APPARATUS, METHOD AND SYSTEM FOR CONTROLLING A LOAD DEVICE VIA A POWER LINE BY USING A POWER NEGOTIATIION PROTOCOL

Abstract

The present invention proposes to use a power negotiation connection (e.g. the VBUS channel) of a power delivery interface for transmitting or receiving control commands or, respectively, status information to/from a lighting device. The power negotiation connection can be used as a communication channel that is fully independent of the data connection. It uses, for example, different protocols and different wires than the data connection. Control commands, such as dim level or color, can be encoded in a vendor defined message of a related power negotiation protocol.

Claims

1. An apparatus for controlling a load device, said apparatus comprising: a control unit adapted to use a power negotiation protocol signaling in order to exchange at least one of control and status information with the load device, wherein the power negotiation protocol used to exchange the control or status information is a USB Power Delivery power negotiation protocol; and a transceiver for transmitting or receiving, only via power supply USB pins, the control or status information to/from the load device over a power line used for supplying power to said load device.

2. The apparatus according to claim 1, wherein the control unit is adapted to encode the control or status information in a vendor defined message according to the USB Power Delivery power negotiation protocol.

3. The apparatus according to claim 1, which is adapted to receive or transmit control commands or status packets from/to a lighting control system.

4. The apparatus according to claim 3, wherein the apparatus is adapted to receive or transmit the control commands or the status information from/to the lighting control system by using a UPnP lighting control protocol.

5. The apparatus according to claim 1, which is adapted to signal to an installer or user an information which indicates a successfully established communication channel over the power line to the load device.

6. A load device comprising an apparatus according to claim 1.

7. The load device of claim 6, wherein said load device is a lighting device or a sensor device.

8. A power supply device comprising an apparatus of claim 1.

9. A system comprising a power supply device of claim 8 and at least one load device of claim 6 which is connected to the power supply device.

10. The system of claim 9, wherein the power supply device comprises a USB-PD power supply unit having a power input (PI) and a data port (DP).

11. The system of claim 9, further comprising a hub device having a power supply from mains and a data connection supporting UPnP, wherein the hub device is adapted to relay messages between vendor specific lighting codes and lighting related UPnP packages.

12. A method of controlling a load device said method comprising: using a power negotiation protocol signaling in order to exchange at least one of control and status information with the load device; and transmitting or receiving the control or status information, only via power supply USB pins, over a power line used for supplying power to the load device, wherein the power negotiation protocol used to exchange the control or status information is a USB Power Delivery protocol.

13. A computer program product comprising code means for producing the steps of the method of claim 12 when run on a computing device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In the following drawings:

[0040] FIG. 1 shows a lighting device which is powered by a USB connection;

[0041] FIG. 2 shows a USB power delivery communications stack; and

[0042] FIG. 3 shows a schematic block diagram of control system according to an embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

[0043] The following embodiments are directed to a power negotiation connection (i.e. the V.sub.BUS channel) of a USB-PD interface for transmitting control commands to a lighting device. This power negotiation connection is a communication channel that is fully independent of the data connection. It uses, for example, different protocols and different wires than the data connection.

[0044] FIG. 1 shows an exemplary power control system where a desk lamp is powered by USB. The USB powered desk lamp comprises a number of light emitting diodes (LEDs) mounted in a head 10 of the desk lamp, a cable with USB connector 11 at the end, and potentially a driver box that has a manually operated switch 12.

[0045] Conventionally, for control of the desk lamp from USB side a USB enumerated plug and play control system needs to be added requiring also data lines to be connected.

[0046] A first beneficial feature of the USB-PD standard is exploited, namely the feature that power negotiation is also available when power supply is active and electrical current is flowing. This is different from other systems, such as Power over Ethernet (PoE), where a negotiation is only possible for a fresh connection before the supply voltage is switched on. A second beneficial feature is that negotiation is mainly not using the USB data connection channel. However a new connection channel has been developed for power delivery, which is using the power conductors for the data connection in parallel by installing powerline modems on both sides of the USB connection.

[0047] In the embodiments, the power negotiation connection is suggested to be additionally used for control of the USB powered load or end device. This is beneficial as the power negotiation connection is totally independent of the USB data connection and the related processing. In addition, a cabling with only two wires is required for power supply and control, leaving the data pins of the USB connection totally open.

[0048] Thus, using the power negotiation channel of USB-PD for control signaling between load device and host reduces the required cables, makes maximum use of installed copper, and allows increased cable lengths.

[0049] Moreover, as the modem devices for the new negotiation channel are indispensable for USB-PD, it is expected that related standardized chips will be available at low cost in the future. The negotiation channel can be used for transmitting manufacturer specific codes via the power supply line to the controlled load device. This can be achieved via proprietary manufacturer related codes.

[0050] For USB-PD, the current standard USB Power Delivery Specification Revision 1.2 is online available at www.usb.org, which describes the negotiation technique using a dedicated communication channel.

[0051] FIG. 2 shows a USB-PD communication stack between a power supply device 20 and a load device 30, wherein a physical layer (PHY) functionality 204 of this channel at the power supply device 20 and a physical layer functionality 304 of this channel at the load device 30 are responsible for sending and receiving messages across the power line 40 (i.e. V.sub.BUS). Both physical layer (PHY) functionalities 204, 304 comprise a transceiver that superimposes a signal on the power supply line 40 and are responsible for managing data on the power supply line 40. This includes—among others—avoiding collisions on the power supply line 40 and recovering from such collisions when they occur. They also detect errors in the messages using a cyclic redundancy code check (CRC).

[0052] Additional functionalities on both sides at higher layers of the communication stack are respective protocol functionalities 203, 303, policy engine functionalities 202, 302, and device policy manager functionalities 201, 301. Information is successively transferred and converted through all layers of the communication stack in the downward direction at one communication end and then via the power supply line 40 to the other communication end where it is successively transferred and converted through all layers of the communication stack in the upward direction, and vice versa. Thereby, the device policy manager 201 at the power supply device 20 can exchange information with the device policy manager 301 at the load device 30.

[0053] The USB-PD specification allows for a data message to be communicated over the V.sub.BUS channel for power negotiation, for performing a self-test, yet also for transferring a vendor specific code.

[0054] According to the embodiments, control commands for the USB powered load device, such as dim level and color in case of a lighting device or other commands related to the functionality of the load device, can be encoded in the vendor defined message. This has several benefits over using the data connection for communicating such commands to the lighting device. The load device does not need capabilities for the USB data connection and the USB power supply and control connection can be simplified to only two wires and pins. As a result, the typical cable length limitation of USB can be largely overcome.

[0055] USB-PD uses a carrier of 23.2 MHz modulated with the information to avoid any noise from the power supplies. Continuous Phase Frequency Shift Keying (FSK) is used to encode bits of the control commands or status information for transmission on the V.sub.BUS channel. The used bit rate may be in the order of 300 Kbps. Of course, the present invention is not limited to such kind of modulation, carrier frequency or data rates.

[0056] The USB-PD V. 1.2 specification defines control messages and data messages which can be used in the present embodiments to exchange control and status information between power supply side and the powered load side.

[0057] Three types of data messages can be used to exchange information between a pair of port partners and range from 48 to 240 bits in length. Those used to expose capabilities and negotiate power, those used for the built-in self-test (BIST) and those which are vendor defined and which can be used for signaling the additional control and status information of the present embodiments.

[0058] One vendor defined message (VDM) code has been defined. The VDM that is suggested to be used for transferring control and/or status information for a load device consists of a header, vendor ID and one or more ‘objects’ (16 bits for the first object, 32 bits for each subsequent object). To ensure vendor uniqueness of VDMs, all VDMs shall contain a USB vendor identity (ID) in the first VDM object. The VDM consists of at least one data object, the first VDM object, and may contain up to a maximum of six additional VDM objects. If a port at a load device receives a VDM that it does not know, it may simply ignore the message.

[0059] In case of lighting devices or lamps, vendor defined codes may be provided for e.g. lamp status, type, colors available, temperature, age, efficiency etc. In addition, control messages can be provided for controlling the lighting device, such as e.g. setting flux-level, percentage of max power (dim level), color temperature color etc.

[0060] As the negotiation can be achieved by only using the power contacts, such a proposed lighting device can be connected only over a single pair cable not wasting copper and isolation for data connection.

[0061] FIG. 3 shows a schematic block diagram of a control system according to a first embodiment. At the USB power supply end (e.g., USB host or hub), a power supply unit (P) 56 is adapted to convert an alternating current AC power input supplied to a power input terminal PI into a required DC power. The DC power is supplied via a capacitance C and an isolation reactance L to the power supply line (V.sub.BUS) 40 which may optionally be shielded by a grounded coaxial shielding 44 together with the second ground (GND) line 42. At the other end of the USB cable, the DC power is supplied to a load device (L) 66 via another capacitance C and isolation reactance C which are used for suppressing undesired AC components.

[0062] According to the first embodiment, a data port DP is provided at the power supply side so as to input or output control or status data exchanged via the power supply line 40. To achieve this, a control unit 50 and a transceiver which consists of a transmitter part (TX) 52 and a receiver part (RX) 54 are provided to generate the above mentioned vendor defined message (VDM) based on input data supplied via the data port DP and to transmit or, respectively, receive VDMs via the power supply line 40. The transmitter part 52 is adapted to modulate the VDM according to the USB-PD specification and the receiver part 54 is adapted to demodulate a received VDM according to the USB-PD specification. The modulated VDM is then coupled to the power supply line 40 via an AC coupling capacitance C.sub.AC. The resistance R at the output of the transmitter part 52 serves to adapt the output resistance of the transmitter part 52 to the resistance of the USB cable.

[0063] A similar configuration with a control unit 60, a transceiver consisting of a transmitter part 62 and a receiver part 64, a resistor R and an AC coupling capacitor C.sub.AC is provided at the load device 66. As these components function in the same manner as the corresponding components at the power supply side, a detailed description is omitted here. Additionally, the control unit 60 can be coupled to the load device 66 so as to control the load device 66 based on a received control command or to detect a status which is to be signaled towards the power supply device.

[0064] Thereby, status and control information forwarded via modulated VDMs coupled to the power supply line 40 can be exchanged between the power supply device and the load device. As an example, the power supply device may transmit control messages to the load device so as to control a functionality of the load device, and the load device my transmit a status information to the power supply device so as to indicate a predetermined status. As an example of such status information, an indicator may be used to signal to an installer or user that a connection to a lighting device using USB-PD negotiation channel for controls has been established.

[0065] In the above first embodiment, the USB-PD negotiation modems provided for the power negotiation via the power supply line V.sub.BUS can be “misused” only for a control channel to a load device connected via a single pair cable without making use of USB-PD negotiation at all. This may be very beneficial as the related chips are supposed to be available in high volume at low price. The controlled load device 66 is thus only connected with two poles and still controllable.

[0066] According to a second embodiment, the proposed message transfer via the USB power supply line is used for relaying UPnP lighting control messages, e.g., from a USB data channel. In UPnP networking, each device has a Dynamic Host Configuration Protocol (DHCP) client and searches for a DHCP server when the device is first connected to the network. If a DHCP server is available, i.e., the network is managed, the device uses the IP address assigned to it. If no DHCP server is available, i.e., the network is unmanaged and the device uses Auto IP to get an address. To control a UPnP device, a control point invokes an action on the device's service. To do this, a control point sends a suitable control message to the control URL for the service. In response, the service returns any results or errors from the action. The effects of the action, if any, may also be modeled by changes in the variables that describe the run-time state of the service. When these state variables change, events are published to all interested control points.

[0067] As an additional building block of the second embodiment a lighting grade USB-PD hub is proposed having a power supply from mains and a USB or any other data connection supporting UPnP. The hub is relaying all messages between vendor specific USB-PD lighting codes and lighting related UPnP package. The related messages are published by the UPnP Forum in “Lighting Controls V 1.0” online available at http://upnp.org.

[0068] Using the proposed signaling for UPnP makes special sense as the typical protocols used on USB connections are related with UPnP. But also other lighting control languages or protocols (among others: XCLIP, DALI, KNX etc.) can be supported in the same way.

[0069] To summarize, it has been proposed to use a power negotiation connection (e.g. the V.sub.BUS channel) of a power delivery interface for transmitting or receiving control commands or, respectively, status information to/from a load device. The power negotiation connection can be used as a communication channel that is fully independent of the data connection. It uses, for example, different protocols and different wires than the data connection. Control commands, such as dim level or color, can be encoded in a vendor defined message of a related power negotiation protocol.

[0070] The present invention is not restricted to the above embodiments and not limited to USB connections. It can be used in any interface or connection technology where a power negotiation function via a power supply line is provided, and for any kind of load devices and, more specifically, for any kind of indoor lighting and/or connection of LED module(s) inside a luminaire or for any kind of sensor device.

[0071] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

[0072] Any processing and/or control and/or signaling functions of the described embodiments can be implemented as program code means of a computer program and/or as dedicated hardware. The computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium, supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

[0073] In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality.

[0074] A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.