Method and apparatus for detecting direction of a magnetic field

摘要

An integrated system of sensors that can be used to detect a direction of an externally applied magnetic field is disclosed. In one embodiment, the system can be incorporated into a compact package that can be used within an electronic device. A processor can use signals provided by the sensor system to provide an indication of the direction of the externally applied magnetic field. In one embodiment, the sensors can take the form of analog sensors such as Hall Effect sensors configured in such a way that the direction of the externally applied magnetic field can be deduced based in part upon detection signals provided by the Hall Effect sensors. In one embodiment, the Hall Effect sensors can be stacked one atop the other in such a way that relative signal strength of the detection signals from the sensors can indicate the direction of the externally applied magnetic field.

主权项

1. A sensor system carried by an electronic device and configured to detect an external magnetic field emitted by a magnetic source embedded in a cover that is external to the electronic device, the electronic device having a top portion and a bottom portion opposite the top portion, the sensor system comprising:
a single substrate formed of non-magnetic material and having a first surface and a second surface and displaced from the first surface; a first magnetic sensor at the first surface, the first magnetic sensor detecting the external magnetic field at the top portion; a second magnetic sensor at the second surface, the second magnetic sensor detecting the external magnetic field at the bottom portion, wherein the first magnetic sensor and the second magnetic sensor concurrently (i) detect the external magnetic field and (ii) provide a first detection signal and a second detection signal, respectively, corresponding to a first magnetic field strength and a second detection signal corresponding to a second magnetic field strength, respectively; and a processing circuit coupled to the first magnetic sensor and the second magnetic sensor, the processing circuit using a difference between the first detection signal and the second detection signal to provide a direction of the external magnetic field and determine whether the cover is disposed on the top portion or the bottom portion, the processing circuit generating operation instructions that cause the electronic device to operate in accordance with a current position of the cover.