TPS23753A: Schematic review

Hello Kungyeh Chen,

Because of the Thanksgiving holiday in the U.S., TI E2E design support forum responses may be delayed this week. Thank you for your patience.

Regards,

Rohit Parashar.

Hi Kungyeh,

Thanks for reaching out to us!

Please allow us 3-7 business days to look through the schematic and get back to you. 

Best regards,

Diang

Hi Kungyeh,

Thanks for your patience. Please find my comments below.

By the way, I am not quite familiar with the data part of PoE, so I did not check the part on the output side of U115.

1.It is recommended to let the common mode choke on the data side rather than on the power & data mixed side. The PoE dc common mode current may cause the choke saturated.

2.It is recommended to have 2 rectifiers. Since the PoE dc voltage may come from either PR12-36 or from PR45-78.

3.The total capacitance between VDD-VSS needs to be less than 0.15 uF. Normally additional capacitance is 0.1 uF.

4.You need to add bleeder resistors for capacitor series connection to balance their voltage.

5.Could you share the datasheet of the flyback transformer?

Best regards,

Diang

Hi Diang,

Attached is the datasheet you requested.

Thanks.ha3803.pdf

Hi Kungyeh,

Thanks for your datasheet. The transformer parameters look good to me for your case.

Best regards,

Diang