Patent ID: 6759886
Filing Date: 2004-07-06
Classification: G06F,H03K

Abstract:
A clock generating circuit generating a plurality of clock signals having different frequencies, comprising:a plurality of stages of frequency-dividing circuits connected in series, each of said plurality of stages outputting a respective clock signal to be coupled to a respective buffer circuit for operation at a corresponding clock freguency, a phase control circuit having a first input receiving a reference clock signal and a second input receiving the clock signal output by a last of said plurality of stages as a feedback clock signal, and said phase control circuit outputting an output clock signal to a first of said plurality of stages, wherein the output clock signal of the phase control circuit coincides in phase with both the feedback clock signal and the reference clock signal, wherein each of said frequency-dividing circuits includes a plurality of stages of flip-flops connected in series, wherein an input terminal of a first stage of the flip-flops receives a first potential, each flip-flop capturing a potential at its input terminal in a period during which an input clock signal of said each frequency-dividing circuit is at a second potential, outputting the captured potential in response to a change of the input clock signal of said each frequency-dividing circuit from the second potential to the first potential, and being reset in response to an output of the first potential from a last stage of said plurality of stages of flip-flops, to output the second potential, and an output clock signal of a predetermined flip-flop of said plurality of flip-flops is an output clock signal of said each frequency-dividing circuit.