Method and apparatus for enabling a timing synchronization circuit

摘要

A timing control circuit includes a synchronization circuit and a detection circuit. The synchronization circuit includes a main delay line configured to receive an input clock signal and delay the input clock signal by a time interval to generate an output clock signal and a control circuit configured to control the main delay line to vary the time interval to synchronize the input clock signal with a feedback clock signal generated from the output clock signal responsive to assertion of an enable signal. The detection circuit is configured to receive the input clock signal and the feedback clock signal, detect a phase alignment error between the input clock signal and the feedback clock signal, and assert the enable signal responsive to the phase alignment error exceeding a predetermined amount. A method for synchronizing clock signals includes receiving an input clock signal; delaying the input signal by a time interval to generate an output clock signal; controlling the time interval to synchronize the input clock signal with a feedback clock signal generated from the output clock signal responsive to assertion of an enable signal; detecting a phase alignment error between the input clock signal and the feedback clock signal; and asserting the enable signal responsive to the phase alignment error exceeding a predetermined amount.