A enhanced DLL includes a delay chain, a phase detector and a delay control unit. The delay chain is arranged to delay a reference clock signal to generate a delayed reference clock signal and reflect the delay control setting on the delayed reference clock signal, wherein the delay chain is periodically reset according to a period of the reference clock signal. The phase detector is coupled to the delay chain, and arranged to detect a phase shift between the delayed reference clock signal and the reference clock signal, thereby to generate a control value. The delay control unit is coupled to the delay chain and the phase detector, and arranged to adjust the delay control setting based on the control value.