TPS2378: Looking for the IC which can replace the TPS2378

Hi Subin,

Thanks for reaching out!

A 25.5-W PD summary can be found in:

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1308064/faq-some-25-5-w-poe-pd-controllers-their-key-features?tisearch=e2e-sitesearch&keymatch=%2520user%253A525282#

Below are some reference designs with 5-V. You should be able to search and find them:

TPS23731EVM-095 using TPS23731

TPS23734EVM-094 using TPS23734

TIDA-00617 using TPS23751

TPS23751EVM-104 using TPS23751

PMP6672 using TPS23754

Please let me know if you have any further questions.

Best regards,

Diang

I don't think they are the proper ones because, they are the IC which contains DC/DC Controller not DC/DC converting function itself.

The intention of the question is that I do not want to add further peripheral circuit around PD IC but minimize as possible as I can while I use the PD IC with DC/DC Converting function(24->5V) without peripheral circuit.

e.q. If I use TPS23731, I should add all the peripheral circuit for DC/DC Convert to the developing circuit.

And I have a further question.

According to the PoE law, we can think PSE - PD system for sure.

Can you tell me about the hierarchy between PSE - PD?

For example, PSE should be higher(or >=) class than PD. Or it could be the type of PSE should be higher(or >=) than PD.

Regards,

Subin Ko.

+ If PD is type1 and PSE is type2, does PSE send out the proper power to PD after Detecting PD?(I want to know the exact power by number)

Related to hierarchy, I would like to know whether your answer's will not violate the law of PoE.(Including IEEE802.3 af, IEEE802.3at)

Hi Subin,

Thanks for your reply.

Our 25.5-W rated PDs do not have integrated DC/DC converter.

You may need build the peripheral circuit using our reference designs (for example, TPS23731EVM-095 for TPS23731, https://www.ti.com/tool/TPS23731EVM-095). We have shared the schematic to help build the circuit in the portfolio page. If you need further help please feel free to contact us.

For your questions:

- PSE should be higher(or >=) class than PD. Or it could be the type of PSE should be higher(or >=) than PD.

PSE could be either higher or lower than PD in terms of type/class. In bt feature, power demotion is anytime that PD gets the power lower than it’s requesting (power will be only demoted to Type boundary).

-  If PD is type1 and PSE is type2, does PSE send out the proper power to PD after Detecting PD

PSE will set its power limit based on PSE's power budget and PD's classification. If PD is set as Class-3 Type-1, and PSE is Type-2 and not in power demotion mode, the PSE will set Class-3 power limiting to this PD port. 

- I would like to know whether your answer's will not violate the law of PoE.(Including IEEE802.3 af, IEEE802.3at)

The standards (af, at, or bt) of TI's reference designs will be shown in the EVM user's guide. For example,

Best regards,

Diang 

Dear Mr.Xing,

I have a 2 inquiries.

1. Please recommend me the PD EV circuit which is compatible with TPS23861 PSE Controller.(PD should be select 802.3af. It's for PoE not PoE+)

2. Please tell me whether the TPS23861 contain the power switch or not.

The intention of question no.2 is that I'd like to confirm whether I could adapt the end span architecture to the TPS23861 and the PD part which you will recommend.

+ ★ we should select end span method not mid span and power signal and data will be transfer through the 1,2,3,6 pin on LAN cable

Hi Subin,

Thanks for your reply.

1. Please recommend me the PD EV circuit which is compatible with TPS23861 PSE Controller.(PD should be select 802.3af. It's for PoE not PoE+)

I saw you need input/output power 25.5W max. In this case you need at or bt PD.  

In most of case, at standard devices cover the features of af standard; bt standard devices cover the features of at standard. So, TPS23861 can work with TPS23731EVM-095, even TPS23731EVM-095 is compatible with bt standard. So do other 25.5-W PDs I recommended before. 

2. Please tell me whether the TPS23861 contain the power switch or not.

TPS23861 does not have integrated power switch. You will need add external FETs. You can refer TPS23861EVM-612 reference design
(https://www.ti.com/tool/TPS23861EVM-612)

Best regards,

Diang

Hi Subin,

I will close this thread for now. If you have further questions please reply or open a new thread.

Best regards,

Diang