Power conversion circuit and operating method thereof

A power conversion circuit used for generating an output voltage, comprising:

• an error amplifying circuit, having a first operation mode and a second operation mode and configured to provide an output signal;
• a first comparison circuit, coupled to the error amplifying circuit and configured to receive the output signal and a ramp signal to generate a first comparison signal;
• a second comparison circuit, configured to receive the output voltage and a first reference voltage and provide a second comparison signal;
• and
• a control circuit, coupled to the error amplifying circuit, the first comparison circuit and the second comparison circuit and configured to provide a control signal to the error amplifying circuit according to the first comparison signal, the second comparison signal and an enabling signal to control an operation mode of the error amplifying circuit,
• wherein when the error amplifying circuit operates in the first operation mode, the output signal is an error amplifying signal;
• when the error amplifying circuit operates in the second operation mode, the output signal is a second reference voltage.