A programmable Hall sensor for camshaft applications

A chopped Hall sensor for camshaft applications is presented which provides a programmable "true power-on" switching level. The proposed chopping technique and self-compensation methods for temperature drift and technology spread provide a correct output state immediately after power-on even at zero speed of the target wheel. An end-of-line calibration for the customer is implemented using surface micromachined cavity fuses. A novel combination of chopping and enhanced self-calibration algorithm adjusts the magnetic switching point and improves phase accuracy.