Development of advanced diagnostic functions in very high volume automotive sensor applications

We present an opportunity for an overall system improvement of a very high volume automotive application based on advanced low-level on-chip signal diagnosis. We put our focus on advanced on-sensor diagnosis and added functionality at the very lowest level close to the magnetic signal of an automotive wheel speed sensor. Besides adding diagnosis for the sensor, this enables diagnostics of the entire mechanical system including the magnetic circuit which is crucial for correct operation. We followed a pre-development path starting with extensive automated measurements, simulations, a micro-controller based implementation, a field programmable gate array (FPGA) and finally a fully integrated application specific integrated circuit (ASIC). ASIC-blocks can be used for integration in the series product. We demonstrate the low-resource implementation of a lowest level sensor diagnostic signal processing circuit based on harmonic distortion analysis. The development path is reviewed with focus on reuse in the light of the specific requirements, advantages and drawbacks of each approach.