Head-mounted augmented reality (AR) devices can track pose of a wearer's head to provide a three-dimensional virtual representation of objects in the wearer's environment. An electromagnetic (EM) tracking system can track head or body pose. A handheld user input device can include an EM emitter that generates an EM field, and the head-mounted AR device can include an EM sensor that senses the EM field (e.g., for determining head pose). The generated EM field may be distorted due to nearby electrical conductors or ferromagnetic materials, which may lead to error in the determined pose. Systems and methods are disclosed that measure the degree of EM distortion, as well as correct for the EM distortion. The EM distortion correction may be performed in real time by the EM tracking system without the need for additional data from imaging cameras or other sensors.

According to an embodiment of the present disclosure, an integrated circuit includes: at least one sensing element configured to generate a sensed signal responsive to an electrical or magnetic phenomenon; an analog-to-digital converter configured to convert the sensed signal into a digital signal; and a digital processor configured to detect a target frequency of the electrical or magnetic phenomenon by iteratively applying a first real-valued coefficient to samples of the digital signal using real-valued arithmetic.

A magnetic field measuring device with a holding body and a plurality of magnetoelectric cantilever sensors, each of which is designed to output one electrical voltage signal while it bends in the presence of a magnetic field, the cantilever sensors being non-positively connected or bonded to the holding body.

A vertical Hall sensor circuit comprises an arrangement comprising a vertical Hall effect region of a first doping type, formed within a semiconductor substrate and having a stress dependency with respect to a Hall effect-related electrical characteristic. The vertical Hall sensor circuit further comprises a stress compensation circuit which comprises at least one of a lateral resistor arrangement and a vertical resistor arrangement. The lateral resistor arrangement has a first resistive element and a second resistive element, which are parallel to a surface of the semiconductor substrate and orthogonal to each other, for generating a stress-dependent lateral resistor arrangement signal on the basis of a reference signal inputted to the stress compensation circuit. The vertical resistor arrangement has a third resistive element of the first doping type for vertically conducting an electric current flow, for generating a stress-dependent vertical resistor arrangement signal on the basis of the reference signal. The vertical Hall sensor circuit further comprises a first circuit for providing a first signal to the arrangement, the first signal being based on at least one of the stress-dependent lateral resistor arrangement signal and the stress-dependent vertical resistor arrangement signal.

A circuit for monitoring an output voltage of a hall sensor includes an input port electrically connected to a first hall-sensor output terminal; an output port to output a monitoring voltage; a holder electrically connected to the input port to save the voltage of the input port; a first buffer including a first output terminal and first input terminal having an input impedance higher than an output impedance, having a voltage corresponding to a voltage of the first output terminal, and electrically connected to the holder; a second buffer including a second output terminal and second input terminal having an input impedance higher than an output impedance, having a voltage corresponding to a voltage of the second output terminal, and electrically connected to the input port; and an amplifier producing the monitoring voltage by amplifying a difference in voltages between the first output terminal and the second output terminal.

The present disclosure is directed to an electronic circuit having a Hall effect element and a resistor bridge, all disposed over a common semiconductor substrate. The resistor bridge includes a first set of resistive elements having a first vertical epitaxial resistor and a first lateral epitaxial resistor coupled in series, and a second set of resistive elements having a second vertical epitaxial resistor and a second lateral epitaxial resistor coupled in series. The first set of resistive elements and the second set of resistive elements can be coupled in parallel. The resistor bridge can be configured to sense a stress value of the Hall effect element.

Adjusting of calibration parameters for a sensor. The adjusted calibration parameters may be used to correct the raw data of the sensor. It is provided to calculate new calibration parameters only when accuracy of the calibration parameters currently available is no longer adequate, and suitable measurement data are available for a recalibration of the sensor. Otherwise, the components necessary for calibrating the sensor data may be deactivated in order to reduce energy consumption.

Magnetic-field sensors use magnetic closed-loops with magnetic-field sensing elements, e.g., magnetoresistance (MR) elements, and diagnostic circuitry operating in a separate frequency band than that used for magnetic field sensing. The MR elements can be used in a first stage of a high gain amplifier which provides a feedback signal to a feedback coil in a feedback configuration to provide a magnetic feedback field. The magnetic feedback field attenuates the sensed magnetic field so that the MR elements operate in a linear range. Magnetic stray field effects and any limited linearity of magnetic-field sensing elements can be masked by the loop gain of the closed loop. For a magnetic closed-loop, a negative feedback configuration can be used or a positive feedback configuration can be used with a loop-gain of less than one. The diagnostic signal traverses the closed-loop and provides information regarding correct or incorrect functioning of the loop components.

An apparatus for providing a bias current to a hall sensor includes: a bias provider configured to provide the bias current to the hall sensor; and a processor configured to produce a bias current control value based on a node voltage between the hall sensor and the bias provider, wherein the bias provider is configured to vary the bias current based on the bias current control value.

A magnetic sensor array device is comprised of an array of magnetic sensors arranged on a common semiconductor substrate to measure the multi-axis magnetic field of an arbitrary sized region at high speed with high spatial resolution and high magnetic resolution. This invention further improves a multi-axis magnetic sensor array device fabricated on a common semiconductor substrate with additional optimizations to provide for variable spatial resolution, variable magnetic resolution, and a novel secret key derivation.