Patent ID: 6972539
Filing Date: 2005-12-06
Classification: G11B,Y10S

Abstract:
1. A disk drive comprising: (a) a disk; (b) a head actuated over the disk; (c) a spindle motor for generating a torque output to rotate the disk, the spindle motor comprising a plurality of windings; (d) a power driver comprising a plurality of commutation switches for selectively energizing the windings; (e) a commutation sequencer for controlling the commutation switches to configure the windings into a plurality of commutation states over a plurality of commutation intervals; (f) a phase modulator for phase modulating the commutation intervals; and (g) a current modulator for controlling a current applied to the windings in each of the commutation states to substantially reduce discontinuities in the torque output of the spindle motor caused by the phase modulator.