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US 8,350,563 B2Granted
Magnetic field sensor and method used in a magnetic field sensor that adjusts a sensitivity and/or an offset over temperature
AssigneeAllegro MicroSystems, LLC
InventorsDavid J. Haas, Ravi Vig
Life of this patent
Estimating the term…
Abstract
A magnetic field sensor and a method associated with the magnetic field sensor provide gain correction coefficients and/or offset correction coefficients stored in the magnetic field sensor in digital form. The gain correction coefficients and/or offset correction coefficients can be used to generate analog control signals to control a sensitivity and/or an offset of an analog signal path through the magnetic field sensor.
Claims20
A magnetic field sensor, comprising:
- a magnetic field sensing element configured to generate a magnetic field signal;
- a gain adjustable analog circuit coupled to receive a signal representative of the magnetic field signal, coupled to receive a gain control signal, and configured to generate a gain adjusted signal having a gain responsive to the gain control signal;
- a coefficient table memory configured to receive and store a plurality of gain correction coefficients, wherein pairs of the plurality of gain correction coefficients are associated with boundaries of respective temperature segments, each temperature segment bounded by a pair of temperatures;
- a temperature sensor configured to generate a temperature signal representative of a temperature;
- and
- a segment processor coupled to receive a signal representative of the temperature signal, configured to identify a temperature segment in which the temperature signal falls, coupled to receive a pair of gain correction coefficients associated with the identified temperature segment, and configured to interpolate between the pair of gain correction coefficients in accordance with the temperature signal to generate an interpolated gain correction value, wherein the gain control signal is an analog signal related to the interpolated gain correction value.
3 more elements
A method of adjusting a magnetic field sensor, comprising:
- measuring a temperature with the magnetic field sensor during field operation;
- identifying with the magnetic field sensor in which one of a predetermined plurality of temperature segments the field measured temperature lies;
- identifying with the magnetic field sensor a pair of predetermined calibration temperatures associated with boundaries of the identified temperature segment;
- identifying with the magnetic field sensor a pair of gain calibration coefficients associated with the boundaries of the identified temperature segment, the pair of gain calibration coefficients stored within the magnetic field sensor;
- interpolating with the magnetic field sensor between the pair of gain calibration coefficients to establish an interpolated gain correction value;
- and
- applying an analog signal related to the interpolated gain correction value to a gain adjustment circuit within the magnetic field sensor.
4 more elements
A magnetic field sensor, comprising:
- a magnetic field sensing element configured to generate a magnetic field signal;
- an offset adjustable analog circuit coupled to receive a signal representative of the magnetic field signal, coupled to receive an offset control signal, and configured to generate an offset adjusted signal having an offset responsive to the offset control signal;
- a coefficient table memory configured to receive and store a plurality of offset correction coefficients, wherein pairs of the plurality of offset correction coefficients are associated with boundaries of respective temperature segments, each temperature segment bounded by a pair of temperatures;
- a temperature sensor configured to generate a temperature signal representative of a temperature;
- and
- a segment processor coupled to receive a signal representative of the temperature signal, configured to identify a temperature segment in which the temperature signal falls, coupled to receive a pair of offset correction coefficients associated with the identified temperature segment, and configured to interpolate between the pair of offset correction coefficients in accordance with the temperature signal to generate an interpolated offset correction value, wherein the offset control signal is an analog signal related to the interpolated offset correction value.
3 more elements
A method of adjusting a magnetic field sensor, comprising:
- measuring a temperature with the magnetic field sensor during field operation;
- identifying with the magnetic field sensor in which one of a predetermined plurality of temperature segments the field measured temperature lies;
- identifying with the magnetic field sensor a pair of predetermined calibration temperatures associated with boundaries of the identified temperature segment;
- identifying with the magnetic field sensor a pair of offset calibration coefficients associated with the boundaries of the identified temperature segment, the pair of offset calibration coefficients stored within the magnetic field sensor;
- interpolating with the magnetic field sensor between the pair of offset calibration coefficients to establish an interpolated offset correction value;
- and
- applying an analog signal related to the interpolated offset correction value to an offset adjustment circuit within the magnetic field sensor.
4 more elements
Dependencies are inferred from the claim text.