| 摘要 |
A semiconductor IC(Integrated Circuit) and a controlling method thereof are provided to control updating of a DLL(Delay Locked Loop) circuit according to a change of an outer clock in a power-down mode, thereby obtaining operational stability of an internal circuit. A DLL controller(100) controls activation of a DLL block(200) in a power-down mode according to a change of an outer clock. The DLL block provides comparison results between a feedback clock and a reference clock to the DLL controller. The DLL block produces a delay fixed clock periodically updated in response to the reference clock. The DLL block comprises a phase comparator and a shift register. The phase comparator receives the reference clock and the feedback clock, and generates a shift control signal and a clock period shift sensing signal.
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