Patent ID: 6965488

Claim:
A disk drive comprising: (a) a disk; (b) a head; (c) a voice coil motor (VCM) for actuating the head radially over the disk, the VCM comprising a voice coil; (d) a plurality of driver switches for controlling a voltage applied to the voice coil; and (e) a pulse width modulated (PWM) signal generator for generating PWM control signals applied to the driver switches, the PWM control signals comprising: a PWM cycle time; a Tforward time interval of the PWM cycle time wherein a positive control voltage is applied to the voice coil; a Treverse time interval of the PWM cycle time wherein a negative control voltage is applied to the voice coil; and a Tdead time interval of the PWM cycle time wherein a substantially zero control voltage is applied to the voice coil, wherein the Tdead time interval is adjusted to control a magnitude of an actual ripple current flowing through the voice coil.