Instantaneous overpower control method and circuit

The invention provides an instantaneous overpower control method and circuit. When a CS pin of a controller detects that a source voltage when a power tube is conducted is greater than a maximum peak current limit threshold value in a normal mode in the controller in several continuous periods, the controller is judged to be in an instantaneous overpower state at the moment, a peak current of the CS pin of the controller is raised, the working frequency of the controller is improved, the controller works in an over-power working mode, and an instantaneous overpower state can be quitted under the two conditions that an output state is recovered to be normal or the timing of the maintaining time is ended within the maintaining time of the instantaneous over-power state, and the controller recovers to a normal working mode. According to the instantaneous overpower control method and the circuit, the normal large dynamic state and the instantaneous overpower state can be distinguished, that is, the normal large d