| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a spread spectrum clock generating circuit with a simple configuration by which excellent spread spectrum can be attained. <P>SOLUTION: In the spread spectrum clock generating circuit provided with: a frequency phase comparator for detecting a phase difference between a reference clock CLK and a generated clock CK; a charge pump 13 for generating a charging/discharging signal in response to the detected phase difference; a loop filter 14 for generating a difference signal in response to the charging/discharging signal; a spread spectrum modulation circuit 19 for modulating the difference signal to generate a spread spectrum modulation signal; and a clock generator 20 for generating the clock CK with a frequency in response to the spread spectrum signal, the spread spectrum modulation circuit 19 generates the spread spectrum modulation signal whose period is changed into a plurality of different periods. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
