Flyback Converter using TOP254YN

Posted by: Viswagopal on 11/13/2014

Hi,

I am Designing a SMPS circuit for an application which requires 30-35 W power.
Here are my specifications
Input voltage range 65-265VAC,Output Voltage 12V,2.5A,Flyback topology ,Transformer Core EE25,Switching frequency 132khz.I'm interested in using TOPSwitch having a package TO-220.I have designed the circuit using PI expert which recommends using TOP254YN.
However going by the PI product application notes i found 35W output power is feasible with TOP255YN or TOP256YN with EF25 core. I am confused with going by the expert design or should i have to change the TOPswitch along with core.Attached schematic file for reference

Regards
Viswagopal

Files

TOPSwitch-HX_PIDesign10_SCH.pdf (29.96 KB)

Comments

Hi,

Thanks for sharing the information and all the input.
I get a little bit confusion though, do you mean you want to use EE25 core, but the PI expert generated the design with EF25 core? If that is the case, you could modify the transformer core in the transformer spec that included in the PI-expert manually, then the design with EE core will be generated.
Concerning the question of feasible choice with TOP255YN or TOP256YN, it means both of the devices is applicable to your design. Bigger size part with higher current rating MOSFET typically has less Rdson, which may improve the thermal performance and efficiency depends on different applications. You could determine it by the test results and requirement for the power supply.

First of all i thank you for taking time to answer my query

I want to use only Transformer core EE25 and PI Expert have also generated the circuit(design passed with no optimization) which you can see in the file i have attached in my previous comment. My question is whether the generated circuit can produce 30W output. The reason i ask is, i have seen all of TOPSwitchHX application notes and product documents where i do not find EE25 core generating 30W power using TOPSwitch 254YN

Regards
Viswagopal

Hi,
Thanks for clarifying the information.
If the design using PI-Expert is passed without warnings, then theoretically you should be able to use EE25 for your design. However, it is always necessary to verify the design by bench testing.