Delay locked loop clock generator

Abstract

A delay locked loop (DLL) clock generator circuit is provided for generating a clock signal Clk according to a pair of input signals to the circuit. One of the input signals is a reference signal, and the second input signal is a feedback signal of a voltage controlled delay line circuit. The DLL circuit includes a phase detector that can be reset to expand the locking range for detecting a phase difference between the reference signal and the feedback signal. Based on the detected phase difference, the phase detector provides an output signal that is further processed by the DLL circuit to generate a number of delayed signals to a frequency multiplier. Using the delayed signals, the frequency multiplier generates a frequency multiplied clock signal having a frequency that is a multiple of the frequency of the reference signal.