First delay locking method, delay-locked loop, and semiconductor memory device including the same

Abstract

According to one embodiment, a method of performing fast locking in a delay locked loop circuit is disclosed. The method includes performing a first comparison comparing an input clock signal to a first feedback clock signal that is a non-inverted feedback clock signal, and performing a second comparison comparing the input clock signal to a second feedback clock signal that is the feedback clock signal inverted. The method also includes, based on the first and second comparisons, selecting one of the non-inverted feedback clock signal or the inverted feedback clock signal to synchronize with the input clock signal. In addition, the method includes synchronizing the selected clock signal with the input clock signal.