Controlling system for optical storage apparatus using pulse width modulator

An optical storage apparatus for confirming that an optical head for reading data on an optical storage medium reaches a predetermined position, said optical storage device comprising:

• a stopper provided in the predetermined position;
• moving means for moving said optical head in such a direction as to traverse a track on said optical storage medium;
• a drive circuit for driving said moving means;
• a comparing circuit for comparing a value of current flowing across said drive circuit with a current indicating value;
• a pulse width modulation circuit for modulating a width of the drive pulse given to said drive circuit in accordance with a control signal;
• a switch circuit for switching an input of the control signal to said pulse width modulation circuit over to an output of said comparing circuit and a drive signal;
• and
• a control circuit for switch-controlling said switch circuit, giving the drive signal by which said pulse width modulation circuit outputs the drive pulse having a fixed pulse width, monitoring the value of current flowing across said drive circuit, and confirming that said optical head impinges upon said stopper and stops by monitoring the value of current.