DLL CIRCUIT AND METHOD OF CONTROLLING THE SAME

摘要

A DLL(Delay Locked Loop) circuit and a control method for producing a clock having the improved duty ratio property are provided to complete delay locking operation by setting up the delay control code according to the phase of the feedback clock. A first delay controlling measure(140) controls the unit delay of the first delay line(110) in response to the first phase sensing signal. A second delay controlling signal is controlled in response to the second phase sensing signal and the second delay controlling measure on the unit delay of the second delay line. The second delay controlling measure again controls the unit delay of the second delay line in response to the first delay controlling signal and half period information signal. A half period sensing unit produces the half period information signal of the reference clock based on the first unit delay information signal and the second unit delay information signal.