Patent ID: 7619849
Filing Date: 2009-11-17
Classification: G11B

Abstract:
1. A magnetic disk drive including: a magnetic disk; a magnetic head adapted to access a target track formed on the magnetic disk to write or read information; a voice coil motor adapted to produce a drive force applied to the magnetic head; and a control circuit adapted to control a drive power supplied to the voice coil motor so as to bring the travel speed of the magnetic head close to a predetermined target speed during a seek operation adapted to move the magnetic head over the target track; wherein the control circuit determines a provisional current or voltage in accordance with the difference between the predetermined target speed and the actual travel speed in an acceleration zone adapted to accelerate the magnetic head to the predetermined target speed, and wherein if the provisional current or voltage exceeds a limit that is sequentially calculated and increases as an elapsed time from the start of acceleration increases, the control circuit sets the limit as a current or voltage of a drive power supplied to the voice coil motor to control the motor; wherein if the limit exceeds the provisional current or voltage, the control circuit sets the provisional current or voltage as the current or voltage of the drive power supplied to the voice coil motor to control the motor.