Disk drive comprising spin down circuitry having a power clamp circuit for enhancing power and braking control
US6549361B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 19, 2000 |
| Grant date | Apr 15, 2003 |
| Priority date | — |
| Expiry date | Apr 19, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/54
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A disk drive is disclosed comprising a disk, a head actuated radially over the disk, 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 from the BEMF during a spin down mode, the internal supply voltage for parking the head. A signal generator generates a periodic signal, the periodic signal for periodically grounding the windings during the spin down mode in order to boost the internal supply voltage, wherein grounding the windings applies a braking torque to the spindle motor. A power clamp circuit clamps the internal supply voltage to a predetermined level to protect against an over-voltage condition without disabling the braking torque applied to the spindle motor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.