Fast restart sleep signature in power over ethernet
View Patent ↗An energy efficient sleep signature in power over Ethernet. In one embodiment, a signature of a powered device is first detected. It is then determined whether the detected signature is indicative of an unknown powered device. In one example, a detected signature of an approximately 25 kΩ impedance is indicative of an unknown powered device. Where the detected signature is indicative of an unknown powered device a normal PoE startup powering process can be used that includes a conventional detection, classification and powering process. Where the detected signature is indicative of a powered device that was previously known to the PSE, then powering of the PD can proceed with a fast-restart powering method that retains previous powering parameters.
1. A method, comprising:
detecting a signature of a powered device by a power sourcing equipment (PSE), the powered device coupled to the PSE via a network cable, the PSE configured to deliver power to the powered device via the network cable;
determining whether the detected signature is indicative that the powered device was previously known to the PSE or that the powered device was previously unknown to the PSE;
when the determination indicates that the powered device was previously unknown to the PSE, then using a first startup process including performing a classification of the powered device by the PSE prior to a delivery of power; and
when the determination indicates that the powered device was previously known to the PSE, then using a second startup process including powering the powered device using a classification of the powered device previously performed by the PSE for the powered device.
2. The method of claim 1 , wherein the detecting comprises measuring an impedance presented by the powered device.
3. The method of claim 2 , wherein the detecting further comprises accessing a value stored in a memory device, the value being associated with the powered device.
4. The method of claim 2 , wherein the detecting further comprises accessing a value stored in a memory device, the value being associated with the power sourcing equipment port.
5. The method of claim 1 , wherein a determination that a powered device impedance is approximately 25 kΩ is indicative that the powered device was previously unknown to the PSE.
6. The method of claim 1 , wherein a determination that a powered device impedance is substantially different than 25 kΩ is indicative that the powered device was previously known to the PSE.
7. The method of claim 1 , wherein a stored value in memory is indicative that the powered device was previously known to the PSE.
8. The method of claim 7 , wherein a stored value in memory identifies that the classification of the powered device was previously performed by the PSE.
9. The method of claim 7 , wherein a stored value in memory identifies a power profile of the powered device that was previously determined by the PSE.
10. The method of claim 7 , wherein a stored value in memory identifies a last saved state of the powered device that was previously stored by the PSE.
11. The method of claim 1 , wherein the PSE and the powered device are located in an automotive vehicle.
12. A power sourcing equipment (PSE), comprising:
a port;
a detection module that is configured for detecting a signature of a powered device coupled to the port via a network cable;
a memory storing one or more values related to power profiles of known devices, wherein the values were determined by the PSE; and
a controller that is configured to:
access the memory to identify whether the signature is indicative that the powered device is one of the known devices;
when the determination indicates that the powered device is not one of the known devices, then use a first startup process including to perform a classification of the powered device prior to a delivery of power; and
when the determination indicates that the powered device was previously known to the PSE, then use a second startup process including to use a classification of the powered device previously performed by the PSE for the powered device.
13. The PSE of claim 12 , wherein the detection module is configured to distinguish between a first impedance of approximately 25 kΩ and a second impedance having a value that is substantially different than 25 kΩ.
14. The PSE of claim 12 , wherein the controller accesses one of the power profiles from the memory when the controller determines that the powered device was previously classified by the PSE.
15. The PSE of claim 12 , wherein the values related to the power profiles reflect, for each of the known devices, a last saved state of the known device.
16. A method, comprising:
detecting a signature of a powered device at a power sourcing equipment (PSE) configured to deliver power to the powered device via a network cable;
determining from the signature whether the powered device was previously classified by the PSE;
when the determination indicates that the powered device was previously classified by the PSE, then powering the powered device using a classification of the powered device that was stored in a memory by the PSE prior to the detection of the signature of the powered device.
17. The method of claim 16 , wherein the detecting comprises measuring an impedance presented by the powered device.
18. The method of claim 16 , further comprising accessing a power profile of the powered device from the memory.
19. The method of claim 16 , wherein the power profile includes a power classification of the powered device.
20. The method of claim 16 , wherein the power profile includes a last saved state of the powered device.