| 主权项 |
1. A magnetic sensor comprising:
a magneto-electric transducer which generates an output voltage depending on a strength of a magnetic field; a switch circuit which alternately switches between a first bias state under which a bias voltage in a first direction is applied to the magneto-electric transducer to acquire the output voltage and a second bias state under which a bias voltage in a second direction perpendicular to the first direction is applied to the magneto-electric transducer to acquire the output voltage; an amplifier circuit which generates an amplification voltage by amplifying the output voltage; a subtractor circuit which performs a first subtraction process of generating a first subtraction voltage by subtracting an amplification voltage obtained under an immediately prior first bias state from an amplification voltage obtained under the second bias state and a second subtraction process of generating a second subtraction voltage by subtracting an amplification voltage obtained under an immediately prior second bias state from an amplification voltage obtained under the first bias state in a serial and parallel manner; a selector circuit which alternately selects the first subtraction voltage and the second subtraction voltage to output a select voltage; and a filter circuit which generates a filtered voltage by smoothing out ripples of the select voltage, wherein the amplifier circuit generates, as the amplification voltage, a positive phase amplification voltage and a negative phase amplification voltage which are in reversed phases, wherein the subtractor circuit generates, as the first subtraction voltage, a first positive phase subtraction voltage and a first negative phase subtraction voltage, the first positive phase subtraction voltage calculated by subtracting the positive phase amplification voltage obtained under the immediately prior first bias state from the positive phase amplification voltage obtained under the second bias state, and the first negative phase subtraction voltage calculated by subtracting the negative phase amplification voltage obtained under the immediately prior first bias state from the negative phase amplification voltage obtained under the second bias state, and wherein the subtractor circuit generates, as the second subtraction voltage, a second positive phase subtraction voltage and a second negative phase subtraction voltage, the second positive phase subtraction voltage calculated by subtracting the positive phase amplification voltage obtained under the immediately prior second bias state from the positive phase amplification voltage obtained under the first bias state, and the second negative phase subtraction voltage calculated by subtracting the negative phase amplification voltage obtained under the immediately prior second bias state from the negative phase amplification voltage obtained under the first bias state. |
