DLL CIRCUIT, UPDATE CONTROL APPARATUS IN DLL CIRCUIT AND UPDATE METHOD OF DLL CIRCUIT

摘要

A delay locked loop (DLL) circuit includes a phase detection unit configured to generate a phase detection signal by comparing a phase of a reference clock signal with a phase of a feedback clock signal. An update control apparatus is configured to generate a valid interval signal and an update control signal by determining a difference between the number of first logical values and the number of second logical values of the phase detection signal in response to the reference clock signal. A shift register configured to update a delay value granted to a delay line in response to the update control signal when the valid interval signal is enabled.