Patent ID: 7885353

Claim:
A spread spectrum clock control apparatus for exercising control to supply a phase control signal to a phase interpolator that receives an input clock signal and varies the phase of an output clock signal thereof in accordance with the phase control signal, and to frequency-modulate the output clock signal of said phase interpolator, said apparatus comprising; a counter that receives the input clock signal and counts the input clock signal; a circuit that generates the phase control signal based upon result of the count; and a counting operation control circuit that receives a control signal, which is for turning an SSC (Spread Spectrum Clock) function ON and OFF, and exercises control so as to enable the counting operation by the counter if the control signal indicates SSC-function ON, and disable the counting operation of the counter at the moment a count value in the counter reaches a predetermined value when the control signal has become a value indicating SSC-function OFF, wherein said counting operation control circuit performs control for halting supply of the clock signal to the counter at the moment the count value in the counter reaches a predetermined value when the control signal has become the value indicating SSC-function OFF.