Phase-locked loop circuit
AssigneeRenesas Electronics Corporation
InventorYoshitaka Hirai
Life of this patent
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Abstract
A first exemplary aspect of an embodiment of the present invention is a phase-locked loop circuit including: a voltage-current converter that converts a control voltage into a control current, the control voltage generated according to a phase difference between an input pulse signal and a feedback pulse signal fed back from an output side of a current controlled oscillator; the current controlled oscillator that generates an output pulse signal having a frequency according to the control current; a current detection unit that detects the control current; and a frequency range switch that switches a frequency range of the output pulse signal according to the detected control current.
Claims9
A phase-locked loop circuit comprising:
- a voltage-current converter that converts a control voltage into a control current, the control voltage generated according to a phase difference between an input pulse signal and a feedback pulse signal fed back from an output side of a current controlled oscillator;
- the current controlled oscillator that generates an output pulse signal having a frequency according to the control current;
- a current detection unit that detects the control current;
- a frequency range switch that switches a frequency range of the output pulse signal according to the detected control current;
- and
- a lock detection circuit that detects a lock state in which the output pulse signal is locked to the input pulse signal,
- wherein the frequency range switch switches the frequency range of the output pulse signal according to the detected control current and a detection result of the detection circuit.
A phase-locked loop circuit comprising:
- a voltage-current converter that converts a control voltage into a control current, the control voltage generated according to a phase difference between an input pulse signal and a feedback pulse signal fed back from an output side of a current controlled oscillator;
- the current controlled oscillator that generates an output pulse signal having a frequency according to the control current;
- a current detection unit that detects the control current;
- and
- a frequency range switch that switches a frequency range of the output pulse signal according to the detected control current,
- wherein the frequency range switch comprises one or a plurality of capacitors, each of the capacitors connected to an inverter in the current controlled oscillator through a switch.
Dependencies are inferred from the claim text.