UCC28180: ucc28180启动问题

你好，能不能帮我向工程师转述以下问题，

Generally speaking, when designing a flyback switching power supply, it is usually designed according to the default input of AC85-265V. The technical documents about TI also design the flyback switching power supply according to this input range, such as the example in the datasheet of uc3842. However, if the front stage of the flyback switching power supply is a PFC circuit, the initial input of the flyback switching power supply is AC85-265V, but when the PFC gets power from the auxiliary winding of the flyback switching power supply, the PFC will output 390V when it works normally, then the input of the flyback switching power supply is DC-390V. How should the flyback switching power supply be designed at this time? Just increase the derating? Is the minimum voltage input still considered to be AC85V?