Patent ID: 7915966

Claim:
A resonance type voltage control oscillator for generating a signal with a frequency corresponding to an input voltage, comprising: an inductor unit configured to include two inductors serially coupled to each other; a variable capacitance unit coupled to the inductor unit in parallel; a negative resistance unit configured to serve as a negative resistor coupled to the inductor unit in parallel; a first variable resistor configured to have a resistance value corresponding to an input first control signal, the first variable resistor being coupled between a connection between resistors in the negative resistance unit and a negative side source voltage; a second variable resistor configured to have a resistance value corresponding to an input second control signal, the second variable resistor being coupled between a positive side source voltage and a connection between the inductors; and a variable resistor control circuit unit configured to generate the first control signal and the second control signal and control respective resistance values of the first variable resistor and the second variable resistor, wherein the variable resistor control circuit unit is configured to control the respective resistance values of the first variable resistor and the second variable resistor to set current flowing in the inductor unit, the variable capacitance unit and the negative resistance unit to a desired current value, wherein the variable resistor control circuit unit includes: a first control circuit unit configured to generate the first control signal; and a second control circuit unit configured to generate the second control signal, and the first control circuit unit includes: a first reference transistor configured to have a resistance value equal to a total resistance value of the negative resistance unit; a constant current source coupled between the positive side source voltage and a current input end of the first reference transistor, the constant current source being configured to supply a predefined constant current to the first reference transistor; a third variable resistor coupled between a current output end of the first reference transistor and the negative side source voltage; and a first resistor control circuit configured to control a resistance value of the third variable resistor to set a voltage of a connection between the constant current source and the first reference transistor to a predefined reference voltage, and the first control signal comprises a control signal supplied from the first resistor control circuit to the third variable resistor.