TPS2373: Power Mux or ORi-ing for Type 4 POE

Hi Ashfaaq,

Thanks for reaching out. May I know if you want power oring or power muxing in your case? What is the max load power you need?

Dual PD power oring (Max power = Class-8):

- You can refer PMP20859 which is a 30W design. But you can make it a higher power one. TPS2373 is not recommended considering two TPS2373 have the VC_IN & VC_OUT pins for startup bootstrap, while there is only one DC/DC circuit. TPS2372-4 is recommended here. 

Dual PD power muxing (Max power > Class-8):

- Using power limiting circuit and mix the power at the output side. It can offer active power limiting function to avoid either PD has > 71.3-W input power, but it is high cost, large size. (You can search PMP22477 for the power sharing circuit). TPS2373-4 is recommended for this design.

- Parallel two PDs together. The PDs normally can balance the power passively if the layout, cable condition, temperature, and other factors are similar. But this power balance is not guaranteed by active control.TPS2372-4 is recommended for this design.

Best regards,

Diang

Hi Diag,

Thanks for your valuable response.

May I know if you want power oring or power muxing in your case?
     -- My Device had two modes Low power mode(<71.3W) and high power mode(140W).

I have POE and an Aux adapter as power source, where POE will be used in Low power mode and Aux adapter(12V) will be used in high power mode,

Also in case of POE, I have two RJ45 port and I need POE on either of these ports.( Type-4 POE 71.3-W). 

Hence I am exploring different approaches like Power Muxing , where I can mux 2 PD(Type-4 POE 71.3-W) to operate in high power power by sharing the load between two PDs.

If the Power Muxing is not possible, I prefer to go with OR-ing circuits similar to the block diagram you have shared for PMP20859. 



May you please suggest suitable Ti solutions for my design?

Hi Ashfaaq,

Thanks for your reply.

I will be out of office until Mar 27. Sorry for the delay response in E2E and thanks for your patience.

Best regards,

Diang

Hi Diang,

Thanks for your response.

Would anyone from your team be available to assist me with this while you're away? It would be very helpful for us to close this out soon.

Hi Diang & Team,

Please find the below image. I have 2 RJ45 with POE-type 4 and I am planning to have two PDs in parallel and to combine the output of PDs and connect it to a single DC-DC converter. PMP20859 -This is really helpful. But is there any evaluation board available with 12Vout/ 70W.

Hi Ashfaaq,

Thanks for feedback. You can order 2 TPS2372-4EVM and connect them externally. Please find attached document for more details

7840.Beyond BT High-Power PoE Solution using the TPS23880 and TPS2372-4_slva986.pdf

Best regards,

Diang