TPS2372: PMP21115: Non Isolated DC DC converter

Hello Akash,

 PoE can be nonisolated, and we have several reference designs that are non isolated. The PMP21115 design is a dual PoE with smooth transition, which is a more complex design beyond just the DC-DC design. 

The topology criteria is more related to the overall system. Typically we see flybacks, bucks and forward designs, hence our reference designs mainly fall under these.

Topology depends on if the system needs to be isolated, the output voltage/power level, and cost vs size vs efficiency prioritization.

Isolation is up to the customer, if they think their end equipment needs to be isolated for end user safety and device safety. Typically, if the device is something a person is going to be touching (ie a phone or something with buttons) we recommend isolation. If it is something like lights on the ceiling, which no one will be touching while they are powered, non isolation can be used. If you are unsure, we recommend isolation since that is safer for both the user and the device. 

If this post answers your question, please indicate so by marking this thread as resolved. Thank you.

Regards, 

Michael P.

Applications Engineer

Texas Instruments