To avoid loss of control when there is no FG pulse generation circuit or an FG pulse generation circuit gets out of order.
A motor control unit 102 controls and regulates the linear velocity of a disc motor 403 using an FG pulse signal. Using the inputted FG pulse signal, a microcomputer 105 computes the number of revolutions, and compares the result of computation with a target number of revolutions stored in a storage device 103 to determine the presence or absence of an FG pulse generation circuit 404. If there is no FG pulse generation circuit 404, the microcomputer does not carry out constant angular velocity control. Thus, when there is no FG pulse generation circuit 404 or an FG pulse generation circuit 404 is out of order, constant angular velocity control is not carried out. Therefore, the disc motor is prevented from being damaged.
| JPH06309856 | COMPACT DISK DEVICE |
| JPS5693160 | CHECKING SYSTEM OF MAGNETIC DISK DEVICE |
AKIYAMA KAZUO
MINAGAWA MASANORI
Hironori Honda
Toshimitsu Ichikawa
Takeshi Takamatsu
Yuriko Hamada
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