Patent ID: 7498884

Claim:
A self-calibrating resistor-capacitor oscillator for generating an oscillation signal comprising: a resistor part including a first resistor having a resistance value reduced with increase in temperature and a second resistor connected in series with the first resistor and having a resistance value increasing with increase in temperature, the resistor part having a resistance value formed by the first and second resistors connected in series with each other; a bias circuit generating a preset first reference voltage, and a ramp current to be proportional to the first reference voltage and inversely proportional to the resistance value of the resistor part; a capacitor part having a capacitance value; a ramp and hold circuit supplying the ramp current to the capacitor part to charge the capacitor part during a charging time set according to a period of the oscillation signal, and maintaining a both-end voltage of the capacitor part after the charging; a first comparator comparing a size of the first reference voltage with a size of the both-end voltage of the capacitor part; a first charge pump for outputting a control voltage varying in response to a control signal; a control logic outputting the control signal for increasing and decreasing the control voltage outputted from the first charge pump in response to a comparison result of the first comparator, receiving the oscillation signal through feed-back, and setting the charging time during which the ramp and hold circuit supplies the ramp current to the capacitor part, in response to the received oscillation signal; and an oscillator part for outputting the oscillation signal having a frequency controlled in response to the control voltage of the first charge pump.