Magnetic disk drive

摘要

A magnetic disk drive drives a switch and supplies induced power of a motor to an actuator to retract a magnetic head, if a power supply voltage is judged as being below a predetermined level. The switch is driven using an output voltage of a step-up circuit. The step-up circuit operates from before the power supply voltage drops below the predetermined level, so that the switch can be driven immediately. This makes it possible to efficiently supply the induced power to the actuator.