A power converter comprising a first capacitor, a flyback conversion module, a soft-start module, and a feedback control module. The flyback conversion module is coupled with the first capacitor and configured to receive a first control voltage across the first capacitor. The soft-start module is coupled with the first capacitor and is configured to charge the first capacitor during a startup stage, to increase the first control voltage to an expected voltage value at the end of the startup stage. The feedback control module is coupled with the flyback conversion module and is configured to control the flyback conversion module to output a substantially constant voltage or current after the startup stage. Wherein the expected voltage value is a value of the first control voltage when the flyback conversion module outputs a substantially constant voltage or current after the startup stage.