INTEGRATED MAGNETORESITIVE SPEED AND DIRECTION SENSOR

摘要

An integrated circuit magnetoresistive speed and direction sensor, including methods and systems thereof, are disclosed herein. The sensor illustrated and described herein generally utilizes an AMR (Anisotropic Magnetoresistive) bridge circuit. Using this technology allows for increased air gap performance as compared to conventional Hall-effect element based sensors. The AMR sensor disclosed herein is capable of sensing ring magnets or bar magnets magnetized with one or more magnet poles along the desired travel. The number of poles of the magnet should be optimized based upon the application design. The AMR bridge design of the AMR sensor disclosed herein produces minimal offsets, which results in optimal performance thereof. In order to obtain speed and direction information, two bridge circuits can be placed within proximity (i.e., the exact location and shape of the bridge can be determined based upon the target and desired performance) of each other. The signals of the two bridge circuits can be compared on the integrated electronics, which are co-located on the silicon thereof. The bridges are generally rotated 45 degrees to reduce and/or eliminate offsets, which provide the sensor with a large air gap performance.