Power off velocity control for disk drives
US6140784A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 9, 1999 |
| Grant date | Oct 31, 2000 |
| Priority date | — |
| Expiry date | Jun 9, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/54
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and circuit for controlling a voice coil motor (VCM) for a disk drive actuator assembly such that the actuator assembly moves to a landing area at a constant velocity when the disk drive loses power. The circuit includes a sense amplifier for sensing and amplifying current to the VCM, a current integrator for determining the actual velocity of the actuator assembly during every seek, an H-bridge driver, which controls the direction of current to the VCM and magnitude of voltage across the VCM and a window compare and logic block that receives and sorts information from the integrator, and a timer. The window compare and logic block determines the direction of current and magnitude of voltage to apply to the VCM. During a loss of power, e.g. a power down or sudden loss of power, the actuator assembly is controlled through a sequence of movements, depending on the position and actual velocity of the actuator assembly/transducer head at the moment power was lost, to ensure that the transducer head is retracted to the landing area at a constant velocity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.