A disk drive is disclosed comprising a pulse width modulated (PWM) signal generator
for generating PWM control signals applied to the driver switches of a voice coil
motor (VCM). The PWM control signals comprise a PWM cycle time, a Tforward time
interval of the PWM cycle time wherein a positive control voltage is applied to
the VCM, a Treverse time interval of the PWM cycle time wherein a negative control
voltage is applied to the VCM, and a Tdead time interval of the PWM cycle time
wherein a substantially zero control voltage is applied to the VCM. The Tdead time
interval is adjusted to control a magnitude of an actual ripple current flowing
through the VCM.