Patent Application
20120126612
This application claims priority under 35 U.S.C. §119(a) to Great Britain Application Serial No. 1019819.0 filed Nov. 23, 2010, which is incorporated herein by reference in its entirety for all purposes.
1. Field of the Invention
The invention is in the field of communications over power lines or the like; and in particular it relates to power supply units for devices configured to communicate over power lines or the like.
2. Description of the Related Art
Powerline broadband modems are currently used for broadband communications using powerlines as the connecting medium, i.e., Powerline Communications network. The connection points for this network (electrical sockets) are commonly found to contain a large collection of electrical equipment (for example, a media center in a living room). For reasons such as safety and noise reduction it is usual to provide a relatively low (safe) voltage external power supply unit providing a DC supply to power, from the mains AC supply, many types of appliances. Where such an appliance is of a type configured to receive broadband data via the same power line as the mains electricity system, the appliance may comprise circuits for decoupling digitally encoded signals from the AC voltages of the power line and/or for injecting digitally encoded signals into the power line. Therefore the appliance requires direct connection to the AC mains supply for such data communication. In addition, such a device may require a representation of the AC mains zero-crossing points (for timing etc.). This would suggest a need for a cable between the power supply unit and the appliance requiring at least six lines, two for the DC power, two for the zero crossing signal, and two for the communications. The resultant six-wire cable would be stiff, bulky, and unwieldy and the connection required would be larger than ideal.
Embodiments of the invention will now be described, by way of example only, by reference to the accompanying drawings, in which:
The present invention may be embodied in various forms. One embodiment of the present invention is as an external Power Supply Unit (PSU) for an appliance that includes rectification circuitry operable to converting an AC voltage from mains power lines to at least one DC voltage, decoupling circuitry operable to decoupling broadband data signal from said mains power lines, timing circuitry operable to providing a signal representative of the mains AC voltage timing, and conveyance circuitry operable to conveying the DC voltage output, ground reference signal, signal representative of the mains AC voltage timing and a broadband data signal to said appliance. In this embodiment, the conveyance circuitry has no more than four conductors.
The PSU may be operable to modulate the signal representative of the mains AC voltage timing onto either the DC voltage output or the broadband data signal. The circuitry operable to providing a signal representative of the mains AC voltage timing may include a zero-crossing detector. The PSU may further include circuitry operable to modulating the DC voltage output with the signal representative of the mains AC voltage timing. The PSU may be operable such that the DC voltage output, the ground reference and the signal representative of the mains AC voltage timing are output on a single pair of conductors included within the conveyance circuitry. The modulating of the DC output may include causing the DC output to ripple between two levels at a frequency dependent on the signal representative of the mains AC voltage timing.
In one embodiment, the conveyance circuitry includes a total of one pair of conductors, the power supply unit being operable to carry the broadband data signal, the modulated DC output, and the ground reference on the one pair of conductors. The power supply unit may further include filtering circuitry operable to remove noise and/or raise the output impedance of the circuitry operable to converting a mains AC voltage to at least one DC voltage, to allow the injection of the broadband data signal on the same pair of conductors as those operable to carry the modulated DC output and ground reference. The conveyance circuitry may terminate with a conventional coaxial DC connector.
Alternatively the conveyance circuitry may include a total of two pairs of conductors, the power supply unit being operable to carry the broadband data signal on an additional pair of conductors. The PSU may be operable such that the modulated DC voltage output is conveyed by modulation of the common mode voltage, or current, of the broadband data signal, on a pair of conductors included within the conveyance circuitry, a third conductor being operable to carry the ground reference, the conveyance circuitry including a total of three conductors.
The PSU may be operable such that the signal representative of the mains AC voltage timing is arranged to control an oscillator at a rate dependent on the frequency of the zero-crossing of its input signal to modulate the DC signal. The modulation may be arranged to employ feedback modulation, where the oscillator's reference signal is obtained from the modulated DC output signal. Alternatively, the oscillator may use a fixed reference, and feed an error amplifier operable to output an error signal for appropriate control of the duty cycle of the circuitry operable to converting a mains AC voltage to at least one DC voltage so as to modulate the DC output.
As a further alternative to those described above, the PSU may be operable such that the signal representative of the mains AC voltage timing is conveyed by modulation of the common mode voltage, or current, of the broadband data signal on a pair of conductors included within the conveyance circuitry, the conveyance circuitry including a total of four conductors, the other two conductors being operable to convey the DC voltage output and ground reference signal. As an alternative, the signal representative of the mains AC voltage timing may be conveyed by modulation of the differential mode of the broadband data signal, e.g. by using FSK techniques.
In a further aspect of the present invention there is provided an appliance requiring a DC power supply for operation, and further including a power line communication modem for modulation and demodulation of broadband data signal onto mains electrical powerlines, the modem requiring a mains timing signal for proper operation. The appliance includes a two or three-line input for receiving input signals conveyed thereto on two, or three conductors. The appliance is operable such that the input signals include the DC power supply, the broadband data signal, and the mains timing signal. The appliance includes circuitry operable to obtaining the mains timing signal and low pass filtering circuitry operable to separating the DC component of the signal for supply of the power. The appliance may include a two-line input and further include high pass filtering circuitry and circuitry, such as a signal transformer, for decoupling of broadband data signal received on the input. The circuitry operable to obtaining the mains timing signal may include a band pass filter. The appliance may include a three-line input, the circuitry operable to obtaining the mains timing signal may include a divider circuit connected between two lines of the three line input, the two lines carrying the broadband data signal. In a further aspect of the invention there is provided a package including a power supply unit of the first aspect of the invention and an appliance of the second aspect of the invention.
A method of conveying a DC voltage output and ground reference signal, a signal representative of the mains AC voltage timing and broadband data signal over no more than four conductors includes first modulating the signal representative of the mains AC voltage timing onto either the DC voltage output or the broadband data signal. The method may be performed using three conductors, the modulated DC component of the DC voltage output also being carried as common mode signal offset on the pair of conductors carrying the broadband data signal, the third conductor carrying the ground reference. The method may include modulating the DC voltage output with the signal representative of the mains AC voltage timing prior to carrying the modulated DC signal and a ground reference on a first pair of conductors. The method may include coupling the broadband signal to the first pair of conductors, thereby performing the method using only two conductors. Alternatively, the method may include using four conductors, with the broadband signal being carried on a second pair of conductors.
Alternatively, the signal representative of the mains AC voltage timing may be modulated as a common mode signal, or a differential mode signal, on the pair of conductors carrying the broadband data signal. The method may be performed using four conductors, the other two conductors being used to carry the DC voltage output and ground reference signal.
For reasons such as safety and noise reduction it is usual to provide a relatively low (safe) voltage DC supply to power many types of appliances such as, for example, a computing device, telephone, audio device, video device, wireless device/router, printer, laptop computer, television, stereo, music storage device, audio amplifier, speaker, and/or the like. This is preferably provided by an external AC/DC converter (power supply unit—PSU) which is powered by the mains electricity system and provides a lower voltage DC output. However, where the appliance is configured to receive broadband data via the same power line as the mains electricity system, it typically includes circuits configured to decouple digitally encoded signals from the AC voltages of a power line and/or configured to inject digitally encoded signals into the power line. Therefore the appliance requires direct connection to the AC mains supply.
The AC to DC module 830 is configured to convert the AC line voltage of a power line 115 to one or more DC voltages (e.g., +/−5 v, +/−9 v, +/−12 v, or the like) on one or more conductors 860. The power supply unit 900 may also include an optional filter 920 in electrical communication between AC to DC module 830 and the power line 115, or between AC to DC module 830 and signal coupling circuitry 840. The filter 920 is configured to protect other components of power supply unit 900 from electrical noise generated by AC to DC module 830. Filter 920 can be a low-pass filter, for example. The filter 920 can also couple an external AC socket 925 to the power line 115. The filter 920 can then also serve to remove noise generated by any appliances attached to AC socket 925. A further filter may also be provided on the output side of the AC to DC module 830.
As noted, power supply unit 900 also includes signal coupling circuitry 840 in electrical communication with power line 115 and configured to send and receive digitally encoded signals over one or more conductors 870. Signal coupling circuitry 840 includes the transformer 850 and can optionally also include one or more of, all of, any combination of, or part(s) of: coupling capacitor 160, signal conditioner 155, an over-voltage protection device 930, and a fuse 940. Signal coupling circuitry 840 may include an entire communication interface or merely a part thereof with the remaining part of the communication interface optionally residing in the appliance attached thereto.
Zero crossing circuitry 910 includes, in this example, a LED (light-emitting diode) 950 and an adjacent photo detector 960. In the zero crossing circuitry 910, the LED 950 is in electrical communication with power line 115 and is configured to emit light pulses that are synchronized to the waveform of the AC line voltage. Photo detector 960 receives the light pulses and produces a timing signal that can be communicated over one or more conductors 970 to an appliance.
Power supply unit 900 is connected to an appliance by cabling 860, 870, and 970. Cabling provides communication between an appliance and power supply unit 900. Cabling may be integral with power supply unit 900. The cabling may include one or more conductors 860 (typically two) configured to convey the one or more DC voltages between power supply unit 900 and the appliance, one or more conductors 870 (typically two) configured to convey the digitally encoded signals between an appliance and power supply unit 900 and one or more conductors (typically two) for communicating the timing signal from the zero-crossing circuitry 910. Therefore there are typically six output conductors from the AC/DC converter. Where the power supply unit 900 is detachable from an appliance, the conductors 860, 870, 970 may be wrapped together by a common insulation layer, or else each may be insulated separately from the other conductors. Conductors 870 are optionally rated for the digitally encoded signals but not rated for voltages as high as the AC voltages found on the power line.
AC to DC module 830 of the example illustrated by
Conductors 860 and 870, and 970 (not shown), together can include cabling. Cabling can be integral with, or detachable from, power supply unit 1000. Cabling can also terminate in a connector configured to mate with a corresponding receptacle on an appliance (not shown).
However such a connector would have to be larger than a conventional two-wire DC power connection, and the resultant cable needs to be larger and stiffer than a two-wire cable. This is not desirable, and it would be preferable if a standard two wire output PSU with conventional connector could be used in the situations discussed above.
Such a PSU should include:
Furthermore, the appliance should further include:
PSU 300 operates by using the zero crossing detector and modulator 320 to modulate the zero-crossing signal, which represents the mains timing of the input AC voltage, onto the DC output of the AC-DC module 310. This modulated DC output is then passed through filter 330, on a single pair of wires 390. Broadband signals are then coupled to the same pair of wires.
The appliance 345 is adapted by being further provided (by way of input module, or otherwise) with a 50-60 Hz Band Pass Filter 350, for separating out the timing signal from the zero-crossing detector, a Low Pass Filter 370 for separating out the DC component, and a High Pass filter 380 and signal transformer (not shown) for handling the broadband data signals prior to sending the resultant data to the modem. The broadband data signal (or signals) is preferably spectrally contained within frequencies greater than 1 MHz (which could be in more than 1 band).
The power cable 390 in this embodiment is standard two-wire cable which can terminate in a standard DC connector. The two-wire cable carries DC power and ground, the broadband data signals, and a representation of the AC mains zero-crossing point, e.g. a modulation of the DC voltage synchronized to the AC mains frequency. Connection may be made with ferrites at each end to reduce radiation.
An alternative to the two-wire solutions above are a four-wire solution, wherein the zero-crossing signal is modulated on the DC signal as described above, but with the broadband data carried on separate wires. This reduces the need for filtering the DC signal while still allowing use of low cost connectors (3.5 mm jacks, USB, RJ11 etc.). Another alternative to the two-wire solutions is a three-wire solution in which power and GND are carried by two wires and the broadband data and zero-crossing signal are superimposed on a third wire with respect to GND.
The above examples illustrate circuits configured to couple digitally encoded signals to and from a power line. Alternative embodiments may include other circuits configured to decouple a digitally encoded signal from a power line and/or to inject a digitally encoded signal into a power line. Examples of such circuits include those illustrated in US 2007-0075843 A1, filed Aug. 24, 2006.
Circuitry described herein that performs particular functions may be a microprocessor, micro-controller, digital signal processor, microcomputer, central processing unit, field programmable gate array, programmable logic device, state machine, logic circuitry, analog circuitry, digital circuitry, and/or any device that manipulates signals (analog and/or digital) based on hard coding of the circuitry and/or operational instructions, which may be considered singularly or in combination a “processing module.” The processing module, module, processing circuit, and/or processing unit may be, or further include, memory and/or an integrated memory element, which may be a single memory device, a plurality of memory devices, and/or embedded circuitry of another processing module, module, processing circuit, and/or processing unit. Such a memory device may be a read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, cache memory, and/or any device that stores digital information. Note that if the processing module, module, processing circuit, and/or processing unit includes more than one processing device, the processing devices may be centrally located (e.g., directly coupled together via a wired and/or wireless bus structure) or may be distributed located (e.g., cloud computing via indirect coupling via a local area network and/or a wide area network). Further note that if the processing module, module, processing circuit, and/or processing unit implements one or more of its functions via a state machine, analog circuitry, digital circuitry, and/or logic circuitry, the memory and/or memory element storing the corresponding operational instructions may be embedded within, or external to, the circuitry including the state machine, analog circuitry, digital circuitry, and/or logic circuitry. Still further note that, the memory element may store, and the processing module, module, processing circuit, and/or processing unit executes, hard coded and/or operational instructions corresponding to at least some of the steps and/or functions illustrated in one or more of the FIGs. Such a memory device or memory element can be included in an article of manufacture.
The present invention has been described above with the aid of method steps illustrating the performance of specified functions and relationships thereof. The boundaries and sequence of these functional building blocks and method steps have been arbitrarily defined herein for convenience of description. Alternate boundaries and sequences can be defined so long as the specified functions and relationships are appropriately performed. Any such alternate boundaries or sequences are thus within the scope and spirit of the claimed invention. Further, the boundaries of these functional building blocks have been arbitrarily defined for convenience of description. Alternate boundaries could be defined as long as the certain significant functions are appropriately performed. Similarly, flow diagram blocks may also have been arbitrarily defined herein to illustrate certain significant functionality. To the extent used, the flow diagram block boundaries and sequence could have been defined otherwise and still perform the certain significant functionality. Such alternate definitions of both functional building blocks and flow diagram blocks and sequences are thus within the scope and spirit of the claimed invention. One of average skill in the art will also recognize that the functional building blocks, and other illustrative blocks, modules and components herein, can be implemented as illustrated or by discrete components, application specific integrated circuits, processors executing appropriate software and the like or any combination thereof.
The present invention may have also been described, at least in part, in terms of one or more embodiments. An embodiment of the present invention is used herein to illustrate the present invention, an aspect thereof, a feature thereof, a concept thereof, and/or an example thereof. A physical embodiment of an apparatus, an article of manufacture, a machine, and/or of a process that embodies the present invention may include one or more of the aspects, features, concepts, examples, etc. described with reference to one or more of the embodiments discussed herein. Further, from figure to figure, the embodiments may incorporate the same or similarly named functions, steps, modules, etc. that may use the same or different reference numbers and, as such, the functions, steps, modules, etc. may be the same or similar functions, steps, modules, etc. or different ones.
Unless specifically stated to the contra, signals to, from, and/or between elements in a figure of any of the figures presented herein may be analog or digital, continuous time or discrete time, and single-ended or differential. For instance, if a signal path is shown as a single-ended path, it also represents a differential signal path. Similarly, if a signal path is shown as a differential path, it also represents a single-ended signal path. While one or more particular architectures are described herein, other architectures can likewise be implemented that use one or more data buses not expressly shown, direct connectivity between elements, and/or indirect coupling between other elements as recognized by one of average skill in the art.
The term “module” is used in the description of the various embodiments of the present invention. A module includes a processing module, a functional block, hardware, and/or software stored on memory for performing one or more functions as may be described herein. Note that, if the module is implemented via hardware, the hardware may operate independently and/or in conjunction software and/or firmware. As used herein, a module may contain one or more sub-modules, each of which may be one or more modules.
While particular combinations of various functions and features of the present invention have been expressly described herein, other combinations of these features and functions are likewise possible. The present invention is not limited by the particular examples disclosed herein and expressly incorporates these other combinations.
The present invention has also been described above with the aid of method steps illustrating the performance of specified functions and relationships thereof. The boundaries and sequence of these functional building blocks and method steps have been arbitrarily defined herein for convenience of description. Alternate boundaries and sequences can be defined so long as the specified functions and relationships are appropriately performed. Any such alternate boundaries or sequences are thus within the scope and spirit of the invention.
Moreover, although described in detail for purposes of clarity and understanding by way of the aforementioned embodiments, the present invention is not limited to such embodiments. It will be obvious to one of average skill in the art that various changes and modifications may be practiced within the spirit and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1019819.0 | Nov 2010 | GB | national |
