Patent ID: 7564320

Claim:
A voltage-controlled oscillator (VCO), comprising: an oscillation unit, having an inductor, for generating an oscillation signal according to a biasing current; a current mirror, for providing the biasing current, the current mirror comprising: at least one first transistor, coupled between a first voltage level and a current source; at least one second transistor, coupled to the first voltage level, a gate of the second transistor is coupled to a gate of the first transistor and the current source; a switch module, coupled to the current mirror; and a control module, coupled to the switch module, for controlling the switch module to adjust the biasing current; wherein the biasing current provided into the oscillation unit is flowing from the inductor; and wherein the current mirror comprises a plurality of the second transistors, the switch comprises a plurality of switches, the switches are coupled between the plurality of the second transistors and the oscillation unit, and the control module controls on/off state of each of the switches to adjust the biasing current.