In one aspect, a wake-up circuit is provided for triggering a determination of an absolute rotational position of a rotatable shaft of a motor in an electric power steering system of a vehicle. The wake-up circuit includes a plurality of inputs coupled to separate phases of the motor. A voltage boosting circuit is operable to increase a back electromotive force (EMF) voltage induced on one or more of the inputs by rotation of the rotatable shaft of the motor and produce at least one voltage-boosted back EMF voltage. A comparator circuit is operable to compare the at least one voltage-boosted back EMF voltage to a reference voltage and trigger a monitoring system to perform the determination of the absolute rotational position of the rotatable shaft of the motor in the electric power steering system based on a result of the compare during an ignition off state of the vehicle.