Abstract: A magnetic field sensor comprises a substrate, a first coil supported by the substrate and configured to carry a first current in a first direction to generate a first magnetic field, and a second coil supported by the substrate and nested within the first coil to form a gap between the first and second coils, the second coil configured to carry a second current in a second, opposite direction to generate a second magnetic field. A plurality of magnetic field sensing elements is configured to detect the first and second magnetic fields. A switching network is coupled to the plurality of magnetic field sensing elements and configured to connect the plurality of magnetic field sensing elements to form a first bridge circuit having a first arrangement of the magnetic field sensing elements and a second bridge circuit having a second arrangement of the magnetic field sensing elements.

Abstract: A magnetic field sensor includes a first magnetic field sensing element first generating a first signal having a first axis of maximum sensitivity, a second magnetic field sensing element for generating a second signal and having a second axis of maximum sensitivity, one or more detectors for receiving an output of the first magnetic field sensing element or the second magnetic field sensing element, and a processor that receives an output of the one or more detectors and uses the output of the one or more detectors to calculate a first constant Kc and a second constant Ks and then uses Kc and Ks to compensate for an orthogonality error between the first axis of maximum sensitivity and second axis of maximum sensitivity. The detectors include peak detectors and/or zero-crossing detectors that compare the output of the first input signal or the second input signal with a threshold or zero.

Abstract: A magnetic field sensing system may include a first magnetic field sensing element; a second magnetic field sensing element; means for generating a first magnetic field having a first non-zero frequency; means for generating a second magnetic field having a second frequency; a conductive target positioned to generate a reflected magnetic field in response to the first magnetic field; means for producing a first signal representing the first magnetic field and the reflected magnetic field during a first alternating time period; means for producing a second signal representing the second magnetic field during a second alternating time period; means for calculating an error value as a function of the first and second signals, wherein the error value is based, at least in part, on the second signal during the first time period; and means for applying the error value to the first signal during the first alternating time period.

Abstract: A driver circuit includes a power terminal, a reference terminal, and a bridge circuit. The bridge circuit comprises a first switch coupled to the power terminal, a second switch coupled in series between the first switch and the reference terminal to form a first output terminal between the first and second switches, a third switch coupled to the power terminal, and a fourth switch coupled in series between the third switch and the reference terminal to form a second output terminal between the third and fourth switches. The second and fourth switches are PNP BJT devices.

Abstract: Magnetic field sensors and associated techniques use a Hall effect element in a current spinning arrangement in combination with a rippled reduction feedback network configured to reduce undesirable spectral components generated by the current spinning and other circuit elements.

Abstract: A magnetic field sensor comprises a magnetoresistance element with a variable conductivity that changes based on a function of a magnetic field strength and angle of an external magnetic field and a voltage across the magnetoresistance element. A circuit is included to monitor an electrical current through the magnetoresistance element during operation and to apply a constant voltage across the magnetoresistance element based on the monitored electrical current so that the variable conductivity does not change as result of a changing voltage across the magnetoresistance element.

Abstract: A driver circuit includes a power terminal, a reference terminal, and a bridge circuit. The bridge circuit comprises a first switch coupled to the power terminal, a second switch coupled in series between the first switch and the reference terminal to form a first output terminal between the first and second switches, a third switch coupled to the power terminal, and a fourth switch coupled in series between the third switch and the reference terminal to form a second output terminal between the third and fourth switches. The second and fourth switches are PNP BJT devices.

Abstract: A magnetic field sensor comprises a magnetoresistance element with a variable conductivity that changes based on a function of a magnetic field strength and angle of an external magnetic field and a voltage across the magnetoresistance element. A circuit is included to monitor an electrical current through the magnetoresistance element during operation and to apply a constant voltage across the magnetoresistance element based on the monitored electrical current so that the variable conductivity does not change as result of a changing voltage across the magnetoresistance element.

Abstract: A magnetic field sensor includes a first magnetic field sensing element configured to produce a first signal representing a detected external magnetic field; a circular vertical hall element configured to produce a second signal representing an amplitude of the external magnetic field; and an error compensation circuit coupled to receive the first and second signal, compute an error value based on the amplitude of the external magnetic field, and apply the error value to the first signal to compensate for an error in the first signal.

Abstract: A magnetic field sensor includes a semiconductor substrate, a circular vertical Hall (CVH) sensing element comprising a plurality of Hall elements arranged over an implant region in a semiconductor substrate, adjacent ones of the plurality of vertical Hall element at predetermined angles from each other. A CVH output stage may comprise one or more of drive circuits to drive the plurality of vertical Hall elements and produce an analog signal, and a filter coupled to the CVH output stage to receive the analog signal. The filter may be configured to remove a DC component from the analog signal to produce a filtered signal. An analog-to-digital converter may be coupled to receive the filtered signal and produce a digital signal. A processor stage may be coupled to receive the filtered signal and operable to compute an estimated angle of the external magnetic field.

Abstract: A magnetic field sensor includes a circular vertical Hall (CVH) sensing element to produce a signal representing an external magnetic field as detected by the CVH sensing element, a sigma-delta analog-to-digital converter to generate a converted signal, modulators to produce quadrature modulated signals from the converted signal, and a processor to produce an estimated angle of the external magnetic field using the quadrature modulated signals. An arctangent function may be used to calculate the estimated angle. A sliding window integration scheme may be used over one or more CVH cycles.

Abstract: A sensor circuit may include one or more feedback loops to process and attenuate ripple and/or a test signal. The sensor circuit may comprise at least one magnetic field sensing element to generate a magnetic field signal representing a magnetic field to be measured, a test signal generator circuit configured to generate a test signal and combine the test signal with the magnetic field signal to generate a combined signal, and a signal path for processing the combined signal. The signal path may comprise an amplifier circuit to amplify the combined signal, an analog-to-digital converter (ADC) to convert the combined signal to a digital combined signal, and a feedback circuitry coupled to receive the digital combined signal and extract the test signal. A test comparator circuit compares the extracted test signal to a reference signal.

Abstract: A sensor circuit is provided with a chopper-stabilized amplifier circuit configured to receive a signal from at least one magnetic sensing element, a sigma-delta modulator (SDM) configured to receive a signal from the chopper-stabilized amplifier circuit, and a feedback circuit configured to reduce ripple in a signal generated by the chopper-stabilized amplifier circuit. The feedback circuit includes a demodulator to demodulate a signal from the SDM in a digital domain by inverting a bit stream of the signal from the SDM according to a frequency chopping rate, a digital integrator configured to integrate an output signal of the demodulator to form an integrated signal, and a digital-to-analog converter (DAC) configured to convert the integrated signal to an analog signal and provide the analog signal to the chopper-stabilized amplifier circuit.

Abstract: A magnetic field sensor comprises a substrate, a first coil supported by the substrate and configured to carry a first current in a first direction to generate a first magnetic field, and a second coil supported by the substrate and nested within the first coil to form a gap between the first and second coils, the second coil configured to carry a second current in a second, opposite direction to generate a second magnetic field. A plurality of magnetic field sensing elements is configured to detect the first and second magnetic fields. A switching network is coupled to the plurality of magnetic field sensing elements and configured to connect the plurality of magnetic field sensing elements to form a first bridge circuit having a first arrangement of the magnetic field sensing elements and a second bridge circuit having a second arrangement of the magnetic field sensing elements.

Abstract: A magnetic field sensor comprises a first coil configured to generate a magnetic field having a first frequency and induce a reflected magnetic field from a target. A second coil configured to generate a diagnostic magnetic field having a second frequency is included. The diagnostic magnetic field is configured not to induce a reflected magnetic field from the target that is measurable by the magnetic field sensor. At least two magnetic field sensing elements detect the reflected magnetic field and the diagnostic magnetic field and generate a signal representing the reflected magnetic field and the diagnostic magnetic field. A processing circuit is coupled to the at least two magnetic field sensing elements and configured to receive the signal, extract a diagnostic magnetic field portion of the signal representing the diagnostic magnetic field, and generate an error signal if a fault is detected.

Abstract: A method of calibrating a magnetic field sensor includes setting a first input signal at a first input node of a processor of the magnetic field sensor to a constant value. While the magnetic field sensor experiences a magnetic field, a first transition at an output node of the processor is measured. A second input signal at a second input node of the processor is set to the constant value. While the magnetic field sensor experiences the magnetic field, a second transition of at the output node of the processor is measured. An orthogonality error value is calculated based on a deviation of the first transition and the second transition. The first and/or second input signal is adjusted by modifying the first and/or second input signal by a function of the calculated orthogonality error value to compensate for the orthogonality error.

Abstract: A magnetic field sensor includes a first magnetic field sensing element first generating a first signal having a first axis of maximum sensitivity, a second magnetic field sensing element for generating a second signal and having a second axis of maximum sensitivity, one or more detectors for receiving an output of the first magnetic field sensing element or the second magnetic field sensing element, and a processor that receives an output of the one or more detectors and uses the output of the one or more detectors to calculate a first constant Kc and a second constant Ks and then uses Kc and Ks to compensate for an orthogonality error between the first axis of maximum sensitivity and second axis of maximum sensitivity. The detectors include peak detectors and/or zero-crossing detectors that compare the output of the first input signal or the second input signal with a threshold or zero.

Abstract: A sensor circuit is provided with a chopper-stabilized amplifier circuit configured to receive a signal from at least one magnetic sensing element, a sigma-delta modulator (SDM) configured to receive a signal from the chopper-stabilized amplifier circuit, and a feedback circuit configured to reduce ripple in a signal generated by the chopper-stabilized amplifier circuit. The feedback circuit includes a demodulator to demodulate a signal from the SDM in a digital domain by inverting a bit stream of the signal from the SDM according to a frequency chopping rate, a digital integrator configured to integrate an output signal of the demodulator to form an integrated signal, and a digital-to-analog converter (DAC) configured to convert the integrated signal to an analog signal and provide the analog signal to the chopper-stabilized amplifier circuit.

Abstract: A sensor circuit may include one or more feedback loops to process and attenuate ripple and/or a test signal. The sensor circuit may comprise at least one magnetic field sensing element to generate a magnetic field signal representing a magnetic field to be measured, a test signal generator circuit configured to generate a test signal and combine the test signal with the magnetic field signal to generate a combined signal, and a signal path for processing the combined signal. The signal path may comprise an amplifier circuit to amplify the combined signal, an analog-to-digital converter (ADC) to convert the combined signal to a digital combined signal, and a feedback circuitry coupled to receive the digital combined signal and extract the test signal. A test comparator circuit compares the extracted test signal to a reference signal.

Abstract: A magnetic field sensor includes a semiconductor substrate, a circular vertical Hall (CVH) sensing element comprising a plurality of Hall elements arranged over an implant region in a semiconductor substrate, adjacent ones of the plurality of vertical Hall element at predetermined angles from each other. A CVH output stage may comprise one or more of drive circuits to drive the plurality of vertical Hall elements and produce an analog signal, and a filter coupled to the CVH output stage to receive the analog signal. The filter may be configured to remove a DC component from the analog signal to produce a filtered signal. An analog-to-digital converter may be coupled to receive the filtered signal and produce a digital signal. A processor stage may be coupled to receive the filtered signal and operable to compute an estimated angle of the external magnetic field.