Patent ID: 6526011
Filing Date: 2003-02-25
Classification: G11B

Abstract:
A control apparatus for controlling velocity of a spindle motor in an optical disk reproducing system, comprising:a widest signal detector for (i) detecting the widest pulse width of at least one of an eight-to-fourteen modulation (EFM) signal and an EFM-PLUS signal in response to a main clock signal and (ii) generating first status signals representing the status of the detected pulse width in response to a frame clock signal, said frame clock signal being divided by a first predetermined number j; a narrowest signal detector for generating second status signals representing the status of the narrowest pulse width of the first status signals in response to the frame clock signal, said frame clock signal being divided by a second predetermined number k, where k is greater than j; and an overrun controller for (i) performing one of up-counting, down-counting and holding a previously counted result, according to the frame clock signal divided by the second predetermined number and the second status signals, (ii) comparing the currently counted result with overrun upper limit and lower limit values, and (iii) generating first and second flag signals to brake the rotation of the spindle motor according to the compared result.