RC OSCILLATION CIRCUIT CAPABLE OF ADJUSTING OSCILLATION FREQUENCY AND METHOD OF THE SAME

摘要

An RC oscillation circuit capable of adjusting an oscillation frequency and a method of the same are provided to adjust the frequency of an RC oscillation signal rapidly and accurately regardless of environmental change like process error or temperature variation. An RC(Resistor-Capacitor) oscillator(200) has a variable resistor and a variable capacitor, and generates an RC oscillation signal oscillating with a frequency determined by resistance of the variable resistor and capacitance of the variable capacitor. A counter(300) receives a reference oscillation signal with a fixed frequency, and generates a first clock number by counting the number of clocks of the reference oscillation signal oscillating during one period of the RC oscillation signal. A frequency control part(400) adjusts the frequency of the RC oscillation signal by controlling the resistance of the variable resistor and the capacitance of the variable capacitor so that the difference between the first clock number and a predetermined second clock number is smaller than a first threshold value.