Patent ID: 7800455

Claim:
A phase-locked loop circuit comprising: a voltage-controlled oscillator comprising; an oscillator circuit comprising a first transistor and a second transistor, and a current source comprising a first current path and a second current path for supplying a current controlled by a voltage input to the current source, to the oscillator circuit through the first and second current paths, wherein the second current path comprises a third transistor and a fourth transistor; wherein one of a source and a drain of the second transistor is electrically connected to one of a source and a drain of the first transistor; wherein a gate of the first transistor is electrically connected to a gate of the second transistor; wherein the other of the source and the drain of the first transistor is electrically connected to one of a source and a drain of the third transistor; wherein the other of the source and the drain of the third transistor is electrically connected to a third power supply line; wherein the other of the source and the drain of the second transistor is electrically connected to one of a source and a drain of the fourth transistor; wherein the other of the source and the drain of the fourth transistor is electrically connected to a first power supply line; wherein a gate of the fourth transistor is electrically connected to a second power supply line; and wherein a gate of the third transistor is electrically connected to the other of the source and the drain of the second transistor and the one of the source and the drain of the fourth transistor.