Switching converter with fixed frequency during current limiting and control circuit and method

The invention discloses a switching type converter with fixed frequency during current limiting, a control circuit and a control method. The switching type converter is a switching type power converter which converts an input power supply into an output power supply. The switching type converter comprises a power stage; the conversion control circuit comprises a current limiting control circuit used for comparing a current monitoring signal with a sensing signal limiting threshold value to generate a current limiting control signal, and the current monitoring signal is related to the output current of the output power supply; and the PWM control circuit is used for generating a PWM signal according to the output voltage of the output power supply. The first state of the PWM signal has a first fixed time. When the current limit control signal indicates that the output current exceeds the current limit threshold value, the PWM control circuit is used for controlling the switching frequency of the pulse width mo