| 摘要 |
PURPOSE:To prevent the damage of a head, by stopping a drive current to a voice coil motor when it is detected that the drive current of the carriage is abnormally large at disc start so as to increase much data recording area. CONSTITUTION:A reference voltage VS is set to a terminal 30. A voltage drop of a resistor RE is extracted from a signal line 28 as a signal VG to be discriminated and the signals VG and VS are compared at a voltage comparison circuit 31. The circuit 31 outputs an abnormal detecting signal DT of 0 level when the signal VG is higher than the signal VS. At the disc start, an FF32 is set to 0, an output of an NOR gate 33 goes to 1, a transistor 34 is turned on, a drive current flows to an exciting coil 35c of a relay 35, a normally closed contact 35s is opened and a voice coil motor drive current applied to a drive circuit is shut. |
