Individual MR transducer head/disk/channel adaptive bias current system
US5412518A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 16, 1993 |
| Grant date | May 2, 1995 |
| Priority date | — |
| Expiry date | Dec 16, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2005/0018
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus is disclosed for adaptively controlling the biasing current applied to magnetoresistive (MR) read heads within a magnetic disk drive to provide optimized bias for each head/disk/channel component combination. An optimized bias current for each head is ascertained and stored on the disk surface at the time of manufacture. During each power up operation the values are transferred to random access memory which is accessed during the execution of each head switch command to apply bias current in accordance with the optimized value to the active MR head. Periodic reoptimization and updating of the stored values is effected by general error measurement circuitry that forms a part of the device control system and is invoked to perform the reoptimization upon the occurrence of an event such as a predetermined duration of power on operation subsequent to the last reoptimization procedure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.