Disk drive

摘要

To provide a disk drive capable of inhibiting the occurrence of acoustic noise caused by a voltage pulse when the head is retracted using a speed control method using voltage obtained by rectifying a back electromotive force after the power source has been cut off from the rotation of a spindle motor. Retraction control circuit is used to control the on and off modes of transistors in accordance with the speed of VCM. The voltage across VCM becomes a voltage that can be regulated with VCM voltage control circuit. At this time, voltage is supplied to the terminals based on the voltage of ISO5V that is the rectified voltage of the back electromotive force of the spindle motor and the pulsating voltage is synchronized and produced at both terminals. As a result, the potential difference across VCM is such that the pulsating voltage is negated and acoustic noise is inhibited.

主权项

1. A spindle motor circuit comprising:
A. a power lead and a common lead; B. first, second, and third spindle motor coil leads and a fourth spindle motor common lead; C. a first drive circuit coupled between the power lead and the common lead, and having a first driver output coupled to the first spindle motor coil lead; D. a second drive circuit coupled between the power lead and the common lead, and having a second driver output coupled to the second spindle motor coil lead; E. a third drive circuit coupled between the power lead and the common lead, and having a third driver output coupled to the third spindle motor coil lead; and F. a damping circuit having four resistors and four switches, each resistor having one end and another end and the one ends of the four resistors being connected together:
i. a first switch selectively connecting the first spindle motor coil lead to the another end of a first resistor,ii. a second switch selectively connecting the second spindle motor coil lead to the another end of a second resistor,iii. a third switch selectively connecting the third spindle motor coil lead to the another end of a third resistor, andiv. a fourth switch selectively connecting the fourth spindle motor common lead to the another end of a fourth resistor.