Patent ID: 6765746
Filing Date: 2004-07-20
Classification: G11B

Abstract:
A method of supplying, upon power-off of a power supply for a disk drive, a current to a voice coil motor to drive a head actuator that supports a head, thereby retracting the head onto a ramp provided outside a disk medium near an outer periphery of the disk medium, comprising:determining, during operation of the disk drive, a retract time period required to move the head from a position of the head to a predetermined retract change position, using a back electromotive force that occurs, upon the power-off of the power supply, in a spindle motor used to rotate the disk medium; supplying the voice coil motor with a current generated by the back electromotive force of the spindle motor for the retract time period after the power-off of the power supply, thereby moving the head toward the retract change position; and supplying, when the retract time period has elapsed after the power-off of the power supply, the voice coil motor with a current generated by discharge of a retract capacitor that accumulates a charge from the power supply, thereby moving the head onto the ramp.