Circuit and method for detecting a legacy powered device in a power over Ethernet system
AssigneeSilicon Laboratories Inc.
InventorsJohn Christopher Gammel, Endre Kovaks
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Abstract
In an embodiment, a power source equipment (PSE) device includes a network port configurable to couple to a network cable and a detection circuit coupled to the network port. The detection circuit is configured to apply a powered device (PD) detection voltage signal including first and second voltages to the network port and to sample a line current of the network port in response to the first and second voltages to detect a complex impedance indicating that a legacy PD is coupled to the network port.
Claims20
A power source equipment (PSE) device comprising:
- a network port configurable to couple to a network cable;
- and
- a detection circuit coupled to the network port and configured to apply a powered device (PD) detection voltage signal including first and second voltages to the network port, the detection circuit to sample a line current of the network port in response to the first and second voltages to detect a complex impedance indicating that a legacy PD is coupled to the network port.
A system for providing power to a powered device (PD) in a Power over Ethernet (PoE) system, the system comprising:
- a plurality of network ports, each of the plurality of network ports configurable to connect to a network cable;
- and
- PD detection circuitry including a plurality of PD detection circuits, each PD detection circuit associated with a network port of the plurality of network ports and configured to apply a PD detection voltage signal to the network port and to sample a line current of the network port in response to the PD detection voltage signal to determine a complex impedance indicating that a legacy PD is coupled to the network port.
A method of detecting a legacy powered device (PD), the method comprising:
- applying a PD detection voltage signal having a first voltage and a second voltage to a network port of a power source equipment (PSE) device;
- measuring line currents of the network port in response to the first and second voltages to detect a complex impedance indicating the legacy PD is coupled to the network port.
Dependencies are inferred from the claim text.