Disk drive employing power source modulation for reducing power consumption

A disk drive comprising:

• a disk including a recording surface having a plurality of data tracks, each data track having servo sectors and data regions disposed between the servo sectors, the servo sectors including servo information;
• transducer means for writing and reading from the data regions and reading servo information from the servo sectors;
• a spindle motor having a plurality of windings, the spindle motor coupled to the disk to rotate the disk;
• a spindle motor driver having switching elements coupled to the plurality of windings for selectively providing current to the spindle motor;
• track-following control means being responsive to the servo information for causing the transducer means to remain on track;
• and
• programmable means for performing a power-saving idle operation of causing the spindle motor driver to sequentially (1) turn off all of the switching elements so that no current is provided to the spindle motor and (2) turn on selected ones of the switching elements to provide current to the spindle motor, the power-saving idle operation being performed while the track-following control means causes the transducer means to remain on track for multiple disk revolutions.