TPS23754: PMP4909 reference design uses the TPS23754 PoE controller

Hi Tan,

Any particular reason why customer is interested in this relatively older reference design? The TPS23754EVM-383 is a more recent design that has been used in many projects and what we recommend for this power level and output voltage.
www.ti.com/.../slvu304c.pdf

It's design files can be found in the below link.
e2e.ti.com/.../1329763

Please let me know if this is what you're looking for. Thanks!

Regards,
Darwin

Hi Darren,

Thanks for confirming the EVM is okay. Note the transformer was designed by Wurth and Pulse so its construction design is proprietary to them and not TI so we don't have this information.

However please see below links to their datasheets:

www.mouser.com/.../750311320-471096.pdf
www.mouser.com/.../P675-9591.pdf

Regards,
Darwin

Hi Darren,
Please see my comments below:

1. It may be good for customer to understand the active clamp forward topology in detail. I like using the below app note as a reference. But at a high level, it's a combination of input voltage, turns ratio, and extra margin. Q5 is higher because the duty cycle is part of consideration. We do not recommend going lower in FET rating.
www.ti.com/.../slua535.pdf

2. Please see comments regarding the schematic:

R54 looks large. I recommend starting with 1k ohms
R55 is 2x higher than the EVM. You may want to double check your output current limit when testing.
I'm not sure what CTR is U8 but be sure it is 80-160% like used in the EVM.

For the most part the connections are correct. However, I notice majority of the component values are very different from the EVM. We recommend that the design stay close to the EVM for a known working solution.

Regards,
Darwin