Apparatus and method for controlling velocity of spindle motor in optical disk reproducing system
US6526011B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 20, 2000 |
| Grant date | Feb 25, 2003 |
| Priority date | — |
| Expiry date | Apr 20, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/005
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A control apparatus and method for controlling a velocity of a spindle motor included in an optical disk reproducing system to prevent a forward or backward overrun of a spindle motor are disclosed. A widest signal detector of the apparatus detects the widest pulse width of an eight-to-fourteen modulation (EFM) signal according to a main clock signal and generates a first status signal representing a status of the pulse width of the detected signal according to a frame clock signal, which is divided by a first predetermined number j. A narrowest signal detector of the apparatus generates a second status signal representing a status of the narrowest pulse width of the first status signals according to the frame clock signal divided by a second predetermined number k, where k is greater than j. An overrun controller increases or decreases or holds a previously counted result according to the frame clock signal divided by the second predetermined number and the second status signal. The overrun controller compares the currently counted result with overrun upper limit and lower limit values and generates first and second flag signals braking the rotation of the spindle motor according …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.