Discharge mechanism in HDD

Abstract

  The risk of electrical discharge between the head and disk in a Hard Disk Drive (HDD) system is discussed. Discharge can cause GMR/TMR element to degrade and/or damage the disk, which would result in quality degradation. Within this paper, the root cause and the mechanism of such discharge and HDD design concept are discussed to avoid the issue. More specifically, our study shows that the voltage difference between head and disk should be within +1∼-1 volt range and it indicates that discharge issue is not parts oriented, but rather must be resolved by balancing the electrical charge of the whole HDD system.