Patent ID: 8129988

Claim:
A method of adjusting the sensitivity of a device including a magneto-resistive sensor and increasing the range of response of that device to an external magnetic field, characterized in that it consists in applying a known predetermined magnetic bias field H bias that is not homogeneous and is subject to known variations between a minimum value H biasmin and a maximum value H biasmax in a direction such that it has a non-zero component of the field perpendicular to a detection direction of said magnetoresistive sensor that also corresponds to a direction of anisotropy of a layer of the magnetoresistive sensor, so that the magnetic field to be measured can be determined by a monotonic function from the resistance variation of said magneto-resistive sensor, wherein the bias magnetic field is caused to vary linearly between the minimum value H biasmin and the maximum value H biasmax , and wherein the resistance R of said magnetoresistive sensor is given by the following equation: R = R 0 + R 1 ( H bias ⁢ ⁢ ma ⁢ ⁢ x - H bias ⁢ ⁢ m ⁢ ⁢ i ⁢ ⁢ n ) ⁢ ∫ H bias ⁢ ⁢ m ⁢ ⁢ i ⁢ ⁢ n H bias ⁢ ⁢ ma ⁢ ⁢ x ⁢ H H 2 + u 2 ⁢ ⁢ ⅆ u where: R 0 is the resistance of the magnetoresistive sensor in the absence of an external field; R 1 is the component of the resistance of the magnetoresistive sensor that is affected by the presence of an external magnetic field; H is the external magnetic field to be measured; and u is the variable varying from the minimum value H biasmin to the maximum value H biasmax of the bias magnetic field H bias .