Patent ID: 6449113
Filing Date: 2002-09-10
Classification: G11B

Abstract:
A device for reading magnetic information, which device has at least one read head comprising at least one magnetoresistive bar for generating data pulses which represent information read by the head, characterized in that:the device includes a control loop for controlling the power dissipated in the magnetoresistive bar, the control loop is controlled by a control signal whose value is representative of a regulated value of the power which is to be dissipated by said bar, and includes regulating means for simultaneously regulating the value of a current flowing through the magnetoresistive bar and the value of a voltage present across said bar, and a current multiplier arranged to receive a first current representative of the control signal, a second current representative of the current flowing through the magnetoresistive bar, and a third current representative of the voltage present across said bar, said multiplier generating a fourth current having a value whose square is proportional to the quotient between the values of the second and third currents, multiplied by the value of the first current, and the control loop has a time constant which is large with respect to the duration of the data pulses.