摘要 |
A clock circuit for supplying an output clock signal to a logic circuit, includes a phase difference-to-voltage converter producing a voltage signal corresponding to a phase difference between a basic clock signal and a feedback clock signal, a voltage-controlled phase controller controlled by the voltage signal from the phase difference-to-voltage converter and outputting a first clock signal, a clock supply circuit receiving the first clock signal, and supplying a second clock signal, as the output clock signal, through to the logic: circuit, a dummy clock circuit having a dummy capacitance circuit, receiving the first clock signal, and outputting a third clock signal, and a selector selectively supplying the phase difference-to-voltage converter, with a selected one of the output of the clock supply circuit and the output of the dummy clock circuit, as the feedback clock signal.
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