Semiconductor device including delay locked loop having periodically activated replica path

摘要

A delay locked loop adapted to delay an external clock signal and to output an internal clock signal, the delay locked loop including a renewal signal generator that outputs a renewal signal that is selectively activated and inactivated, a replica path that is active when the renewal signal is activated and is inactive when the renewal signal is inactivated, the replica path delaying the internal clock signal by a delay time of a normal path of a semiconductor device to output a replica internal clock signal when the renewal signal is activated, a control signal generator adapted to vary and to output a delay control signal according to a phase difference between the external and the replica internal clock signals, and a variable delay circuit adapted to delay the external clock signal by a time corresponding to the delay control signal and to output the internal clock signal.