Optical disk motor servo and method for closed loop speed control
US5870363A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 25, 1996 |
| Grant date | Feb 9, 1999 |
| Priority date | — |
| Expiry date | Oct 25, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B19/26
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical disk drive in which changes in rotational speed are achieved under closed loop control, avoiding significant undershoots or overshoots in speed, increasing access time and reducing power. The speed control is suitable for use in a CLV system, in an CAV/CLV scheme, or in any system in which the speed of the disk must be changed at various times. Feedback from the motor, rather than data read from the disk, determines and controls motor speed during all search operations. The disk motor servo determines the desired motor speed for a target track through a speed profile table. The speed profile table can be designed to accommodate a combination of CAV mode and CLV mode of operation such that the disk drive system can run at the maximum data transfer rate permitted by the data processing electronics, or to minimize power consumption. Through closed loop control, the system ensures that the speed of the motor is quickly and accurately changed to the desired speed, typically by the time the optical pickup reaches a target track during a search operation. The closed loop control also allows the disk drive system to be designed for a lower tolerance level and still achieve jitte…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.