Patent ID: 8598867

Claim:
A circuit for detecting a movement of an object, comprising: at least one magnetic field sensing element for generating a DIFF signal proportional to a magnetic field associated with the object, wherein the DIFF signal has cycles including a present cycle; at least one motion detector configured to generate a motion signal indicative of the movement of the object, wherein the motion signal has edges associated with the cycles of the DIFF signal, wherein the at least one motion detector comprises: a threshold generator circuit coupled to receive the DIFF signal and configured to generate a threshold signal; at least one threshold selection module coupled to receive the threshold signal, configured to save samples of the threshold signal, configured to select samples of the threshold signal associated with a prior cycle of the DIFF signal a predetermined number of cycles before the present cycle, and configured to generate a selected threshold signal related to the selected samples of the threshold signal; and a comparator coupled to receive a signal representative of the selected threshold signal, coupled to receive the DIFF signal, configured to compare the signal representative of the selected threshold signal with the DIFF signal, and configured to generate the motion signal.