External magnetic field angle determination
First Claim
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1. A sensor configured to measure an angle of an external magnetic field, the sensor comprising:
- a first half-bridge comprising a first magnetoresistive resistor and a second magnetoresistive resistor, wherein the first magnetoresistive resistor and the second magnetoresistive resistor have barber-pole stripes;
a second half-bridge comprising a third magnetoresistive resistor and a fourth magnetoresistive resistor, wherein the third magnetoresistive resistor and the fourth magnetoresistive resistor do not have barber-pole stripes, the third magnetoresistive resistor is rotated with respect to the fourth magnetoresistive resistor by an angle of 90 degrees, and the first magnetoresistive resistor and the second magnetoresistive resistor are arranged parallel to the third magnetoresistive resistor; and
a modulation unit configured to modulate the external magnetic field with an Alternating Current (AC) field in a continuous manner and generate a magnetic modulation field with both a sine signal and a cosine signal, wherein the external magnetic field is superposed by a rotating magnetic field vector.
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Abstract
Magnetoresistive sensors are commonly used for angular detection in many automotive applications. According to an exemplary embodiment of the present invention, a sensor is provided in which a first half-bridge has magnetoresistive resistors with barber-pole stripes and in which a second half-bridge has magnetoresistive resistors without barber-pole stripes. One of the resistors without barber-pole stripes is rotated with respect to the other three resistors by 90°. This may provide for an improved angle determination with reduced angular errors due to offset.
18 Citations
16 Claims
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1. A sensor configured to measure an angle of an external magnetic field, the sensor comprising:
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a first half-bridge comprising a first magnetoresistive resistor and a second magnetoresistive resistor, wherein the first magnetoresistive resistor and the second magnetoresistive resistor have barber-pole stripes; a second half-bridge comprising a third magnetoresistive resistor and a fourth magnetoresistive resistor, wherein the third magnetoresistive resistor and the fourth magnetoresistive resistor do not have barber-pole stripes, the third magnetoresistive resistor is rotated with respect to the fourth magnetoresistive resistor by an angle of 90 degrees, and the first magnetoresistive resistor and the second magnetoresistive resistor are arranged parallel to the third magnetoresistive resistor; and a modulation unit configured to modulate the external magnetic field with an Alternating Current (AC) field in a continuous manner and generate a magnetic modulation field with both a sine signal and a cosine signal, wherein the external magnetic field is superposed by a rotating magnetic field vector. - View Dependent Claims (2, 3, 4, 5, 9, 10, 11)
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6. A method for measuring an angle of an external magnetic field, the method comprising:
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modulating the external magnetic field in two directions with an Alternating Current (AC) field in a sensor comprising a first half-bridge and a second half-bridge, the first half-bridge has a first magnetoresistive resistor and a second magnetoresistive resistor, wherein the first magnetoresistive resistor and the second magnetoresistive resistor have barber-pole stripes, and the second half-bridge has a third magnetoresistive resistor and a fourth magnetoresistive resistor, wherein the third magnetoresistive resistor and the fourth magnetoresistive resistor do not have barber-pole stripes, the third magnetoresistive resistor is rotated with respect to the fourth magnetoresistive resistor by an angle of 90 degrees, and the first magnetoresistive resistor and the second magnetoresistive resistor are arranged parallel to the third magnetoresistive resistor; and exciting a first coil and a second coil in a continuous manner to generate a magnetic modulation field, wherein the first coil is excited by a sine signal and the second coil is excited by a cosine signal, and the external magnetic field is superposed by a rotating magnetic field vector. - View Dependent Claims (7, 12, 13, 14, 15, 16)
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8. A non-transitory computer-readable medium, in which a computer program for measuring an angle of an external magnetic field is stored which, when executed by a processor, causes the processor to execute a method for measuring an angle of an external magnetic field, the method comprising:
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modulating an Alternating Current (AC) magnetic field in two directions in a sensor comprising a first half-bridge and a second half-bridge, the first half-bridge has a first magnetoresistive resistor and a second magnetoresistive resistor, wherein the first magnetoresistive resistor and a second magnetoresistive resistor have barber-pole stripes, and the second half-bridge has a third magnetoresistive resistor and a fourth magnetoresistive resistor, wherein the third magnetoresistive resistor and the fourth magnetoresistive resistor do not have barber-pole stripes, wherein the third magnetoresistive resistor is rotated with respect to the fourth magnetoresistive resistor by an angle of 90 degrees, and the first magnetoresistive resistor and the second magnetoresistive resistor are arranged parallel to the third magnetoresistive resistor; and exciting a modulation unit comprising a first coil and a second coil in a continuous manner for generation of a magnetic modulation field, wherein the first coil is excited by a sine signal and the second coil is excited by a cosine signal, and the external magnetic field is superposed by a rotating magnetic field vector.
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Specification