CLOCK GENERATION CIRCUIT AND SEMICONDUCTOR DEVICE PROVIDED THEREWITH

摘要

PROBLEM TO BE SOLVED: To solve a problem wherein malfunction of communication is generated by varying a frequency of a clock due to noise from outside in a case where there is no supplied signal in a circuit which makes negative feedback control so that the supplied signal and the feedback signal maintain a fixed phase relationship between the signals.

SOLUTION: The present invention includes a PLL circuit and an oscillator circuit, where a switch for switching an output between a signal from the PLL circuit and a signal from the oscillator circuit is provided to switch from a connection to the PLL circuit to a connection to the oscillator circuit in a case where there is no received signal.

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