OFFSET CORRECTION PROGRAM AND ELECTRONIC COMPASS

摘要

When an external magnetic field is applied to a sensor section (12) due to various causes, the characteristic curve does not pass the intersection of coordinates of resistance (voltage) and magnetic field but deviates therfrom. In other words, an offset voltage component (Roff) is generated. In order to determine a correction value for canceling the offset voltage component, difference between output voltages is determined from two stages where the bias magnetic field is inverted and the bias magnetic field is controlled until the difference becomes substantially zero. A corresponding bias magnetic field (current value) when the difference between output voltages becomes substantially zero is employed as a correction value (correction bias). Since correction can be made even when an offset voltage is applied, magnetic detection can be carried out accurately.