A semiconductor Hall plate-based sensor can provide information about package stress and can be substantially immune to the influence of magnetic fields. In an example, the sensor can include a Hall plate and an excitation circuit. The excitation circuit can provide signals to respective node pairs of the Hall plate. A measurement circuit can receive information about a first electric signal at a first pair of nodes in response to a first portion of the excitation signal, and can receive information about a second electric signal at a second pair of nodes in response to a second portion of the excitation signal. The first and second electric signals can indicate a charge carrier mobility characteristic of the semiconductor, which can be used to provide an indication of physical stress on the sensor.

A semiconductor-based stress sensor can include a bipolar transistor device with first and second collector terminals. An excitation circuit can provide an excitation signal to an emitter terminal of the bipolar transistor device, and a physical stress indicator for the semiconductor can be provided based on a relationship between signals measured at the collector terminals in response to the excitation signal. The signals can indicate a charge carrier mobility characteristic of the semiconductor, which can be used to provide an indication of physical stress. In an example, the physical stress indicator is based on a current deflection characteristic of a base region of the transistor device.

Current sensing techniques. In an example, a current sensing method includes: generating a first magnetic field measurement; generating a second magnetic field measurement; generating a frequency estimate of a current; calculating a root-mean-square (RMS) value of an estimated amplitude of the current; and generating a temperature estimate of an integrated circuit (IC) configured to perform the method. The method also includes generating a first weighting factor and a second weighting factor based on the frequency estimate, the RMS value, and the temperature estimate, the first weighting factor to control amplification of the first magnetic field measurement and the second weighting factor to control amplification of the second magnetic field measurement.

A digital compass with two or more multi-axis magnetometers and a processing element to determine a heading and detect any offset error in the heading is described. One electronic device includes first and second magnetometers. The second magnetometer can be disposed at least a specified distance or co-located and offset at least a specified angle from the first magnetometer. A processing device determines a magnetic field at the electronic device using a first output from the first magnetometer, detects an offset error in the magnetic field using a second output from the second magnetometer, and reports the offset error in the magnetic field.

A method of determining a gradient of a magnetic field, includes the steps of: biasing a first/second magnetic sensor with a first/second biasing signal; measuring and amplifying a first/second magnetic sensor signal; measuring a temperature and/or a stress difference; adjusting at least one of: the second biasing signal, the second amplifier gain, the amplified and digitized second sensor value using a predefined function f(T) or f(T, ΔΣ) or f(ΔΣ) of the measured temperature and/or the measured differential stress before determining a difference between the first/second signal/value derived from the first/second sensor signal. A magnetic sensor device is configured for performing this method, as well as a current sensor device, and a position sensor device.

A sensor apparatus comprises an electrically conductive chip carrier comprising a busbar, a first connection and a second connection, and a differential magnetic field sensor chip which is arranged on the chip carrier and has two sensor elements. The form of the busbar is such that a measurement current path running from the first connection to the second connection through the busbar comprises a main current path and a bypass current path, wherein the main current path and the bypass current path run parallel to one another, and a bypass current flowing through the bypass current path is less than a main current flowing through the main current path. The magnetic field sensor chip is configured to capture a magnetic field induced by the bypass current.

Methods and apparatus for a current sensor having an elongate current conductor having an input and an output and a longitudinal axis. First, second, third and fourth magnetic field sensing elements are coupled in a bridge configuration and positioned in a plane parallel to a surface of the current conductor such that the second and fourth magnetic field sensing elements comprise inner elements and the first and third magnetic field sensing elements comprise outer elements. Embodiments of the sensor reduce the effects of stray fields on the sensor.

An angle sensor comprising: a plurality of magnetic field sensing elements configured to detect a magnetic field and generate a respective plurality of analog magnetic field signals; a plurality of analog frontend circuits each analog frontend circuit associated with a respective magnetic field sensing element; and a digital feedback circuit configured to generate digital magnetic field signals from the plurality of analog magnetic field signals and generate digital error correction values, wherein the plurality of analog frontend circuits are configured to obtain the digital error correction values from the digital feedback circuit, generate analog correction values from the digital error correction values, and apply the analog correction values to the plurality of analog magnetic field signals to generate a plurality of corrected analog magnetic field signals.

An exemplary wearable sensor unit includes 1) a magnetometer comprising a vapor cell comprising an input window and containing an alkali metal, and a light source configured to output light that passes through the input window and into the vapor cell along a transit path, and 2) a temperature control circuit external to the vapor cell and configured to create a temperature gradient within the vapor cell, the temperature gradient configured to concentrate the alkali metal within the vapor cell away from the transit path of the light.

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.