Patent ID: 7397318

Claim:
A voltage-controlled oscillator comprising: a voltage-controlled oscillation section which controls oscillation frequency through a voltage applied to a variable-capacitance element; a frequency control bias circuit which applies a frequency control bias to a first end of the variable-capacitance element; a temperature compensation bias circuit which applies a temperature compensation bias to a second end of the variable-capacitance element; and a temperature compensation bias generation circuit which generates the temperature compensation bias and supplies the temperature compensation bias generated to the temperature compensation bias circuit, the temperature compensation bias generation circuit having: a transistor having a collector or drain connected to the temperature compensation bias circuit, a base or a gate, and an emitter or a source; a first resistor having a first end connected to the collector or drain of the transistor and having a second end that is grounded; a second resistor having a first end connected to the base or gate of the transistor; a base or gate bias application terminal connected to the other end of the second resistor; a third resistor having a first end connected to the emitter or source of the transistor; and an emitter or source bias application terminal connected to the other end of the third resistor.