Disk drive utilizing bemf of spindle motor to increase vcm voltage

Abstract

A disk drive is connectable to a power supply having a fixed DC voltage. The disk drive includes a voice coil motor (VCM) and a spindle motor having a plurality of windings and a rotor rotatable at a variable spin-rate. A spindle motor driver is coupled to the fixed DC voltage and at least one of the windings for controlling the spin-rate of the rotor. The rotor has permanent magnets that induce an AC voltage across the windings while the rotor is rotating. A rectifier circuit rectifies the AC voltage across at least one of the windings to produce a rectified DC voltage. A first switch provides the rectified DC voltage to a first node. A second switch provides the fixed DC voltage to the first node. The first node has a first node DC voltage that is determined by the rectified DC voltage provided by the first switch and the fixed DC voltage provided by the second switch. The first node DC voltage is greater than the fixed DC voltage during a track seeking operation in the disk drive. A VCM driver includes switching elements that selectively provide the first node DC voltage to the VCM. The increased VCM voltage allows faster access times and more efficient VCM operation.