Embodiments describe herein generally pertain to implantable medical device (IMDs), and methods for use therewith, that can be used to automatically switch an IMD from its normal operational mode to an MRI safe mode, and vice versa, within increased specificity. In certain embodiments, a controller of the IMD uses a magnetic field sensor to determine whether a first magnetic field condition is detected, and uses an accelerometer to determine whether a positional condition is detected. In response to the first magnetic field condition being detected, and the positional condition being detected, the controller can use the magnetic field sensor to determine whether a second magnetic field condition is detected, which differs from the first magnetic field condition. The controller can then cause the IMD to enter the MRI safe mode based at least in part on the first and second magnetic field conditions and the positional condition being detected.

Systems and methods for providing a visualization capability to map magnetic fields. The system utilizes a high-sensitivity magnetic field sensor (e.g., a magnetometer inside a tube made of magnetic shielding material) disposed on one side of a magnetic field modulation screen to acquire measurement data representing an image of a magnetic field. The magnetic field modulation screen includes a multiplicity of magnetic field-generating pixel elements (e.g., current-carrying loops made of electrically conductive material). Optionally, the system also uses compressive sensing techniques to reduce the amount of measurement data required to reconstruct an image of the original magnetic field. Compressive sensing is enabled by not supplying current to a different selected individual magnetic field-generating pixel element of the magnetic field modulation screen at successive sampling times.

A resistive sensor system includes resistive sensor pairs formed of first and second sensors of opposite sensitivity directions to a measured property. Each resistive sensor pair includes one of the first sensors having a first terminal and a second terminal, and one of the second sensors having a third terminal and a fourth terminal. The fourth terminal is coupled to the second terminal of the first sensor. The system further includes multiple noninverting switch elements, each having a noninverting output coupled to the first terminal of one the first sensors, and multiple inverting switch elements, each having an inverting output coupled to the third terminal of one of the second sensors. For each resistive sensor pair, the noninverting and inverting switch elements receive a switch signal for controlling the noninverting and inverting switch elements such that the first and second sensors are biased in opposition to one another.

A resettable bipolar switch sensor is disclosed which comprises a bipolar magnetic hysteresis switch sensor, a reset coil, an ASIC switch circuit and a power reset circuit. The bipolar magnetic hysteresis switch sensor comprises a substrate and a magnetoresistive sensing arm located on the substrate. The magnetoresistive sensing arm is of a two-port structure composed of one or more magnetoresistive sensing unit strings arranged in series, parallel, or series-parallel. The magnetization direction of a free layer of a TMR magnetoresistive sensing unit is determined by an anisotropy field Hk, and together with the magnetization direction of a reference layer and the applied magnetic field, it can orient in an N or S direction. The reset coil is located between the substrate along with the magnetoresistive sensing unit, or it is located on a lead frame below the substrate. The direction of the reset magnetic field is either N or S. The ASIC switch circuit comprises a biasing circuit module, a reading circuit module, and an output circuit module. The power reset circuit is connected to the reset coil. This device has the advantages of low power consumption and small size in addition to the capability to set initial state of the switch sensor.

The present disclosure relates to semiconductor structures and, more particularly, to 3-contact hall sensors and methods of manufacture and modes of operation. The structure includes: a plurality of sensing blocks each of which include a plurality of contacts; a first switching element connecting to a first set of sensing blocks of the plurality of sensing blocks; and a second switching element connecting to a second set of sensing blocks of the plurality of sensing blocks.

Provided is a magnetic sensor circuit in which increase of a delay time period is suppressed to be small without reducing a noise suppressing effect, in a case where there are multiple magnetic field detection axes. A magnetic sensor circuit is configured to subject detection signals obtained from multiple magnetic-field detection axes to time division processing, and includes a magnetic detector including at least two magnetic sensors, a switching circuit selecting a magnetic sensor represented by a selection signal to transmit the detection signal, a comparator, a control circuit, and output terminals. The control circuit supplies the selection signal to the switching circuit, and determines that the magnetic field is detected in a case where the number of times that a signal level of the signal supplied from the switching circuit exceeds a reference level reaches the number of set times that is set to a plurality of times.

A resistive sensor system includes resistive sensor pairs formed of first and second sensors of opposite sensitivity directions to a measured property. Each resistive sensor pair includes one of the first sensors having a first terminal and a second terminal, and one of the second sensors having a third terminal and a fourth terminal. The fourth terminal is coupled to the second terminal of the first sensor. The system further includes multiple noninverting switch elements, each having a noninverting output coupled to the first terminal of one the first sensors, and multiple inverting switch elements, each having an inverting output coupled to the third terminal of one of the second sensors. For each resistive sensor pair, the noninverting and inverting switch elements receive a switch signal for controlling the noninverting and inverting switch elements such that the first and second sensors are biased in opposition to one another.

Various implementations include earbud cases with a Hall effect sensor configured to aid in detecting whether the case is open or closed. Certain additional implementations include a holder for a Hall effect sensor in an earbud case. In some particular aspects, a case for a set of earbuds includes: a top section including a set of magnets; and a base section movably coupled with the top section, the base section having: an upper compartment including a set of slots for holding the earbuds; and a lower compartment, having: a printed circuit board (PCB); a holder coupled with the PCB; and a Hall effect sensor coupled with holder, wherein the holder separates the Hall effect sensor from the PCB.

Systems and methods for providing a visualization capability to map magnetic fields. The system utilizes a high-sensitivity magnetic field sensor (e.g., a magnetometer inside a tube made of magnetic shielding material) disposed on one side of a magnetic field modulation screen to acquire measurement data representing an image of a magnetic field. The magnetic field modulation screen includes a multiplicity of magnetic field-generating pixel elements (e.g., current-carrying loops made of electrically conductive material). Optionally, the system also uses compressive sensing techniques to reduce the amount of measurement data required to reconstruct an image of the original magnetic field. Compressive sensing is enabled by not supplying current to a different selected individual magnetic field-generating pixel element of the magnetic field modulation screen at successive sampling times.

A magnetic field sensor apparatus includes a sensor signal generator generating a sensor signal responsive to a magnetic field. A switching level provider provides during a power up mode a switching level based on a most recently updated valid one of a first and a second value of a default switching level. If an update triggering condition occurs, the not most recently updated one of the first and second values of the default switching level is updated and the most recently updated one of the first and second values of the default switching level is maintained unchanged until a next update triggering condition occurs, so that the first and second values of the default switching level are updated alternately on consecutive triggering conditions.