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US 2011/0298450 A1Published application
Circuits and Methods for Generating a Threshold Signal Used in a Motion Detector
AssigneeAllegro MicroSystems, LLC
InventorsAndrea Foletto, Andreas P. Friedrich
Life of this patent
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Abstract
A circuit to detect a movement of an object provides a threshold selection module that uses one or more threshold signals identified prior to a present cycle of magnetic field signal in order to establish a threshold signal used for a present cycle of the magnetic field signal. A method associated with the circuit is also described.
Claims39
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.
3 more elements
A method of detecting a movement of an object, comprising:
- generating a DIFF signal proportional to a magnetic field associated with the object, wherein the DIFF signal has cycles including a present cycle;
- and
- generating 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 generating the motion signal comprises:
- generating a threshold signal in accordance with the DIFF signal;
- saving samples of the threshold signal;
- selecting samples of the threshold signal associated with a prior cycle of the DIFF signal a predetermined number of cycles before the present cycle;
- generating a selected threshold signal related to the selected samples of the threshold signal;
- and
- comparing a signal representative of the selected threshold signal with the DIFF signal to generate the motion signal.
6 more elements
A method of detecting movement of an object, comprising:
- generating a magnetic field signal with at least one magnetic field sensing element, wherein the magnetic field signal is proportional to a magnetic field associated with the object, wherein the magnetic field signal has cycles including a present cycle;
- generating a tracking signal that track at least a portion of the magnetic field signal;
- and
- using the tracking signal to generate a selected threshold signal in accordance with a prior cycle of the magnetic field signal prior to the present cycle.
1 more element
Dependencies are inferred from the claim text.