Method and apparatus to control a step motor of an optical disk driving system

An apparatus to control a step motor in an optical disk driving system to move a sled which transfers a pickup unit, including a playing unit, a coarse search unit, and a driving unit. The playing unit generates a first step pulse at a first interval of time set by a disk speed according to a comparison between a sled control signal and a tracking driving signal in a playing mode with a predetermined threshold. The coarse search unit generates a second step pulse at a second interval of time stored in a table according to a number of motion steps and a motion direction corresponding to an amount of motion of the pickup unit due to operations in a search mode. The driving unit drives the step motor based on the first and second step pulses.