Disk drive comprising VCM stall detector for velocity control of an actuator arm
US6867944B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 31, 2000 |
| Grant date | Mar 15, 2005 |
| Priority date | — |
| Expiry date | Apr 15, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/5547
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention may be regarded as a disk drive comprising a disk, a head, an actuator arm for actuating the head radially over the disk, and a voice coil motor (VCM) for rotating the actuator arm about a pivot, the VCM comprising a coil comprising a VCM resistance R. A back EMF voltage detector measures a back EMF voltage across the coil, and a current detector detects a current I flowing through the coil. An IR voltage detector, responsive to the current I detected by the current detector, detects an IR voltage proportional to the current I times the VCM resistance R. A voltage compensator substantially cancels the IR voltage from the measured back EMF voltage to generate a compensated back EMF voltage. A control voltage generator, responsive the compensated back EMF voltage, generates a control voltage applied to the coil to generate the current I flowing through the coil. A stall detector compares the current I detected by the current detector to a threshold, wherein a VCM stall condition is detected if the current I exceeds the threshold for a predetermined interval.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.