Patent ID: 6078200
Filing Date: 2000-06-20
Classification: G06F,H03L

Abstract:
A clock signal generator comprising:a phase shifter for receiving an external clock signal having a first clock period to output at least three first clock signals having said first period and phases shifted consecutively from one another, said phase shifter being connected to and outputting said first clock signal to a mixer;said mixer for selecting two of said first clock signals, for mixing the selected two of said first signals based on mixing control signals received from a mixing ratio controller, and to output an internal clock signal;a phase comparator connected to said mixer and receiving said internal clock signal therefrom, for comparing said internal clock signal against said external clock signal to output a comparison signal representing a phase difference between said external clock signal and said internal clock signal and also representing whether said external clock signal leads or lags said internal clock signals;said mixing ratio controller connected to said phase comparator and said mixer, receiving said comparison signal from said phase comparator representing said phase difference, generating said mixing control signal based on said phase difference and outputting said mixing control signals to said mixer; andan initializing circuit connected to said phase comparator, said mixing ratio controller, and said mixer receiving said comparison signal from said phase comparator, and outputting signals to said mixing ratio controller and said mixer for controlling said mixer to select one of said first clock signals as an initial internal clock signal during an initialization period so as to determine which two of said first clock signals are to be selected in said mixer thereafter.