Patent ID: 6882146

Claim:
A method for determining an orientation of an external magnetic field with giant magneto-resistor (GMR) sensors, comprising: a) providing a sensor circuit comprising at least a first and a second sensor sub-circuit that are connected parallel to one another, the first and the second sensor sub-circuit each respectively comprising at least a first and a second GMR sensor that are connected in series and that are respectively arranged in opposite internal magnetic orientation, the internal magnetic orientation of the GMR sensors of the first sensor sub-circuit being essentially perpendicular to the internal magnetic orientation of the GMR sensors of the second sensor sub-circuit, the sensor circuit being fed by a current source, and draining through a current sink; b) obtaining three respective sensor voltages from a first point, a second point, and a third point in the first and the second sensor sub-circuit, the first point lying on a connecting line from the current sink to the second GMR sensor, the second point lying on a connecting line from the second GMR sensor to the first GMR sensor, and the third point lying on the connecting line from the first GMR sensor to the current supply; c) generating a first difference voltage using a first difference circuit from the three sensor voltages of the first sensor sub-circuit, and generating a second difference voltage from a second difference circuit from the three sensor voltages of the second sensor sub-circuit; d) calculating a scaling factor from the first difference voltage and the second difference voltage; and e) determining the orientation of an external magnetic field by scaling the first difference voltage and the second difference voltage with the scaling factor.