DEVICE AND METHOD FOR REDUCING THERMAL INTERFERENCE OF MR HEAD OF DISK DRIVE

摘要

PROBLEM TO BE SOLVED: To remove the ringing and unnecessary offset of a read signal by making resistance values equal to a 1st and a 2nd specific resistance value in response to a 1st and a 2nd control input and generating the 2nd control input in response to the detection of a thermal event. SOLUTION: An effective resistance value is given by a resistance R1 and the programmed resistance value of a resistance R1 and a variable resistance value circuit 132 and the cutoff frequency of a filter 112 varies as the resistance value of the variable resistance value circuit 132 varies. In a normal operation period of a read channel, the resistance value of the variable resistance value circuit 132 is relatively high impedance and the effective resistance value of the filter 112 becomes substantially equal to the resistance value of the resistance R1. When thermal variation is detected, the effective resistance value of the filter 112 decreases to increase the cutoff frequency. This effective resistance value decreases by programming the variable resistance value circuit 132 to a specific resistance value in response to the input signal from a control circuit 110.