Inductive angular position sensor
AssigneeSemiconductor Components Industries, LLC
InventorJacques Jean BERTIN
Life of this patent
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Abstract
An inductive sensor may track an angle of a movable element. In some cases, it is desirable to operate the inductive sensor using battery power so that turns are tracked properly even when power is lost. The disclosed inductive sensor includes circuitry to conserve power, such as a non-resonant driver that allows for fast measurements without wasting energy and a difference encoder that can estimate the angle within a range without the need for digitization and complicated processing.
Claims20
An inductive sensor comprising:
- an exciter coil configured to generate a magnetic field corresponding to an excitation current;
- a rotor coil mechanically coupled to a movable element configured to generate a plurality of coil voltages at a plurality of receiver coils according to a different angle-dependent inductive coupling between the rotor coil and each of the plurality of receiver coils;
- and
- a difference encoder including a plurality of comparators configured to output comparisons of the plurality of coil voltages while the inductive sensor is in a low-power mode, the comparisons defining angle states of the movable element.
A method for sensing a rotating element, the method comprising:
- transmitting an excitation current to an exciter coil to generate a magnetic field;
- rotating a rotor coil, coupled to the rotating element, in order to generate a different angle-dependent inductive coupling between the rotor coil and each of a plurality of receiver coils;
- receiving, during a measurement period, a plurality of coil voltages from the plurality of receiver coils;
- generating a set of pair-wise comparisons of the plurality of coil voltages;
- and
- determining an angle state of the rotating element for the measurement period based on the set of pair-wise comparisons.
An inductive sensor comprising:
- receiver coils including a first receiver coil, a second receiver coil, and a third receiver coil;
- a rotor coil mechanically coupled to a shaft and configured to generate a first coil voltage at the first receiver coil, a second coil voltage at the second receiver coil, and a third coil voltage at the third receiver coil as the shaft is rotated;
- a difference encoder including a first comparator coupled to the first receiver coil and the second receiver coil, a second comparator coupled to the second receiver coil and the third receiver coil, and a third comparator coupled to the third receiver coil and the first receiver coil, the first comparator, the second comparator, and the third comparator configured to output a set of comparisons;
- and
- a processor configured by software instructions to determine an angle state of the shaft for a measurement period based on the set of comparisons.
Dependencies are inferred from the claim text.