Power sourcing unit for power over ethernet system

A power sourcing unit for a power over ethernet system. The unit includes a chassis with a power supply guide and a CPU guide, and a power supply including a power supply connector. The unit also includes a printed circuit board including first and second connectors and being coupled to a plurality of RJ-45 jacks, and a CPU line card including a CPU connector. The power supply guide engages the power supply to allow the power supply to be slid into and out of the unit to couple the power supply connector to the first connector of the printed circuit board. The CPU guide engages the CPU line card to allow the CPU line card to be slid into and out of the unit to couple the CPU connector to the second connector of the printed circuit board. The CPU line card allows the unit to be coupled to a network. Multiple power sourcing units can be daisy-chained together.

TECHNICAL FIELD

The present invention relates to systems and methods for the distribution of data and power over a local area network, and, more particularly, to power over ethernet power sourcing units.

BACKGROUND

Interest in power over ethernet technology has increased with the adoption of the power over ethernet IEEE 802.3af standard in June of 2003. Generally, power over ethernet technology allows standard ethernet cables to carry not only data signals, but also power to the devices connected to the cables. In this manner, power can be provided by the ethernet cable itself, rather than requiring a separate source of power for the connected devices.

The standard requires a power sourcing unit, which supplies up to 15.4 watts of power (at 48 volts) to a powered device. The standard utilizes pins1/2and3/6, or pins4/5and7/8, of the eight-pin ethernet cable for both data and power transfer. To avoid damaging non-compliant devices that may be connected to the power over ethernet system, the standard specifies a method for detecting compliant devices by applying a small, current-limited voltage to check for the presence of a 25 k ohm impedance in the connected device. Only if the power sourcing unit detects this impedance is the full 48 volts applied.

There are many potential applications for power over ethernet technology. For example, wireless access points can be placed at desired locations throughout a building without requiring a separate source of power. Another potential application includes internet protocol (IP) telephones, for which a central power supply with a backup uninterrupted power supply (UPS) is desirable. Other applications for which this technology may be desirable include IP cameras, security badge readers, etc.

The advantages associated with power over ethernet technology can include: reduced cabling costs, because both power and data are provided over a single ethernet cable; increased reliability, because a centralized power source can utilize an UPS to guarantee uninterrupted power to all powered devices; and increased network management, to allow powered devices to be monitored and controlled remotely.

It is desirable to provide enhanced functionality for the power sourcing units of power over ethernet systems.

SUMMARY

Embodiments of the present invention are directed to systems and methods for the distribution of data signals and power over a local area network, and, more particularly, to power over ethernet power sourcing units.

In one embodiment, a power sourcing unit includes a chassis, a plurality of jacks, a printed circuit board, and a removable power supply. In one embodiment, the unit also includes a removable CPU line card that allows the unit to be connected to a network.

In one embodiment, the power supply and the CPU line card are removable from the power sourcing unit without requiring a cover of the unit to be removed.

In some embodiments, multiple power sourcing units can be daisy-chained together.

The above summary of embodiments made in accordance with the present invention is not intended to describe each disclosed embodiment or every implementation of the present invention. The figures and the detailed description that follow more particularly exemplify embodiments of the invention. While certain embodiments will be illustrated and described, the invention is not limited to use in such embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Embodiments of the present invention are directed to systems and methods for the distribution of data signals and power over a local area network, and, more particularly, to power over ethernet power sourcing units. Example embodiments illustrated herein are power sourcing units made in compliance with the IEEE Std. 802.3af™-2003, which is incorporated by reference herein in its entirety. The power sourcing units described herein are configured to deliver both data signals and power over an ethernet cable to a powered device.

Referring now toFIGS. 1-9, an example embodiment of a power sourcing unit100of a power over ethernet system is shown. The unit100generally includes a chassis105and a cover110that is removably coupled to the chassis105. Also included are brackets115that can be used to couple the unit100to, for example, a rack. In the example embodiment, the chassis105and cover110are made of metal.

A front surface120of the chassis110includes a plurality of apertures122,124, and126that are sized to accept a plurality of port modules128, each including a plurality of jacks129. In the example shown inFIGS. 1-8, the unit100includes three port modules128, each port module128including sixteen (16) jacks129. More or fewer port modules128can be provided, as described further below.

In the example shown, each of the jacks129of the port module128is an RJ-45 jack. The jacks129in each port module128are arranged vertically in pairs so that an ethernet cable carrying a data signal from, for example, an ethernet switch can be coupled to a lower jack129, and an ethernet cable to, for example, a powered device can be coupled to the corresponding upper jack129to carry the data signal and power from the unit100to a powered device. SeeFIG. 21described below. An LED131positioned below each pair of jacks129indicates power for that pair of jacks129.

Also included on the front surface120of the chassis105are a COM-in port130and a COM-out port132. In the example shown, the COM-in port130and the COM-out port132are each standard D-sub9pin connectors. As described further below with reference toFIG. 22, the COM-in port130and the COM-out port132can be used to couple multiple units100together.

As shown, for example, atFIGS. 1,2,5, and8, the cover110includes slots107and109formed therein. The slots107and109are positioned to cover apertures162and164in chassis105(seeFIG. 9). Heat generated within the unit100can be dissipated through the apertures162,164and the slots107,109. For example, one or more fans associated with a power supply210(described further below) in the unit100can move air through the apertures162,164and the slots107,109of unit100to dissipate heat generated therein.

A back surface140of the unit100includes a power supply cover142and a CPU cover144. The power supply cover142includes an aperture147to allow a power cord to be plugged into the unit100to power on the unit100. In optional embodiments, the power supply cover142also includes an aperture148for receipt of a switch, such as a toggle switch, used to turn the unit100on and off. In the illustrated embodiment, the power supply cover142and the CPU cover144extend substantially an entire width of and cover the back surface140of the unit100.

The CPU cover144includes an aperture154for a port150of a CPU line card410. In addition, the CPU cover144includes an aperture152for an LED to indicate power to the CPU line card410, as well as an aperture154for an LED to indicate network connectivity for the CPU line card410. The CPU line card410is described further below with reference toFIGS. 16 and 17.

A plurality of fasteners146are used to couple the power supply cover142and the CPU cover144to the chassis105of the unit100. The fasteners146are configured to allow either the power supply cover142or the CPU cover144to be independently removed from the chassis105.

Referring now toFIGS. 9-17, the internal components of the unit100are illustrated. Unit100generally includes power supply210, a printed circuit board310, and an optional CPU line card410.

The power supply210, which is coupled to power supply cover142, converts an alternating current (AC) power source to direct current (DC) to power the unit100and any powered devices coupled to the unit100. In the example, the power supply210is a power supply with product no. DS625-9-401 manufactured by Astec Power of Carlsbad, Calif. In the example embodiment, the power supply210converts the AC power source to provide 48 volts DC to the printed circuit board310. The power supply210includes a connector215that mates with a connector315mounted on the printed circuit board310to couple the power supply210to the printed circuit board310. In the example shown, connector215is a port and connector315is a plug, although in alternative embodiments the locations of the port and plug can be interchanged.

The example power supply210includes slots212,214running the depth of the supply210. The slots212,214correspond to guide pins172coupled to a bottom surface of the chassis105. The power supply210can be slid into the unit100(seeFIG. 10) by placing the power supply210into a cavity174formed between the chassis105and cover110at the back surface140, and sliding the power supply210in a direction A so that the slots212,214ride along the guide pins172until the connector215accepts connector315of the printed circuit board310. Guide posts316on connector315(seeFIG. 15) further guide the connector315into the connector215. The fasteners146on the power supply cover142can then be tightened to lock the power supply210into place in the unit100.

The power supply210can likewise be removed from the unit100by loosening the fasteners146and sliding the power supply210out of the cavity174in a direction opposite to that of direction A. The same or a different power supply210can then be placed into the cavity174as described above. In this manner, the power supply210is removable from the unit100without requiring the cover110to be removed from the chassis105.

The printed circuit board310includes a plurality of logic components and a plurality of tracings etched thereon to electrically connect the various components mounted on the circuit board310. Components on the printed circuit board310are powered through the conversion of the 48 volts DC provided by the power supply210to approximately 3.3 volts DC. In addition, the printed circuit board310delivers up to 48 volts DC to each jack129in each port module128that is connected to a powered device.

The printed circuit board310includes connector315, port modules128, and a COM module134including COM-in port130and COM-out port132mounted thereon. The printed circuit board310also includes a connector317for mating with a connector415of CPU line card410.

Referring now toFIG. 15A, the interconnection of example components mounted on printed circuit board310is shown. Generally, an 8-bit microcontroller192processes and controls other components on the printed circuit board310and, for example, communicates with power supply210and CPU line card410, if present. In addition, a CPLD194functions to control various aspects of the unit100such as, for example, various LEDs and multiplex serial communication signals to the CPU line card410and microcontroller192.

Referring now toFIGS. 16 and 17, CPU line card410is illustrated in greater detail. Generally, CPU line card410allows unit100to be coupled to a network. For example, CPU line card410can be configured with an IP address on a network. The CPU line card410facilitates communication between the unit100and remote devices on the network. In the embodiment shown, the CPU line card410can forward statistics associated with the unit100to devices on the network, as well as allow remote access to the unit100.

In one example, the CPU line card410can communicate to a remote device on the network when an error condition occurs, such as a failed jack129in a module128. The remote device can then reconfigure the unit100by, for example, shutting down the failed jack129and/or turning on one or more additional jacks129.

In the illustrated example, the CPU line card410includes a printed circuit board430coupled to the CPU cover144. The printed circuit board430includes connector415and port450mounted thereto. Connector415mates with connector317on printed circuit board210to allow communication between the CPU line card410and the printed circuit board210. Port450is visible through aperture150of the CPU cover144and accepts an ethernet plug of an ethernet cable to connect the CPU line card410to, for example, the network.

In the example shown, the CPU line card410can be inserted into and removed from the unit100without requiring removal of the cover110. Specifically, to insert the CPU line card410into the unit100, the CPU line card410is inserted in the direction A into a cavity178formed between the chassis105and cover110in the back surface140of the unit100. SeeFIG. 9. Once inserted into the cavity178, non-conductive CPU guide railways182,184(seeFIGS. 11 and 12) formed adjacent to the bottom surface of the chassis105guide sides442,444of the printed circuit board430of the CPU line card410so that the CPU line card410can be slid in the direction A until connector415is coupled to connector317on printed circuit board310. Fastener146on CPU cover144can then be tightened to couple the CPU line card410to the unit100. In a like manner, the CPU line card410can be removed from the unit100by loosening the fastener146and sliding the CPU line card410in a direction opposite to direction A out of the unit100.

The unit100is configured to recognize when a CPU line card410is inserted and/or removed. In one embodiment, the CPU line card410can be inserted and removed without requiring the unit100to be powered down.

In example embodiments, if the unit does not have a CPU line card410, a dummy cover plate (not shown) can be coupled to the unit100to cover cavity178. The dummy cover plate can be configured in a manner similar to that of CPU cover144, except that the dummy cover plate would not include an aperture154for port150.

Referring now toFIGS. 18-20, another embodiment of a power sourcing unit500is illustrated. Unit500is similar to unit100described above, except that only a single port module128is provided on printed circuit board310. Therefore, only aperture122includes a port module128. In the example shown, apertures124,126are therefore covered using blanks552and554. In addition, an overlay560is applied to the front surface120to mask blanks552,554. In other embodiments, two port modules128can be provided, and only aperture126covered by blank554. In this manner, a different number of port modules128and associated jacks can be provided while maintaining a standard chassis size.

In example embodiments, as shown inFIG. 21, power sourcing unit100can be placed between an ethernet switch565and one or more powered devices570to supply data signals from the ethernet switch565, as well as power from unit100, to the powered device570.

In addition, more than one power sourcing unit100can be used in a power over ethernet system. For example, inFIG. 22, an example power over ethernet system600is illustrated including a plurality of power sourcing units602,604,606,608, and610. In the example shown, the power sourcing units602,604,606,608, and610are daisy-chained to one another by connecting the COM-out port132of one unit to the COM-in port130of the next unit.

Generally, in one example embodiment, each unit602,604,606,608, and610is automatically and uniquely assigned an identification code at the time of performance of a boot-up routine in each unit, which is typically initiated in sequence for each unit. Each unit602,604,606,608,610thereby assigns itself a particular identification code and directs the next unit to assign itself an identification code different than the one assigned to itself (such as one greater than the one assigned to itself). For example, the CPLD194can provide an identification code to either the CPU line card410or the microcontroller192. The assigned identification code can be used to communicate with a specific unit602,604,606,608, and610.

For example, a device can be coupled to the COM-in port130of unit602to serially communicate with any of units602,604,606,608, or610. Power sourcing unit602includes a CPU line card410, which facilitates communication between a device located remotely on a network and units602,604,606,608, and610. In this manner, a single IP address can be assigned to a plurality of units602,604,606,608, and610that are daisy-chained together to allow for remote management of the units602,604,606,608, and610. In the example shown, a single CPU line card410can allow up to five units602,604,606,608, and610to be communicated with remotely.

More or fewer units can daisy-chained together. In addition, the system600can be periodically polled to identify if additional power sourcing units have been added or removed from the system. If a power sourcing unit has been added, a unique identification code can be automatically assigned to the new unit.

Additional details regarding the daisy-chaining of multiple units can be found in U.S. patent application Ser. No. 10/308,258, filed on Dec. 2, 2002 and entitled “Systems and Methods for Automatic Assignment of Identification Codes to Devices,” the entirety of which is hereby incorporated by reference.