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.

In one aspect, a linear sensor includes at least one magnetoresistance element that includes a first spin valve and a second spin valve positioned on the first spin valve. The first spin valve includes a first set of reference layers having a magnetization direction in a first direction and a first set of free layers having a magnetization direction in a second direction orthogonal to the first direction. The second spin valve includes a second set of reference layers having a magnetization direction in the first direction and a second set of free layers having a magnetization direction in a third direction orthogonal to the first direction and antiparallel to the second direction. The first direction is neither parallel nor antiparallel to a direction of an expected magnetic field.

Methods and apparatus for a magnetic field sensor having first and second arrays of magnetic field sensing elements with at least first and second orthogonal axes of sensitivity. The first array of magnetic field sensing elements is spaced a first distance from the second array of magnetic field sensing elements. A turns counter counts a number of times a magnetic pole pair of a moving target passes the magnetic field sensing elements with a selected pole pair resolution and a module determines absolute angular position of the target from differential signals from the first and second arrays of magnetic field sensing elements and the turns counter. The first distance is configured to match a pitch of the poles of the target.

The present disclosure relates to chopper amplifier circuits with inherent chopper ripple suppression. Example implementations can realize a doubly utilized chopper amplifier circuit that is a current-saving circuit with a wake-up function that is capable of providing a self-wake signal in order to change into a fast, low-jitter/low-latency mode, and to provide a wake-up signal for a sleeping microprocessor or a system in response to signal changes.

Methods and apparatus for determining and transmitting speed and/or direction information for a rotating target by a magnetic field sensor. A reference channel signal is generated for a target from at least one magnetic field sensing element and a virtual channel signal in quadrature with the reference channel signal is generated. A tangent signal is generated. A slope of an arctangent of the tangent signal is determined, wherein the slope corresponds to rotational speed of the target. The speed and/or direction of the target can be transmitted by a sensor IC.

A sensor includes: a reference magnetic field generator configured to generate a reference magnetic field that is modulated at a first frequency, a first magnetic field sensing element that is configured to generate a first internal signal that is modulated at a second frequency, and a second magnetic field sensing element that is configured to generate a second internal signal that is modulated at the second frequency. A first amplifier is configured to receive the first internal signal and output a first amplified signal; and a second amplifier is configured to receive the second internal signal and output a second amplified signal. A gain adjustment circuit is configured to produce a gain adjustment signal and adjust a gain of at least one of the first amplifier and the second amplifier based on the gain adjustment signal.

A magnetic sensor includes a piezomagnetic component which includes a first piezomagnetic element and a second piezomagnetic element that are arranged opposite to each other, a magnetostrictive component which includes a first magnetostrictive element and a second magnetostrictive element arranged opposite to each other on the same side of the first piezomagnetic element and the second piezomagnetic element, respectively, and a piezoelectric component which includes a first piezoelectric element deposited underneath the first piezomagnetic element, a second piezoelectric element deposited underneath the second piezomagnetic element, a third piezoelectric element deposited underneath the first magnetostrictive element, and a fourth piezoelectric element deposited underneath the second magnetostrictive element. The first piezoelectric element and the second piezoelectric element are electrically connected to a power supply circuit, and produce first deformation, which is applied to the first piezomagnetic element and the second piezomagnetic element to produce an alternating magnetic field.

A Hall sensor circuit includes a first Hall sensor, a second Hall sensor, a first preamplifier circuit, a second preamplifier circuit, a subtractor circuit, and a duty cycling circuit. The first preamplifier circuit includes an input and an output. The input is coupled to the first Hall sensor. The second preamplifier circuit includes a first input, a second input, and an output. The first input is coupled to the second Hall sensor. The subtractor circuit includes a first input coupled to the output of the first preamplifier circuit, a second input coupled to the output of the second preamplifier circuit, and an output coupled to the second input of the second preamplifier circuit. The duty cycling circuit is coupled to the second preamplifier circuit and the second Hall sensor.

A magnetic field measuring apparatus includes an A/D conversion unit, an integration unit, and a post-processing unit. The A/D conversion unit is configured to sample a signal at a predetermined sampling frequency and perform conversion into digital data, the signal being based on an output voltage from a superconducting quantum interference device configure to detect a magnetic field emanating from a living organism. The integration unit is configured to obtain a biological magnetic field signal based on a value obtained by integrating the digital data, the biological magnetic field signal indicating a magnetic field emanating from the living organism. The post-processing unit is configured to perform decimation processing on the biological magnetic field signal output from the integration unit.

An interference type optical magnetic field sensor device 1 has a light emitter 10 emitting first linearly polarized light, a first optical element 30 emitting a first linearly polarized wave and a second linearly polarized wave orthogonal to the first linearly polarized wave with respect to incident the first linearly polarized light, and emitting a second linearly polarized light with respect to incident third linearly polarized wave and a forth linearly polarized wave orthogonal to the third linearly polarized wave, a magnetic field sensor element 50 disposed at least a portion thereof within a predetermined magnetic field an optical path unit 40 connected to the first optical element and the magnetic field sensor element, and having a first optical path propagating the first linearly polarized wave and the forth linearly polarized wave, and a second optical path propagating the second linearly polarized wave and the third linearly polarized wave, a detection signal generator 60 outputting a detection signal by separating the second linearly polarized light into an S polarization component and a P polarization component, converting the S polarization component and the P polarization component into an electric signal, and an optical branching element 20 transmitting the first linearly polarized light to the first optical element, and branching the second linearly polarized light to the detection signal generator, wherein the magnetic field sensor element emits the first linearly polarized wave and the second linearly polarized wave as incident light, and emits the third linearly polarized wave with respect to the first linearly polarized wave and the forth linearly polarized wave with respect to the second linearly polarized wave as return light.