Fractional n-pll circuit, oscillator, electronic device, and moving object
AssigneeSeiko Epson Corporation
InventorNobutaka SHIOZAKI
Life of this patent
Estimating the term…
Abstract
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.
Claims19
A fractional N-PLL circuit comprising:
- a voltage controlled oscillator that is configured to set a plurality of output frequency ranges with respect to a control voltage range;
- a frequency selection circuit that searches for the plurality of output frequency ranges of the voltage controlled oscillator to select one output frequency range;
- a division circuit that is provided on a signal path from an output end of the voltage controlled oscillator to an input end of the voltage controlled oscillator;
- and
- a division setting circuit that performs delta-sigma modulation to set a division ratio of the division circuit,
- wherein the division setting circuit performs, while the frequency selection circuit is searching for the plurality of output frequency ranges, the delta-sigma modulation at a frequency lower than a frequency after the frequency selection circuit terminates the search.
Dependencies are inferred from the claim text.