Hysteresis offset cancellation for magnetic sensors
AssigneeAllegro MicroSystems, LLC
InventorsJohn Cummings, William P. Taylor, David J. Haas
Life of this patent
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Abstract
Presented is a sensor that includes a magnetoresistive (MR) sensing device to sense a magnetic field and to produce an AC signal voltage proportional to the sensed magnetic field. The sensor also includes circuitry, coupled to the MR sensing device, to remove DC offset from the AC signal voltage. The DC offset may be related to the hysteresis characteristics of the MR sensing device. To remove DC offset, the circuitry may obtain an averaged DC offset and subtract the averaged DC offset from the AC signal voltage to produce a sensor output signal.
Claims25
A sensor, comprising:
- a magnetoresistive (MR) sensing device to sense a magnetic field and to produce an AC signal voltage proportional to the sensed magnetic field;
- and
- circuitry, coupled to the MR sensing device, to receive the AC signal voltage and to remove DC offset from the received AC signal voltage.
A current sensor comprising:
- a conductor to which a current to be measured in applied;
- a MR sensing device, responsive to a magnetic field generated in the conductor when current is applied to the conductor, to produce an AC signal voltage proportional to the current;
- and
- circuitry, coupled to the MR sensing device, to receive the AC signal voltage and to remove DC offset from the received AC signal voltage.
A method comprising:
- sensing a magnetic field with an MR sensing device and producing an AC signal voltage proportional to the sensed magnetic field;
- and
- removing DC offset from the AC signal voltage.
A sensor comprising:
- a sensing device to sense a magnetic field and to produce an AC signal voltage proportional to the sensed magnetic field;
- first circuitry, coupled to the sensing device, to determine an averaged DC offset for the AC signal voltage;
- and
- second circuitry, coupled to the first circuitry, to remove at least a portion of the averaged DC offset from the AC signal voltage.
Dependencies are inferred from the claim text.