| 摘要 |
PURPOSE:To reduce a load on a power source by rotating a DC motor for disk driving, and then driving a stepping motor for head positioning after the rotational frequency of the DC motor increases above a prescribed value. CONSTITUTION:The rotational frequency of a DC motor for disk driving is detected by detecting a clock signal written on a disk by a clock head 1 and inputted to a synchronizing circuit 4 through a pulse generating circuit 3. Its output is supplied to a monostable circuit 5, which outputs a ''1'' successively to the reset terminal of a counter 6 when the frequency of a pulse signal increases above a prescribed value, and consequently a switching element 9 is turned on to energize the energizing winding 10 of a stepping motor as a head positioning mechanism. Therefore, both the motors are never actuated at the same time, and a maximum current from a power source is suppressed. |
