| 摘要 |
<p>PURPOSE:To always realize predetermined servo characteristic irrespective of variation in the output voltage of a battery by generating a PWM signal corresponding to the output voltage of the battery. CONSTITUTION:A control circuit 2 calculates a synchronizing signal output from a synchronizing signal generator 3, an FG signal output corresponding to the rotation of a spindle motor 5, a speed error signal and a phase error signal based on the PG pulse. A speed error signal and a phase error signal are respectively multiplied by a speed addition gain and a phase addition gain, added, and a PWM signal responsive to the added error signal is supplied to a spindle motor driving circuit 4. Here, the coefficients of the speed and phase addition gains are set in response to the output voltage of a battery 10. Thus, predetermined servo characteristic can be always realized irrespective of the variation in the voltage of the battery.</p> |
