Allegro Microsystems, LLC

National Semiconductor Corporation

David Jamie Haas

William P Taylor

Michael C Doogue

Ravi Vig

Michael J Gaboury

Shaun D Milano

Juan Manuel Cesaretti

Craig S Petrie

Michael G Ward

John Cummings

Alexander Latham

Hernán D Romero

Georges El Bacha

Jonathan Lamarre

Gregory Delmain

Paul A David

Steven Daubert

Virag V Chaware

Jesse Lapomardo

Monica J Thomas

Douglas Michael Hannan

Roman Prochazka

Richard Stary

Sina Haji Alizad

Milan Valenta

Akshay Pai

A method is provided for use in a sensor, the method comprising: selecting a switching cycle for the sensor; transitioning the sensor into a state in which at least one component of the sensor is periodically turned on and off in accordance with the switching cycle; sampling an analog signal to generate a sampled signal, the analog signal being generated by at least one sensing element, the analog signal being sampled only during periods in which the at least one component of the sensor is turned on; and generating an output signal based, at least in part, on the sampled signal and outputting the output signal.

Adaptive switching frequency selection

A magnetic field sensor includes a current source configured to generate a bias current, a plurality of magnetic field transducers, each having power terminals coupled to the current source and output terminals at which an output signal of the transducer is provided, wherein the power terminals of each of the plurality of magnetic field transducers are electrically coupled together in series so that the bias current flows through each of the plurality of magnetic field transducers in series. A capacitively-coupled summing amplifier has a plurality of inputs, each configured to receive the output signal of a respective one of the plurality of magnetic field transducers, and an output at which an amplified and summed signal is provided, wherein the capacitively-coupled summing amplifier is configured to amplify and sum the received output signals of the plurality of magnetic field transducers.

Magnetic field sensor with stacked transducers and capacitive summing amplifier

Method and apparatus for trimming a magnetic field sensor having a first magnetic field sensing element. The trimming includes the use of a curve for normalized sensitivity of the first magnetic field sensing element derived from a first curve corresponding to current through a coil in a first direction at a first time. This produces a field affecting the first magnetic field sensing element versus an external field. The trimming further includes a second curve corresponding to current through the coil in a second direction opposite to the first direction at a second time to produce a field affecting the first magnetic field sensing element versus an external field.

Methods and apparatus for trimming a magnetic field sensor

Methods and apparatus for providing an integrated circuit having a drive current source, a magnetic sensing element coupled to the drive current source, the magnetic sensing element having first and second differential outputs, and first and second current elements to provide respective currents in relation to the drive current source, wherein the first current element is coupled to the first differential output and the second current element is coupled to the second differential output. In illustrative embodiments, an IC output can output a voltage corresponding to the currents of the first and second current elements.

Methods and apparatus for sensor diagnostics

A current sensor integrated circuit to sense a current through a resistor includes a substrate, a tub disposed in the substrate, an analog front end disposed in the tub and comprising an amplifier having inputs coupled across the resistor and a charging circuit configured to bias the analog front end and the tub to a bias voltage that is a predetermined offset voltage greater than a common mode voltage associated with the resistor. In embodiments, the analog front end is biased to a first bias voltage and the tub is biased to a second, different bias voltage.

Current sensor integrated circuit with common mode voltage rejection

A sensor integrated circuit includes a main processing channel that responds to an input signal by generating a first processed signal from the input signal. Also included is a diagnostic processing channel that responds to the input signal by generating a second processed signal from the input signal. The main processing channel has a first response to disturbances and the diagnostic processing channel has a second response to disturbances that is slower than the first response of the main processing channel. A checker circuit in the sensor integrated circuit detects faults in the sensor IC and generates a fault signal when the first processed signal and the second processed signal differ from each other by more than a threshold amount.

Systems and methods for comparing signal channels having different common mode transient immunity

A sensor integrated circuit can include sensors with differing levels of sensitivity, a first processing channel that responds to a first analog signal generated by a first sensor to generate a first processed signal, and a second processing channel that responds to a second analog signal generated by the second sensor to generate a second processed signal. Where the first sensor can include a pressure or optical sensing element, and the second sensor can include a pressure or optical sensing element. A checker circuit uses the processed signals to detect faults in the sensor integrated circuit.

Sensor integrated circuits and methods for safety critical applications

A sensor integrated circuit includes at least two processing channels responsive to the same or different analog input signals to generate respective processed signals. The two processing channels are non-homogenous and, in some embodiments have different processing accuracies. A checker circuit receives the first and second processed signals and is configured to detect a fault in the sensor integrated circuit when the first and second processed signals differ from each other by more than a predetermined amount.

In one aspect, a magnetic field sensor includes a chopper stabilized amplifier and a plurality of Hall-type elements in parallel and connected to the chopper stabilized amplifier. In another aspect, a magnetic field sensor includes a chopper stabilized amplifier and a plurality of Hall quad elements in parallel and connected to the chopper stabilized amplifier. In a further aspect, a current sensor has a bandwidth of 1 MHz and includes a chopper stabilized amplifier and a plurality of Hall quad elements, fabricated in silicon, in parallel and connected to the chopper stabilized amplifier.

Magnetic field sensor

A magnetic field sensor and a method associated with the magnetic field sensor provide gain correction coefficients and/or offset correction coefficients stored in the magnetic field sensor in digital form. The gain correction coefficients and/or offset correction coefficients can be used to generate analog control signals to control a sensitivity and/or an offset of an analog signal path through the magnetic field sensor.

Magnetic field sensor and method used in a magnetic field sensor that adjusts a sensitivity and/or an offset over temperature

Presented is a sensor that includes a magnetoresistive (MR) sensing device to sense a magnetic field and to produce an AC signal voltage proportional to the sensed magnetic field. The sensor also includes circuitry, coupled to the MR sensing device, to remove DC offset from the AC signal voltage. The DC offset may be related to the hysteresis characteristics of the MR sensing device. To remove DC offset, the circuitry may obtain an averaged DC offset and subtract the averaged DC offset from the AC signal voltage to produce a sensor output signal.

Hysteresis offset cancellation for magnetic sensors

A control loop circuit for use in a closed-loop control system that controls a system such as a linear motor is presented. The control loop circuit includes a lead-lag compensator that features a lead compensation network configured to reduce output noise without substantially changing the effect of the lead compensation in the control system's frequency response.

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Concord, NH, United States of America

David Jamie Haas