SAWTOOTH WAVE GENERATING CIRCUIT AND SWITCH MODE POWER SUPPLY HAVING THE SAME

摘要

performed after calibrating the output of the sawtooth sawtooth signal generating circuit, and it includes a switch mode power supply is It is disclosed. A sawtooth wave generating circuit is a capacitor, the calibration circuit, a charge circuit and a discharge circuit. The capacitor is coupled between the first node and the ground. A calibration circuit on the basis of the feedback signal and the sawtooth signal from the sawtooth first node generates a plurality of voltage signals, to select one of the voltage signals to generate a calibrated output signal. Charging circuit charges the capacitor in response to a calibration output signal. The discharge circuit discharges the capacitor in response to a short pulse signal. Therefore, regardless of the operating condition a sawtooth wave generating circuit to generate a stable saw-tooth signal.