Circuit and method for optimizing bias supply in a magnetoresistive head based on the thermal properties of the MR head itself

摘要

A method and apparatus adaptively controls the biasing current applied to individual magnetoresistive (MR) heads within a Direct Access Storage Device (DASD) to provide an optimized bias current based on the thermal properties of each MR read head. An optimal bias current is determined by using a ratio of resistances of the MR read head at different bias levels. The use of the resistance ratio allows the bias level to be optimally adjusted for each individual MR read head within a DASD unit based on the physical geometry of the individual MR stripe within the MR read heads. The optimal bias supply enhances MR read head sensitivity, improves the signal-to-noise ratio, and thereby reduces errors in reading data from magnetic storage media within the DASD. The maximum allowable bias current level is controlled so as to preserve the overall life expectancy of the MR heads.