| 摘要 |
PURPOSE:To safely and surely perform head loading and prevent accident by changing the number of revolutions of a spindle motor stepwise during the time until it is increased to the final steady number of revolutions in a magnetic disc. CONSTITUTION:The number of revolutions of a spindle motor 1 is detected in a circuit 2 and is compared 3 with the reference signal from a circuit 4, the result whereof is sent to a motor drive control circuit 5. According to the input of low-high speed switching signal HLS, the circuit 4 outputs the signal corresponding to the number of revolutions f1 up to the time t3 when the low speed region control ends from the power source input time to and outputs the signal corresponding to the number of revolutions f2 after the time t3. Further, according to the changeover of the signal HLS, the circuit 6 supplies the current i2 to the drive switching circuit 7 up to the time t3 and does so after increasing the same to the current i1 after said time. This results in that the motor 1 receives two stages of changes B in the number of revolutions until it attains the steady number of revolutions. |
