Patent ID: 8115559

Claim:
An oscillator, comprising: a current bias circuit tracking a temperature change of the oscillator by using a control voltage and generating a plurality of bias voltages to supply a substantially constant bias current in light of the temperature change; and a ring oscillator comparing differential output signals generated according to the bias voltages and generating an oscillation signal as a result of the comparison, wherein the current bias circuit comprises: a first voltage-current conversion circuit converting the control voltage to a reference current; a current-voltage conversion circuit sensing the temperature change of the oscillator and converting the reference current to a sensing voltage according to a result of the sensing; and a second voltage-current conversion circuit converting the sensing voltage to the bias current, wherein the first voltage-current conversion circuit comprises: a first comparator comparing the control voltage and a voltage of a feedback node and generating a first comparison voltage; a transistor supplying a power voltage to the feedback node in response to the first comparison voltage; and a reference current generation circuit generating the reference current based on a voltage of the feedback node.