Fractional N-PLL circuit, oscillator, electronic device, and moving object

摘要

In order to appropriately set an operation range of a voltage controlled oscillator without excessively increasing a frequency at which delta-sigma modulation is performed, a fractional N-PLL circuit includes: a voltage controlled oscillator that is configured to set plural output frequency ranges; a frequency selection circuit that selects one output frequency range; a division circuit; and a division setting circuit that sets a division ratio of the division circuit. The division setting circuit performs, while the frequency selection circuit is searching for the plural output frequency ranges of the voltage controlled oscillator, the delta-sigma modulation at a frequency lower than a frequency after the frequency selection circuit terminates the search.