Help with POE design issues

zhangliyuan

Help with POE design issues [Copy link]

I am going to design a POE circuit now. I checked the information on the Internet, and most of them are introductions to the principles of POE. It is said that POE power supply is negotiated power supply, and there are 4 processes:
1. Detection: At the beginning, the PSE device outputs a very small voltage at the port until it detects that the connection at the cable terminal is a powered device that supports the IEEE802.3af standard.
2. PD device classification: After detecting the powered device PD, the PSE device may classify the PD device and evaluate the power loss required by this PD device.
3. Start power supply: During a configurable startup period (generally less than 15μs), the PSE device starts to supply power to the PD device from a low voltage until a 48V DC power supply is provided.
4. Power supply: Provide a stable and reliable 48V DC power to the PD device to meet the power consumption of the PD device not exceeding 15.4W. 5. Power off: If the PD device is disconnected from the network, the PSE will quickly (generally within 300-400ms) stop supplying power to the PD device and repeat the detection process to detect whether the cable terminal is connected to the PD device.

I want to know how to realize these processes in the circuit? Do you have any solutions or information to provide guidance?

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POE circuit is commonly known as Ethernet power supply, I don't know what the original poster designed

What do you want to design?

Basic Information Forum Download Center

In addition, Texas Instruments TI and Linear Technology now have parameter designs for reference.

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POE Design Information

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TI's POE reference design solution,

You can refer to tps2375evm on TI's official website

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Available on TI official website