Power over Ethernet on data pairs and spare pairs

摘要

Power Sourcing Equipment (PSE) provides a PoE supply voltage over data wires to a Powered Device (PD). A PSE controller controls a first FET that couples the PoE voltage to the data wire pairs and controls a second FET that couples the data wire pairs to the spare wire pairs. Upon powering up, the PSE controller keeps the two FETs open and performs a detection routine on any devices connected to the data pairs and spare pairs. If a PoE-compatible PD is detected as being coupled to the data pairs, the first switch is closed. If it is determined that the PoE voltage should also be coupled to the spare pairs, the second FET is also closed. The method prevents the PoE voltage from being applied to the spare pairs when the device connected to the spare pairs is not PoE compatible and maintains backwards compliance with IEEE PoE PDs.

主权项

1. A Power over Ethernet (PoE) system comprising:
Power Sourcing Equipment (PSE) selectably connectable to a set of data wire pairs and to a set of spare wire pairs in an Ethernet system for providing a PoE voltage over at least the data wire pairs; a Powered Device (PD) connected to the PSE by at least the data wire pairs to receive the PoE voltage; and a PSE controller as part of the PSE, the PSE controller comprising:
a first output port (OUT1);a second output port (OUT2);a first switch control port coupled to a first switch, the first switch selectively coupling the PoE voltage to the data wire pairs;a second switch control port coupled to a second switch, the second switch selectively coupling the OUT1 to the OUT2; andprocessing circuitry configured for performing the method comprising:
keeping the first switch and the second switch off during a detection and classification routine, performed via the OUT1 and the OUT2;performing the detection and classification routine to determine if the PoE voltage should be applied to both the data wire pairs and the spare wire pairs, or to only the data wire pairs, or to neither the data wires pairs or the spare pairs;keeping the second switch off while turning on the first switch to supply the PoE voltage to only the data wire pairs if it is determined that the PoE voltage should only be provided to the data wire pairs; andturning on the second switch and the first switch to supply the PoE voltage to both the data wire pairs and the spare wire pairs if it is determined that the PoE voltage should be provided to both the data wire pairs and the spare wire pairs.