WO2017001281A1

WO2017001281A1 - A power supply and a power supply method

Info

Publication number: WO2017001281A1
Application number: PCT/EP2016/064544
Authority: WO
Inventors: Hendrikus Gerardus VAN HORCK
Original assignee: Philips Lighting Holding B.V.
Priority date: 2015-07-02
Filing date: 2016-06-23
Publication date: 2017-01-05

Abstract

The invention provides a power supply for delivering power to a device over a power line. A monitoring circuit is used for monitoring data on a data channel which communicates with the device. A controller is adapted to interrupt the supply of power to the device over the power line in response to monitoring of data on the data channel when the monitored data is indicative of device inactivity. In this way, a forced reboot takes place when the device is judged to have entered a deadlocked or crashed state. The monitored data is indicative of lighting device inactivity when: the data comprises a DALI command requiring the lighting device to provide a DALI feedback message yet the data does not further comprise said DALI feedback message; or the data comprises a DALI command for changing an aspect of the light output of the lighting device and the data further comprises a DALI feedback message from the lighting device indicating that it has not changed said aspect of its light output.

Description

A power supply and a power supply method

FIELD OF THE INVENTION

This invention relates to a power supply and a power supply method, in particular for powering devices which may enter a deadlock condition. BACKGROUND OF THE INVENTION

Some devices require a reboot when they enter a deadlock condition, during which they cease to communicate or respond to instructions as desired.

When a device enters such a deadlock condition, the correct functioning of a system using the device will be compromised. For example, the device may comprise a sensor, which is used to control the behavior of a system in an automated way. If the sensor ceases to communicate, the automated control will no longer take place. However, in many cases it is difficult to determine that the device is no longer functioning correctly.

An example is an intelligent lighting system, in which sensors are used to control the lighting, such as occupancy sensors, ambient light sensors or temperature sensors. The lighting control may be gradual so that it is not quickly apparent when there is a device error.

There is therefore a need for a way to detect functional errors in devices and to provide an automated solution to recover the correct system behavior. SUMMARY OF THE INVENTION

The invention is defined by the claims.

According to examples in accordance with an aspect of the invention, there is provided a power supply for delivering power to a lighting device over a power line, the power supply comprising:

a monitoring circuit for monitoring data on a data channel (DALI bus) which communicates with the lighting device; and

a controller for controlling the supply of power to the power line, wherein the controller is adapted to provide a temporary interruption to the supply of power to the device over the power line in response to monitoring of data on the data channel when the monitored data is indicative of device deadlock.

The temporary interruption is timed such that a reboot of the device is forced. Thus, the temporary interruption is selected to a have a duration having regard to the nature of the device, and in particular the time required for the device to be rebooted. The power supply itself detects a device error, based on a period of device inactivity which exceeds that expected during the normal device behavior. In response, a reboot is provided by interrupting the power supply. The interruption is temporary, so that it is sufficient to instigate shut down and re-starting of the device, but it is not a permanent shut down. The duration of the interruption will be selected to provide the desired reboot function. This system thus enables a fully automated reboot function to be implemented in response to a suspected deadlock of a device.

A decoder may be provided for decoding data on the data channel, wherein the monitoring circuit is for monitoring data content on the data channel. In this way, data content is decoded and analyzed rather than simply measuring an activity level e.g. voltage level.

The power supply may comprise a combined power line and data line bus terminal for connection to a power and communications bus, for example a digital addressable lighting interface (DALI) bus as specified by the IEC62386 standard or a Power over Ethernet connection.

The power supply may be for a DALI lighting system. In this case, the invention then also provides a lighting system, comprising:

the DALI power supply as defined above which forms the DALI control gear; one or more lamps powered by the control gear; and

a DALI power and communications bus between the control gear and a DALI bus powered control device.

The control device may for example supply power to sensors or wireless transmitters or receivers. By interrupting the power supply to the control device, the power supply to the connected devices is also interrupted so that for example the sensors and (if applicable) the application controller are rebooted.

The lighting system for example comprises a DALI luminaire. Examples in accordance with another aspect of the invention provide a power supply method for delivering power to a lighting device over a power line, the method comprising:

providing power to a lighting device over the power line;

monitoring data on a DALI bus which communicates with the device; and providing a temporary interruption to the supply of power to the device over the power line when the monitored data is indicative of device inactivity.

The condition indicative of lighting device inactivity may comprise a condition in which the data comprises a DALI command requiring the lighting device to provide a feedback message yet the data not comprising said feedback message. The lack of an acknowledgement being sent by the lighting device is indicative of the lighting device having reached a state of deadlock. The condition indicative of lighting device inactivity may comprise a condition in which the data comprises a DALI command for changing an aspect of the light output of the lighting device (12) and the data further comprising a feedback message from the lighting device indicating that it has not changed said aspect of its light output. The acknowledgement being sent by the lighting device indicating it has not changed its light output as required is indicative of the lighting device having reached a state of deadlock. For the avoidance of doubt, a state of deadlock need not concern the lighting device as a whole. There may be various services running on, for example, a microchip in the lighting device; one service for communicating the current state to a DALI controller and another service for controlling the light output of the lighting device. It is possible that one of these services reaches a state of deadlock and not the other, or that both reach a state of deadlock.

The controller of the power supply may make use of a memory to store messages sent to the lighting device and track feedback messages sent by the lighting device to detect missing or incorrect feedback messages. The controller may further store the address of the lighting device or the group(s) that the lighting device is assigned to, in order to determine if a feedback message (and a state change) is required.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the invention will now be described in detail with reference to the accompanying drawings, in which:

Fig. 1 shows a generic example of power supply;

Fig. 2 shows a power supply for multiple devices; Fig. 3 shows a luminaire having a DALI power supply; and

Fig. 4 shows a luminaire having a Power over Ethernet power supply.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The invention provides a power supply for delivering power to a device over a power line. A monitoring circuit is used for monitoring data on a data channel which interfaces with the device. A controller is adapted to interrupt the supply of power to the device over the power line in response to monitoring of data on the data channel when the monitored data is indicative of device deadlock. In this way, a forced reboot takes place when the device is judged to have entered a deadlocked or crashed state.

Figure 1 shows a generalized example of a power supply 10.

The power supply is for delivering power to a device 12 over a power line 14. It receives input power 15 for example from a mains input.

A monitoring circuit 16 is used to monitor data on a data line 18 which connects to the device. The term data is intended to cover a voltage level, or just the presence of a voltage, or a more complicated signal such as data packets. A controller 20 is used to control the supply of power to the power line 10 and it interrupts the supply of power to the device 12 if determined necessary based on the monitoring of data on the data line. In particular, when the monitored data is indicative of a deadlocked or crashed state, a power supply interruption is used to provide a reboot of the device 12.

The power supply may be termed a "smart" power supply in that it controls the supply of power in an adaptive manner. The device 12 that is supplied is in this way monitored to determine if it is active. For example, the data stream is analyzed to determine if the power supply should be temporarily removed from the device (and all other connected devices) in order to force all connected devices to go through a reset/power on cycle. In this way, the power supply acts as a watchdog for the system.

The system addresses the problem that many types of device are prone to internally crash without this being noticed. The interrupt function, in order to reset all connected devices, is of particular interest for bus systems, for example where power is included as part of the bus signal.

The interruption of the power supply may last for a defined time in order to force a reboot of all connected devices.

In a most simple implementation, the data line 18 could be a simple high/low voltage line, and the presence of a high voltage is indicative of device activity. However, the data line may instead carry transmission data according to a particular protocol. In this case, the monitoring circuit may comprise a decoder and a data analyzer, so that the analysis results can be used to decide to switch off the power output for a specific time. This specific time depends on the application, and should be chosen such that a guaranteed reboot of the connected devices occurs. The power supply itself in this way detects a device error and takes corrective action.

Figure 2 shows a power supply 10 connected to two devices 12a, 12b. The power output is provided to both devices, and they multiplex their communications data on a common bus 20.

The common bus 20 carries data in a particular data format. In this case, the monitoring circuit 16 of the power supply 10 has a decoder 17 for decoding data on the data line, and the data content is analyzed.

In the example of Figures 1 and 2, the power supply comprises a separate power line terminal which provides the output 10 and a data line terminal to which the data line 18 or common bus 20 is connected. The power supply may instead comprise a combined power line and data line bus terminal for connection to a power and communications bus.

An application of the invention to a lighting system using such a bus will now be described in detail, based on the Digital Addressable Lighting Interface (DALI), with reference to Figure 3.

A conventional DALI network consists of a controller and one or more lighting devices (e.g., electrical ballasts and dimmers) that have DALI interfaces. The controller monitors and controls each lighting device by means of a bi-directional data exchange. The DALI protocol permits devices to be individually addressed or to

simultaneously address multiple devices. Data is transferred between the controller and the devices by means of an asynchronous, half-duplex, serial protocol over a two-wire differential bus. Such conventional DALI devices use a single pair of wires to form the bus for communication to all devices on a single DALI network.

The DALI network may include various sensors and wireless receivers for receiving remote wireless commands. Such sensors may be provided as part of a particular lighting unit, i.e. within a luminaire housing, or they may be separate stand-alone sensors, which also communicate with the DALI network either over the two-wire differential bus, or else wirelessly. This invention relates to devices which are powered either directly or indirectly by the power supply 10. Thus, they have a wired connection to the power supply 10.

Figure 3 shows a DALI luminaire 30 having a power supply 10 as described above for powering an LED arrangement 32 and other devices. The power supply may be referred to as the DALI control gear. The power supply has a single terminal for connection to a shared power and communications bus 34. The monitoring circuit 16 includes a DALI command interpreter 17.

The power supply 10 may have another direct power supply output. The power provided over the DALI bus has a limit, whereas a separate power output with a larger output power capability is connected to the load which in this example is an LED lamp, although it may be another lamp.

The bus 34 powers an application controller 36 (which is the device being powered) which for example connects (and routes power) to sensors 38 as well as powering and receiving wireless commands from a wireless receiver 40. The monitoring circuit 16 monitors the data content on the power and communications bus 34.

By interrupting the power supply to the application controller 36, the power supply to the sensors 38 is also interrupted so that the sensors may be rebooted.

The operation of the power supply involves providing power to a device such as the application controller 36 over the power line or shared power and communications bus, and monitoring data on the data line or on the shared power and communications bus. The supply of power to the device is interrupted when the monitored data is indicative of device deadlock, based on a particular period of inactivity.

The bus 34 is shared between multiple devices. However, only one device at a time can send commands, and by decoding the data on the bus, it is possible to determine whether or not there is still any device sending commands. Depending on the kind of communication signals that are decoded and monitored, individual devices can also be detected that are no longer working. The DALI bus cam convey address information about the connected devices. DALI can use addressing, but also broadcasting to all devices at once is also supported.

The sensor(s) 38 and receiver 40 are not directly connected to the DALI bus 34 in this example. They constitute an input to the application controller 36 which determines the data to send. The command interpreter 17 monitors the bus 34, and the application controller 16 has the task of detecting whether the sensor 38 and radio 40 are still active or not. The application controller 36 may then simply stop communicating if malfunction is suspected, which will trigger the power supply 10 to turn off and reboot the entire system.

For a typical DALI system, the interruption to cause a reboot can be short, for example a few seconds. According to the specification, 5 seconds is sufficient to ensure power on behavior.

DALI is an example of a system in which there is communication and power delivered by a shared bus. This is one example of a power-line communication system.

The invention can be applied to any power line communication system, since all such systems generally enable the power supply to have control over the power delivered to a connected device as well as to communicate with the connected device. Another example of power-line communication system is defined by the IEEE Power over Ethernet (PoE) standard.

This standard defines the interaction between power sourcing equipment (PSE) and power devices (PD). One Ethernet cable can transport both data and power (e.g. 13 W) to the power devices. Making use of efficient solid state lighting (SSL) sources, such as light emitting diodes (LEDs), the power delivered by one Ethernet cable is sufficient to illuminate one or more work desks or another limited office space.

Power device controllers are attached as an interface between the device to be controlled, such as a lighting device, and the Ethernet cable.

The power device controllers have the possibility to shut down their controlled device by two means. Firstly, according to the PoE standard there is a shut down signal commanding the device not to conduct any current. Secondly, the power device controller can cut the power flow to the device by means of an internal switch.

This shut down mechanism may be used to switch off any device powered and controlled by the power device controller. Thus, the power supply interruption approach of the invention may be implemented by a power device controller of a Power over Ethernet system.

The use of the Power over Ethernet standard for lighting applications is for example described in WO 2011/055284.

Figure 4 shows in schematic from the system configuration. The power supply 50 is a Power over Ethernet power source device. It is connected to the luminaire 52 by an Ethernet cable, which transmits power and also allows bidirectional communication. It connects to a power device controller 54, which itself controls the delivery of power to the lighting unit 56. The power device controller 54 may be part of a luminaire 52 as shown, or it may be an external interface component. The luminaire may include sensors and transmitters or receivers as in the example above, shown schematically as unit 58. The power device controller 54 is thus able to implement the interruption of power supply to the lighting unit and to the other components. The power device controller 54 may be able to control the supply of power to different units independently or it may implement a global power control for all components within or powered by the luminaire 52.

The power supply can send messages and monitor received messages, for example in the form of TCP/IP data. For example, the power supply 50 can send a PING or other message to the luminaire 52 to check if a response is returned. In the absence of a response, or with a slow response, a power interrupt cycle can then be implemented.

Alternatively, the power supply 50 may expect a regularly repeated message indicating correct functioning of the luminaire (and all of its components such as sensors etc.) and trigger a power cycle interruption when the expected message is not received. Alternatively, there may be full communication and reporting between the power device controller 54 and the power supply 50 in respect of the functioning of the devices associated with the luminaire 52.

The two examples above relate to the use of a power supply system for intelligent lighting.

The same approach may however be used in non-lighting applications. For example, the invention may be used to monitor the output of a set-top box or a computer, for example. In the case of a computer, a period of no change to the graphics that are generated typically indicates a deadlock condition.

The invention is thus not limited to a DALI system or to a Power over Ethernet system. Instead, any network in which a power supply is able to monitor data activity as well as controlling the supply of power to devices may make use of the invention, in order to provide an automatic reboot function.

The power and data do not need to be conveyed over a shared physical line.

For example, data communication may be transmitted wirelessly between the device and the power supply. As long as there is a control device which is able both to control the supply of power to a connected device and to monitor communications from the connected device, the invention may be implemented.

Thus, the invention is of particular interest for power line communication type systems, as there is a direct coupling between the communication line and power delivery line. However, it may be applied when the communication/data channel and power delivery line are physically separated but still under a shared control.

The determination of a deadlock (or crash or freeze) situation will be different for different devices. Some devices perform repeated polling signaling, the absence of which is indicative of a device error. The period of inactivity which is representative of an error event will thus be different for different devices, and may range from fractions of a second, to seconds to tens of seconds or even minutes.

The duration of the required interrupt to a power supply to initiate a reboot operation will also vary depending on the device. Some devices have capacitive energy storage, so that a longer interrupt may be required to the power supply to cause the desired reboot. Again, the power supply interruption may typically last for seconds or tens of seconds.

The various parameters will be designed taking into account the application in which the power supply is to be used. Some of these parameters may also be configurable.

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. 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. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

Claims

CLAIMS:

1. A power supply (10) for delivering power to a lighting device (12) over a power line (14), the power supply comprising:

a monitoring circuit (16) for monitoring data on a DALI data bus (18) which communicates with the lighting device; and

a controller (20) for controlling the supply of power to the power line (14), wherein the controller (20) is adapted for monitoring the data on the DALI data bus (18) and further for providing a temporary interruption to the supply of power to the lighting device (12) over the power line in response to detecting a condition indicative of lighting device inactivity,

wherein the condition indicative of lighting device inactivity comprises:

a condition in which the data comprises a DALI command requiring the lighting device (12) to provide a DALI feedback message yet the data not comprising said DALI feedback message; or

a condition in which the data comprises a DALI command for changing an aspect of the light output of the lighting device (12) and the data further comprising a DALI feedback message from the lighting device indicating that it has not changed said aspect of its light output.

2. The power supply according to claim 1, wherein the DALI command sent to the lighting device (12) is a group command sent to a first group, and the condition further comprises the lighting device (12) being part of the first group.

3. The power supply according to claim 1, wherein the DALI command sent to the lighting device (12) is a single address command, and the condition further comprises the lighting device (12) being addressable by said address.

4. The power supply according to claim 1, wherein the DALI command sent to the lighting device (12) is a broadcast command.

5. A lighting system, comprising:

a power supply (10) as claimed in claim 1 which forms DALI control gear; one or more lamps (32) powered by the control gear; and

a DALI power and communications bus (34) between the control gear (10) and a DALI bus powered control device (36).

6. A lighting system as claimed in claim 5, further comprising one or more sensors (38) which communicate with the control device (36) and a wireless receiver (40) for receiving wireless control commands to the control device (36).

7. A power supply method for delivering power to a lighting device (12) over a power line, the method comprising:

providing power to the lighting device (12) over the power line (14);

monitoring data on a DALI data bus (18) which communicates with the lighting device (12); and

providing a temporary interruption to the supply of power to the device (12) over the power line (14) when detecting a condition indicative of lighting device inactivity; wherein the condition indicative of lighting device inactivity comprises:

a condition in which the data comprises a DALI command requiring the lighting device (12) to provide a feedback message yet the data not comprising said feedback message; or

a condition in which the data comprises a DALI command for changing an aspect of the light output of the lighting device (12) and the data further comprising a feedback message from the lighting device indicating that it has not changed said aspect of its light output.

8. The power supply method according to claim 7, wherein the DALI command sent to the lighting device (12) is a group command sent to a first group, and the condition further comprises the lighting device (12) being part of the first group.

9. The power supply method claims according to claim 7, wherein the DALI command sent to the lighting device (12) is a single address command, and the condition further comprises the lighting device (12) being addressable by said address.

10. The power supply method according to claim 7, wherein the DALI command sent to the lighting device (12) is a broadcast command.