Initialization and synchronization for pulse power in a network system

1. A method comprising:

identifying at a first powered device in communication with power sourcing equipment, a second powered device in communication with the first powered device, wherein the first powered device is receiving pulse power from the power sourcing equipment;

notifying the power sourcing equipment of the second powered device at the first powered device; and

performing a power initialization at the first powered device with the second powered device before passing the pulse power to the second powered device,

wherein the power initialization is performed at a power level lower than the power level of the pulse power received from the power sourcing equipment.

2. The method of claim 1 wherein the first powered device comprises:

a local isolation switch for a first pulse power initialization with the power sourcing equipment at start-up of the first powered device and for receiving the pulse power from the power sourcing equipment; and

an output isolation switch for said power initialization with the second powered device and for passing the pulse power to the second powered device.

3. The method of claim 1 wherein the pulse power comprises pulses of power transmitted at or above 60 volts.

4. The method of claim 1 wherein the power sourcing equipment performs a safety check with the second powered device.

5. The method of claim 4 wherein the safety check comprises a cable capacitance and shock fault test.

6. The method of claim 4 wherein the safety check comprises a capacitance test and further comprising identifying a minimum off time between pulses of the pulse power based on the capacitance test.

7. The method of claim 4 wherein performing the safety check comprises:

modulating cable capacitance voltage and measuring discharge time;

setting a load voltage threshold based on a calculated cable capacitance; and

determining a pulse power duty cycle.

8. The method of claim 1 wherein said notifying the power sourcing equipment of the second powered device comprises communicating timing adjustments based on changes in line capacitance due to the second powered device.

9. The method of claim 1 wherein said power initialization is repeated for each phase in a multi-phase pulse power system in which pulses are offset from one another between phases.

10. The method of claim 1 wherein one of the first and second powered devices is configured to operate as another power sourcing equipment node for at least one downstream device.

11. The method of claim 1 wherein a difference between the power level of the power initialization and the power level of the pulse power is at least 170 volts.

12. A method comprising:

operating a first powered device with pulse power received from power sourcing equipment;

identifying a second powered device in communication with the first powered device;

notifying the power sourcing equipment of the second powered device; and

performing a power initialization with the second powered device before passing the pulse power to the second powered device,

wherein the power initialization is performed at a power level lower than the power level of the pulse power received from the power sourcing equipment.

13. The method of claim 12 further comprising synchronizing the first powered device with a waveform associated with the power initialization received from the power sourcing equipment before operating with the pulse power.

14. The method of claim 12 further comprising operating the first powered device as a power sourcing equipment node for the second powered device.

15. The method of claim 12 wherein said power initialization is repeated for each phase in a multi-phase pulse power system in which pulses are offset from one another between phases.

16. An apparatus comprising:

an input for receiving pulse power from power sourcing equipment; and

a controller for identifying a powered device in communication with the apparatus, notifying the power sourcing equipment of the powered device, and performing power initialization with the powered device before passing the pulse power to the powered device,

wherein the power initialization is performed at a power level lower than the power level of the pulse power received from the power sourcing equipment.

17. The apparatus of claim 16 further comprising an isolation switch for use in performing an initial power initialization with the power sourcing equipment at start-up of the apparatus.

18. The apparatus of claim 16 further comprising an output isolation switch for said power initialization with the powered device and for passing pulse power to the powered device.

19. The apparatus of claim 16 wherein said power initialization is repeated for each phase in a multi-phase pulse power system in which pulses are offset from one another between phases.

20. The apparatus of claim 16 further comprising a bootstrap power supply for providing a local energy storage.