A multifunction integrated circuit for automotive sensors

The implementation and use of a unique and very versatile CMOS integrated circuit which converts changes in physical parameters such as capacitance or resistance into a pulse width modulated digital signal is described. The circuit has an additional output which can be used to indicate when a predetermined set-point has been reached. The circuit, in combination with resistive or capacitive sensors, can be used to provide digital inputs to microprocessors and other digital control and diagnostic systems. Several applications are described and the integrated circuit is discussed. The multifunction analog/digital integrated circuit interface chip along with appropriate sensors offers unique sensor systems which could be reliable, accurate and inexpensive.