Patent ID: 7289288

Claim:
A method for operating a disk drive, the disk drive comprising a disk, a head actuated over the disk, a spindle motor for rotating the disk at an operating speed in response to a spindle control current and having a plurality of windings which generate a back electromotive force (BEMF) voltage, and a BEMF detector for generating a BEMF signal based on the BEMF voltage, wherein the disk has a plurality of tracks, each track including a plurality of data sectors and a plurality of servo wedges, the method comprising the steps of: maintaining the disk at the operating speed during a track following operation by updating, in a wedge spindle speed control mode, the spindle control current in response to a wedge speed error determined based on a wedge-to-wedge time between the servo wedges; switching to a BEMF spindle speed control mode before executing a high-speed seek; maintaining the disk at the operating speed by updating the spindle control current in response to a BEMF speed error generated based on the BEMF signal during the high-speed seek; and switching back to the wedge spindle speed control mode during a seek settle time.