| 摘要 |
PURPOSE:To move a magnetic head surely to a prescribed CSS area by detecting a level of a main power supply voltage and applying a current of a fixed direction to a voice coil with a residual power supply voltage when the main power supply voltage is lowered at a fixed level or below from the result of detection. CONSTITUTION:When the main power supply voltage VC is decreased to a fixed level or below and the operation of a magnetic disc device comes to a stop, a Zener diode 31 of a main power supply detection circuit 30 is turned off and a transistor (TR)32 is turned off. If the power supply voltage VC is decreased to a fixed level or below, residual power supply voltages VB+, VB- are generated from a generating circuit. When the level of the main power supply voltage VC is lowered and the operation of the magnetic disc device comes to a stop, a retract current IR in response to the residual power supply voltage is fed to the voice coil 20. In adjusting the direction of the retract current IR and its current value V to the voice coil 20 in advance, the magnetic head is moved to the CSS area on a disc face. |
