Abstract:
An apparatus for carrying electrical data signals and electrical power over a power line is disclosed. The apparatus includes a data processing device, a power supply, and a data signal transceiver. The apparatus also includes an interference filter coupled to the power line and to the power supply and configured to reject electromagnetic interference. A coupling circuit that is electromagnetically coupled to the power line is also disclosed. The coupling circuit is configured to transmit and receive data signals carried through the power line. The coupling circuit is coupled to the data signal transceiver. The data signal transceiver is configured to transmit and receive the data signals to and from the data processing device.

Description:
FIELD OF THE INVENTION 
     The invention relates generally to the field of power line networking technologies. Further, the invention relates to a signal interface between a computer&#39;s power supply line and a computer&#39;s data communications interface. 
     BACKGROUND OF THE INVENTION 
     Power line technology (PLT) has been and will continue to be introduced to the consumer market at a fast pace to support in home networking or other local network situations. For example, multiple computers in the home may be networked together by utilizing the home&#39;s power line circuitry to carry data communication signals at a frequency different from the frequency at which power is transmitted. Further, other data processing devices may be networked in the home in a similar manner. For example, appliance devices in the home may be networked using power line technology as well as in home communication devices, such as telephones, video devices, home security devices, monitoring devices, etc. 
     Conventionally, personal computers (PCs) are not necessarily optimized to support PLT. Currently, a basic architecture of an add-on PLT system is either an internal PC card (e.g., ISA or PCI), that the user installs in an existing computer, or an external stand-alone box with a USB or parallel cable interfaced to the PC. The PLT module, whether it be internal or external, must be coupled in some manner to the power line. Generally, the PLT module is coupled to the power line by plugging a signal coupler module into an empty power outlet in the vicinity of the personal computer. In order to accomplish this coupling, the existence of an empty power outlet is needed, which is rarely the case in the vicinity of a personal computer system, because monitors, printers, and other accessories are normally present and connected to a power strip. In the case that an empty outlet is available, the user is forced to couple the PLT module to a relatively noisy power node, where the PC is directly connected, without adequate filtering. Coupling the PLT module to a noisy power node has the potential to affect operation and performance of the PLT network, depending on the type of power supply used for the PC and any accessories connected to it. 
     In the case that a power strip is being used, conventional power strips may contain filters, which effectively decouple high-frequency signals from the power line. Therefore, it is not necessarily appropriate to couple a PLT adapter to the power strip for optimum performance, because some of the high-frequency signals, which the power strip may filter out, may be needed for proper PLT home networking communication. Even if the power strip does not contain filters, it is not appropriate to couple a PLT module to the power strip or to an outlet in its vicinity because of the excessive noise and low impedance presented by the PC power supply and all its peripherals connected to the strip. 
     In a typical PLT networking interface, a transformer interface is used to couple the high-frequency data carrier signal to the power line. The transformer&#39;s primary winding is connected to the alternating current (AC) outlet of the power line through a coupling capacitor. The transformer&#39;s secondary winding is connected to a data carrier signal driver/receiver within the PC or the PLT module. The transformer isolates the PC system from the power line and at the same time rejects AC electrical power signal component. Furthermore, the transformer is coupled to the power line by a physical connector other than the PC power cable, to avoid any interference caused by the PC switching power supply. 
     Prior coupling technology is generally rudimentary, as an external port needs to be provided on a PC to support the connection of the data carrier signal to the power line, when the PC is already connected to the power line through the PC power cord. Further, a complete, self-contained interconnection module is required from the PC to the AC power outlet to provide the necessary coupling function. Thus, substantial expense for PLT networking devices lies in the redundancy of connections to the power line network, where the PC is already connected. 
     Referring to FIG. 1, a personal computer (PC)  10  of the prior art is depicted. PC  10  includes, among other hardware, a PC power supply  15 . PC power supply  15  conventionally includes a power cord  20  including an AC plug  25 , for coupling to a conventional power receptacle. In an exemplary embodiment, AC plug  25  may be, but is not limited to a J-type plug. In a typical implementation, an electromagnetic interference (EMI) filter  25  is coupled between power cord  20  and PC power supply  15 . A conventional EMI filter  25  includes a capacitor  30  coupled across the hot (H) and neutral (N) terminals of AC plug  25 . A transformer  35  is coupled between the H and N terminals and to the capacitors  40  and  45  coupled between the H terminal and ground and between the N terminal and ground respectively. Power line EMI filter  25  is typically present in most switching power supplies. Transformer  35  is commonly implemented as two common mode choke (same toroid) inductors in series with the power supply terminals  50  and  55 . The two inductors are wound on a common toroid, and their purpose is to suppress EMI emission from the internal power supply circuitry by de-coupling high-frequency noise from the power line (inductors typically present high impedance to high-frequency). In a conventional implementation, the value of such inductors is on the order of one milliHenry (mH). In a conventional implementation capacitor  30  which may be on the order of 0.1 microFarads (uF) may or may not be added across H and N to further de-couple noise injected to the power through the PC power cord. 
     Accordingly, there is a need for a PLT networking device that couples the signal driver/receiver within the PC to the power line without an external port, power/signal line, and/or interconnection module. Further, there is an alternative need for a PLT adapter for retrofitting existing PCs, having a PLT analog front end (AFE) card, the PLT adapter including data signal input, a power line input and a power output for coupling to the PC power supply. Further, there is another alternative need for a power strip that is optimized for PLT home networking. The power strip includes a power filter built into the power strip with a PLT coupler. 
     SUMMARY OF THE INVENTION 
     An exemplary embodiment of the invention relates to an apparatus for carrying electrical data signals and electrical power over a power line. The apparatus includes a data processing device, power supply, and a data signal transceiver. Further, the apparatus includes an interference filter coupled to the power line and to the power supply and configured to reject electromagnetic interference. Further still, the apparatus includes a coupling circuit electromagnetically coupled to the power line. The coupling circuit is configured to transmit and receive data signals carried through the power line. The coupling circuit is also coupled to the data signal transceiver. The data signal transceiver is configured to transmit and receive the data signals to and from the data processing device. 
     Another exemplary embodiment of the invention relates to a power strip configured for power line networking. The power strip includes an electrical plug. The power strip also includes a power filter for rejecting electromagnetic interference. The power filter is coupled to the electrical plug. The power strip further includes an inductor coupled to the power filter and coupled to a signal coupling. Further still, the power strip includes a power outlet coupled to the power filter. 
     Yet another exemplary embodiment of the invention relates to a power line networking adapter. The power line networking adapter includes a power line coupling input. The power line networking adapter also includes an interference filter coupled to the power line coupling input. Further, the power line networking adapter includes an electromagnetic circuit coupled to the filter circuit. Further still, the power line networking adapter includes a data signal connector coupled to the electromagnetic circuit. 
     Still yet another exemplary embodiment of the invention relates to a method of coupling a data processing device to a power line, the power line carrying electrical power and a data signal. The method includes coupling a power supply for the data processing device to the power line through an interference filter, the interference filter is configured to reject electromagnetic interference. The method also includes electromagnetically coupling a data signal carrier from a data signal transceiver to the power line to provide an electromagnetic coupling circuit. The electromagnetic coupling circuit is configured to transmit and receive the data signal being carried over the power line 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will become more fully understood from the following detailed description, taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like elements, in which: 
     FIG. 1 is a diagram of a power cord for a PC including an EMI filter; 
     FIG. 2 is a diagram of an exemplary embodiment of a power line networking interface; 
     FIG. 3 is a diagram of another exemplary embodiment of a power line networking interface; 
     FIG. 4 is a diagram of an exemplary embodiment power line networking module; 
     FIG. 5 is a diagram of an alternative exemplary embodiment of a power line networking module; and 
     FIG. 6 is a diagram of a power strip including a power filter with a coupler for power line networking. 
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     The following patent applications are hereby incorporated by reference in their entirety: 
     Commonly assigned U.S. patent application, Ser. No. 09/679,238, entitled “POWER SUPPLY ARCHITECTURE FOR POWER-LINE NETWORKING,” filed concurrently herewith; and 
     Commonly assigned U.S. Patent Application, Ser. No. 09/679,413, “POWER SUPPLY WITH SMALL-SIGNAL COUPLING FOR POWER-LINE NETWORKING,” filed concurrently herewith. 
     Commonly assigned U.S. Patent Application, Ser. No. 09/679,414, entitled “POWER SUPPLY WITH DIGITAL DATA COUPLING FOR POWER-LINE NETWORKING” filed concurrently herewith. 
     Referring now to FIG. 2, an exemplary embodiment of a PC  200 , includes a power supply  210  and a PLT analog front end (AFE)  220 . PLT AFE  220  may be a part of power supply  210  as described in the incorporated references entitled “POWER SUPPLY WITH SMALL-SIGNAL COUPLING FOR POWER-LINE NETWORKING,” and “POWER SUPPLY WITH DIGITAL DATA COUPLING FOR POWER-LINE NETWORKING” Power supply  210  is utilized to receive power input from a power source, such as, but not limited to, a typical in home (or other, such as an office) power line (120 volts, 60 hertz, e.g.). PLT AFE  220  is utilized to send and receive data signals to and from PC  200  (PLT AFE  220  operates as a communications driver/receiver or transceiver). In an exemplary embodiment, power supply  210  is coupled to an AC plug  225  through an EMI filter  230 . Also, in an exemplary embodiment EMI filter  230  includes a capacitor  235  coupled between the N terminal of AC plug  225  and a transformer  270 , an inductor  240  coupled in series with AC plug  225  and power supply  210 , and to capacitors  255  and  260  coupled between PC power terminals  245  and  250  respectively and to ground  265 . EMI filter  230  is used to filter out noise being generated in switching power supply  210 , so that when PC  200  is connected to the power line, high-frequency noise generated by power supply  210  is not sent through the power line. EMI filter  230  is used to filter out noise being generated switches and in power supply  210 , so that when PC  200  is connected to the power line, high frequency noise generated by power supply  210  is not sent through the power line. As depicted in FIG. 2 the traditional PC switching power supply is modified to simplify the architecture of a power line interface design. The power supply is modified in such a way as to optimize the data carrier signal coupling from the PC to the power line without the need for an external connection from the PC motherboard power line. 
     In the exemplary embodiment depicted in FIG. 2, a coupling transformer  270  is connected to the H and N terminals through a low-frequency blocking capacitor  235 , which replaces the existing 0.1 microFarad (uF) capacitor  35  (see FIG.  1 ). Further, in an exemplary embodiment an optional resistor  275  may be added in parallel with capacitor  235  to discharge capacitor  235  when AC plug  225  is unplugged. EMI line filter  230  still serves to reject high-frequency signals produced by power supply  210 . PLT AFE  220  then is configured to send and receive data signals generally in the range from 2 megahertz to 50 megahertz, or in an exemplary embodiment from 4 megahertz to 22 megahertz. In a particular embodiment, transformer  270  and EMI filter  240  may be incorporated as a part of PC  200 , such as, but not limited to, as a portion of the motherboard of PC  200 . Further, EMI filter  230  and transformer  270  may be incorporated into part of power supply  210  with a connection to PLT AFE  220  within the PC  200  case. 
     Referring now to FIG. 3, another exemplary embodiment of a PC  300  includes a power supply  310  and a PLT AFE  320 . In this exemplary embodiment, a wire represented as wire  330  is wound on the same toroid core that supports the two common-mode one milliHenry (mH) inductors  335  of EMI filter  340 . Coupling wire  330  with the existing core of inductors  335  provides an efficient coupling mechanism for the high-frequency data carrier to and from PLT AFE  320  and to and from an AC plug  345 , without the need for a coupling capacitor or an additional transformer. In an exemplary embodiment, filter  340  and hence wire  340  may be incorporated into PC  300 , or in an alternative embodiment, EMI  340  includes wire  330  which may be external to PC  300  and configured as a power cord adapter module. 
     Referring to both FIGS. 2 and 3, each of the embodiments has a primary advantage of reducing costs as compared to conventional PLT coupling interfaces. The cost of an external port on the PC and a stand-alone cable along with a coupling module to the power line may be eliminated by using circuitry depicted in FIGS. 2 and 3 without sacrificing performance of a network. A further advantage of embodiments depicted in FIGS. 2 and 3 are the convenience of the end user of a network product because to use this technology, an end user needs to only connect the PC power cord to an AC outlet. No external connection to and from the PC to the power line is required other than the power cord itself. Another advantage of the embodiment depicted in FIG. 3 is that the coupling circuit to the power line may not have a pronounced loading effect on the power as compared with the impedance associated with a separate data communications line and a separate power supply line. Multiple loading effects on the power line are therefore eliminated. 
     Users of personal computers or other electronic or data processing devices having an add-on PLT card or add-on PLT device may require a data signal connection to the power line. FIG. 4 depicts a PLT module  430  for enabling PLT functionality on devices being upgraded or retrofitted with a PLT card or PLT device. A module  400  for coupling between an AC power supply  405  and a load  410 , such as, but not limited to a PC, and further between AC power supply  405  and a PLT jack  420 , is depicted in FIG.  4 . Module  400  includes the same circuitry as depicted in FIG. 2, however, the circuitry to interface between power supply  405 , load  410 , and PLT jack  420  is integrated into a single module (or adapter)  430 , which may be a module (or adapter) connected at the PC, at the AC plug, or anywhere in between. 
     The use of PLT module  430  adds significant benefits to the application of power line networking in existing PC systems. First, an empty outlet is not required in the vicinity of the PC system to couple the add-on module to the power line, which in some cases means that the purchase of an additional power strip can be avoided. Second, the user is not burdened with the task of figuring out the best location to couple the add-on card to the power line, which would probably imply customer support calls and the like, and is not forced to reconfigure the existing interconnections of power cords to fit an additional clumsy plug module. Third, but not so limited, the PLT module  430  is an intermediate module between the power line and the PC power supply, in addition to being a high-frequency signal coupler with an effective filter to minimize noise from the PC switching power supply that may effect adequate operation of the networking system. 
     Module  430 , which may be referred to as a PLT adapter, can be inserted externally between the AC socket of the PC power,supply and the power cord that normally plugs into the AC socket. The PLT module  430  may have an input socket on one side much like the one found in the PC power supply, and an output plug on the other side, similar to the plug found in the PC power cord (that fits into the PC power supply socket). Furthermore, PLT module  430  would include a PLT interface jack  420  which may be a standard RJ11 type or BNC connector, or any other type of jack or connector, where the PLT add-on module would be connected for coupling to the power line. In an exemplary embodiment, PLT module  430  could be completely molded in plastic, with input and output elements available for connection to the PC power supply, the power line, and the PLT add-on card or PLT device (internal or external). In an alternative embodiment, PLT module  430  may be completely embedded and molded within the PC power cord itself. Accordingly, the power cord itself would be a PLT adapter with an output for connection to the PLT add-on module, and the normal AC power connections to the power line at one end and the PC power supply at the other end. PLT module  430 , although conceptually packaged in a different manner than the circuitry described with respect to FIG. 2, includes a power line filter to de-couple noise from the PC power supply and the high-frequency signal coupling mechanism, as depicted in FIG.  2 . 
     Referring now to FIG. 5, an exemplary PLT networking interface  500  is depicted. PLT networking interface  500  includes a PLT networking module  510  coupled between an AC power source  520 , a load, such as a PC  530 , and a PLT jack  540 . PLT module  510  utilizes the same circuitry as depicted and described with respect to FIG.  3 . As described with respect to FIG. 4, PLT module  510  is a power cord adapter with a coupling apparatus for power line networking. In particular, module  510  includes a PLT jack  540  for coupling to a PLT AFE to send and receive data signals to and from PLT AFE through AC power supply  520 . 
     Referring now to FIG. 6, a PC power strip  600  is depicted. PC power strip includes a power cord  605  coupled to an electrical plug  610 . Power cord  605  is coupled to a power filter with a PLT coupler  620 . Power filter with PLT coupler  620  may be, in an exemplary embodiment, circuitry depicted in FIG. 4 or circuitry depicted in FIG. 5, for example. Power strip  600  includes an integrated PLT jack  630  and a plurality of electrical outlets  640 . Power strip  600  includes a built-in coupling apparatus  620  for PLT networking, including adequate filtering to de-couple noise from the computer system and its peripherals coupled to electrical outlets  640 . The solution offers consumers a way to efficiently couple high-frequency signals to the power line without being effected by the specific PC and peripherals used. Power strips  600 , may be generalized, in an exemplary embodiment, to an improved wall-mount power adapter for PLT home networking, or to an improved wall electrical outlet containing an output jack for PLT signal coupling, having similar internal circuit topology as the power strip, such as the circuitry depicted in FIGS. 4 and 5. PLT jack  630  may be, but is not limited to a standard RJ11 type jack. In an exemplary embodiment power strip  600  includes electrical outlets  650  which may be unfiltered outlets. Outlets  650  may be used to provide electrical power and data signals to devices that are already PLT compliant (i.e., the devices already contain filters, such as, but not limited to EMI filters  430  and  510 , depicted in FIGS. 4 and 5. In alternative exemplary embodiments electrical outlets  650  may not be present. 
     The use of power strip  600  adds significant benefits to the application of PLT networking. An empty outlet is not required in the vicinity of the PC system to couple a PC add-on card to the power line, which in some cases may avoid the purchase of an additional power strip. The user is not burdened with the task of deciding the best location to couple the add-on card to the power line, which would probably imply customer support calls to the card manufacturer and is not forced to reconfigure the existing inner connections of power cords to fit an additional clumsy plug module. Power strips  600  provides an intermediate filtering effect between the power line and the PC power supply with all peripherals, in addition to being a high-frequency signal coupler for the PLT data carrier signal, which minimizes noise from the various power supply interfaces and can substantially improve performance and operation of the PLT home networking system. 
     Although exemplary embodiments refer to personal computers coupled to a home power line, the invention may also be applied to other types of devices communicating on a network, not necessarily a home network, and not necessarily a personal computer. 
     Further, while the exemplary embodiments refer to specific types of jacks, couplers, and plugs, the terms are to be interpreted broadly. The embodiments may encompass those situations in which any type of electrical or optical, RF, ultrasonic, and the like coupling is made between the data processing device and the power supply. 
     Further still, those who have skill in the art will recognize that the invention is applicable with many different hardware configurations, software architectures, communications protocols, and organizations or processes. 
     While the detailed drawings, specific examples, and particular formulations given describe exemplary embodiments, they serve the purpose of illustration only. The materials and configurations shown and described may differ depending on the chosen performance characteristics and physical characteristics of the application. For example, the type of networking or networking protocols used may differ. The systems shown and described are not limited to the precise details and conditions disclosed. Furthermore, other substitutions, modifications, changes, and omissions may be made to the design, operating conditions, and arrangement of the exemplary embodiments without departing from the scope of the invention as expressed in the appended claims.