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US 10,520,560 B2Granted
Magnetic field sensing apparatus and detection method thereof
AssigneeiSentek Inc.
InventorsFu-Te Yuan, Meng-Huang Lai
Life of this patent
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Abstract
A magnetic field sensing apparatus and detection method thereof are provided. The magnetic field sensing apparatus includes an anisotropic magneto-resistive (AMR) magnetic field detector, a reference magnetic field detector, and a controller. The AMR magnetic field detector generates a first output voltage according to a detected magnetic field. The reference magnetic field detector generates a second output voltage according to the detected magnetic field. The controller identifies whether an absolute value of a field density of the detected magnetic field is larger or smaller than a predetermined value or not, and selects the first output voltage or a saturation voltage to be a magnetic field detection result accordingly.
Claims13
A magnetic field sensing apparatus, comprising:
- an anisotropic magneto-resistance (AMR) magnetic field detector, generating a first output voltage according to a detected magnetic field;
- a reference magnetic field detector, generating a second output voltage according to the detected magnetic field;
- and
- a controller, coupled to the AMR magnetic field detector and the reference magnetic field detector, identifying whether an absolute value of a field density of the detected magnetic field is larger than or smaller than a predetermined threshold value according to the second output voltage to select the first output voltage or a saturation voltage to be a magnetic field detection result,
- wherein the controller comprises:
- a comparator, receiving the second output voltage and a threshold voltage, and generating a comparison result signal according to comparison of the second output voltage and the threshold voltage;
- and
- a selector, coupled to the comparator, receiving the first output voltage and the saturation voltage, and selecting the first output voltage or the saturation voltage to be the magnetic field detection result according to the comparison result signal,
- wherein the threshold voltage is equal to a voltage value of the second voltage generated by the reference magnetic field detector when receiving the detected magnetic field where the absolute value of the field density is equal to the predetermined threshold value,
- wherein the AMR magnetic field detector operates in a linear region or a non-linear region according to the absolute value of the field density of the detected magnetic field, the predetermined threshold value is set according to a threshold field density corresponding to the linear region and the non-linear region,
- wherein a boundary between the linear region and the non-linear region occurs at the threshold field density,
- wherein when the absolute value of the field density of the detected magnetic field is not larger than or smaller than the predetermined threshold value, the controller selects the saturation voltage to be the magnetic field detection result.
9 more elements
A magnetic field detection method, comprising:
- providing an AMR magnetic field detector to generate a first output voltage according to a detected magnetic field;
- providing a reference magnetic field detector to generate a second output voltage according to the detected magnetic field;
- and
- identifying whether an absolute value of a field density of the detected magnetic field is larger than or smaller than a predetermined threshold value according to the second output voltage to select the first output voltage or a saturation voltage to be a magnetic field detection result,
- wherein the step of identifying whether the absolute value of the field density of the detected magnetic field is larger than or smaller than the predetermined threshold value according to the second output voltage, thereby selecting the first output voltage or the saturation voltage to be the magnetic field detection result accordingly comprises:
- providing a comparator to compare the second output voltage and a threshold voltage or compare the second output voltage and a first threshold voltage as well as a second threshold voltage to generate a comparison result signal;
- providing a selector to select the first output voltage or the saturation voltage to be the magnetic field detection result according to the comparison result signal;
- and
- when the absolute value of the field density of the detected magnetic field is not larger than or smaller than the predetermined threshold value, selecting the saturation voltage to be the magnetic field detection result,
- wherein the threshold voltage is equal to a voltage value of the second voltage generated by the reference magnetic field detector when receiving the detected magnetic field where the absolute value of the field density is equal to the predetermined threshold value,
- wherein the first threshold voltage is equal to the voltage value of the second voltage generated by the reference magnetic field detector when receiving the detected magnetic field where the field density is equal to the predetermined threshold value, the second threshold voltage is equal to the voltage value of the second voltage generated by the reference magnetic field detector when receiving the detected magnetic field where the field density is equal to a negative predetermined threshold value, the predetermined threshold value is an additive inverse of the negative predetermined threshold value,
- wherein the AMR magnetic field detector operates in a linear region or a non-linear region according to the absolute value of the field density of the detected magnetic field, the magnetic field detection method further comprising:
- setting the predetermined threshold value according to a threshold field density corresponding to the linear region and the non-linear region,
- wherein a boundary between the linear region and the non-linear region occurs at the threshold field density.
11 more elements
A magnetic field sensing apparatus, comprising:
- an anisotropic magneto-resistance (AMR) magnetic field detector, generating a first output voltage according to a detected magnetic field;
- a reference magnetic field detector, generating a second output voltage according to the detected magnetic field;
- and
- a controller, coupled to the AMR magnetic field detector and the reference magnetic field detector, identifying whether an absolute value of a field density of the detected magnetic field is larger than or smaller than a predetermined threshold value according to the second output voltage to select the first output voltage or a saturation voltage to be a magnetic field detection result,
- wherein the controller comprises:
- a comparator, receiving the second output voltage, a first threshold voltage and a second threshold voltage, comparing the second output voltage and the first threshold voltage as well as the second threshold voltage to generate a comparison result signal;
- and
- a selector, coupled to the selector, receiving the first output voltage and the saturation voltage, selecting the first output voltage or the saturation voltage to be the magnetic field detection result according to the comparison result signal,
- wherein the first threshold voltage is equal to a voltage value of the second voltage generated by the reference magnetic field detector when receiving the detected magnetic field where the field density is equal to the predetermined threshold value, the second threshold voltage is equal to the voltage value of the second voltage generated by the reference magnetic field detector when receiving the detected magnetic field where the field density is equal to a negative predetermined threshold value, the predetermined threshold value is an additive inverse of the negative predetermined threshold value,
- wherein the AMR magnetic field detector operates in a linear region or a non-linear region according to the absolute value of the field density of the detected magnetic field, the predetermined threshold value is set according to a threshold field density corresponding to the linear region and the non-linear region,
- wherein a boundary between the linear region and the non-linear region occurs at the threshold field density,
- wherein when the second output voltage is larger than the first threshold voltage or smaller than the second threshold voltage, the selector selects the saturation voltage to be the magnetic field detection result according to the comparison result signal.
9 more elements
Dependencies are inferred from the claim text.