can some1 help me to calculate Rf and R1.Iam just an amater but have to make the flyback converter in lab tommorrow. I searched a formula to calculate them but T.T .Thanks a lot in advance
Uin= 30-63V Uout=10v=const,f=100khz
thank you for your fast response
but i mean Rf . i read a bachelor thesis : output frequency of uc3845 = 1/2 switched frequency= 50khz. and output frequency = 1.72/Rf*cf.
i dont know where the value 1.72 come from.
The formula for switching frequency is expected to be arbitrary. It depends on the reference voltage and the amplitude of the oscillator ramp. The derivation of the formula isn't really important.