Self-Calibrating Gear-Tooth Sensor

The sensor's design integrates a magnet and monolithic silicon IC for optimal performance. A single Hall-effect sensor and signal-processing circuitry switch in response to changing magnetic signals created by rotating ferrous targets. The TPOS feature provides an accurate reading of the sensor's position in relation to the target upon power up. Switch points are air-gap independent for improved output accuracy and duty cycle. An updated algorithm fine-tunes switch points in running mode, maintaining design specifications even when there are large changes in air gap. The sensor consists of a samarium cobalt magnet and Hall-effect IC. Close proximity of the magnet to the IC provides excellent heat sinking.

Allegro MicroSystems Inc., 115 Northeast Cutoff, Worcester, MA 01606, (508) 854-5363, allegromicro.com