FIG. 5 is a dynamic response curve of the general multi-mode control method of the present invention for the flyback circuit in FIG. 4 during load switching, and a dynamic response curve adopting the technology for improving the dynamic response herein. This is the embodiment of the present invention. FIG. 5a is a dynamic result of switching the load from 700Ω to 5Ω before using the dynamic improving method herein, and FIG. 5b is a dynamic result of switching the load from 700Ω to 5Ω after using the dynamic improving method herein. Before using the technology, the undervoltage of the output voltage is 1.3V and the recovery time is 11.86 ms; after using the technology, the undervoltage of the output voltage is 0.332V and the recovery time is 0.932 ms, and the dynamic performances are greatly improved. FIG. 5c a dynamic result of switching the load from 5Ω to 700Ω before using the dynamic improving method herein, and FIG. 5d is a dynamic result of switching the load from 5Ω to 700Ω after using the dynamic improving method herein. Before using the technology, the overvoltage of the output voltage is 0.584V and the recovery time is 126.3 ms; after using the technology, the using the technology, the undervoltage of the output voltage is 1.3V and the recovery time is 11.86 ms; after using the technology, the overvoltage of the output voltage is 0.152V and the recovery time is 43.4 ms, and the dynamic performances are greatly improved. The dynamic results of the example are greatly improved.