| abstract |
A delay-locked loop (DLL) which receives a reference clock signal and outputs an output clock signal is provided. The DLL includes a phase detector, a delay chain, an anti-false lock (AFL) circuit, and a loop filter. The phase detector outputs a first comparison signal according to a phase comparison between the reference clock signal and the output clock signal. The delay chain generates a plurality of strobe clock signals and the output clock signal by delaying the reference clock signal for different intervals. The AFL circuit outputs a second comparison signal according to a phase comparison between the reference clock signal and the strobe clock signals. The loop filter controls the delay time of the output clock signal according to the first and the second comparison signals in order to lock the delay time of the output clock signal at a preset value. |