Abstract: A Power over Ethernet (PoE) system having a Power Sourcing Equipment (PSE) and a Powered Device (PD) configured for interacting over four pairs of wire provided for supplying power from the PSE to the PD. The PSE and the PD are configured to perform separate PD classification procedures over first and second 2-pair sets to support PoE operations that are not defined by the IEEE 802.3af standard.

Abstract: A novel system and methodology for controlling an output of Power Sourcing Equipment in a Power over Ethernet system based on a current limit threshold. The PSE has an auto-zero circuit for comparing a monitored output current of the PSE with the current limit threshold to control the output of the PSE.

Abstract: A power supply system for providing power over a communication link has current limit circuitry for restricting an output current of the system based on a current limit threshold, and threshold circuitry for setting the current limit threshold in accordance with an output parameter of the system. In particular, the threshold circuitry may control the current limit threshold in accordance with an output voltage of the system so as to achieve a substantially constant output power of the system.

Abstract: Novel system and methodology for adjusting a current limit threshold in a Power over Ethernet (PoE) system in accordance with requirements of a Powered Device (PD). A system for supplying power to a PD over a communications link has a requirement determining circuit for determining a PD's requirement, and a control circuit for setting a parameter restricting an output signal of the PSE in accordance with the determined PD's requirement. The control circuit may set a current limit threshold of the PSE and/or the PD in accordance with the determined PD's requirement, such as a power requirement.