| 摘要 |
PURPOSE:To attain the setting of a comparatively fast object speed while preventing malfunction of movement of a head because of the fluctuation in a power suply voltage by controlling an object speed converting gain to a prescribed value in response to rise or drop of the power supply voltage. CONSTITUTION:When a power supply voltage 4 of a power applied to an actuator moving the head rises, the potential rise at a node 20 whose potential is equal to a potential of a reference power supply 13 when the voltage is normal is suppressed by a diode 16 and a reference current flowing to a gain setting terminal 15 of an object speed converter 2 is constant. On the other hand, when the voltage V falls down, the voltage at the node 20 is also dripped in proportion thereto and the reference curent flowing to the terminal 15 is dropped. Thus, the reduction in the force of the actuator is coped with at deceleration by reducing an object speed signal at the drop in the power supply voltage and the rise in the transient moving speed is prevented at the voltage rises. As a result, an error of head movement due to the fluctuation in the power supply voltage is prevented and the comparatively fast object speed is set. |
