Allegro Microsystems, LLC

Steven E Snyder

Devon Fernandez

Andrea Foletto

P Karl Scheller

Kristann L Moody

James E Burgess

Jay M Towne

Eric Burdette

Logan G Stewart

Jonathan Zimmermann

Pablo Daniel Pareja Obregón

Philip Suyderhoud

Steven Ricco

Craig McConnell

Matthew Nealon

Peter G Wells

Michael Chen

Jacob Harer

Systems, methods, and apparatuses for magnetic field sensors with self-test include a detection circuit to detect speed and direction of a target. One or more circuits to test accuracy of the detected speed and direction may be included. One or more circuits to test accuracy of an oscillator may also be included. One or more circuits to test the accuracy of an analog-to-digital converter may also be included. Additionally, one or more IDDQ and/or built-in-self test (BIST) circuits may be included.

Systems and methods for magnetic field sensors with self-test

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 motion of the object and a detector responsive to the magnetic field signal and to a threshold signal and configured to generate a comparison signal having edges occurring in response to a comparison of the magnetic field signal to the threshold signal. A threshold generator is configured to generate the threshold signal at a first level when a peak-to-peak value of the magnetic field signal is greater than a first predetermined value and at a second level when the peak-to-peak value of the magnetic field signal is less than a second predetermined value different than the first predetermined value.

Magnetic field sensor with an adjustable threshold

A sensor configured to generate a sensor output signal at a sensor output coupled to a pull up voltage through a pull up resistor includes a sensing element configured to generate a sensing element output signal indicative of a sensed parameter and a processor responsive to the sensing element output signal and configured to generate a processor output signal indicative of the sensed parameter. A digital output controller is responsive to the processor output signal and to a digital feedback signal and is configured to generate a controller output signal. An analog output driver is responsive to the controller output signal and configured to generate the sensor output signal at a first predetermined level or at a second predetermined level and a feedback circuit coupled between the sensor output and the digital output controller is configured to generate the digital feedback signal in response to the sensor output signal.

Sensor output control methods and apparatus

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.

Digital interpolation of switch point to reduce switch point jitter

A method for synchronization of an input signal includes providing the input signal to a first signal path associated with a first clock and to a second signal path associated with a second clock, detecting an edge of the input signal by detecting values of the input signal along the first signal path at a first rising edge of the first clock and at a second rising edge of the first clock, detecting a value of the input signal along the second signal path at an edge of the second clock, and selecting the input signal from the first signal path or from the second signal path according to the detected value of the input signal along the second path when an edge of the input signal along the first path is detected.

Dual edge synchronization of analog input to reduce switch point jitter

A magnetic field sensor for detecting motion of an object includes error detection circuiting and processing. Magnetic field sensing elements are configured to generate at least two magnetic field signals in response to a magnetic field associated with the object which signals are used by detectors to generate right and left channel signals with edges indicative of motion of the object. A direction calculation processor responsive to right and left channel signals generates a direction signal having a state indicative of a direction of motion of the object and an output signal generator generates an output signal having a pulse indicative of the direction of motion of the object in response to the direction signal. An error detection processor responsive to the output signal and to the direction signal is configured to detect an error in at least one of the direction signal and the output signal.

Methods and apparatus for error detection in a magnetic field sensor

Systems, methods and apparatuses for magnetic field sensors with self-test include a detection circuit to detect speed and direction of a target. One or more circuits to test accuracy of the detected speed and direction may be included. One or more circuits to test accuracy of an oscillator may also be included. One or more circuits to test the accuracy of an analog-to-digital converter may also be included. Additionally one or more IDDQ and/or built-in-self test (BEST) circuits may be included.

A magnetic field sensor uses upper and lower thresholds. The upper and lower thresholds are limited such that they have a minimum separation distance between equivalent voltage levels of the upper and lower thresholds.

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New Boston, NH, United States of America

Steven E Snyder