Phase compensation for an inductive position sensor

Abstract

An interface circuit for a position sensor system including an oscillator generating an oscillation signal having a carrier frequency and a primary phase, a primary coil responsive to the oscillation signal, and a secondary coil electromagnetically coupled to the primary coil by a target and configured to generate a secondary signal having the carrier frequency and a secondary phase provides phase compensation. The interface circuit includes a sampling and conversion circuit configured to sample the secondary signal during sample periods and convert the secondary signal into a digital signal, a demodulator coupled to receive the digital signal and configured to demodulate the digital signal in order to generate a position signal indicative of a position of the target, a phase detector coupled to receive the position signal and configured to detect an alignment of the secondary phase with respect to the sample periods and generate a phase detector output signal indicative of whether the secondary phase is aligned with the sample periods, and a delay circuit responsive to the phase detector output signal and configured to apply a delay to the sampling and conversion circuit if the phase detector output signal indicates that the secondary phase is not aligned with the sample periods.