Switching power supply and control circuit and control method thereof

The invention relates to a switching type power supply and a control circuit and a control method thereof. The switching type power supply comprises a power level circuit and a control circuit. The control circuit includes a first amplification circuit, a second amplification circuit, a ramp signal generation circuit, and a comparator. Wherein the first amplification circuit generates an amplification signal according to a difference value between the low-pass filtering signal and the feedback signal. The second amplification circuit generates an adjustment signal according to a difference between the feedback signal and the quick response signal. The comparator compares the amplified signal with the ramp signal to generate a pulse width modulation signal for generating a switch control signal. The adjustment signal is used for adaptively adjusting the amplification signal or the ramp signal. Wherein the low-pass filtering signal is related to a signal generated after the high-frequency part of the reference