Role of large electrolytic capacitor in Electrical Transient protection for Power-Over-Ethernet

Karlis Tucs77

Hi everyone.

I was reading the Application Report Electrical Transient Immunity for Power-Over-Ethernet

because I need to improve the protection for POE in our already made board.

I was wondering is the 220uF/100V capacitor a necessary?

Is it just the bulk capacitance in a way that it is only meaningful for load transients or is it important for ESD/EFT/Surge protection too?

Thanks in advance,

Karlis

over 5 years ago

0 Thomas Amlee over 5 years ago

TI__Genius 9230 points

Hi Karlis,

Are you referring to the bulk capacitance PSE circuit diagrams? Let me notify our PSE expert of your question.

Thanks,
Tom Amlee
PoE PD Apps Engineer

0 Karlis Tucs77 over 5 years ago in reply to Thomas Amlee

Intellectual 320 points

Hi Thomas. Ohh, sorry I forgot to highlight what I am refering to:

0 Penny Xu over 5 years ago in reply to Karlis Tucs77

TI__Genius 15655 points

Hi Karlis,

This large cap also helps with the surge protection. If you look at figure 13 and 14, the cap creates current path during surge event. Thanks.

Best regards,

Penny

Power management

Power management forum

Role of large electrolytic capacitor in Electrical Transient protection for Power-Over-Ethernet