Performance of GMR-Elements in Sensors for Automotive Application

In the paper an introduction to the principle of the GMR-effect, and investigations into three types of GMR sensor are presented. Attention is hereby directed to the automotive applications ABS/ESP, engine management systems and transmission control. A sensitive GMR element with an integrated circuit has been developed fulfilling all requirements of the automotive environment for incremental speed sensors. The measurements of the sensors were performed using both active (magnetic) and passive (steel) impulse wheels in a temperature range of -40°C to 170°C. In addition to these investigations, simulations of the magnetic field have been performed to define the magnetic circuit. In order to be able to quantify a direct system advantage, the functionality is discussed compared to products in mass production based on Hall and AMR technology.