TPS23756: Design review

Max Clark

Part Number: TPS23756
Other Parts Discussed in Thread: , UCC24612

Hello,

I'm attaching a schematic from a POE PD design using the TPS23756. It should be able to accept input from a 48VDC PSE or a 12VDC wall adapter. The wide input range is the reason I selected this device. The output should provide 5V at no more than 600-700mA. I tried to keep it as simple as possible in order to reduce the BOM because of size constraints. I would like to hear some opinion about this design. Please don't focus on details like g.e. the Class Selection resistor. I'm mostly concerned about the Transformer which is designed for 36-72VDC input and at 12V its power may derate considerably. Thank you in advance!

over 3 years ago

0 Michael Pahl over 3 years ago

TI__Mastermind 21320 points

Hello,

First, I would not use a diode flyback at 5V. I strongly discourage this. Use a sync flyback or ACF instead.

Second, the TPS23756EVM has 5V output at accepts 12V adapter. You can copy this.

Alternatively, we have a reference design that is 5V/13W that accepts Wide-Vin (12V). I can share over private messenger. Thanks.

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 Max Clark over 3 years ago in reply to Michael Pahl

Prodigy 10 points

Hello Michael,

Thank for your suggestions. Yes, I could use the TPS23756EVM however it has much more components which means the cost and board size will increase and such a case I would prefer to be my last option. Only the first order (pre-order) is 10.000pcs so every cent counts. If you can share the mentioned reference design I would be grateful. Do you think I can obtain a good result by keeping this design and chaning only the secondary part (to sync flyback ) by using the UCC24612 and the right MOSFET? Thank you.

Kind Regards,

Max

+1 Michael Pahl over 3 years ago in reply to Max Clark

TI__Mastermind 21320 points

Mark,

Please accept my connect request and we can work in private messenger.

Potentially but that is not the least expensive option. The least expensive would be self driven so no sync rectifier is required. That is the design I can share.