Thanks My Friend
You know if I can use the MicroSim formula for quasi-resonant switching power supplies?
The answer lies in what the transformer's primary sees during its operation. I am not a power supply expert and certainly is not experienced in designing a quasi-resonant SMPS. However, one thing is always true is that you want to consider the worse case circuit condition that the transformer primary sees. One of the worse case for the transformer primary, in determining the maximum operating flux density, is the frequency range. If you look at the equation, you will see that the lower the switching frequency, the higher the operating flux density of a given transformer with a fixed number of turns.