transformer

Hi,

It is really hard to have the exact answer on this question as it will depend on how much difference of the turns and what is the difference in turns of the inductance too.

Genereally if you design the power supply with a feedback control circuit, you will get what the voltage you design even the turn is different. But because the turns is different, and the same output voltage you get, then the flyback voltage will be changed. In this mean, you will need to verify the maximum drain voltage on the Mosfet. Another inportant thing you will need to watch out is the maximum working flux density if you use different transformer, make sure the transformer is not saturated.

thank U sir for the respondYou are right it's hard to comment about this kind of questionsbut what if the turns of secondary is just a little bit more for example instead 7t it's 9tdoes it hurt your tny278? i'm working with flyback protocol 

If the difference is very few, it should not hurt the power supply. However, again it all depends on how much margin you have when you design the transformer. That is why it is alway necessary to check what is the maximum drain voltage during high input voltage startup wit full load, and what is the calculated flux density for the transformer during normal operation, what is the margin for it.

When you say the difference is very few, it is on the secondary turns, how about the inductance difference?  

i got it , the inductance is related to nuber of turns and core and ... .

I forgot to think about the inductance because the diffrent core causes the diffrent flux density

so I decide to wind my own trans

regards