To provide an electronic compass capable of performing magnetic detection accurately, by correcting offset applied to a magnetometric sensor even under an environment where there is a leakage magnetic field.
When an external magnetic field is applied to a sensor part 12 by various causes, a characteristic curve is shifted, without having to pass a coordinate intersection point between a resistance (voltage) and the magnetic field. Namely, an offset voltage portion (Roff) is generated. In order to determine a correction value for canceling the offset voltage portion, the difference of an output voltage is determined from two stages where a bias magnetic field is inverted, and the bias magnetic field is controlled, until the difference becomes almost 0. A corresponding bias magnetic field (current value), when the difference of the output voltage becomes almost 0, is used as the correction value (correction bias). As a result by, since correction can be performed, even if offset voltage is applied, magnetic detection can be performed accurately.
COPYRIGHT: (C)2008,JPO&INPIT
YAMADA YUKIMITSU
Amada Masayuki
Yoshimasa Okada