Pulse power initialization and synchronization in network systems

Abstract

To enable initialization and synchronization for pulse power in a network system.SOLUTION: In one embodiment, a method includes transmitting from power sourcing equipment, low voltage pulse power to a powered device in a communications network, performing a safety test, enabling high voltage pulse power operation at the power sourcing equipment upon passing the safety test, and transmitting high voltage pulse power from the power sourcing equipment to the powered device. The powered device synchronizes with a waveform of the low voltage pulse power.SELECTED DRAWING: Figure 29

Description

[Technical field]

[0001] The present disclosure relates generally to power transmission in a network, and more particularly to pulsed power initialization and synchronization in a network system. [Background technology]

[0002] Power over Ethernet (PoE) is a technology for supplying power from power sourcing equipment (PSE) to powered devices (PDs) over a link section on a wired communications network. In a traditional PoE system, power is supplied over the cable used by data over a distance of a few meters to about 100 meters. When longer distances are required or when fiber optic cables are used, the limitations of traditional PoE mean that power must be supplied from a local source such as a wall outlet. Furthermore, the power capacity of today's PoE systems is limited and may be insufficient for many classes of devices. [Brief description of the drawings]

[0003] [Figure 1] 1 illustrates an example of a communications network in which embodiments described herein may be implemented. [Diagram 2] 1 illustrates an example of a network device useful for implementing embodiments described herein. [Diagram 3] FIG. 2 is a block diagram illustrating components of a pulse power system, according to one embodiment. [Figure 4] 4 is a flow chart illustrating low voltage initialization of a pulse power system in accordance with one embodiment. [Diagram 5] 4 is a flow chart illustrating high voltage initialization of a pulse power system in accordance with one embodiment. [Figure 6] FIG. 1 illustrates a high voltage initialization pulse limit within a safe region according to one embodiment. [Figure 7]1 is a flow chart illustrating a cable capacitance and safety test according to one embodiment. [Figure 8] FIG. 1 is a block diagram illustrating an enhanced safety power system for supplying pulsed power, according to one embodiment. [Figure 9A] 8 is an example circuit for use with the cable capacitance and safety test of FIG. 7, according to one embodiment. [Figure 9B] 9B shows the cable current and voltage corresponding to the change in state of the switches in the circuit of FIG. 9A. [Figure 9C] 1 is an example circuit for use in another cable capacitance and safety test, according to one embodiment. [Figure 9D] 9D shows the cable current and voltage corresponding to the change in state of the switches in the circuit of FIG. 9C. [Figure 10A] FIG. 2 is a block diagram illustrating a circuit for use in synchronization, according to one embodiment. [Figure 10B] 10B shows the voltage on the cable in response to changes in the state of the switches in the circuit of FIG. 10A. [Figure 11A] 5 is a block diagram showing a circuit for use in the low voltage initialization of FIG. 4 according to one embodiment. [Figure 11B] 11B shows cable voltage and housekeeping power in response to changes in state of the power sourcing equipment switch of the circuit of FIG. 11A. [Figure 11C] 1 is an example of a low voltage start-up circuit, according to one embodiment. [Figure 12A] FIG. 11B is a block diagram showing details of the housekeeping power supply circuit of FIG. 11A. [Figure 12B] 11D shows details of the housekeeping power supply circuit of FIG. [Figure 12C] FIG. 12C is a block diagram of the housekeeping power supply circuit of FIG. 12B. [Figure 13A] 6 is a block diagram showing a circuit for use in the high voltage initialization of FIG. 5 according to one embodiment. [Figure 13B] 13B shows cable voltage and housekeeping power in response to changes in state of the power sourcing equipment switch of the circuit of FIG. 13A. [Figure 14] FIG. 9 is a circuit box diagram showing a safety crowbar / shorting relay added to the high voltage supply of the circuit of FIG. 8. [Figure 15] 1 illustrates a cable with optical fiber and two twisted pairs connecting a power sourcing equipment to a powered device to provide enhanced and safe power, according to one embodiment. [Figure 16] 16 illustrates details of one of the twisted pairs shown in FIG. 15 according to one embodiment. [Figure 17] 1 illustrates an example of power and data distribution to multiple powered devices, according to one embodiment. [Figure 18] FIG. 2 is a simplified block diagram illustrating example voltage and power levels between power sourcing equipment and powered devices in an enhanced safe power system, according to one embodiment. [Figure 19] FIG. 2 is another simplified block diagram illustrating example voltage and power levels between power sourcing equipment and powered devices in an enhanced safe power system, according to one embodiment. [Figure 20] FIG. 1 is a block diagram illustrating an example of a multi-node three-phase pulse power system, according to one embodiment. [Figure 21] 21 shows an example of three-phase pulsed power voltages and currents for the system shown in FIG. 20 using constant power loads from the endpoint nodes. [Figure 22] 1 illustrates a simplified circuit of a two-phase pulse power system on a cable with four wire pairs, according to one embodiment. [Diagram 23] 1 illustrates the synchronization of the power source modulator switches and the powered device modulator switches in a four-phase pulsed power system. [Figure 24] 24 shows the four-phase pulse power system of FIG. 23 with one phase dropped. [Diagram 25] FIG. 2 is a block diagram illustrating a point-to-point topology, according to one embodiment. [Figure 26] FIG. 2 is a block diagram illustrating a daisy chain topology, according to one embodiment. [Figure 27]FIG. 2 is a block diagram illustrating a multi-drop topology according to one embodiment. [Figure 28] FIG. 2 is a block diagram illustrating a hybrid multi-drop / daisy chain topology, according to one embodiment. [Figure 29] FIG. 2 is a block diagram illustrating a power sourcing equipment and two powered devices in a multi-drop / daisy-chain hybrid topology in a powered-off state according to one embodiment. [Diagram 30] 30 illustrates the power sourcing equipment and powered device of FIG. 29 during power sourcing equipment detection of the first powered device. [Diagram 31] 30 shows the power sourcing equipment and power receiving devices of FIG. 29 upon powering up of the first power receiving device. [Diagram 32] 1 illustrates a training phase for a first powered device. [Diagram 33] 4 illustrates an identification phase for a first powered device. [Diagram 34] This shows a final safety check before enabling high voltage pulsed power in the power sourcing equipment. [Diagram 35] 1 shows a power sourcing equipment transmitting high-voltage pulsed power to a first power receiving device. [Diagram 36] 1 illustrates a power sourcing equipment establishing communication with a first powered device. [Figure 37] 1 illustrates detection of a second powered device at a first powered device and initialization of the second powered device. [Figure 38] 13 shows a power supply device checking the safety of a second powered device and a transmission line. [Figure 39] 1 shows a power sourcing equipment transmitting high voltage pulsed power to both powered devices. [Diagram 40] 1 shows a power sourcing equipment that supplies high voltage pulsed power and communicates with both powered devices.

[0004] Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

[0005] Description of exemplary embodiments overview Aspects of the invention are set out in the independent claims and preferred features are set out in the dependent claims. Features of one aspect may be applied to any aspect alone or in combination with other aspects.

[0006] In one embodiment, a method generally includes transmitting low-voltage pulsed power from a power sourcing equipment to a powered device, performing a safety test, enabling high-voltage pulsed power operation in the power sourcing equipment upon passing the safety test, and transmitting the high-voltage pulsed power from the power sourcing equipment to the powered device, wherein the powered device is synchronized with a waveform of the low-voltage pulsed power.

[0007] In another embodiment, a method generally includes receiving, at a powered device, low-voltage pulsed power from a power sourcing equipment, synchronizing timing of a modulator of the powered device with a waveform of the low-voltage pulsed power received from the power sourcing equipment, and operating with the high-voltage pulsed power received from the power sourcing equipment.

[0008] In another embodiment, a method generally includes receiving high-voltage pulsed power from a power sourcing equipment at a powered device with a modulator switch open, coupling an isolation voltage at the powered device when the pulses of the high-voltage pulsed power are on, energizing housekeeping circuitry of the powered device, and turning on a modulator switch of the powered device after a certain number of high-voltage pulses are received.

[0009] In yet another embodiment, a method generally includes identifying, at a first powered device in communication with a power sourcing equipment, a second powered device in communication with the first powered device, where the first powered device is receiving high-voltage pulsed power from the power sourcing equipment; notifying the power sourcing equipment of the second powered device; and performing a low-voltage power initialization at the first powered device with the second powered device before passing the high-voltage pulsed power to the second powered device.

[0010] A further understanding of the features and advantages of the embodiments described herein may be realized by reference to the remaining portions of the specification and the attached drawings.

[0011] Exemplary embodiments The following description is presented to enable those skilled in the art to make and use the embodiments. Descriptions of specific embodiments and applications are provided only as examples, and various modifications will be readily apparent to those skilled in the art. The general principles described herein can be applied to other applications without departing from the scope of the embodiments. Thus, the embodiments should not be limited to those shown, but should be accorded the widest scope consistent with the principles and features described herein. For clarity, details related to technical materials known in the technical field related to the embodiments have not been described in detail.

[0012] In traditional Power over Ethernet (PoE) systems used to simultaneously transmit power and data communications, power is delivered over the same twisted pair cable used for data. The range of these systems is limited to a few meters to about 100 m (meters). Traditional PoE over communications cables is generally limited to about 90 W (watts) based on IEEE 802.3bt, but many classes of powered devices benefit from power delivery in excess of 100 W, and sometimes even more than 1000 W. For example, traditional PoE does not provide enough power for high-power communications systems such as remote radio heads or fronthaul routers, as found in cellular networks, which typically require 300 W to 1000 W to operate. Also, enterprise products that provide switching, routing, and power to access points and IP (Internet Protocol) telephone systems often require about 1000 W to 1500 W of power. In traditional systems, when a larger power delivery rating is required, power is delivered to the remote device via a local power source. However, in network communication systems such as 5G cellular buildouts or other communication systems, and in buildings with multiple decentralized routers connected to each floor, AC (alternating current) grid power is not always available, may not be cost-effective to build initially, or may be impractical in some locations (e.g., wireless base stations), and is often prohibitively expensive. For example, in locations listed as "colocation," power is typically charged per connection rather than per consumption, making each additional AC connection very expensive. DC (direct current) power systems are not an adequate solution over long distances, so AC grid power systems are often used. Thus, a means of powering these and other devices is needed without the need for additional AC outlets or other types of secondary power feeds.

[0013] Increasing the power available in multifunction cables to hundreds or even thousands of watts can enable many new options for network deployments running key devices such as workgroup routers, multi-socket servers, large displays, wireless access points, fog nodes, or other devices. This capability greatly reduces installation complexity and improves total cost of ownership for a much wider set of devices that have their power and data connectivity needs met from a central hub.

[0014] To overcome the above problems, power and data delivery systems can be designed to carry higher data rates and higher power supplies combined in a single cable (and may also carry integrated thermal management cooling), as described in U.S. Patent Application No. 15 / 910,203, filed March 2, 2018 ("Combined Power, Data, and Cooling Delivery in a Communications Network"), which is incorporated herein by reference in its entirety. These connections can be point-to-point, such as from a central hub to one or more remote devices (e.g., a full hub-and-spoke layout). In another example, a single multi-function cable can be run almost to a cluster of powered devices and then split, as described in U.S. Patent Application No. 15 / 918,972, filed March 12, 2018 ("Splitting of Combined Delivery Power, Data, and Cooling in a Communications Network"), which is incorporated herein by reference in its entirety. High power applications raise further safety concerns and may require additional testing or safety checks at start-up and during power transfer.

[0015] The embodiments described herein provide for the safe delivery of high power over data in a network system (also referred to herein as advanced power over data or extended safety power (ESP)) through the use of pulsed power with fault detection and safety protection. Power may be transmitted in a network system (e.g., a network communication system) with or without communication. As used herein, the term "pulsed power" refers to power delivered in pulses that vary between a very small voltage (e.g., close to 0V (volts), 3V) during a pulse-off interval and a larger voltage (e.g., 12V or more) during a pulse-on interval. High-voltage pulsed power (e.g., greater than 56V, 60V or more, 300V or more) may be transmitted from a power sourcing equipment (PSE) to a powered device (PD) and used to power the powered device, while low-voltage pulsed power (low-voltage pulse) (e.g., about 12V, 30V or less, 56V or less) may be used for short intervals for start-up (e.g., initialization, synchronization, charging local energy storage, powering up a controller, testing, or any combination thereof). As described in detail below, an initialization process (either a low-voltage or high-voltage initialization process) may be performed before transmitting high-voltage pulsed power to synchronize the PSE and PD and provide a safe start-up. The initialization process may include, for example, safety tests including cable capacitance tests, and synchronization of modulator switch (pulse) timing between the power sourcing equipment and the powered device. As described below, initialization may be performed for multiple phases in a multi-phase pulsed power system and various network topologies.

[0016] For example, as described in U.S. Patent Application Serial No. 16 / 380,954, filed April 10, 2019, entitled "Multiple Phase Pulse Power in a Network Communications System," which is incorporated herein by reference in its entirety, one or more embodiments may use multiple phase (polyphase) pulsed power to achieve lower losses, substantially 100% duty cycle power delivery to the powered device (e.g., continuous uninterrupted power to the output with overlapping phase pulses), while increasing the reliability of each power connection to deliver high power and providing safe operation over extended lengths of cable. A multiple pair cable may be used, e.g., with DC pulses on each pair, timed to provide 100% net duty cycle continuous power at the powered device (or load). Pulsed power delivery may occur, for example, over cables, transmission lines, bus bars, backplanes, PCBs (printed circuit boards), and power distribution systems.

[0017] The ESP system can test network devices or cables to identify faults or safety issues. The system can be configured to identify, for example, transmission errors, phase faults (in multi-phase systems), overcurrents, arcing events, time-based control synchronization faults, MAC drops, or other communication or power faults or errors. These faults can be identified on a per-phase basis in multi-phase systems. As described below, low-voltage initialization can be used to start up (or restart) to test the network and components (described below with respect to the flowchart in FIG. 4). High-voltage initialization (described below with respect to the flowchart in FIG. 5) can also be used to allow the addition of new PDs or hot-swap replacement of PDs without the need for a low-voltage initialization process.

[0018] In addition to performing tests at start-up and initialization, tests can be performed continuously during high voltage operation to safely power the ESP system. In one or more embodiments, fault sensing can be performed through low voltage safety checks combined with digital interlocks that use data systems to provide feedback on the state of the power system and set the power operating mode, as described in U.S. Patent Application Serial No. 15 / 971,729, filed May 4, 2018, entitled "High Power and Data Delivery in a Communications Network with Safety and Fault Protection," which is incorporated herein by reference in its entirety. Fault sensing can be performed during low voltage start-up or between high power pulses in a pulsed power system. Pulsed power can include source voltage pulsed power (unipolar or bipolar), or load current pulsed power with low voltage fault detection between high voltage power pulses. Fault sensing can include, for example, line-to-line fault detection with low voltage sensing of the cable or powered device, and line-to-ground fault detection with a neutral ground. Touch-safe fault protection can also be provided by cable and connector designs that are touch-safe even when high voltages are applied. Power safety features provide for safe system operation and possibly the installation and removal (disconnection) of components, including replacing components without interfering with normal operation of the system (ie, hot-swappable).

[0019] The off-time between pulses may be used, for example, for line-to-line resistance testing of faults, and the pulse width may be proportional to the DC line-to-line voltage (e.g., about 1 ms at about 1000V) to provide touch-safe fault protection. Tests (fault detection, fault protection, fault sensing, touch-safe protection) may include auto-negotiation between the PSE and the PD. Auto-negotiation may use low voltage (e.g., 24VDC (Volts Direct Current) or less, 5-12VDC, 56VDC, or other suitable low voltage (e.g., less than 60VDC)) resistance analysis. Pulsed power high voltage DC may be used with pulse-to-pulse determination for touch-safe line-to-line fault investigation between pulses for personal safety. For line-to-line contact shock protection, source pulse off-time between pulses may be provided for resistance across the line detection between pulses.

[0020] During high voltage operation as part of the use of high resistance neutral ground circuits, ground-fault-detection (GFD) and ground-fault-isolation (GFI) line-to-ground fault detection can be implemented to provide fast high voltage shutdown with ground fault protection (shock protection). High voltage DC supply line-to-ground fault protection circuits can be used to quickly turn off the power supply and provide touch-safe shock protection. GFD and GFI can provide shutdown in about 10 μs (microseconds), for example. The neutral grounding method with the power supply can also be used to allow higher peak pulse line-to-line voltages within the wire / conductor insulation and insulation rating for line-to-ground protection and also provide touch-safe line-to-ground faults for personal safety and to meet safety standards. The system can also be designed with adjustable time and current vs. voltage for personal shock protection.

[0021] In one or more embodiments, the system may also test for heat buildup using thermal modeling of the cable, as described in U.S. Patent Application No. 15 / 604,344, entitled "Thermal Modeling for Cables Transmitting Data and Power," filed May 24, 2017, which is incorporated herein by reference in its entirety. For example, heat buildup may be detected by tracking changes in cable current and calculating cable current temperature. Cable temperature is a function of amperage, cable gauge, and cable length. Using known parameters and assuming a wire size (e.g., 22 AWG), the temperature limit of the cable in a bundle environment may be calculated. Temperature ranges may be defined, for example, as normal, minor, major, and critical (e.g., minor is defined within 20°C of the cable temperature limit, major is defined within 10°C of the cable temperature limit, and critical is defined at the cable temperature limit). If the temperature range is within the minor range, the system may force a power renegotiation to reduce the current on the line. If the temperature is within a critical range, the port may be de-energized. Temperature may be calculated for each wire, each wire pair, the 4-pair cable, or any combination thereof.

[0022] In one or more embodiments, the system may also perform wire fault and electrical imbalance detection, as described in U.S. patent application Ser. No. 16 / 020,881, entitled "Wire Fault and Electrical Imbalance Detection for Power over Communications Cabling," filed Jun. 27, 2018, which is incorporated by reference in its entirety.

[0023] In one or more embodiments, the PSE can inform the PD of the power levels it can provide, and the PD can then select the appropriate power level to use. The PSE and PD can negotiate a power level, for example, 15W, 30W, 60W, 90W, 150W, 200W, 250W, 300W, or any other appropriate power level. If no fault is detected, the system can auto-negotiate up to the maximum power available. If the power is increased, fault detection may continue as described above. Fault detection may include, for example, a heat buildup check, an electrical imbalance check (wire-to-wire imbalance check, pair-to-pair imbalance check), or a short circuit / fault protection check. The system may be configured to perform one or more of these checks in any order, or to perform several steps simultaneously. One or more of the safety checks may be performed continuously or at specific intervals. For example, the wires may be monitored one by one in a continuous loop within a 10 millisecond window. If a fault is detected or a particular PSE voltage is exceeded, the power output is shut down. If the fault is minor (e.g., one or more parameters are close to but not over the limit), the power may be reduced by renegotiating the power level. If the fault persists, the port may be shut down. An alarm may also be generated. In one or more embodiments, packet and idle (link) monitoring may be used to shut down the power. If the wire is lost, the link is lost, providing per-wire fault protection.

[0024] Actions based on the monitored (or calculated) current can also be taken. For example, if the cable current exceeds the maximum cable current limit, the port may be shut down. If the cable current reaches a certain range, the line card (PD) may be forced to perform a power negotiation with the PSE to reduce the current on the line. The current may be monitored per wire, per wire pair, per cable, or any combination. The current ranges may be defined as normal, minor, major, and critical (e.g., minor is defined within 20% of maximum current, major is defined within 10% of maximum current, and critical is defined at maximum current). If the range is minor, a renegotiation may be performed to reduce the cable current. If the critical current is reached, the port may be de-energized.

[0025] In one or more embodiments, one or more parameters may be user-defined. For example, cable impedance, cable length, cable gauge, and cable voltage rating may be set for an ESP system or link. The ESP system may set a maximum voltage, maximum current, or maximum power based on these parameters. As described herein, the system may perform cable safety testing based on cable capacitance. The system may also perform GFI and line-to-line fault testing, as described above for low and high voltage. If a fault is identified, the system may set a fault latch and attempt one or more automatic restarts. One or more components in the ESP system may include one or more visual indicators (e.g., LEDs (light emitting diodes)) to identify, for example, low voltage operation, high voltage operation, or system / component / cable faults.

[0026] In one or more embodiments, machine learning can be implemented by periodically monitoring and collecting data (e.g., current, voltage, cable capacitance, faults, temperature, etc.) to further define tolerance limits and account for variations in electrical performance based on cable, environment, or component aging. For example, analytical models can be defined and updated based on data trends used to update voltage, load current, and operational limits to account for variations in electrical parameters to avoid false system failures.

[0027] In one or more embodiments, as described below, the PSE can provide over 100 W over a combined cable for power and data (e.g., over copper or fiber optics) along with data to multiple PDs. In one or more embodiments, the system can safely provide over 2000 W of power over cable lengths of over 1500 meters. The system can also safely provide higher power (e.g., 6000 W) over cable lengths of less than 25 meters, which is highly beneficial for decentralizing large enclosure systems and eliminating backplane / large enclosure system designs. It should be understood that the power levels and cable distances described herein are provided as examples and that other power levels provided over different cable lengths may be used without departing from the scope of the embodiments.

[0028] The system may be configured to meet safety standards, including, for example, IEC (International Electrotechnical Commission) Standard No. 62368-3:2017 ("Audio / video information and communication technology equipment-Part 3:Safety- aspects for DC power transfer through communication cables and ports"), IEC 60950-1:2005 ("Information technology equipment-Safety-Part 1:General requirements"), IEC 60947 ("Low-voltage switchgear and control gear"), or any other suitable standard that provides touch-safe shock protection for personnel in high voltage (higher power) applications of the extended safety power system. The system may be configured to limit shock currents, for example, across HVDC power (e.g., 1100V, 550V, 380V) to a line-to-ground fault limit of about 5mA (e.g., less than 10mA) and line-to-line fault limit of about 0.5A for 1 millisecond using about 2.5kohm (e.g., for short cable runs or smart digital sensing technology). In another example, the worst case shock exposure time may be 12 milliseconds. To meet safety standards, appropriate techniques (e.g., fail-safe safety agency approved listed components, redundant circuitry or redundant components) may be employed.

[0029] The off-time of the pulse may be configured based on the capacitance of the cable pair, and the maximum pulse power on-time may be designed to be below the limits set by the body shock current and standards (e.g., UL (Underwriters Laboratories) Standards 62368 and 60950, or NFPA (National Fire Protection Association) NEC (National Electrical Code) 70 Chapters 7, 8, and 9, Tables 11A and 11B, IEC / TR 60479-5, 60479-1, IEC-60947-1, IEC-60947-2, IEC-60947-3, IEC-60335-1, IEC-60990, IEC-60065, IEC-61000-4, or any other suitable standard or requirement). In one or more embodiments, the on-time and off-time pulse widths may be dynamically set in response to changes in cable characteristics. Continuously supplying net current to the PD may be necessary to determine the phase relationship of the pulses in a multiple transmission pair system. The embodiments described herein may be configured to meet single fault protection or other safety requirements. It should be understood that the standards and limits discussed herein are provided by way of example only, and that other safety limits or standards may be used without departing from the scope of the embodiments.

[0030] Referring now to the drawings, and initially to FIG. 1, an example of a communication network in which embodiments described herein may be implemented is shown. For simplicity, only a few nodes are shown. The embodiments operate in the context of a data communication network including multiple network devices. The network may include any number of network devices communicating through any number of nodes (e.g., routers, switches, gateways, controllers, access points, or other network devices) that facilitate the passage of data within the network. The network devices may communicate through or with one or more networks (e.g., a local area network (LAN), a metropolitan area network (MAN), a wide area network (WAN), a virtual private network (VPN) (e.g., Ethernet Virtual Private Network (EVPN), Layer 2 Virtual Private Network (L2VPN)), a virtual local area network (VLAN), a wireless network, an enterprise network, a corporate network, a data center, an Internet of Things (IoT) network, the Internet, an intranet, or any other network).

[0031] In one or more embodiments, the network is configured to pass power along with data and provide both data connectivity and power to network devices such as switches 14, routers, access points 15, or other electronic components and devices. Signals may be exchanged between communications equipment and power transmitted from power sourcing equipment (PSE) 10 to powered devices (PDs) 14, 15, 17, 19. In one or more embodiments, the system provides power to and from the network (e.g., switch / router system) using an interface module 16 (e.g., an optical transceiver module) configured to transmit and receive both data (fiber delivered data) and power (high power energy). In one or more embodiments, power and data may be provided over cables including both optical fibers and electrical wires (e.g., copper wires), as described in U.S. Patent Application Serial No. 15 / 707,976, filed September 18, 2017 ("Power Delivery Through an Optical System"), which is incorporated herein by reference in its entirety. In one or more embodiments, the system may further provide cooling and combine power, data, and cooling in a single hybrid cable system, for example as described in the above-referenced U.S. patent applications Ser. Nos. 15 / 910,203 and 15 / 918,972.

[0032] As shown in the example of FIG. 1, the system can use building power provided to a central network device (hub) (PSE) 10, which may be located, for example, in a premises / entry room. Power can be transmitted from building entry points to endpoints (switches 14, access points 15) and / or at power levels greater than 100 W (watts) (e.g., 250 W, 500 W, 1000 W, 2000 W, or any other power level), where the endpoints may be located at distances greater than 100 meters (e.g., 1 km (kilometer), 10 km, or any other distance). The central network device 10 comprises a power supply unit (PSU) 11 and network interfaces (e.g., fabric 12, line cards 13) for receiving and distributing power (e.g., building power from a power grid, renewable energy sources, generators, or batteries). In the example shown in FIG. 1, line card A receives data from outside the building (e.g., the street or other location), and line cards B, C, and D distribute power and data.

[0033] The central hub (combined power and data source) 10 is operable to provide bulk power from an internal power system (e.g., a PSU 11 capable of supplying power of 5 kW, 100 kW, etc. or more, and capable of driving a number of devices 14, 15, each in the range of 100 W to 3000 W (e.g., 100 W or more, 900 W or more, 1000 W or more) or any other suitable power range. The PSU 11 may provide, for example, PoE (Power over Ethernet), PoF (Power over Fiber), HVDC (High Voltage Direct Current), Pulsed Power HVDC, or AC (Alternating Current). The central network device 10 receives external power and transmits power from a communications network (e.g., the central hub 10 (PSE) and multiple The central network device 10 may be operable to transmit power over a composite cable 18 for power and data delivery within a network including a number of network devices 14, 15, 17, 19 (PDs). The central network device 10 may include, for example, a router, a convergence system, or any other suitable line card system. It should be understood that this is merely an example and that any other network device operable to transmit power and optical data may be used. One or more of the line cards 13 may also include an interface module 16 (shown in the remote network devices 14, 15) operable to transmit power and data over the cable 18.

[0034] The network may include any number or arrangement of network communication devices (e.g., switches 14, access points 15, routers, or other devices operable to route (switch, forward) data communications). In one example, the network includes multiple groups of access points 15, each group located on a different floor or zone. One or more of the network devices 14, 15 may also use PoE to provide power to downstream nodes (e.g., PoE devices 19). For example, one or more of the network devices 14, 15 may use PoE to provide power to electronic components such as IP (Internet Protocol) cameras, VoIP (Voice over IP) phones, video cameras, point of sale devices, security access control devices, residential devices, building automation devices, industrial automation devices, factory equipment, lighting (building lighting, street lights), traffic signals, fog nodes, IoT devices, sensors, and many other electrical and electronic components and devices. In one or more embodiments, a redundant central hub (not shown) may provide backup or additional power or bandwidth as needed in the network. In this case, the remote network devices 14, 15 would include another interface module 16 for connecting to another cable 18 that provides power and data from the redundant central hub. As described in more detail below, the network can be arranged in a variety of topologies including, for example, point-to-point, daisy-chain, multi-drop, or hybrid multi-drop / daisy-chain for providing high voltage pulsed power to downstream devices (e.g., PD 17 in communication with switch 14).

[0035] As previously mentioned, the central hub 10 may provide power and data directly to each network device 14 (point-to-point connection as shown by the switch 14 connected to line cards B and D in FIG. 1), or may use one or more splitter devices (not shown) to connect multiple network devices, allowing the network to go beyond a point-to-point topology and build passive stars, buses, tapers, multi-layer trees, and the like. For example, a single long cable 18 may be routed to a conveniently located intermediate splitter device (e.g., a passive splitter) that serves a cluster of physically close endpoint devices. One or more control systems for power and data may interact between the central hub 10 and the remote devices 15 (and their interface modules 16) to ensure that each device receives a fair share of each resource from the splitter devices, as described in the above-referenced U.S. patent application Ser. No. 15 / 918,972.

[0036] In one or more embodiments, the cable (composite cable, multifunction cable, multipurpose cable, hybrid cable) 18 extending from the network device 10 to the switch 14 and the access point 15 is configured to transmit power and data and includes both optical fiber and wires. The cable 18 may include, for example, two power lines (conductors) and two data lines (optical fiber). This is merely one example, and it should be understood that the cable 18 may include any number of power or data lines. For example, instead of using two optical fiber paths to transmit data from the central hub 10 to the remote devices 14, 15 and from the remote devices to the central hub, a bidirectional optical system may be utilized where one wavelength of light goes downstream (from the central hub 10 to the remote devices 14, 15) and a different wavelength of light goes upstream (from the remote devices 14, 15 to the central hub 10), thereby reducing the number of fibers in the cable from two to one. The cable 18 may also include additional optical fiber or power lines. Cable 18 may be formed from any material suitable for carrying both power and optical data (e.g., copper, fiber) and may carry any number of electrical wires and optical fibers in any arrangement. Cable 18 may transmit one or more of power, data (electrical), data (optical), and cooling.

[0037] As mentioned above, the cable 18 may also carry cooling for thermal management of the remote network communication devices 14, 15. For example, in one or more embodiments, the cable 18 extending from the central hub 10 to the remote network devices 14, 15 may be configured to transmit a combination of power, data, and cooling in a single cable. In this embodiment, the cable 18 may be formed from any material suitable for carrying power, data (e.g., copper, fiber), and coolant (liquid, gas, or multi-phase) and may carry any number of electrical wires, optical fibers, and cooling tubes in any arrangement.

[0038] The cable 18 includes a connector at each end configured to mate with an interface module 16 at the network device 10, 14, 15. The connector may include a combination connector (copper and fiber hybrid) for power and data configured to connect to an optical transceiver, for example, as described in the above-referenced U.S. patent application Ser. No. 15 / 707,976. The connector may include, for example, a modified RJ-45 type connector.

[0039] In one or more embodiments, the connector and cable 18 are configured to meet standard safety requirements for line-to-ground and line-to-line protection at the relevant high voltages by means including clearance and creepage distances, and touch-safe technology. The connector may include safety features including, for example, shorting pins for hot plugging and hot unplugging without current surge or interruption for arc protection of the connector. The connector may further include additional insulating material for hot plugging and hot unplugging with current surge or interruption with arc flash protection, and reliability life from arcing. The power connector terminals of the insulated cable are preferably configured to meet the requirements for touch voltage or current accessibility.

[0040] As previously mentioned, one or more of the network devices 10, 14, 15 may include an interface module 16 operable to provide a combination of power and data from the PSE 10 or receive a combination of power and data at the PD 14, 15. In one or more embodiments, the interface module 16 may comprise an optical transceiver module configured to provide (or receive) power along with optical data. For example, in one embodiment, the interface module 16 includes a modified transceiver module incorporating copper wires with a fiber connector system to provide power via an optical transceiver to the powered device 14, 15 for use by the network communications device, as described in U.S. Patent Application No. 15 / 707,976, referenced above, or U.S. Patent Application No. 15 / 942,015, filed March 30, 2018, entitled "Interface Module for Combined Delivery Power, Data, and Cooling at a Network Device," which is incorporated herein by reference in its entirety. It should be understood that these are merely examples of interface modules that may be used to provide or receive high power and optical data.

[0041] The interface module 16 (optical module, optical transceiver, optical transceiver module, optical device, optical module, silicon photonics module) is configured to provide or receive power. The interface module 16 operates as an engine to convert optical signals to electrical signals bidirectionally, or generally as an interface to copper or optical fibers of the network elements. In one or more embodiments, the interface module 16 may include a pluggable transceiver module of any form factor (e.g., SFP (small form-factor pluggable), QSFP (quad small form-factor pluggable), CFP (C form-factor pluggable), etc.) and may support data rates of up to 400 Gbps, for example. Hosts of these pluggable optical modules include line cards 13, switches 14, access points 15, or other network devices of the central network device 10. The hosts may include electronic components and circuits operable to interface printed circuit boards (PCBs) with telecommunication lines in a telecommunication network. The host may be configured to accept any number or type of pluggable transceiver modules configured to perform one or more operations and to transmit and receive signals.

[0042] It may also be seen that the interface module 16 may be configured to operate in a point-to-multipoint or multipoint-to-point topology. For example, QFSP may break out to SFP+. One or more embodiments may be configured to enable load shifting. The interface module 16 may also be configured to operate with AOC (active optical cable) and with form factors used in UWB (ultra-wideband) applications, including, for example, Ultra HDMI (high-definition multimedia interface), serial high bandwidth cable (e.g., Thunderbolt), and other form factors.

[0043] The interface module 16 provides the power supplied to the switches 14 and access points 15 in locations where standard power is not available. The interface module 16 may be configured to utilize a portion of the energy to make intelligent decisions, as described below, so that the power source 10 knows when it is safe to increase the power on the lines without damaging the system or endangering the operators. The interface module 16 may include one or more sensors, monitors, or controllers for use in monitoring and controlling power and data, as described in more detail below with respect to FIG.

[0044] In one or more embodiments, there is no need for additional electrical wiring for the communication network, and all network communication devices operate using power provided by the extended safety power system. In addition to the network devices 10, 14, 15 including interface modules 16 operable to transmit and receive power over wires and optical data over fiber, the network may also include one or more network devices including conventional optical modules that process and transmit only optical data. These network devices receive power from a local power source, such as a wall outlet. Similarly, specialized variations of the transceivers 16 may eliminate the optical data interface and interconnect only power (e.g., moving the data interconnect to a wireless network). As previously mentioned, one or more network devices may also receive cooling over the cables 18 in addition to power, data, or power and data.

[0045] In one or more embodiments, a distributed control system including components located on a controller at a central hub and processors at remote devices may communicate over fiber links in composite cable 18. Monitoring information from power sensors (e.g., current, voltage) or data usage (e.g., bandwidth, buffer / queue size) may be used by the control system in managing or allocating power or data.

[0046] The system may be configured to deliver PoE, PoF, high voltage DC (HVDC), AC power, pulsed power, multi-phase pulsed power, or any combination thereof. HVDC power may include steady state HVDC or pulsed power HVDC. Steady state HVDC and pulsed power HVDC may be unipolar or bipolar (switching DC) as described in the above-referenced U.S. patent application Ser. No. 15 / 971,729. In one or more embodiments, the system may employ a dual power mode with detection and negotiation between the power source 10 and the powered devices 14, 15. This negotiation distinguishes and accommodates different power delivery schemes, such as standard PoE or PoF, high power, pulsed power, or other power modes that can be powered via the interface module 16. For example, standard PoE distribution can be used for remote network devices rated at less than about 100 W. For high power remote powered devices, pulsed power or other high voltage technologies can be used to create an efficient energy distribution network.

[0047] As described in detail below, the remote network devices 14, 15, 17 can communicate their power and data requirements to the central network device 10 using a small amount of power at startup. The powered devices 14, 15, 17 can then configure themselves for full power operation accordingly. In one example, the power type, safe operation of the modules, and data rates are negotiated between the central hub (PSE) 10 and the network devices 14, 15, 17 via data communication signals over optical fiber. The interface module 16 communicates any operational failures, including loss of data. Such failures may result in power being immediately turned off or switching to a low power (low voltage) mode. Full power supply may not be re-established until the powered devices are again able to communicate in a low power mode where higher power can be safely applied.

[0048] It should be understood that the above-mentioned network devices and topologies shown in FIG. 1 are merely examples, and the embodiments described herein may be implemented in networks including different network topologies or network devices without departing from the scope of the embodiments. The network (or one or more portions of the network) may be configured for power delivery only, or for power and communication. The network may include any number or type of network communication devices (e.g., routers, switches, gateways, controllers) that facilitate the passage of data through the network, network elements (e.g., servers, virtual machines, clients) that act as endpoints or hosts, and any number of network sites or domains in communication with any number of networks. Thus, the network nodes may be used in any suitable network topology, which may include any number of servers, virtual machines, switches, routers, or other nodes interconnected to form large, complex networks, which may include cloud computing or fog computing. The nodes may be coupled to other nodes or other networks via one or more interfaces employing any suitable connections, which provide viable paths for electronic communication along with power.

[0049] FIG. 2 illustrates an example of a network device 20 (e.g., central hub (PSE) 10, switch (PD) 14, access point (PD) 15 of FIG. 1) that may be used to implement the embodiments described herein. In one embodiment, the network device 20 is a programmable machine that may be implemented in hardware, software, or any combination thereof. The network device 20 includes one or more processors 22, sensors 23 (e.g., power sensors (e.g., voltage, current sensors), communication sensors, thermal sensors), memory 24, interfaces 26, optical modules 28 (e.g., power+optical interface module 16 of FIG. 1), and a power module / controller 29. The network device may also include one or more cooling components 21 (sensors, control valves, pumps, etc.) if the system is configured for combined power, data, and cooling supply.

[0050] Memory 24 may be a volatile memory or non-volatile storage device that stores various applications, operating systems, modules, and data for execution and use by processor 22. For example, components (e.g., code, logic, firmware, etc.) of optical module 28 or controller 29 may be stored in memory 24. Network device 20 may include any number of memory components.

[0051] Network device 20 may include any number of processors 22 (e.g., single-processor or multi-processor computing devices or systems), which may be in communication with a forwarding engine or packet forwarder operable to process packets or packet headers. Processor 22 may receive instructions from a software application or module, which causes the processor to perform the functions of one or more embodiments described herein. Processor 22 may also operate one or more components of power control module 29 for fault detection, auto-negotiation, digital interlock, synchronization, multi-phase control, pulsed power control, low voltage, high voltage control, modulator switch control, etc.

[0052] The controller (power module / controller) 29 may be configured for auto-negotiation, fault detection, initialization, digital interlock, synchronization, multi-phase control, pulsed power control, or other control or management functions. The control system 29 may include components (modules, code, software, logic) located in the central hub 10 and the remote devices 14, 15 and interconnected via a composite cable 18 for power and data (FIGS. 1 and 2). The control system 29 may also receive inputs from power sensors or data monitoring devices, as described below with respect to FIG. 3. The power module / controller 29 of the PD may communicate with the control system of the PSE 10 to initialize operation, synchronize operation (e.g., pulse waveform, current, voltage), auto-negotiate the state of the power system, identify any faults in the power system (e.g., cable or powered device), select a power operating mode, or any combination thereof. As previously described, auto-negotiation may be performed during low-voltage start-up or between pulses in a pulsed power system. One or more control system or power module components may be disposed in the light module 28 .

[0053] The logic may be encoded in one or more tangible media for execution by the processor 22. For example, the processor 22 may execute code stored in a computer-readable medium, such as the memory 24. The computer-readable medium may be, for example, an electronic medium (e.g., RAM (random access memory), ROM (read only memory), EPROM (erasable programmable read only memory)), a magnetic medium, an optical medium (e.g., CD, DVD), an electromagnetic medium, a semiconductor technology medium, or any other suitable medium. In one example, the computer-readable medium includes a non-transitory computer-readable medium. The logic may be used to implement one or more functions described below with respect to the flowcharts of FIG. 4, FIG. 5, and FIG. 7.

[0054] The interfaces 26 may include any number of network interfaces (line cards, ports, connectors) for receiving data or power or for transmitting data or power to other devices. The network interfaces may be configured to transmit or receive data using a variety of different communication protocols and may include mechanical, electrical, and signal circuits for communicating data over a physical link coupled to the network interface. For example, a line card may include a port processor and a port processor controller. The interfaces 26 may include one or more optical and electrical interfaces. If the system is configured for cooling, the interfaces 26 may also include a fluid port. One or more of the interfaces 26 may be configured for PoE+F+C (Power over Ethernet+Fiber+Cooling), PoE+F, PoE, PoF, high voltage pulsed power, multi-phase pulsed power, or similar operation.

[0055] The optical module 28 may include logic, firmware, software, etc. for use in monitoring or controlling the extended safety power system. For example, the optical module 28 may comprise hardware or software for use in power detection, system startup, synchronization, power monitoring and control, or power enable / disable. The optical module 28 may further comprise one or more of a processor or memory component, or an interface 26 for receiving or providing power and data. As previously mentioned, in one or more embodiments, power is provided to the optical module by the power source 27, and the optical module 28 provides power to the remaining components of the network device 20.

[0056] It should be understood that the above-described network device 20 shown in Figure 2 is merely an example, and different configurations of network devices may be used. For example, network device 20 may further include any suitable combination of hardware, software, algorithms, processors, devices, components, or elements operable to facilitate the functions described herein.

[0057] FIG. 3 is a block diagram illustrating components for use in power monitoring and control, startup, synchronization, auto-negotiation, and fault protection in network device 30, according to one embodiment. One or more of the components shown in FIG. 3 may be located in interface module 16 or in communication with one or more components of an interface module (FIGS. 1 and 3). A cable 18 carrying both high power and data is shown with a cable connector 36 coupled to the interface module in FIG. 3. Power is received at electrical interface 37a and data is transmitted and received at optical interface 37b, both of which may be located in optical module 16. Connector 36 may include, for example, a single physical component or a single component with modular parts for each function.

[0058] The network device 30 includes an optical / electrical component 31 for receiving optical data and converting it to an electrical signal (or converting an electrical signal to optical data), and a power component including power detection modules 32a, 32b, a power monitoring and control module 33, and a power enable / disable module 34. Although PoE and pulsed power are described in conjunction with the detection elements 32a, 32b, it should be understood that other power supply methods including AC, DC, and USB may be supported with similar elements. Also, the types of power may be divided into high voltage power and low voltage power. The power components may be isolated from the optical components 31 via isolation components (e.g., insulating materials or elements) that electromagnetically isolate the power circuit from the optical components to prevent interference with the operation of the optical components. The network device 30 may include an auto-detection module 35 that operates with the pulsed power detection module 32a and the PoE detection module 32b. The module 35 may also operate to select a power supply mode (e.g., PoE or pulsed power) based on which supply mode is more efficient based on the operation of the network device. The functionality of one or more of the detection elements 32a, 32b, the auto-detection module 35, the power monitoring and control module 33, or the auto-negotiation module 39 may be combined into a power module and operated within an interface module.

[0059] The auto-negotiation / digital interlock module 39 may be used in implementing one or more fault detection, auto-negotiation, or digital interlock processes. As described in more detail below, auto-negotiation may include communication between the PSE and the PD, and interaction between a controller of a central network device and a controller of a remote network device. As described below with respect to Figures 10A-13B, a gating / modulator 40 may be provided to isolate one or more circuits and modulate pulsed power during system initialization or testing. The network device 30 may further include a bootstrap / housekeeping circuit 38 used during device startup and testing, as described below. One or more control signals or supervisory information may be transmitted over the data lines (e.g., optical fiber) or power lines of the power and data hybrid cable 18 to provide the operating status (e.g., fault / no fault) of the network device, cable, or power circuit.

[0060] 3, each module 32a, 32b is in communication with its own power monitoring and control module 33 and power enable / disable module 34. The circuitry detects the type of power applied to the network device 30, determines whether PoE or pulsed power is the more efficient power delivery method, and then uses the selected power delivery mode. In one or more embodiments, PoE or high voltage pulsed power can be transmitted over the same cable 18.

[0061] The network device 30 is configured to calculate available power and prevent the cable system from being energized when power should not be provided. The power monitoring and control module 33 continuously monitors the power supply to ensure that the system can support the required power supply and does not exceed safety limits (e.g., voltage, current). The power monitoring and control module 33 can also monitor the optical signal and disable power in the absence of optical transitions or communication with the power source. The power monitoring and control function can sense voltage and current flow and report these readings to a central control function. In one embodiment, the network device 30 communicates its power and data requirements and status using a small amount of low voltage power (e.g., 12V or less, 24V or less, 60V or less) upon startup or restart. The network device 30 can then be configured for full power operation (e.g., above 60V, 300V or more, 500V or more, 1000V or more) (e.g., high power enable / disable module 34) if no faults are detected or a safe condition is detected. If a fault is detected, full power operation may not be established until the network devices are communicating in a lower power mode in which high power can be safely applied. The auto-negotiation module 39 communicates with the central network device's control system to select a safe mode of operation (e.g., determine that it is safe to apply high voltage power), identify faults in the circuit (e.g., line-to-line or line-to-ground fault detection), and shut down power if a fault is identified during testing between high voltage pulsed power at start-up or during normal operation. As described below, power may be supplied with or without communication.

[0062] It should be understood that the system shown in Figure 3 is merely an example, and that components may be added, removed, combined, or rearranged without departing from the scope of the embodiments. For example, as previously mentioned, the network device may also be configured without optical interface 37b and optical component 31.

[0063] As described below, the initialization process may be performed at low voltage (FIG. 4) or high voltage (FIG. 5). The high voltage initialization process may be used, for example, to add a new PD or replace a hot swap PD or to simplify the power initialization process, but provide another layer of high voltage safety instead of low voltage safety initialization. FIG. 7 illustrates cable capacitance and shock disturbance testing that may be performed at start-up or any other time to determine if additional cable length has been added. Simplified block diagrams and circuits are shown for cable capacitance and shock disturbance testing (FIGS. 9A and 9C), synchronization after initial power up (FIG. 10A), initial low voltage start-up (FIGS. 11A, 11C, 12A, 12B, and 12C), and initial high voltage start-up (FIG. 13A) according to one or more embodiments. It should be understood that the processes and circuits described herein shown in FIGS. 4-14 are shown for one phase for simplicity, and that these processes and circuits may be replicated for each phase of a multi-phase system, as described below with respect to FIGS. 20-22.

[0064] As described in more detail below, PD initialization may include powering up an initial PD housekeeping voltage with the PD modulator switch off to power the transceiver, PD modulator gate, and microcontroller / DSP. The PD housekeeping voltage may occur during the on-time of the PSE modulator by synchronizing the power converter load operation with the cable voltage waveform. As previously mentioned, initialization may include low-voltage initialization or high-voltage initialization. In one low-voltage initialization example, a low voltage (e.g., 24 VDC) may be applied before switching to a high voltage (e.g., 380 VDC). This may include a long initial on-time period to fully power up the DC housekeeping capacitor to reduce start-up time and then only draw power during the high-voltage pulse. In high-voltage initialization, a short high-voltage pulse may be used to add high-voltage protection during initialization. In another high-voltage initialization example, a nominal time (normal operating pulse width) operating high-voltage pulse and duty / frequency may be used as required for safety testing, including cable capacitance testing. This high-voltage initialization process can be used, for example, for PD hot swap replacement or adding a new PD to a cable with a high-voltage pulse (high-voltage pulse power of the cable).

[0065] In one or more embodiments, low-voltage initialization at the PSE includes transmitting low-voltage pulsed power from the PSE to the PD, performing safety tests (e.g., safety body impact protection test, cable capacitance test), and enabling high-voltage pulsed power operation at the power supply equipment if the safety tests pass. During low-voltage initialization, the PD synchronizes with the waveform of the low-voltage pulsed power. For example, a modulator switch of the PD may be synchronized with a modulator switch of the PSE. As used herein, the term "modulator switch" may refer to one or more modulator switches (e.g., one or more switches with a common control), power modulators, pulse modulators, pulse power modulators, control switches, gate controls, isolation switches, or similar components or groups of components operable to perform the functions described herein. Synchronization may continue during operation of the high-voltage pulsed power.

[0066] In one or more embodiments, low-voltage initialization at the PD includes receiving low-voltage pulsed power from the PSE at the PD, synchronizing the powered device with a waveform of the low-voltage pulsed power received from the power supply equipment, and operating the PD with the high-voltage pulsed power received from the power supply equipment. During initialization at the PD, the modulator switch may be open while energizing housekeeping circuits at the PD. The modulator switch may then be turned on while capacitance and safety tests are performed by the PSE.

[0067] As used herein, the term "synchronize" should be understood to refer to the coordination of pulses at the PSE and PD, for example, via the adjustment of the PSE and PD modulator switch drive or one of the modulator switches with a voltage waveform. Synchronization is used to align the pulses (modulator switches) at the PSE and PD, which may result in a difference in pulse width (modulator switching) between the PSE and PD. For example, as described below with respect to Figures 23 and 24, synchronization may result in a smaller pulse width at the PD than at the PSE. As described below, off / on synchronization between the PSE and PD is performed during initialization and may be updated based on, for example, PSE safety testing or changes in the network (e.g., cable changes, addition of new network devices).

[0068] FIG. 4 shows an overview of the low voltage initialization process, according to one embodiment. In step 41, the PSE (e.g., PSE 10 in FIG. 1) turns on. In one example, the PSU 11 provides 24VDC through a diode to the PSE modulator switch input (shown in FIG. 11A). A low voltage is provided to the PSE modulator switch input, and the modulator switch begins switching at a startup duty cycle, thereby sending low voltage pulsed power (low voltage pulses) to the PD (step 42). In one example, the duty cycle consists of 8ms (milliseconds) on and 4ms off for a period of 12ms (66.7% duty cycle). In step 43, the PD starts up. As described below with respect to FIG. 11A, the PD can use a housekeeping and floating gate voltage of 12 / 3.3V. The PD modulator switch synchronizes with the PSE modulator switch based on the PSE voltage waveform received at the PD (step 45). This allows the PD and PSE to agree on the timing of the modulator switch before the high voltage pulse power is enabled. The PD transceiver and DSP (digital signal processor) (shown in FIG. 8 (85b, 86b)) (or MCU (microcontroller)) start operation and the PD starts a PLL (phase-locked loop) or DLL (digital-locked loop, delay-locked loop) to synchronize the PD modulator switch on / off with the PSE voltage waveform. Details of the synchronization are described below with respect to FIG. 10A and FIG. 10B. In one example, the PD and PSE start communicating when the PD modulator switch is turned on (step 44) and communicate until it is turned off / on with modulation (after step 43 and before the PD starts the PLL and synchronizes the modulator in step 45). In another example, the PD and PSE transceiver start communicating (step 44) during the PD / PSE modulator on time (after the PD starts the PLL and synchronizes the modulator in step 45). It should be understood that a modulator switch being on refers to the switch being closed (current being transmitted through the switch) and a modulator switch being off refers to the switch being open (no current being transmitted through the switch).

[0069] If communication is available, the PD and PSE may optionally auto-negotiate (synchronize) the modulator switch timing (step 46). The PSE performs a capacitance test (step 47a) and a safety test (step 47b). It should be understood that the capacitance test (step 47a) and the safety test (step 47b) may be collectively referred to as a "safety test." The results of the capacitance test may be used to adjust the modulator pulse timing of the PSE and the PD for the calibration and timing of the safety test. For example, the results of the capacitance test may be used to identify minimum off-times and high voltage exposure times, adjust the high voltage exposure times, and set safety fault sensing levels as described below with respect to FIG. 7. The PSE may also collect transmission line parameters (e.g., capacitance) during this test. In one example, the PSE performs a cable leakage test to see if the cable leakage is greater than a certain resistance value (e.g., 100 kohm). If communication is unavailable, static timing parameters may be used. Additional details of cable capacitance and shock fault testing are described below with respect to the flow chart of FIG. 7 and the circuits of FIGS. 9A and 9C. If the PSE safety test fails, an automatic restart may be attempted a set number of times (e.g., 2 times) (steps 42-47b). If the safety test passes, the PSE enables high voltage operation (step 48) (e.g., above 300 VDC). A PD input voltage above the low voltage start-up no-load level (e.g., about 360 VDC) turns on the DC / DC load. The PSE and PD may then agree on voltage and load current synchronization, and high voltage pulsed power operation continues with the PSE transmitting high voltage pulsed power to the PD (step 49). Additional synchronization details are described below with respect to the circuit shown in FIG. 10A.

[0070] FIG. 5 is an overview of a high-voltage initialization process, according to one embodiment. As previously mentioned, high-voltage initialization may be used, for example, to add a new PD or perform a hot-swap (hot plug-in) PD replacement without using the low-voltage initialization procedure described above. High-voltage initialization may also be used to simplify the power initialization start-up process, reducing cost and complexity, while providing another layer of high-voltage safety in lieu of low-voltage initialization. In one or more embodiments, auxiliary power may be provided to the PSE during the initialization phase (LV or HV) to establish control and synchronization of the PSE modulator switch, as well as the communications required to turn the switch on. As described below, cable capacitance and shock fault testing may be followed by a sequence to establish operation and communications (if used) of the modulator switch, and then the high-power high-voltage pulse width modulator switch may be synchronized.

[0071] In one or more embodiments, the powered device receives high-voltage pulsed power from the power supply equipment with a modulator switch of the powered device open, couples an isolated housekeeping voltage at the powered device when the pulses of the high-voltage pulsed power are on, energizes a housekeeping circuit at the powered device, and turns on a modulator switch of the powered device to supply the high-voltage pulsed power to the powered device after a certain number of high-voltage pulses have been received.

[0072] Referring now to FIG. 5, an initial PD housekeeping voltage and a first PD modulator switch operation to establish a communication link during a high-voltage on-pulse to a PD load will be described. In step 50, the PSE transmits high-voltage pulsed power to the PD with the PD modulator switch open. In one or more embodiments, the initial PSE high-voltage modulator can provide a short on-pulse (i.e., a shorter pulse than used during normal operation) within a safer portion of the safety domain (described below with respect to FIG. 6) to improve the safety level of the condition without the PD housekeeping voltage and with the PD modulator switch open. For example, the high-voltage power received at the PD with the modulator switch open may include a short pulse on-time (pulse width), and when the modulator switch is turned on, the high-voltage pulsed power received includes a normal operation pulse on-time (nominal width pulse). When the high-voltage pulse is turned on during auto-negotiation, the isolated housekeeping voltage is coupled to the PD side without affecting the charging of the cable voltage (step 51). The PSE can wait for several high-voltage pulses to automatically turn on the PD modulator switch (step 52). The PSE checks if the PD modulator switch is on (step 53). In one example, the PSE waits for three high voltage pulses over approximately 40 milliseconds to automatically turn the PD modulator switch on until it is commanded to turn off at the end of the high voltage on pulse load period over the communications link. If the PD modulator switch is on, it continues normal operation (step 54). If it is not on, power is shut down until a restart is attempted (step 55).

[0073] FIG. 6 is a graph 60 showing current duration (milliseconds) versus body current (mA). The graph shows a safe region where there is typically little human perception or pain and no dangerous effects. In the dangerous region, there may be reversible effects such as muscle contraction or respiratory problems, or serious effects to the human. As shown in graph 60, the high voltage initialization pulse limits and maximum exposure times are maintained within the safe region. In one or more embodiments, shorter high voltage pulses are possible without impacting load power requirements during the high voltage initialization start-up period that does not require PD load requirements. As shown in the example, a higher level of shock protection can be added due to shorter high voltage on-times and shorter off-time detection times and lower shock energy during the high voltage exposure period.

[0074] As described above with respect to FIG. 4, one or more safety tests may be performed before enabling high voltage pulse power operation at the PSE. The tests may include a safety body impact protection test with cable capacitance test, and calibration adjustments based on the test. In one example, the PSE safety test / capacitance test and analysis may be used to determine the shortest high voltage exposure within the pulse-to-pulse duty / period for auto-negotiation of the next high voltage pulse, as described below, with an accurate capacitance test of the safety body current and an accurate cable voltage droop threshold obtained from a calibration analysis of cable voltage droop due to switching of a known discharge resistor at a specific time in the first 10% (or other suitable percentage) of the RC time in the approximately linear dv / dt region. To calculate cable capacitance more quickly and accurately, one or two known resistors may be switched in for a known time. The capacitance test described below may be performed only at initialization or for every pulse for safety test levels and times, which adds the ability to identify cable capacitance changes on the fly and provides a large cable voltage dv / dt droop level for easier synchronization and timing analysis.

[0075] FIG. 7 is an overview of the process of capacitance testing of a cable interposed between a PSE and a PD. In step 70, a known high voltage pulse is transmitted from the PSE modulator switch on an open and unloaded cable. In one or more embodiments, the cable capacitance voltage is modulated with a known discharge resistive load (e.g., 100 kohm or other suitable resistance value) and an RC time for discharge (time constant of the resistance / capacitance circuit) to measure the time of voltage discharge at the first 10% of droop (step 71). This is an approximately linear relationship of At=RC for the first 0.1 RC time interval, as described below with respect to FIG. 9B. In this example, a maximum resistance value of 100 Kohm is selected as the maximum body resistance used as the body shock protection failure for a maximum body current protection of 3.8 mA at a high voltage level of 380 VDC. In this example, a 10% droop voltage level is also selected for a clean, noise-free sensing level after the high voltage pulse and load current are turned off. With a long cable with high capacitance, the sensing time will be the longest, the off-time of sensing will be longer, and the on-time of the high voltage of the power in a given duty cycle will be longer. In this example, the maximum cable length can have a capacitance of 300 nF, so the time to 10% of the RC time will be S milliseconds using a test resistor of 100 Kohm, so 4 milliseconds can be used as the maximum off-time and the sensing margin with a high voltage on-time of S milliseconds for a 67% duty cycle. Then, in this example, the high voltage exposure time to detect a body failure to latch off the high voltage power or another high voltage pulse in the worst case is 11 to 12 milliseconds. For lower body resistance conditions, the current may be higher and the maximum exposure time may be the same. For this reason, a shorter off-time is selected for 10% droop, and a smaller capacitance and shorter cable length will result in a shorter off-time and total exposure period. Other methods can be used to accurately and reliably measure droop voltages slower than 10% (e.g., 1-2%), significantly reducing the off-time and total exposure period.This value is compared to the dv / dt without the 100kohm load to determine the additional resistance across the cable and identify if there is a fault, step 72. In one example, over 100kohm means the test passes and under 100kohm means there is a fault.

[0076] If a fault is identified, a fault mode is entered until reset (step 74). If the test passes, the cable capacitance is calculated and a load voltage threshold of 100 kohm is set at the fault dv / dt to suppress further faults during the auto-negotiation high voltage pulse off-time (step 75). A maximum high voltage pulse off-time is determined for the 100 kohm fault dv / dt voltage threshold (step 76). This value preferably includes a margin (e.g., dv / dt=10% fault threshold plus an additional 5% margin). A desired duty cycle for the desired power, cable loss, and RMS (root mean square) current on-time is determined (step 77).

[0077] The above process may be performed only at initialization (low or high voltage start-up) or may be repeated at regular intervals or pulses to identify if additional cable length has been added. Cable capacitance and shock fault testing may be performed for each phase of a multi-phase system as described below. It should be understood that the resistance values, margins, and discharge times described above are merely examples and other values ​​may be used without departing from the scope of the embodiments. Additional details of capacitance testing are described below with respect to Figures 9A-9D.

[0078] It should be understood that the processes illustrated in Figures 4, 5, and 7 are merely examples, and that one or more steps can be added, deleted, combined, or reordered without departing from the scope of the embodiments.

[0079] 8, a simplified block diagram of an enhanced safety power system is shown. The block diagram includes circuitry for power equipment 81, which provides power and smart control, and circuitry for powered devices 82, which include a PON (Passive Optical Network) endpoint. The components shown in block 83 represent a single phase and may be replicated for each phase of a multi-phase system, as described below. Modulator switches 84b, 84c, 84d, sensing components 89a, 89b, and start-up power circuit 87b may be replicated for each cable pair / phase.

[0080] The PSE 81 includes an isolated high voltage source (e.g., 380VDC) and a modulator switch 84a with gate. The DSP (digital signal processor) 85a, 85b may include a microcontroller or FPGA (field programmable gate array) digital control and software / firmware. The PSE and PD Tx / Rx 86a, 86b represent transceivers with coupling networks. An isolated power supply 87a is provided for PSE housekeeping. An isolated power supply 87b is provided for PD housekeeping with an example 24VDC input for low voltage initialization and testing. The PD 82 also includes a DC / DC isolated converter 87c to generate a 12V / 3.3V housekeeping voltage with a 60-380VDC input from the output of an example PD (high voltage pulse power operation). In this example, current sense transformers / Hall effect sensors (CS / CT) 88a, 88b are included in the PSE and PD. A safety sensing circuit (Vsense safety) 89a and a PD synchronization voltage sensor (Vsense sync) 89b are located in the PSE and the PD, respectively. As shown in FIG. 8, the PSE includes two PSE modulator switches 84b, 84c and the PD includes one PD modulator switch 84d, shown as a bidirectional switch, to fully isolate the cable pair during the high voltage pulse off-time for accurate voltage droop sensing, proportional to the RC time of the body resistance across the cable during the auto-negotiation safety test between the high voltage pulses. The switches may include, for example, solid state switches or any other suitable devices to provide pulse power modulation synchronized between the PSE and the PD, as described above.

[0081] Additional details of the operation of the portion of the circuit shown in FIG. 8 are provided below with respect to cable capacitance testing (FIGS. 9A and 9C), synchronization (FIG. 10A), low voltage initialization (FIGS. 11A and 11C), low voltage housekeeping (FIGS. 12A, 12B, and 12C), and high voltage initialization (FIG. 13A).

[0082] FIG. 9A is a simplified representation of a circuit 90 for use in the Cable Capacitance and Shock Fault Test (described above with respect to the flow chart of FIG. 7). In this example, the PSE includes resistors R1a, R1b, R2a, R2b, and R3. R3 is a known calibration resistor that is switched across the cable at a known time to accurately calculate the cable resistance and capacitance from the dv / dt voltage droop. The PD includes capacitor Cf, inductors LF1 and LF2, and diode D. Switches S1a, S1b (PSE modulator switch) and switch S2 (test switch) are located in the PSE. The PD includes switch S3 (PD modulator switch). Capacitance C cable represents the cable capacitance, and the inductance L cable represents the cable inductance, and the resistance R cable represents the cable resistance. It should be understood that the simplified circuit shown in Figure 9A is only an example, and that components may be added, removed, or rearranged without departing from the scope of the embodiments. For example, resistors R1a and R1b may be placed to the right of switches S1a and S1b (as seen in Figure 9A).

[0083] FIG. 9B shows the cable current i in the circuit shown in FIG. 9A according to the first embodiment. c (t) and voltage v c (t) one pulse at the PSE test switch S2 and one pulse at the PSE test switch S2 i s 2(t) and PD switch S3 i s3 9B). The timing waveforms of current flow over time at (t) are shown with the changes of state of the PSE switch S1 (shown as S1a and S1b in FIG. 9A and S1 in FIG. 9B), the test switch S2 (S2 in FIG. 9B) and the PD switch S3 (S3 in FIG. 9B). The waveform diagrams show in and Ic_peak are also shown. As before, a known resistor R3 is switched in to determine the cable capacitance. After the PSE modulator switch S1 opens, the voltage on the cable is dv c / dt (b-c) This is due to the fault body resistance (Runknown ) leakage. When switch S2 is closed, the voltage continues to drop as shown by dvc / dt(bc), which is due to the cable leakage or body resistance (R unknown ) represents the cable sag due to leakage or fault body resistance. Switch S2 is then opened and the change in cable voltage represents the cable sag due to leakage or fault body resistance (R unknown ).

[0084] Smart digital systems can be used to increase accuracy and reliability and minimize off-time. As previously discussed with respect to Figure 7, the PSE modulator can be switched on to transmit a pulse with an open / unloaded cable and the cable capacitance voltage can be modulated with a known test resistor of maximum body resistance for safety shock protection. The cable resistance and capacitance can then be tested to within a 10% RC time constant, which is the discharge voltage dvc from the initial voltage Vo and the actual time constant T e (-t / RC) From the first 0.1 RC time, the relationship is approximately linear.

number

[0085] 9C and 9D show another example for use in performing initial cable safety and capacitance testing. FIG. 9C is a block diagram of a circuit, generally designated 91. The PSE includes modulator switches S1a, S1b (collectively referred to as S1 in FIG. 9D), as well as test switches S2 (S2 in FIG. 9D) and S4 in parallel (S4 in FIG. 9D). The PD includes switch S3 (S3 in FIG. 9D). As discussed above with respect to FIG. 9C, FIG. 9D shows the cable current i c (t) and voltage v c 9B , the current i in the PD switch S3 over time as the states of the PSE switch S1, the test switches S2 and S4, and the PD switch S3 change. s3The timing diagram of (t) is shown. Also, the current i S2 (t) and i S2 (t)+i s4 (t) is also shown. In this example, two known switch resistances (R2, R4) provide another calibrated method with larger dv / dt voltage steps for faster, more accurate measurements, signal to noise ratio measurements, and allows for shorter off-time duty cycles and high voltage shock exposure periods for a higher level of safety. With two known resistance steps, the difference in dv / dt can be used to calculate the unknown resistance and cable capacitance between pulses. The S2 and S4 gates can be operated together at the beginning rather than later to speed up the initial dv / dt slope to speed up detection of high voltage off-time events.

[0086] It should be understood that the circuits shown in Figures 9A and 9C, the waveform diagrams shown in Figures 9B and 9D, and the test calculations described above are merely examples, and that other circuits (e.g., combinations of switches, resistors, etc.) can be used to test the safety and capacitance of a cable.

[0087] As described above with respect to steps 45 and 46 of FIG. 4, the PD performs synchronization with the PSE using cable voltage waveform initialization. The process can begin with the PD modulator switch being turned on for communication to control off / on synchronization. The PD can then generate PLL (or DLL) control of the PD modulator switch to control off / on synchronization. The PD can initially turn on the PD modulator switch for a default period within the default on-time of the PSE modulator. The timing of the modulator switch can be modified according to changes made based on PSE safety / capacitance testing and analysis. In one or more embodiments, the synchronization can include a time delay PD modulator switch on load after the PSE modulator high voltage switch on, and PD modulator switch off unload before the PSE modulator high voltage switch off to minimize cable voltage ringing in cable voltage droop safety testing during the high voltage off period, as described below with respect to FIG. 23 and FIG. 24.

[0088] FIG. 10A shows a simplified synchronization control circuit 100 for use after initial power-up. High voltage control is provided with gate control 101 and high voltage switch 102. PSE modulator switches (switch 1 and switch 2) 103 are coupled to PSE gate control 104. As previously described with respect to FIG. 8, the PD includes a PD modulator switch 109 coupled to PD gate control 107 and Vsense sync 106. The load of the PD endpoint is shown at 108. As previously described with respect to the flow chart of FIG. 4, the control of the PD modulator may be performed with pulse-to-pulse off / on command communication after initial power-up (steps 44→45), or the PD modulator control may be performed with PLL synchronization without communication (steps 45→44), or the PD modulator control may be performed with known default timing between the PDE and the PD without communication (steps 45→44). Three different examples of synchronization methods are described below with respect to the circuit shown in FIG. 10A.

[0089] FIG. 10B shows Vccable along with the switch transitions (PSE gate (switch 103), PD gate (switch 109)) and PLL sync (Vsensne sync 106). As shown in FIG. 10A, the voltage VCcable is measured at the cable. The PLL (or DLL) sync indicates the current in the Vsense sync circuit 106.

[0090] In a first example, the PD modulator control is provided using pulse-pulse off / on command communication after initial power-up. The PSE modulator control 104 turns on at low voltage (e.g., 24V) with no pulses. The PD modulator control 107 is on until commanded to turn off with no load other than housekeeping power. A communication link is then established between the PSE and the PD. The PSE modulator 103 begins pulsing with the established on-time and off-time duty cycle and frequency. The PSE sends a command at the end of the modulator on-time data stream period to turn the PD modulator off for X milliseconds and then on again. An off-time command is sent early in the data stream, changed for each pulse, and then the last word sent can be a turn-off-now command for a specific time (knowing that there will be some turn-off delay).

[0091] The second synchronization method provides PD modulator control and PDD synchronization without communication. The Vsense synchronization circuit 106 senses the cable capacitance (Ccable) voltage waveform droop (VCcable) when the PSE gate switch 102 is off through the cable resistance (i.e., midpoint ground resistor and sensing circuit). The Vsense circuit 106 generates a pulse from the positive transition of VCcable after droop with the PSE gate switched on (FIG. 10B). The Vsense pulse is input to a PLL to generate a voltage controlled oscillator (VCO) synchronization pulse. The PLL VCO pulse generates pulse shaping for the PD gate modulator control, which is synchronized with the PSE gate switch control 104 as desired. The voltage waveform droop (VCcable) when the PSE gate switch is off is shown in FIG. 10B. As previously mentioned, VCcable transitions positive when the PSE gate 104 is switched on after droop.

[0092] A third synchronization method provides a pre-established default on-time between the PSE and the PD modulator. One or more embodiments utilize a default pulse width and default delay time of a one-shot monostable multivibrator (MV) to synchronize the PSE default modulator on-time triggered from the cable capacitor voltage waveform's rising dv / dt at the beginning of the PSE modulator pulse on-time. This circuit may include, for example, a differentiator circuit, a bias average trigger threshold circuit, and an op-amp. The circuit may further include an adjustable delay on 105a (e.g., default 100 μs) and an adjustable one-shot multivibrator 105b (e.g., default 7.8 ns). In this example, the PD modulator control is provided with a pulse-to-pulse default on-time until the on-time command of the next pulse being communicated is updated. The PSE modulator initially pulses a default on-time duty cycle (e.g., 8 ms) and period (e.g., 12 ms) to cable the phase / pair with the voltage waveform droop (Vccable) to the PD Vsense synchronization circuit 106. The Vsense synchronization circuit 106 triggers a positive transition on Vccable with the desired delayed pulse width for the PD modulator switch control with the default on-time duty cycle. During the on-time duty cycle, data communication can update or modify the synchronization delay time, pulse width, and period as necessary to synchronize with the PD modulator on-time duty cycle for each next pulse period. The above steps can then be repeated. This provides a pulse-to-pulse change to the on-going synchronization change of on / off time, duty cycle, and frequency from the PSE to maintain PD synchronization for each phase / pair. This sequence also ensures that the PSE modulator voltage is on-fast before the PD modulator switch is turned on, and then off-fast before the PSE modulator voltage switch is turned off for noise transient mitigation.

[0093] FIG. 11A is a block diagram illustrating a simplified PD initial low voltage start-up circuit 110. As discussed above with respect to the flow chart of FIG. 4, a low voltage (e.g., 24V) start-up sequence for PD housekeeping power may be performed prior to PD modulator control or communication. As discussed above with respect to FIG. 10A, high voltage control is provided with gate control 111 and high voltage switch 112. PSE modulator switches (switch 1 and switch 2) 113 are coupled to PSE gate control 114. The PD includes a PD modulator switch 113 coupled to a PD gate control 117 and Vsense sync 116. The PD endpoint load is shown at 118. The circuit shown in FIG. 11A includes a DC / DC housekeeping circuit 120 (e.g., a 24V to 12 / 3.3V transformer) (also referred to as local energy storage). The PSE modulator switch 119 can provide a fixed time (e.g., 100 ms) low voltage (e.g., 24V) on-time for initial start-up power to the cable and PD DC / DC housekeeping circuit 120. The PD DC / DC housekeeping circuit 120 starts up and operates for the fixed time of the PSE modulator switch 113. The PSE modulator 113 then begins pulsing the low voltage (as shown by the PSE gate current in FIG. 11B) with the established on-time and off-time duty cycle and frequency.

[0094] The Vsense circuit 116 generates an enable pulse width from the positive transition of VCcable after the voltage droop due to the PSE gate switching on to operate the DC / DC housekeeping converter 120 for continuation of housekeeping power (FIGS. 11A and 11B). The 24V DC / DC converter provides housekeeping power to the PD circuitry and initiates the PD modulator switch 119 and communication before allowing the 380VDC high voltage modulator to switch to the cable. The OVP (overvoltage protection) circuit disables the DC / DC converter above about 27VDC when the high voltage is turned on. The PD may include a 380V high voltage DC / DC converter for housekeeping (87c in FIG. 8), which takes over the housekeeping power from the 24V DC / DC converter 120.

[0095] FIG. 11B shows the voltage waveform, droop (VCcable) (measured at the cable at the start of the PSE) with the PSE gate control 114 off (modulator switch 113 open). The PSE gate trace shows the modulation of the PSE switch 113. The DC / DC power is measured at the DC / DC housekeeping circuit 120. As mentioned before, VCcable transitions positive when the PSE gate 114 switches on after the droop. The Vsense circuit 116 generates an enable pulse width from the positive transition of VCcable after the voltage droop when the PSE gate switches on to operate the DC / DC housekeeping converter 120 for continuation of the housekeeping power.

[0096] FIG. 11C is a simplified circuit design for use with low voltage start-up. Two twisted pairs are shown, with a PSE modulator switch 113 and a PD modulator switch 119 for each pair. The enable switch 112 is closed for high voltage operation (e.g., 380VDC, >300V, >200VDC). In one example, low voltage operation can be 56V or less (e.g., 24V). The PSE includes a low voltage cable capacitance and fault test circuit 115. In one or more embodiments, the low voltage power-up circuit at the PD is configured with a 0V cutoff above about 27V (for low voltage operation at 24V), allowing hot swapping without isolation circuitry. Alternative start-up power may be provided by the PD's battery for initial power-up. The PD includes a low voltage DC / DC converter 120 for each wire pair, as previously described. Details of the low voltage housekeeping circuit are described below with respect to FIGs. 12A and 12B.

[0097] FIG. 12A is a block diagram illustrating an example of a low voltage housekeeping power supply circuit 121. Circuit 121 includes gate bias and control circuit 122 with inputs enable 1 (from 125), enable 2 (from 126), and disable from PD housekeeping (24 / 12V DC / DC converter 123), and switch 124 (described above with respect to FIGS. 11A and 11C). As shown in FIGS. 11A and 11C, the housekeeping circuit receives power from the cable pair and provides power to the PD modulator switch 119. Converter 123 provides housekeeping power to the PD circuitry and initiates communication with the PD modulator switch, which in turn enables switching of the high voltage modulator.

[0098] FIG. 12B shows a simplified low voltage start-up housekeeping power supply circuit 127. The circuit provides low voltage DC / DC self-startup housekeeping power to the PD end of the cable pair with overvoltage protection shut off by high voltage MOSFET switch M1. In one example, resistors R1, R2, R3, R4, R5, and R6 may each comprise a 1 or 2 Mohm (megaohm) resistor. Diode D1 and switch Q1 may provide overvoltage protection, for example, above 27V. In one example, capacitor C1 is rated at 100μF.

[0099] It can be seen that for a 5W long cable resistance voltage drop, the low voltage at startup can increase from 24V to 56VDC. In one or more embodiments, the low voltage can be 56V or less, and the difference between the high voltage power (at the power-on pulse at the PSE) and the low voltage power can be greater than 200V (e.g., about 324V, about 368V). It should be understood that these voltage levels are merely examples, and other levels can be used. The low voltage is preferably rated to prevent safety issues during low voltage startup (e.g., initialization and synchronization), and the high voltage is preferably rated to provide sufficient power to power the powered device while providing safety checks during the off-pulse interval. As described below, the high voltage power level can be based on the number of phases in a multi-phase power system where the pulses are offset from one another between phases.

[0100] Figure 12C shows a block diagram of circuit 128 corresponding to circuit 127 shown in Figure 12B. In this example, the circuit includes a 28V gate enable, gate bias, and a DC / DC converter (e.g., 16V / 5W) for housekeeping power.

[0101] 13A-13B show a high-voltage start-up according to one embodiment. As described above with respect to FIG. 5, the high-voltage start-up can be used as a high-voltage initialization start-up with a short high-voltage ON pulse for added safety protection, or a normal high-voltage pulse to hot-swap the PD without the need for a low-voltage initialization process. The high-voltage initialization provides safe operation (within the safety region described above with respect to FIG. 6) using a short ON pulse.

[0102] Referring first to FIG. 13A, a block diagram is shown illustrating a simplified initial high voltage start-up circuit 130, according to one embodiment. High voltage control is provided at gate control 131 and high voltage switch 132. PSE modulator switches (switch 1 and switch 2) 133 are coupled to PSE gate control 134. As previously described, the PD includes a PD modulator switch 139 coupled to a PD gate control 137, and a Vsense synchronization circuit 136. The load of the PD endpoint is shown at 138. The circuit 130 shown in FIG. 13A includes a high voltage DC / DC housekeeping circuit 140 (e.g., a 380V to 12 / 3.3V DC / DC converter) in place of the low voltage housekeeping circuit 120 of FIG. 11A. In one example, the high voltage is pulsed on for less than S milliseconds during the high voltage on time of the PSE modulator switch to charge the output to a minimum output housekeeping voltage with a hold-up time until the next high voltage phase, as described below.

[0103] The PSE modulator switch 133 initiates a high voltage pulse with an established on-time (e.g., 8 ms) and off-time (e.g., 4 ms) duty cycle and frequency. The PD's DC / DC initial startup circuit 140 is energized with a first high voltage on-time cycle with a fixed operating time (e.g., 6-8 ms). The Vsense circuit 136 generates an enable pulse width (e.g., 6 ms) from the positive transition of VCcable after the voltage droop when the PSE gate is switched on, and operates the DC / DC housekeeping converter 140 to continue the housekeeping power (Figures 13A and 13B). The high voltage DC / DC converter 138 provides housekeeping power to the PD circuitry, initiates the PD modulator and communication, and then enables the switch of the high voltage modulator to the cable.

[0104] FIG. 13B shows the voltage waveform droop (VCcable) (measured at the cable at PSE initiation) with the PSE gate control 134 off (modulator switch 133 open). The PSE gate trace shows the modulation of the PSE switch 133. The DC / DC power is measured at the DC / DC housekeeping circuit 140. As mentioned before, VCcable transitions positive when the PSE gate 134 switches on after the droop. The Vsense circuit 136 generates an enable pulse width from the positive transition of VCcable after the voltage droop when the PSE gate switches on to operate the DC / DC housekeeping converter 140 for continuation of housekeeping power.

[0105] FIG. 14 is a block diagram of the system 140 showing a simplified circuit of the PSE 141 and PD 142 with a crowbar / shorting relay 150 included in the PSE for safety. As previously described with respect to FIG. 8, the components shown in block 143 represent a single phase and may be replicated for each phase of a multi-phase system. The PSE 141 includes an isolated high voltage source (e.g., 380VDC) and a switch 144a and gate. The PSE and PD Tx / Rx 146a, 146b represent transceivers with coupling networks. The DSPs (Digital Signal Processors) 145a, 145b may be microcontrollers or FPGA (Field Programmable Gate Array) digital control and software / firmware. An isolated power supply 147a is provided for PSE housekeeping. An isolated power supply 147b is provided for PD housekeeping with a 24VDC input for low voltage initialization and testing. A PD DC / DC isolation converter 147c is provided for Vout and 12 / 3.3V housekeeping with 280-380VDC input. Current sense transformers / Hall effect sensors (CS / CTs) 148a, 148b are located in the PSE and PD. A safety sense circuit (Vsense safety) 149a and a PD sync voltage sensor (Vsense sync) 149b are located in the PSE and PD, respectively. As previously mentioned, the PSE includes PSE modulator switches 144b, 144c and the PD includes PD modulator switch 144d.

[0106] In the example shown in FIG. 14, a shorting switch (safety crowbar) 150 is installed in the PSE 141 to enhance high voltage safety. The shorting switch 150 can include, for example, a solid state device (e.g., MOSFET) that is energized on a body shock fault to discharge the cable voltage charging energy. A high voltage relay can also be used. The shorting switch 150 can be energized manually (e.g., with a button on the PSE) by maintenance personnel during installation or maintenance of the equipment as a high voltage lockout. The shorting switch may also be energized with, for example, a safety interlock of the cable connector when disconnected.

[0107] It should be understood that the circuits and block diagrams shown in Figures 8, 9A, 9C, 10A, 11A, 11C, 12A, 12B, 12C, 13A, and 14 are merely examples, and that other arrangements or combinations of components (e.g., resistors, capacitors, diodes, inductors, switches, gates, isolated power supplies, transformers, or sensing circuits), pulse timing, or voltage or power levels may be used without departing from the scope of the embodiments. For example, low-voltage pulsed power may include pulses of power (i.e., pulse on) transmitted at 24V or more and 56V or less, and high-voltage pulsed power may include pulses of power transmitted at 200V or more, 380V or more, or any other suitable level. In one or more embodiments, the difference between the low-voltage power and the high-voltage power is at least 170V.

[0108] 15-19 show simplified examples of an Enhanced Safety Power (ESP) system for providing power over a copper wire pair with a data fiber pair. As described above and below, the enhanced safety power may be delivered over a composite cable with one or more optical fibers for data delivery. FIG. 15 is a simplified block diagram showing a cable extending between a PSE and a PD and carrying two twisted pairs and optical fibers. FIG. 16 is a block diagram showing additional functional components at the PSE and PD for a single twisted pair. FIG. 17 is a block diagram showing a multi-point distribution of ESP to multiple low power PD endpoint loads. FIG. 18 and FIG. 19 show simplified block diagrams showing example power and voltage levels at the input and output of the PSE and PD.

[0109] 15, a simplified example of a data and power delivery system is shown that includes a PSE 150 communicating with a PD 152 that provides power to a load 153 via a composite cable for power and data (e.g., a power over fiber (PoF) cable) 154. In this example, the cable 154 includes two optical fibers 155 (e.g., two-fiber single mode) and two twisted pairs 156 (e.g., copper wire). Control data, shown at 157, may be provided via the optical fibers 155 or the copper (twisted pair) 156, or a separate transmission line. The control data may include, for example, isolation switch synchronization control data, modulator switch control data, bidirectional control data, or other PSE / PD synchronization data. Bidirectional communication data may also be transmitted via the optical fibers 155 or the wires 156. In one example, 10 MB of communication is provided over the copper pairs during high voltage on pulses (e.g., on a high voltage data link). Input power (e.g., AC, HVAC, HVDC, line card 48-56VDC) may be provided at PSE 150. Cable 154 may include any number of optical fibers and wires or wire pairs for providing data and high voltage pulsed power over different cable lengths.

[0110] In one or more embodiments, PoE or high-voltage power (e.g., ESP, pulsed power, multi-phase pulsed power) may be delivered through the same cable and connector. Depending on the capabilities of the PSE 150 and PD 152, the PD may operate in one or more different modes. If the PSE 150 and PD 152 are incompatible (i.e., one is configured for PoE only and the other is configured for ESP only), no power is provided to the circuit. If both the PSE 150 and PD 152 are ESP-operable, the PSE provides high-voltage pulsed power and the PD operates using high-voltage pulsed power. In another example, the PSE, the PD, or both the PD and the PSE may select an operating mode (e.g., using auto-negotiation between the PD and the PSE) based on the most efficient delivery mode.

[0111] FIG. 16 illustrates additional details of one of the twisted pairs shown in FIG. 15, according to one embodiment. A PoF (power over fiber) cable extends between the PSE 160 and the PD 162. In this example, the PD 162 provides power to a 56VDC load 169 (e.g., PoE, PON endpoint, access point, switch). In the simplified example illustrated in FIG. 16, the cable includes two optical fibers and one twisted pair. As previously mentioned, the cable can include any number of wire pairs (e.g., N twisted pairs). In this example, the system provides a high resistance mid-point ground for shock protection. In one example, the mid-point ground reduces the line-to-ground voltage (e.g., 275V line-to-ground, 550V line-to-ground, 190V line-to-ground, 380V line-to-ground). In one or more embodiments, both the feed and return of each transmission pair are switched to implement effective control, with line-to-ground fault detection in 10-100 μs. Cable sensing may be provided in the PSE 160, as previously described. The system may provide line-to-ground (GFI (ground fault interrupter)) shock protection and line-to-line shock protection against cable fault conditions during auto-negotiation at the high voltage pulse off time, as previously described. One or more embodiments provide single point of failure and redundancy for any high voltage path to the cable. In one or more embodiments, the system may use a 12-56 VDC low voltage for initial start-up and default conditions, as previously described, to establish data links and safety interlocks before enabling high voltage operation. In one example, 10 MB communication is provided over the twisted pair during the high voltage on pulse, as shown in transceiver 168.

[0112] FIG. 17 illustrates an example of ESP multipoint distribution to multiple low-power endpoint loads (e.g., 5G wireless sets or other devices). A PSE source 170 provides high power and data to multiple PDs 172 over a PoF cable assembly 174 including fiber and wire. In one or more embodiments, multiphase pulsed power is provided at a voltage of at least 200V on the cable 174. In one example, 1-2kW of power is provided to copper wire pairs with data fiber pairs over 1-10km with 550VDC pulsed power. As previously mentioned, the pulsed power can include any number of phases. As described above, the system can use low voltages of 24VDC or 56VDC for initial start-up and default conditions to establish data links and safety interlocks before enabling high voltage operation. In the example shown in FIG. 17, the 550VDC pulsed power can be distributed to multiple low-power PD PON endpoint loads, such as, for example, 5G wireless sets. In one example, the system provides 1-2 kW of power over copper pairs with data fiber pairs over 1-10 km, providing extended safety power at 380 / 550 VDC with greater than 70% efficiency. The transmission of power from a PSE 170 to multiple downstream PDs 172 in a daisy chain topology (also referred to herein as a hybrid multi / drop daisy chain topology) is described below with respect to Figures 29-40.

[0113] 18 and 19 are block diagrams illustrating a simplified system including examples of power inputs and power outputs at various sections of an ESP system. FIG. 18 shows a PSE with two PSUs 180 receiving 115VAC power at plugs 181. The PSE includes transmitters / receivers for low / high voltage control, PSE modulators, digital control, safety sensing, and communications as shown in block 182. The PSE is coupled to a PD by a power cable 184 (e.g., 14 AWG). In this example, the output at the PSE includes 380VDC, 2000W of power. In this example, the PD is a 1400W PON (passive optical network) endpoint and includes a PD modulator, digital control, and a transceiver / receiver in block 186. The input at the PDU in this example is 380-280VDC and 1474W, and the output at the PSU 188 is 50VDC, 28A, and 1400W.

[0114] FIG. 19 shows a PSE including two PSUs 190 and modules 192 for low / high voltage control, modulation, and communications, as previously described. A PD 196 (including PD modulators, digital control, transceivers / receivers) is coupled to endpoints including rack components 198 (e.g., fabric interconnects, blade servers, etc.). Power is received at a 115 VAC plug 191. In this example, the PD 196 provides 192-400 VDC (1492 W) of power to the rack components 198.

[0115] It should be understood that the power inputs and power outputs shown in the simplified block diagrams of Figures 18 and 19 are merely examples, and that other voltages and power levels can be used without departing from the scope of the embodiments. Also, the cable can include any number of electrical wires or optical fibers, and the system can be configured for single point of failure tolerance for continuous operation with N+N or N+1 redundancy. In one or more embodiments, high voltage to low voltage fail-safe operation can be provided.

[0116] As previously mentioned, the pulse power system can be operated as a multi-phase (poly-phase) system. The initialization, synchronization, testing, and fault detection described herein can be performed on each phase of the poly-phase system. In one or more embodiments, the pulse power system can include a poly-phase pulse power system as described in the above-referenced U.S. patent application Ser. No. 16 / 380,954. In one example, the single conductor pair cable is replaced with a two-phase pulse power transmission system cable with two pairs of power lines, bus bars, power planes, or cable wire pairs. For example, one or more embodiments may include a two-phase pulse power transmission system cable with a three-wire, bus bar, power plane, or cable wire trio. Poly-phase (three or more phases) operation further reduces the RMS current per phase and can effectively provide a continuous DC voltage without bulky filter components. In one or more embodiments, a high or effective 100% duty cycle to the output and split ground (e.g., high resistance mid-ground) may result in higher efficiency with lower RMS current cable losses, enable fast and effective ground fault detection, allow higher voltage and power to the load from a limited cable voltage rating, and allow the implementation of a common mode system (separate ground connections) with lower peak currents for lower EMI / EMC noise emissions and susceptible fields.

[0117] In one or more embodiments, the multi-phase approach allows for significant off-time in a 10 millisecond window, for example, to verify cable shorts, opens, unreported power loss (e.g., low current shorts), or further resistance by humans or animals. This extended off-time significantly improves safety. Multi-phase pulsed power also allows for the use of lower power supply voltages to meet 100% of the requirements of the powered device. As previously mentioned, single-phase systems may need to filter out the off-time with bulky filters, but even then, power efficiency / availability at high loads is around 80%. Using multiple phases with higher duty cycles and higher efficiency can provide significant component benefits and can also result in increased power delivery and improved reliability. For example, the loss of a single phase in a three or more phase system does not affect the availability of 100% continuous duty cycle power at the powered device. As described below, the loss of the front-end circuitry of a power supply phase may not affect operation due to redundant power sources.

[0118]

[0046] Referring now to Figure 20, a block diagram of a multi-node multi-phase pulsed power is shown, according to one embodiment. The simplified example shown in Figure 20 includes a PSE node 200 that supplies power to three or more PDs (e.g., pulse power tap / receivers 212 and node endpoints 214). In this example, the pulse power tap / receivers 212 are separate from the endpoint devices 214, although these nodes may be combined. Also, two or more nodes 214 may be connected to one or more of the pulse power tap / receivers 212.

[0119] The PSE network device 200 comprises an input power interface (e.g., in the example shown in FIG. 1A, three PSUs 205 accepting power cords 209) for receiving input power, a power control system 207 for receiving the input power, transmitting multiple phases of DC pulsed power via cable 211 to multiple powered devices 212, 214 and verifying cable operation within the off-time of the pulses of DC pulsed power, and a cable interface (e.g., power interface 208) for supplying multi-phase DC pulsed power and data (e.g., control data, bidirectional communication over copper wire or optical fiber) via cable 211.

[0120] The pulse power tap / receiver 212 includes an input cable interface 213a for receiving multiple phases of DC pulsed power and data from the PSE 200, an isolation switch (described below), and an interface 213b for transmitting power to the endpoint node 214. The interface 213b may be, for example, an interface connected to the HVDC cable 222, a pulsed power cable, or a direct interface to the endpoint node. The tap / receiver 212 may provide power to one or more nodes 214 along the pulsed power cable system. The tap / receiver 212 may be sized to support individual node power and may implement disconnects for fault isolation or node control based on data link communications. The multiple phase (polyphase) DC pulsed power includes at least two phases to provide a continuous DC voltage at the endpoint node 214. In one or more embodiments, the polyphase pulsed power includes at least three phases to provide continuous power in the event of loss of one phase. One or more of the pulse power tap / receivers 212 also include an output cable interface 213c for transmitting multi-phase DC pulsed power and data over cable to a downstream tap node 212 in a tapered topology (tap node configuration).

[0121] In the example shown in FIG. 20, PSE 200 comprises three PSUs 205 and a pulse power module 206 including a control system 207 and a power interface 208. As shown in FIG. 20, each PSU 205 can be in power communication with the pulse power module 206 via a high voltage rail, a PM (power management) bus line, a 56V line, or any combination thereof. In one example, each PSU 205 is configured for a 1200W power supply providing redundancy and allowing the use of a standard 15A (ampere) power cord / branch circuit. In one example, PSE 200 is operable to supply more than 1500W of total power to nodes 214. In one example, 190V line-to-ground (380V total) eliminates the need for intermediate power conversion.

[0122] The pulse power module control system 207 can provide, for example, timing and sequencing, line detection and characterization, voltage and current sensing, high resistance midpoint ground, fault sensing, communication to the PSU, and data link / control to the remote node. As described herein, the control system 207 can verify cable operation (e.g., verify the integrity of cable operation) during the off-time of a pulse in the DC pulsed power. The pulse power module 206 includes a pulse power modulator, a safety circuit, an initialization circuit, a PMBus, a PMBus I2C (I 2 The present invention may include a multi-threaded, multi-input, and output (I / O) bus, a multi-threaded, multi-input ...

[0123] 20, PSU 205 receives AC power on cable 209 and provides pulsed power on cable 211. In one or more embodiments, pulsed power tap / receiver 212 can combine the phases and provide high voltage (HV) DC power to node / endpoint 214 on cable 222. In another embodiment, pulsed power tap / receiver 212 can provide pulsed power to endpoint 214 on cable 222. In one or more embodiments, pulsed power cable 211 includes two or more optical fibers for providing data with a combined cable for power and data, as described below. In one example, there may be a dedicated fiber (or multiple fibers) for each branch.

[0124] The wires in cable 211 may include two conductor, twisted pair (shielded or unshielded), coaxial or triaxial cable depending on EMC considerations. A separate ground conductor may be provided to address potential common mode noise issues. It should be understood that the term wire as used herein may refer to a single wire or a pair of wires. As described below, the power system may include any number of wires that may be bundled with fiber or other communication transmission media.

[0125] Power is provided to the endpoints 214 via a pulsed power tap / receiver 212 (also called a branch tap, smart branch tap, receiver / converter). In one or more embodiments, the smart branch tap 212 enables branch fault isolation. The tap / receiver 212 may include, for example, an isolation switch (disconnect switch), a data link, and a logic / timing controller. The tap / receiver 212 may be used to initialize the auto-negotiation process, branch fault isolation algorithms, power initialization, and faulty PD replacement. The data link over the pulsed power line enables the implementation of a smart branch tap 212 in each node 214 and independent control (disconnect) of each branch for fault isolation or node management.

[0126] Each of the endpoints 214 may include an HVDC PSU for supplying power to equipment at the endpoint. The endpoints 214 may include, for example, a 56VDC load and may operate, for example, as a PON (passive optical network) endpoint, a 5G node, an access point, a router, a switch, or other type of equipment. The endpoints 214 may also supply power to one or more other nodes (e.g., PoE nodes, IoT (Internet of Things) devices).

[0127] It should be understood that the system shown in Figure 20 is only an example, and that the system may include any number (e.g., two or more) of PSUs 205 to provide multi-phase pulsed power. The network topology and nodes shown in Figure 20 are only an example, and the network may include different topologies and network devices without departing from the scope of the embodiments.

[0128] Multiple PSUs allow for multi-phase operation and may also provide redundancy. For example, if a phase is lost in a system containing three or more phases, power may continue to be supplied to the PD node 214. Each phase is preferably sized to provide a higher peak power to maintain full power to the PD node 214. Further redundancy may be provided by utilizing an N+1 front-end power (FEP) supply. For example, for a total 1500W PD power system, three 1200W FEPs may power the system with full N+N or N+1 redundancy, with each FEP only needing a common 120V, 15A feed.

[0129] As shown in FIG. 21 and described below, the multi-phase pulsed power includes multiple sequences of voltage pulses, each sequence of voltage pulses forming a phase of the multi-phase pulsed power. FIG. 21 shows an example of 75% duty cycle three-phase pulsed power voltages and currents with phase drop, for example, as provided by the system shown in FIG. 20. Idealized waveforms are shown, and the net PD voltage and line current include line loss effects due to constant power loading from the node / endpoint 214. In the example shown in FIG. 21, phase B drops out for two cycles. The three phase voltages (A, B, and C) (223a, 223b, 223c) are shown along with auto-negotiation line sense 224.

[0130] As shown in FIG. 21, during pulse-on times, high-voltage power is supplied from the PSE to the PD, and during pulse-off times when the high-voltage power is off, low voltages may be applied on each phase for use in low-voltage sensing (shown at 224) to verify the integrity of the wire.

[0131] The net PD voltage is shown as a combination of the three phase voltages at 225. The corresponding phase currents (A, B, C) (226a, 226b, 226c) are shown below the voltages. The net line current corresponding to the three phase currents is shown at 227. As shown in FIG. 21, even if one phase is lost (indicated by a drop in phase B), continuous power is provided to the PD node. Each phase can be sized to provide a higher peak power to maintain total power to the PD.

[0132] As shown in Figure 21, two or more transmission lines (e.g., wires or wire pairs) allow for phase coordination of the conduction of each wire (e.g., one wire or pair) so that at least one wire is always ON. When OR is performed in the PD, the result is a continuous DC voltage as shown at 225, eliminating the need for bulky filter components. During phase overlap in a polyphase system, the sum of the cable currents is shared among all ON wires. The individual transmission line currents are proportionally reduced, reducing the total transmission cable losses.

[0133] In one or more embodiments, the off-time can be fixed based on worst case cable length and characteristics or actively controlled based on detected cable characteristics (for higher efficiency / longer range). The on-time (power delivery) of each phase can be fixed based on total pulse power voltage and shock hazard limits based on appropriate body resistance data. Using this approach, maximum pulse overlap can be achieved, thereby reducing cable RMS current and maximizing transmission distance (or minimizing conductor size).

[0134] As mentioned previously, the ideal waveforms are shown in Figure 21. The inductance of the PSE 200, cable 211, and PD receiver 212 may cause some averaging of the cable currents, increasing the overlap current and decreasing the current during the pulse off time (Figure 20). This effect may vary with cable length and type (inductance). The phase currents are shown in Figure 21.

[0135] As shown in FIG. 21, each of the phases is offset from the other (phase shifted duty cycle) to provide a pulsed power consisting of an on pulse and an off pulse. The off pulse can be a small voltage (e.g., 0V, close to 3V) or a value significantly smaller than the on pulse power (e.g., power level difference between the on pulse and the off pulse is at least 170V). As previously mentioned, the on pulse and off pulse times (pulse width, pulse duty cycle) can be selected based on the system design (e.g., number of phases, amount of power supplied) and safety requirements. The pulse duty cycle can also vary between the initialization phase, synchronization phase, test phase, or normal operation. In one example, the start-up duty cycle can include an 8 ms on pulse and a 4 ms off pulse with a period of 12 ms. In another example, the on pulse during high voltage initialization can be as little as 0.5 ms or 1 ms. In one example, the off pulse can be 1 ms, which includes a 100 μs resistance analysis and auto-negotiation time as described in the above-referenced U.S. patent application Ser. No. 15 / 971,729. In another example, an off pulse (between power pulses) of 2 ms to 4 ms may be required to adequately assess environmental safety within a 10 ms time window.

[0136] In one or more embodiments, a central controller in the PSE can adjust the offset between phases and adapt the pulse width for optimization (or following loss of a phase, if necessary). Any changes in pulse timing are communicated to the PD for synchronization.

[0137] It should be understood that the current, voltage, pulse width, duty cycle, and phase overlap described above and shown in Figure 21 are merely examples and may differ from those shown or described herein. For example, the pulse current may be higher during overlap and lower during non-overlap. The difference may depend, for example, on the inductance and capacitance of the pulse transmission (e.g., length of wire and type of cable).

[0138] As mentioned above, a multi-phase pulse power system can include two or more wires or wire pairs. It should be understood that the multi-phase systems described herein can be implemented in systems including different numbers of wires or wire pairs, with the three-phase system shown in Figures 20 and 21 being only one example. The pulse power system can operate with any number of phases (e.g., 2, 3, 4, etc.) without departing from the scope of the embodiments. Also, as mentioned above, the cable can include any number of optical fibers or additional copper wires for data transmission. In one or more embodiments, the cable can also carry cooling, as mentioned above.

[0139] FIG. 22 is a simplified circuit of a multi-phase power system for providing safe power at higher power levels than traditional PoE, according to one embodiment. The PSE is coupled to the PD via a four-pair cable with a connector 232 (e.g., RJ-45 or modified RJ-45). In one example, a 56V two-phase ESP can be used to provide approximately 1.5 times the current and power of traditional PoE. In another example, a 112V two-phase ESP can be used to provide approximately 3 times the current and power of 56VDC PoE. In yet another example, a 150V two-phase ESP can provide approximately 4 times the current and power of 56VDC PoE.

[0140] As mentioned above, the PD modulator and PSE modulator can be synchronized during low voltage initialization or high voltage initialization or during high power operation of each phase of a multi-phase system. In one or more embodiments, the PSE and PD modulator (control) switches (described above) can include timing control such that the PSE pulses on before the PD modulator switch turns on, and the PD modulator switch turns off before the PSE modulator switch turns off for each pulse, as shown in Figures 23 and 24. This can be used to minimize transients in the power distribution system, which reduces EMI and produces cleaner current waveforms for more accurate current sensing.

[0141] Figures 23 and 24 show simplified voltage waveforms and phase currents in a four-phase system, according to one embodiment. Figure 23 shows four-phase 75% duty cycle operation. Voltage pulses are shown at 264a for Phase A, 264b for Phase B, 264c for Phase C, and 264d for Phase D. The cumulative phase currents are shown at 266. As shown in Figure 23, the PSE switch drive is turned on before the PD switch drive at the beginning of the pulse, and at the end of the pulse on interval, the PD switch drive is turned off before the PSE switch drive for each phase.

[0142] Figure 24 shows operation with one phase (phase B) dropped. Voltage pulses are shown at 274a for phase A, 274c for phase C, and 274d for phase D. The cumulative phase current is shown at 276. As can be seen from Figure 24, by adjusting the relative timing of the three functional phases, continuous power is still provided even if phase B is lost.

[0143] As discussed above with respect to Figures 1, 17, and 20, PSEs and PDs can communicate in networks including a variety of topologies (number and placement of PSEs and PDs). The Enhanced Safety Power (ESP) systems described herein can include, for example, one or more PSE nodes and one or more PD nodes in a point-to-point topology, a daisy-chain topology, a multi-drop topology, a hybrid multi-drop / daisy-chain topology, or any combination thereof.

[0144] 25 is a simplified block diagram showing an ESP PSE node 280 in communication with an ESP PD node 282 in a point-to-point topology. The PSE node 280 includes a PSE isolation switch 284, and the PD node includes a PD isolation switch 286 in communication via a transmission line 288. The isolation switches 284, 286 isolate the devices during initialization, synchronization, and testing, as described below. The point-to-point topology is shown in the simplified circuits described above with respect to FIGS. 8-16 and 18-19.

[0145] 26 is a simplified block diagram showing a PSE 280a in communication with a PD 282a via a first transmission line 288a. The PD 282a also communicates with a downstream PSE node 280b via an internal bus 290. The PSE node 280b provides power to another PD 282b via a second transmission line 288b. The PD 282a and the PSE 280b may be located in the same network device and coupled via the internal bus 290. The first PSE 280a performs initialization, synchronization, and safety testing with the first PD 282a. The second PSE 280b performs initialization, synchronization, and safety testing with the second PD 282b.

[0146] An example of a multi-drop topology is shown in Figure 27. A PSE 280 communicates with two PDs 282a, 282b via a transmission line 288. The PSE 280 includes an isolation switch 284, and each PD includes its own isolation switch 286a, 286b.

[0147] FIG. 28 illustrates a multi-drop / daisy-chain hybrid topology, according to one embodiment. The PSE 280 and PSE isolation switch 284 are coupled to a first PD 282a via a transmission line 288a. The PD 282a includes a local isolation switch 286a and an output isolation switch 300a, which can communicate with a downstream PD 282b via a transmission line 288b. As described in detail below, the PSE 280 performs safety checks and synchronizes with the first PD 282a via the local isolation switch 286a. When a second PD 282b is connected to the network, the PD performs initialization and synchronization with the first PD 282a, and after passing the safety checks, receives high-voltage pulsed power via the output isolation switch 300a of the first powered device 282a via the transmission line 288b. This arrangement provides one transmission line monitored by the PSE as in the multi-drop case, and downstream registration is controlled by the PD as in the daisy-chain case, but using a subset of the PSE's functionality.

[0148] Details of the PSE and PD initialization process in a multi-drop / daisy-chain hybrid topology (FIG. 28) according to one embodiment are described below with respect to FIGS. 29-40. As described below, the PSE and PD nodes operate in a multi-drop / daisy-chain hybrid topology with functionality within the PD that allows them to internally perform functions typically performed by a PSE (e.g., low-voltage initialization). However, from the perspective of the network device topology (i.e., looking only at external network devices and links), the PSE and PD form a daisy-chain topology (the transmission line passes through the first PD and directly to the second PD).

[0149] 25-40 show only a single phase and the initialization process described below is for a single phase for simplicity, it should be understood that the process described herein may be repeated for each phase of a multi-phase system. For example, the transmission line 288 may include multiple wire pairs for multi-phase operation and the process described herein may be performed for each phase of a multi-phase system.

[0150] In one or more embodiments, a first power receiving device 322a communicating with the power supplying equipment 320 identifies a second power receiving device 322b communicating with the first power receiving device, and the first power receiving device receives high-voltage pulse power from the power supplying equipment (FIG. 37). The first power receiving device 322a performs a (first) low-voltage initialization together with the power supplying equipment before receiving the high-voltage pulse power (FIGS. 30 to 36). The first power receiving device 322a notifies the power supplying equipment 320 of the second power receiving device 322b, and performs a low-voltage power initialization together with the second power receiving device before passing the high-voltage pulse power to the second power receiving device 322b (FIGS. 37 to 40).

[0151] 29, a block diagram of a multi-drop / daisy-chain hybrid topology is shown. In this example, the PSE 320 is connected to a first PD 322a, which is connected to a second PD 322b. The PSE 320 includes a transceiver 326 in communication with an output isolation switch 332, a high voltage source 328, a low voltage source 330, and a transmission line monitor 334. Each PD 322a, 322b includes a transceiver 342a, 342b in communication with an upstream sense signal 336a, 336b, a bootstrap power supply 338a, 338b (e.g., the housekeeping power supply circuit described above), and a local isolation switch 340a, 340b. Each PD 322a, 322b further includes a high voltage receiver 344a, 344b in communication with an equipment load output 346a, 346b. The first PD 322a includes an output isolation switch 348a for communicating with the second PD 322b. In this example, the second PD 322b also includes an output isolation switch 348b for providing power and data to another downstream PD (using a downstream device detector 350b), although the PD 322b can also be configured without the output isolation switch and downstream detector for operation as an endpoint without pass-through functionality. In the example shown in FIG. 29, the PSE 320 and the PD nodes 322a, 322b are all in a powered-off state with the PSE's isolation switches in the open position.

[0152] 30 illustrates PSE detection and transmission line discovery for the first PD 322a. In this example, the PSE is powered on (output isolation switch 332 is closed), begins transmitting low voltage pulse power (a low voltage detection pulse train), and collects transmission line parameters (e.g., capacitance). The PSE 320 can perform a capacitance test of the cable between the PSE and the PD, as described above.

[0153] 31 shows a first PD 322a drawing power. The PD 322a is powered up by charging a local energy store (bootstrap power supply 338a) which powers the PD controller.

[0154] Figure 32 shows the PD training phase. The PD 322a recovers timing parameters (frequency, phase) from the PSE's low-voltage pulse train (Low-Voltage Pulsed Power Waveform 333) and uses this in the PD isolation switch gate drive waveform to synchronize the PSE modulator switch and the PD modulator switch (described above with respect to Figure 4).

[0155] 33 illustrates the identification phase of the PD 322a. As shown in the upstream detection signal module 336a, the PD 322a can transmit identification data through modulation of the load current while receiving the low voltage pulse train. The identification data is received by the transmission line monitor 334 of the PSE 320.

[0156] FIG. 34 shows a final PSE safety check in which PSE 320 isolates the transmission line after low voltage source 330 is disconnected.

[0157] As shown in Figure 35, high voltage operation is enabled in the PSE 320. The PSE 320 shifts the PD gate drive low voltage pulse train at the low voltage source 330 to a high voltage pulse train at the high voltage source 328 without any frequency or phase shift. The high voltage source 328 of the PSE 320 is now connected to the transmission line via an output isolation switch 332, and the high voltage pulse power is transmitted to the high voltage receiver 344a via the local isolation switch 340a of the first PD 322a.

[0158] 36 illustrates a PSE-PD communication link up. The transceiver 326 of the PSE 320 establishes communication with the PD 322a over the transceiver 342a. The PSE 320 and the PD 322a use the communication link to continue negotiations, set power limits, transmit telemetry, etc.

[0159] FIG. 37 illustrates downstream detection of the second PD 322b at the first PD 322a. As previously described, the first PD 322a has already performed a first low-power voltage initialization with the PSE 320 through the use of its local isolation switch 340a, and now receives high-voltage pulsed power at this local isolation switch. The first PD 322a detects the incoming PD (second PD) 322b and then notifies the PSE 320. The PD 322a can also notify the PSE 320 of any necessary timing adjustments due to changes in line capacitance. If the timing is changed, the PSE 320 and the PD 322a can be resynchronized as needed. Then, classification and synchronization of downstream devices are performed for the PD 322b. The first PD 322a performs low-voltage synchronization and classification operations with the second PD 322b using the reduced PSE functionality inside the first PD controller. The low-voltage power received at the second PD 322b is used to charge the bootstrap power supply 338b and power the PD controller (upstream sense signal 336b).

[0160] 38 illustrates a safety check of a downstream device. The output isolation switch 348 of the first PD 322a is closed and a safety check is performed in the PSE 320 for the entire transmission line to the isolation switches 340b, 348b of the second PD 322b.

[0161] As shown in FIG. 39, if the safety check is passed, the high-voltage pulsed power is transmitted via the first PD 322a to the high-voltage receiver 344b of the second PD 322b, and the supply of high-voltage pulsed power continues at the added node.

[0162] A communication link is set up with the second PD 322b, as shown in Figure 40. The transceivers 326, 342a, 342b are linked up between all three nodes (PSE 320, PD 322a, PD 322b) and the system reaches a steady state.

[0163] As previously mentioned, the above process may be performed for multi-phase pulsed power, with synchronization and validation performed for each phase. A network may also include any number of nodes in any topology, with one or more end nodes configured for pulsed power operation, one or more nodes configured for pulsed power or PoE, and one or more endpoints configured for PoE only. One or more PDs may also include the capability to act as a PSE for downstream nodes, as shown in FIG. 26.

[0164] While the method and apparatus have been described in accordance with illustrated embodiments, those skilled in the art will readily recognize that modifications may be made thereto without departing from the scope of the embodiments. Accordingly, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted in an illustrative and not a limiting sense.

Claims

1. 1. A method comprising: applying pulsed power between a pair of wires arranged to carry the pulsed power to a load, the pulsed power including alternating pulse-on and pulse-off time intervals; During the pulse off time interval, connecting at least one resistor having a known resistance across said wiring for a period of time; monitoring a voltage between the pair of wires before connecting the at least one resistor between the wires and after disconnecting the at least one resistor from the pair of wires; and determining a change in voltage between the pair of wires based on the monitoring, the change in voltage being indicative of a voltage droop from leakage or an unknown fault body resistance.

2. 2. The method of claim 1, wherein said connecting comprises closing a switch connected in series with said at least one resistor between said pair of wires for said period of time, and opening said switch at the end of said period of time.

3. 3. The method of claim 2, wherein the connecting is by closing the switch for a period of time after the pulse-off time interval begins and opening the switch prior to an end of the pulse-off time interval.

4. The connecting step comprises: first connecting a first resistor having a known resistance between the pair of wires during a first time period; during a second time period after the first time period, continuing to connect the first resistor between the pair of wires and secondly connecting a second resistor having a known resistance between the wires; The method of claim 1 , wherein said monitoring comprises monitoring a voltage between said pair of wires during said first time period and said second time period.

5. The method of claim 4 , wherein the determining comprises calculating the unknown fault body resistance for each pulse using differences in voltage aging.

6. The method of claim 5 , wherein the determining further comprises determining a cable capacitance using the difference in voltage change over time.

7. 5. The method of claim 4, wherein the first connecting comprises closing a first switch connected in series with the first resistor across the pair of wires, and the second connecting comprises closing a second switch connected in series with the second resistor across the pair of wires.

8. The connecting step comprises: during a first period of time, first connecting a first resistor having a known resistance between the pair of wires and second connecting a second resistor having a known resistance between the pair of wires; during a second period after the first period, disconnecting the first resistor from between the pair of wirings while simultaneously continuing to connect the second resistor between the pair of wirings; The method of claim 1 , wherein said monitoring comprises monitoring a voltage between said pair of wires during said first time period and said second time period.

9. 9. The method of claim 8, wherein the first connecting comprises closing a first switch connected in series with the first resistor across the pair of wires, and the second connecting comprises closing a second switch connected in series with the second resistor across the pair of wires.

10. An apparatus comprising: A power source configured to output power; a pair of modulation switches, each coupled between the power source and a respective wire of a pair of wires arranged to carry power to a load, the pair of modulation switches configured to open and close to provide pulsed power from the power of the power source, the pulsed power including alternating pulse-on and pulse-off time intervals; at least one resistor having a known resistance; a switch connected in series with the at least one resistor between the pair of wires, the switch being controlled; A controller that controls the switch to: connecting the at least one resistor across the lines for a period of time during a pulse off time interval; monitoring a voltage between the pair of wires before connecting the at least one resistor between the wires and after disconnecting the at least one resistor from the pair of wires; and determining a change in voltage between the pair of wires indicative of a voltage droop from a leakage or an unknown fault body resistance based on the monitoring of the voltage.

11. 11. The apparatus of claim 10, wherein the controller is configured to control the switch to close, thereby connecting the at least one resistor between the pair of wires for the period of time, and to open the switch at the end of the period of time.

12. 12. The apparatus of claim 11, wherein the controller is configured to control the switch to close the switch for a period of time after the pulse-off time interval begins and to open the switch prior to an end of the pulse-off time interval.

13. the at least one resistor comprises a first resistor having a known resistance and a second resistor having a known resistance, a first switch connected in series with the first resistor between the pair of wirings, and a second switch connected in series with the second resistor between the pair of wirings; 11. The apparatus of claim 10, wherein the controller is configured to: control the first switch during a first time period to connect the first resistor between the pair of wires; control the first switch and the second switch during a second time period to continue to connect the first resistor between the pair of wires and to connect the second resistor between the pair of wires; and monitor a voltage between the pair of wires during the first time period and the second time period.

14. The apparatus of claim 13 , wherein the controller is configured to calculate the unknown fault body resistance for each pulse using differences in voltage aging.

15. The apparatus of claim 14 , wherein the controller is further configured to determine cable capacitance using the difference in voltage change over time.

16. the at least one resistor comprises a first resistor having a known resistance and a second resistor having a known resistance, a first switch connected in series with the first resistor between the pair of wirings, and a second switch connected in series with the second resistor between the pair of wirings; 11. The apparatus of claim 10, wherein the controller is configured to: control the first switch and the second switch during a first period to connect the first resistor between the pair of wires and to connect the second resistor between the pair of wires; control the first switch and the second switch during a second period to continue to connect the first resistor between the pair of wires and to connect the second resistor between the pair of wires; and monitor a voltage between the pair of wires during the first period and the second period.

17. 1. A system comprising: Power supply equipment; A power receiving device; a pair of wires coupled between the power supply device and the power receiving device; The power supply device includes: A power source that outputs power; a pair of modulation switches, each coupled between the power source and a respective wire of a pair of wires arranged to carry power to a load, the pair of modulation switches configured to open and close to provide pulsed power from the power of the power source, the pulsed power including alternating pulse-on and pulse-off time intervals; at least one resistor having a known resistance; a switch connected in series with the at least one resistor between the pair of wires, the switch being controlled to connect the at least one resistor between the wires for a period of time during a pulse off time interval; A controller that controls the switch to: connecting at least one resistor across said wiring for a period of time during a pulse off time interval; monitoring a voltage between the pair of wires before connecting the at least one resistor between the wires and after disconnecting the at least one resistor from the pair of wires; and determining a change in voltage between the pair of wires indicative of a voltage droop from a leakage or an unknown fault body resistance based on the monitoring of the voltage.

18. 20. The system of claim 17, wherein the controller is configured to control the switch to close thereby connecting the at least one resistor in series between the pair of wires for the period of time and to open the switch at the end of the period of time.

19. 20. The system of claim 18, wherein the controller is configured to control the switch to close the switch for a period of time after the pulse-off time interval begins and to open the switch prior to an end of the pulse-off time interval.

20. the at least one resistor comprises a first resistor having a known resistance and a second resistor having a known resistance, a first switch connected in series with the first resistor between the pair of wirings, and a second switch connected in series with the second resistor between the pair of wirings; 18. The system of claim 17, wherein the controller is configured to: control the first switch during a first period to connect the first resistor between the pair of wires; control the first switch and the second switch during a second period to continue to connect the first resistor between the pair of wires and to connect the second resistor between the pair of wires; and monitor a voltage between the pair of wires during the first period and the second period.

21. 21. The system of claim 20, wherein the controller is configured to calculate the unknown fault body resistance for each pulse using differences in voltage aging.

22. 22. The system of claim 21, wherein the controller is further configured to determine cable capacitance using the difference in voltage change over time.

23. the at least one resistor comprises a first resistor having a known resistance and a second resistor having a known resistance, a first switch connected in series with the first resistor between the pair of wirings, and a second switch connected in series with the second resistor between the pair of wirings; 18. The system of claim 17, wherein the controller is configured to: control the first switch and the second switch during a first period to connect the first resistor between the pair of wires and to connect the second resistor between the pair of wires; control the first switch and the second switch during a second period to continue to connect the first resistor between the pair of wires and to connect the second resistor between the pair of wires; and monitor a voltage between the pair of wires during the first period and the second period.

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