Programmable, multi-turn, pulse width modulation circuit for a non-contact angular position sensor

Recent requirements from the automotive industry for Electronic Stability Control and Roll Prevention Systems together with better fuel efficiency (i.e. engine power reduction) have dictated the replacement of the Power Steering Hydraulic Pump with an electric motor. The main steering angle sensor for this application needs to be a multi-turn rotary position sensor. This paper presents a circuit based on a design technique that produces a multiple-turn output of a full (0° to 360°) cycle of a Pulse-Width-Modulation (PWM) signal from a single (0° to 360°) turn of a Non-Contact Angular Position Sensor (NCAPS) [1, 2, 3, 4]. While described for use with the NCAPS, the circuit can be used with any rotary or linear sensor with a compatible PWM output.