Differential hall IC for gear-tooth sensing

Abstract The principle, design and application of a geartooth sensor for rough environmental conditions are described. The rotation of a tooth wheel is detected by Hall elements manufactured on a bipolar silicon technology line. Therefore conditioning circuitry can easily be integrated together with the Hall elements on a single chip. A special layout of the Hall elements minimizes their offset voltage and offset voltage drift. An active filter increases maximum possible distance between sensor IC and tooth wheel over a wide temperature range. Full protection against peak pulses and electromagnetic influence is provided.