PI expert: setting parameter

Posted by: hkaiser on 03/10/2011

Hello,
my name is hartmut and it is my first flyback transformer layout (see attachment). I need secondary 3,3V, 7V, 17,(related to RTN) and 6V, 24V (related to gnd1 and isolated from the other 3 outputs). Under specification\stacking I can only set 6V floating and 24V floating separately but not as a group. If I change the pin allocation in winding construction then C15 should connect to gnd1 not to gnd2. I do not need gnd2!
What can I do?

The second question is:
what steps must I take if I want to leave out the Y capacitor?

It would be nice if I can get an answer.
rgs
hartmut

Files

TinySwitch-III_PIDesign1_1.pdf (43.16 KB)

Comments

Hi,

I understand what you would like to do but unfortunately the stacking and pin allocation GUIs do not understand what you really want. This is very good feedback and I will see if we can work to improve this feature. So currently there is no way to fix this or work around it.

Also there is no way to edit the schematic directly either at this time being.

Hope this clarifies things for you.

-Wesley

Hi,

thanks for the answer.
Have you any idea about my second question:

What steps must I take if I want to leave out the Y capacitor?

rgs
hartmut

It really depends on how well you design with the transformer shields. Doing a Y capacitor free design is quite challenging even for experienced designers and often requires several iterations of shield winding design and checking for compliance on EMI scans. Also you need to have at least 8 to 10 dB margin to the limit lines to allow for variations i production transformers.