This application note describes the STEVAL-TSP001V1 demonstration board for the evaluation of a power over Ethernet (PoE) system used to transmit electrical power, along with data, to remote devices over a standard twisted-pair cable in an Ethernet network. A complete power solution for Ethernet-connected powered devices is presented. The power supply fully complies with IEEE 802.3-2005 PoE specifications and delivers the rated output from any compliant source. Example outputs of 3.3 V and 12 V are given in this document, but other requirements can easily be met by implementing small changes.
This document describes the STEVAL-TSP001V1 demonstration board, designed for the evaluation of a Power over Ethernet (PoE) system compliant with IEEE 802.3-2005 (IEEE 802.3af) specifications. The board demonstrates a complete power solution that transmits electrical power and data to remote devices over standard twisted-pair Ethernet cables.
The demonstration board utilizes the ST STHS4257 power over Ethernet interface controller for signature, classification, source connect, and converter start functions. It features a flyback topology DC-DC converter capable of delivering 3.3V and 12V outputs with 1500V isolation to eliminate ground loops. The note details the design choices, circuit descriptions, and electrical characteristics of the system.
| Output Voltage 1 | 3.3 V |
|---|---|
| Output Voltage 2 | 12 V |
| Total Output Power | approximately 10 W |
| Isolation Voltage | 1500 V |
| Board Dimensions | 5"w x 1.5"d x 0.65"h |
| Controller | ST STHS4257 |
| Topology | Flyback |
The power supply fully complies with IEEE 802.3-2005 PoE specifications.
The total power at the output is approximately 10 W.
The ST STHS4257 power over Ethernet interface controller is used.