Disk drive comprising a demand limit circuit for enhancing power management during spin down
US6574062B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 19, 2000 |
| Grant date | Jun 3, 2003 |
| Priority date | — |
| Expiry date | Apr 19, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B19/20
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A disk drive is disclosed comprising a disk, a head, a voice coil motor (VCM) for actuating the head radially over the disk (the VCM having a voltage control input), and a spindle motor for rotating the disk, the spindle motor comprising a plurality of windings and a rotor rotatable at a variable spin rate wherein the rotor generates a back EMF (BEMF) voltage across the windings proportional to the spin rate of the rotor. A plurality of switching elements are coupled to the windings, and switch control logic generates switch control signals applied to the switching elements for commutating the spindle motor during normal operation and for generating an internal supply voltage Vi from the BEMF during a spin down mode, the internal supply voltage Vi applied to the voltage control input of the VCM for parking the head. A demand limit circuit disconnects the internal supply voltage Vi from the voltage control input of the VCM when the internal supply voltage Vi falls below a predetermined level, and reconnects the internal supply voltage Vi to the voltage control input of the VCM once the internal supply voltage Vi recharges to a predetermined level, thereby enhancing power management …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.