Digital Servo IC for Optical Disc Drives

This paper addresses the use of PID regulators to achieve some of the main control goals in an optical disc drive: (i) focusing of the laser spot on the disc surface, (ii) tracking the continuous data spiral during playback, and (iii) radially searching the target location on disc during an access procedure. The servo loops employed to perform the control tasks mentioned above will be described and a dedicated PID-based digital servo integrated circuit (DSIC) will also be introduced.