Patent ID: 8022780

Claim:
A method for adjusting the oscillation frequency of a voltage-controlled oscillator (VCO) in response to a temperature change in the VCO, the method comprising: sensing a temperature of the VCO, the VCO comprising an oscillator and an inductor-capacitor (LC) tank resonator, the LC tank resonator comprising at least one main varactor configured to be controlled by a first control signal, wherein the oscillation frequency of the VCO is configured to be coarsely tuned by the by the at least one main varactor; coupling an auxiliary varactor to the LC tank resonator of the VCO, the VCO being configured such that a change in the capacitance of the auxiliary varactor causing a change in the oscillation frequency of the VCO; controlling the capacitance of the auxiliary varactor using a second control signal generated by a temperature sensor/voltage generator unit, wherein the auxiliary varactor is configured to be coupled directly to the temperature sensor/voltage generator unit through an RC filter; and adjusting the second control signal based on the sensed temperature such that the variation in the VCO oscillation frequency due to VCO temperature change is reduced while maintaining a functional relationship between the second control signal and the sensed temperature, wherein the functional relationship between the second control signal and the sensed temperature is calculated as a product of an expected change in oscillation frequency of the VCO due to temperature and an expected change in capacitance of the auxiliary varactor due to the second control signal divided by a product of a change in sensed temperature and an expected change in the second control signal.