Patent ID: 7609120

Claim:
A voltage-controlled oscillator (VCO) using an LC resonator comprising a first differential amplifier, a second differential amplifier, a LC resonator connected to output of the first and second differential amplifier and a current source which supplies current to the first and second differential amplifier and the LC resonator, the LC resonator comprising: a first resonance circuit in which two serially connected varactor diodes and an inductor are connected in parallel; a second resonance circuit in which one or more inductor L 1 and one or more capacitor C 1 are connected in parallel, the second resonance circuit being serially connected to a port of the first resonance circuit; and a third resonance circuit in which one or more inductor L 2 and one or more capacitor C 2 are connected in parallel, the third resonance circuit being serially connected to the other port of the first resonance circuit.