| 摘要 |
PURPOSE:To ensure turning stop operation by inputting a reset signal inputted to an on/off control terminal of a differential amplifier circuit while retarding it for a time from the input of a turning stop signal inputted from an external operation key until a detection signal produced in a pickup device is lost. CONSTITUTION:When a turning stop signal is inputted from external operation keys 4a,... to keep an on/off control terminal A at the H level, a voltage bring ing a spindle motor 1 to the prescribed number of revolutions is inputted to a revolution number control voltage input terminal B while being switched into O[V], then a negative DC voltage is produced at an output terminal C to provide a reverse a reverse torque to the spindle motor 1. The moment the rotation speed of the spindle motor 1 reaches zero, the level of detected reproducing signal of the pickup device is zero, it is detected by a no signal detection circuit 8 to input the output signal to the on/off control terminal A. The level of the terminal A changes from H to L level by the reset signal and the output voltage of the output terminal C goes to O[V]. Thus, the rota tion speed of the spindle motor 1 reaches zero and the rotation is stopped while keeping the said state. |
