CIRCUIT AND METHOD FOR CALIBRATING GEOMETRIC SIGNAL

摘要

A geomagnetic signal calibrating circuit and a calibrating method are provided to prevent saturation of an output geomagnetic signal by maintaining an offset voltage of an analog signal processing unit constantly. A geomagnetic signal calibrating circuit is composed of a geomagnetic sensor(301) outputting an electrical signal of the size corresponding to a geomagnetic field; an analog signal processing unit(302) outputting a voltage type analog signal by amplifying and filtering a signal output from the geomagnetic sensor; a switching unit(303) provided with plural switching elements(SW1,SW2,SW3), connected between the geomagnetic sensor and the analog signal processing unit, and switched on or off to cut off or output a geomagnetic signal transmitted from the geomagnetic sensor; an analog/digital conversion unit(304) converting the signal output from the analog signal processing unit into a digital signal; and a digital processing unit(305) generating a signal(S1) for controlling offset voltage(VADC) of the analog signal processing unit and a signal(S2) for controlling the switching unit by using the digital signal output from the analog/digital conversion unit, and calibrating the signal of the geomagnetic sensor.