Patent ID: 7057841
Filing Date: 2006-06-06
Classification: G11B

Abstract:
1. A magnetic disk drive having an automatic head retract mechanism, comprising: a judgment circuit operable to judge whether a power supply voltage is below a predetermined level; a switch inserted in a connecting line between a coil of a motor for rotating a magnetic disk and a power terminal of an actuator for driving a magnetic head, and closed or opened depending on a voltage applied to a control terminal thereof; a step-up circuit inserted in a connecting line between the power terminal of the actuator and the control terminal of the switch, and operable to step-up a voltage of power supplied to the power terminal of the actuator, thereby obtaining a voltage to be applied to the control terminal of the switch; and a switch control unit operable to, when the judgment circuit judges that the power supply voltage is below the predetermined level, close the switch by applying the voltage obtained by the step-up circuit to the control terminal of the switch, to supply induced power generated in the motor to the power terminal of the actuator.