Device and method for detecting phase difference and PLL using the same

摘要

A phase detector includes a first control unit and a second control unit to generate a first control pulse and a second control pulse representative of a phase difference between a reference signal and a first clock signal. The first control unit receives the reference signal and the first clock signal and generates the first control pulse. The first control pulse has a first pulse width that varies depending on the phase difference between the reference signal and the first clock signal. The second control unit receives the reference signal and a second clock signal and generates the second control pulse such that the second control pulse substantially overlaps the first control pulse and has a second pulse width that is a preset value. The second clock signal has a frequency higher than that of the first clock signal.