SPINDLE MOTOR CONTROL DEVICE AND CONTROL METHOD THEREOF

• Main Authors: SUMIDA KATSUTOSHI, TESHIROGI KAZUHIRO, SHIMIZU MASANOBU
• Format: Patent
• Language: English
• Published: 24.11.1998
• Edition: 6
• Subjects: INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; PHYSICS

PROBLEM TO BE SOLVED: To maintain a speed capable of reproducing data from a disk without a rotational runaway in the spindle motor control device even in such a case that a reproducing data for controlling a linear speed to be constant cannot be obtained. SOLUTION: When it is confirmed by a clock period monitoring circuit 9 that a period of a clock component of the reproducing data falls within a prescribed range, a period of an FG signal of a frequency generating circuit 14 is detected by a period detecting circuit 15, and its average value obtained by an average value circuit 16 in each time of a fixed period is stored in a storage circuit 17. When no clock is obtained from the reproducing data, a switch 7 is changed from an output of a linear speed constant control circuit 6 over to an output of a constant rotating speed control circuit 20 in receipt of an output of the storage circuit 17 by the clock period monitoring circuit 9, so that the spindle motor 8 is controlled at a constant rotating speed to maintain the speed capable of recording and reproducing data.