| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent the erroneous control of a drive current in the switching of drive waveforms of a spindle motor. <P>SOLUTION: A drive current setting part 425 obtains an actual rotational speed from a rotational speed determination part. When the drive waveform is not changed, the drive current is determined by a feedbak system of a first gain. Drive current data that correspond to the drive waveform data are set in a register 401. When the drive waveform data are switched to curved waveforms in succeeding timing, processing by the feedback system is not performed, and drive current data that are the same as those in immediately preceding timing are set in the register 401. In the succeeding timing, the actual rotational speed is obtained from the rotational speed determination part, and the drive current is determined by a feedback system of a second gain. When the drive waveform data are switched, the processing by the feedback system is skipped once, whereby the erroneous control of the drive current in the switching of the drive waveforms can be prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
