak detector circuit and a second peak detector circuit, both responsive to a magnetic field signal. The second peak detector circuit includes a positive peak detector circuit and a negative peak detector circuit, each of which have a predetermined excursion limit in an outward direction away from a center voltage of the magnetic field signal so as to be less affected by a large signature region in the magnetic field signal. The proximity detector also includes an output control circuit. The output control circuit is configured to provide an output signal, which, during a determined time period, changes state in response to the first peak detector circuit, and which, after the determined time period, changes state in response to the second peak detector circuit.

Calibration circuits and methods for a proximity detector using a first rotation detector for a determined time period and a second rotation detector after the determined time period

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Hooksett, NH, United States of America

Mathew Drouin