Help with power transformer selection

[electrophile]

Hi, I'm designing a power supply using TI's **broken link removed**. This is a dual 12V and 5V output each capable of delivering upto 3A of current. I'm a bit stumped on what kind of transformer I should use. I should also tell that I'll be plugging the primary side of the transformer into a wall AC outlet and hence the primary side is quite clear. The secondary will be fed to a full wave bridge rectifier and this rectified output will act as input to the TPS54383 circuitry. My query is about the current requirements of this transformer. The TPS54383 switches both outputs alternately at a frequency of 300KHz. Since each output should deliver a maximum of 2A would the transformer secondary current be equal to 2A or 4A or something else?

Any help would be really appreciated. Thanks.

 

[kam1787]

**broken link removed**

http://www.brianroth.com/library/national-ps-design.pdf