I have tried to design a Flyback converter with a TinySwitch-III and te PI Expert Suite (Ver 10.1).
The basic parameters are:
Input: 85~265VAC 50Hz
Output: 12VDC, 1.2A (14.4W Simple output)
In the "Design Results" report, in the VMIN (Minimum DC Input Voltage) there is 83.4V.
But, when i tried to calculate this parameter with the formula of application note AN-23 (Page 6, step 5) or AN-16 (Page 13, step 3) the results is about 120V (diferent from 83.4).
My question is:
1) There is a problem with the PI Expert or the formula in application note?
2) Can you show me the correct formula for VMIN?
I atttached the design (.uds file) and the apllication note scan.
PD. Excuse me for my ugly english