Patent ID: 7834711

Claim:
A frequency-variable oscillator comprising: a voltage-to-current converter circuit converting a voltage level of an input signal into a current level within a predetermined range, wherein the voltage-to-current converter circuit comprises, a voltage control unit converting the voltage level of the input signal to a predetermined voltage level, wherein the voltage control unit comprises a comparator comparing the voltage level of the input signal with a voltage level of a feedback voltage, and a voltage range controller controlling a level of an output voltage from the comparator to a predetermined voltage level range and providing the output voltage having the controlled level as the feedback voltage; a voltage-to-current converting unit converting the voltage level from the voltage control unit to the current level within the predetermined range; and a current control unit controlling charging and discharging currents of the oscillator circuit according to the current level of the voltage-to-current converting unit; and an oscillator circuit varying a frequency according to the current level from the voltage-to-current converter circuit and oscillating the varied frequency.