TPS23755: Alternative Flyback Transformers

Rob Grimmer

Prodigy 25 points

Part Number: TPS23755

Hello,

I am currently working on a design with the TPS23755 based closely on the TPS23755EVM-894 reference design from TI.

The flyback transformer used in the EVM is the LDT0950-50 (150uH, 1 : 0.44 : 0.39).

Are there any suitable alternatives to this for a 13W 12V solution?

I am considering the Coilcraft POE13P-12L_ (127uH, 1 : 0.5 : 0.5) or the Wurth 7491199112 (127uH, 1 : 0.5 : 0.5).
These are of course slightly different winding ratios to the recommended transformer. Are they suitable?

I would also like to ask if it is also reasonable to use a smaller transformer for a 7W solution?
For example, the Coilcraft POE70P-12L_ (155uH, 1 : 0.667 : 0.667).

Thanks in advance

over 4 years ago

0 Michael Pahl over 4 years ago

TI__Mastermind 21320 points

Hello Rob,

So it is important to note that the TPS23755EVM-894 uses primary side regulation (PSR). The transformer needs to be designed for this in order to have good regulation.

I sent you a connect request and I can share a Wurth solution.

The transformers you mentioned are not suitable since they are not made for PSR. You could order samples and test the regulation, but I would advise against it.

Another option is the use an optocoupler in the feedback loop so your transformer selection will be wider.

If this post answers your question, please indicate so by marking this thread as resolved. Thank you.

Regards,

Michael P.

Applications Engineer

Texas Instruments

0 Benjamin Bawkon over 4 years ago in reply to Michael Pahl

Expert 1085 points

Michael,

I'm beginning work on a TPS23755EVM-894 based design. Could you connect with me and share the Wurth solution?

Thank You,
Ben

0 Michael Pahl over 4 years ago in reply to Benjamin Bawkon

TI__Mastermind 21320 points

Ben,

If a thread is resolved, please create a new thread. Thank you

I sent you a connect request.