Drive system for micromachined magnetic field sensors
AssigneeInvenSense, Inc.
InventorsBaris Cagdaser, Derek Shaeffer, Joe Seeger, Chiung C. Lo
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Abstract
Described herein are systems, devices, and methods that provide a stable magnetometer. The magnetometer includes a drive element that facilitates flow of a drive current through a node and a sense element operable to detect a magnetic field operating on the drive current. To reduce offset in the detection of the magnetic field, a voltage detector, electrically coupled to the drive element through the node, determines a variation between a node voltage and a target voltage. The voltage detector facilitates suppression of the variation and thereby minimizes the offset in the sense element.
Claims20
A system, comprising:
- a drive element that facilitates flow of a drive current through a node;
- a sense element operable to detect a magnetic field operating on the drive current;
- and
- a voltage detector electrically coupled to the drive element through the node, wherein the voltage detector determines a variation between a node voltage and a target voltage and facilitates suppression of the variation to minimize an offset in the sense element.
A device, comprising:
- a drive element that facilitates flow of a drive current with a drive pulse width of less than 50 percent of the drive period through a node;
- a sense element operable to detect a magnetic field operating on the drive current;
- and
- a drive circuit electrically coupled to the drive element, wherein the drive circuit provides the drive element with the drive current.
A method, comprising:
- reducing a magnetic sensor offset, comprising:
- detecting a voltage at a node coupling a drive element of a magnetic sensor and a sense element of the magnetic sensor;
- determining a variation between the detected voltage and a reference voltage;
- and
- reducing the variation in the detected voltage by using a feedback loop so that the detected voltage approximately matches the reference voltage;
- and
- sensing a magnetic field acting on the drive element at the sense element.
Dependencies are inferred from the claim text.