Technical Field

The exemplary and non-limiting embodiments of the invention relate generally to controllers for lamps, especially for LED lamps.

Background

Lamp technology has advanced in recent years. Emphasis in lamp technology has mainly been on minimising the energy consumption of the lamps. Lamps utilising modern technology are replacing traditional lamps in many applications. For example, gas discharge tubes and incandescent lamps are in many applications replaced with LED (light emitting diode) lamps, which have gained large popularity due to longevity and low energy consumption.

Modern technology also enables various other possibilities related to lamps. For example, remote control of lamps is a promising feature. Flexible control of a lamp requires reliability from the controller of the lamp.

Brief description

The present invention seeks to provide an improved controller of an

LED lamp.

According to an aspect of the present invention, there is provided a controller of an LED illuminating lamp, the controller comprising a processing unit, connectors connecting the controller in series with the LED illuminating lamp, a power harvesting arrangement operationally coupled between the connectors, and a switch electrically coupled between the connectors; the processing unit being configured to control the switch between an electrically conducting state for switching light of the LED illuminating lamp on and an electrically non-conducting state for switching light of the LED illuminating lamp off, and the power harvesting arrangement comprising a first power harvesting unit configured to derive power for the controller from electric power fed to the connectors when the switch is in electrically non-conducting state and a second power harvesting unit configured to derive power for the controller from electric power fed to the connectors when the switch is in electrically conducting state, the controller further comprising a wireless communication unit configured to receive control commands or data for controlling the LED illuminating lamp. Some embodiments of the invention are disclosed in the dependent claims.

Brief description of the drawings

In the following the invention will be described in greater detail by means of preferred embodiments with reference to the attached [accompanying] drawings, in which

Figure 1A illustrates a lamp with a conventional gas discharge tube assembly;

Figure IB illustrates an example where a gas discharge tube has been replaced with an LED lamp;

Figure 1C illustrates another example where a gas discharge tube has been replaced with an LED lamp;

Figures 2A and 2B illustrate an embodiment;

Figure 3 illustrates an example of the structure of a controller.

Detailed description of some embodiments

Figure 1A illustrates a lamp with a conventional gas discharge tube assembly 100. The lamp comprises a gas discharge tube 102 which is connected to mains 104 via an inductive magnetic ballast 106. The lamp assembly comprises also a starter 108 which is required to ignite the gas discharge tube.

Figure IB illustrates an example where a gas discharge tube has been replaced with an LED lamp 110. The LED lamp is comprises an internal power supply 112 at one end of the lamp, and a circuit 114 at the other end of the lamp which short circuits the electric connections at that end. As an LED lamp does not need a starter, it is typical to place a circuit 116 at the place of the starter which is either short circuit or a fuse. In an embodiment, any LED lamp fulfilling the requirements of the LED lamp standard EN62776 issued by International Electrotechnical Commission IEC may be used in the assembly.

If remote control of a lamp assembly is desired, some kind of controller must be installed in association with the lamp assembly. These controllers need uninterrupted power supply. In some solutions the controllers are in parallel connection with power cords of the lamp. Typically this done by integrating a controller to terminal block with 3 -line power cords. Disadvantage of this solution is that relay mechanics are bigger due to 3 in and 3 out power cords from the terminal block. In addition, if terminal block is changed to a smart one, an electrician is needed to make changes creating extra cost.

Another solution is to use batteries in the controller. Disadvantages are that batteries create additional cost, batteries have shorter lifetime than electronics which makes the wireless relay lifetime shorter and batteries also create a fire risk.

Figure 1C illustrates another example where a gas discharge tube has been replaced with an LED lamp 110. In this solution, a controller 120 of the LED lamp has been installed in the place of the starter. The controller is in serial connection with the LED lamp in the same power line feeding the lamp. Thus, there in only one line in and out of the controller.

Figures 2A and 2B illustrate an embodiment, where the controller 116 of the LED lamp 110 has been installed in the place of the starter. Thus, controller comprises the pins or connectors 200, 202 contactable with counterparts of a starter socket. The controller is in serial connection with the LED lamp. In an embodiment, the pins or connectors correspond to the pins or connectors of a starter and the controller may be directly installed in the place of the starter. In an embodiment, an adapter may be used between the controller and the starter socket.

In an embodiment, the controller comprises processing unit 204, a power harvesting arrangement 206, 208 and a switch 210. The processing unit 204 may be configured to control the switch 210 between an electrically conducting state for switching light of the LED illuminating lamp on and an electrically non-conducting state for switching light of the LED illuminating lamp off. Figure 2A illustrates the state when the switch 210 is electrically conducting and Figure 2B the state when the switch 210 is electrically non-conducting.

In an embodiment, the power harvesting arrangement 206, 208 is configured to derive power for the controller from electric power fed or leaked to the pins or connectors irrespective of a state of the switch 210.

In an embodiment, the power harvesting arrangement comprises two separate units, 206, 208. The controller 116 may comprise a first power harvesting unit 208 configured to enable a by-pass current to flow through the controller when the switch 210 is in electrically non-conducting state, the by-pass current being smaller than the current required to switch light of the LED illuminating lamp on. The first power harvesting unit 208 configured to derive power for the controller from the by-pass current. The power harvesting arrangement may further comprise a second power harvesting unit 206 configured to derive power for the controller from electric power fed to the pins or connectors 200, 202, when the switch is in electrically conducting state.

Figure 3 illustrates an example of the structure of the controller 116 in more detail. As in Figures 2A and 2B, the controller 116 of the LED lamp 110 has been installed in the place of the starter. Thus, controller comprises the pins or connectors 200, 202 contactable with counterparts of a starter socket. The controller is in serial connection with the LED lamp.

The processing unit 204 controls 300 the switch 210 between an electrically conducting state for switching light of the LED lamp on and an electrically non-conducting state for switching light of the LED lamp off.

In an embodiment, the switch may be realised with an optotriac or semiconductor relay, for example.

The controller may further comprise a communications unit 302, which may be a wireless communication unit. The communications unit 302 may be configured to communicate with an outside server monitoring the LED lamp and/or at least one other controller of a different LED lamp. For example, the processing unit may receive instructions to set the switch on or off via the communications unit 302. The instructions may come from the server monitoring the LED lamp or lamps or another controller of a different LED lamp, for example.

The communications unit 302 may utilise Bluetooth™ or Bluetooth™ low energy or Bluetooth™ Ultra Low Power (ULP) technology, for example, but other technologies may be used as well. Examples of wireless technologies are IEEE 802.15.4, with Internet Protocol v6 (61owpan), IEEE 802.15.4 with ZigBee, Low Power Wireless Local Area Network, proprietary low-power radio, cellular radio system or any other system suitable for low-power transmission. IEEE stands for the Institute of Electrical and Electronics Engineers.

The controller may further comprise a set of sensors 304 or an interface where sensors are or may be connected. Examples of possible sensors are proximity, pressure, motion and temperature sensors, to name a few. A sensor may also monitor the time intervals when the switch is in on and off positions. The processing unit may receive data from the sensors and control the switch at least partly based on the sensor data. The processing unit may also transmit sensor data to the server monitoring the LED lamp and/or at least one other controller of a different LED lamp. Thus as an example, the processing unit may receive data from a motion sensor that there is movement nearby the lamp and turn the lamp on as long as movement is being detected.

As mentioned, the controller may comprise the second power harvesting unit 206 configured to derive power for the controller from electric power fed to the pins or connectors 200, 202, when the switch 210 is in electrically conducting state. In an embodiment, this may be done based on voltage drop on a diode, which is connected electrically in series with the lamp. Other possibilities are, for example, using a transformer, a resistor, an inductor or other means know in the art. Using diodes is beneficial to achieve small form factor of the starter. The voltage drop across the diodes is rectified and the voltage is used as a power supply for the controller. In this mode, the energy consumption of the controller may be of the order of 0.6W, for example.

When the switch 210 controlled by the processing unit 204 is open, the lamp is turned off. In an embodiment, the first power harvesting unit 208 is connected in series with the lamp. The first power harvesting unit is configured to draw such a small amount of power through the electrical circuitry of the lamp that the lamp does not illuminate since the voltage across the lamp is kept small enough. In this mode the energy consumption of the controller may be of the order of 0.1W, for example.

In an embodiment, this may be done by rectifying the mains voltage

104 connected through the lamp 110 and using a DC-DC converter or similar functionality known in the art to create suitable stable DC-voltage for the controller. Other possibilities are, for example, to use capacitive power supply.

In an embodiment, both the first and the second power harvesting unit are connected to energy storage unit 306. The energy storage unit 306 may be based on capacitors which are separated from the power harvesting units using for example diodes. The energy storage unit 306 provides the operating power for the controller. In an embodiment, the first and the second power harvesting units output a different voltage level. The energy storage may regulate the voltage levels outputted by the power harvesting units so that the voltage applied to the controller is always the same.

The processing unit 204 may also determine information associated with the LED lamp and the communication unit 302 may be configured to transmit information associated with the LED lamp to the outside server monitoring the LED lamp and/or at least one other controller of a different LED lamp. For example, the level of the output voltage generated by the first power harvesting unit can be used to monitor condition of the lamp. The controller 116 may be able to detect if the lamp does not turn on or is dim or if the lamp flickers, for example.

During on-state of the switch 210, if the current flowing through the lamp drops, the second power harvesting unit 206 may not be able to create high enough intermediate voltage. The processing unit may be configured to monitor 308 the intermediate voltage and detect if the intermediate voltage is too low.

The processing unit may turn off the lamp and the first power harvesting unit 208 may be used for powering the controller 116 before the intermediate voltage drops too low for the controller.

The processing unit 204 may try to turn on the lamp a few times, and if the intermediate voltage drops too low in each try, the processing unit may send an error message lamp to the outside server monitoring the LED lamp and/or at least one other controller of a different LED lamp.

As the processing unit 210 changes the state of the switch 210, the controller may automatically change its energy harvesting mode. If the switch is switched from on state to off state, the controller ceases to use the power harvested by the second power harvesting unit 206 and start using the first power harvesting unit 208. In an embodiment, the time to change between modes is around 100ms. During this switching time between modes energy harvesting is not always enough to run the wirelessly controlled relay. Capacitors in the energy storage 306 may keep up the operation during switching the energy harvesting modes.

The embodiments of the invention have several advantages. The controller of the map is operable at all times regardless of whether the lamp is on or off. A wireless controller together with an LED illuminating lamp may be installed to a lamp arrangement in the place of a conventional gas discharge tube and conventional starter without any modifications and the need of a qualified electrician. The controller enables wireless control and monitoring of the LED lamp.

The processing unit 204 may be implemented as an electronic digital computer, which may comprise a working memory (RAM), a central processing unit (CPU), and a system clock. The CPU may comprise a set of registers, an arithmetic logic unit, and a controller. The controller is controlled by a sequence of program instructions transferred to the CPU from the RAM. The controller may contain a number of microinstructions for basic operations. The implementation of micro-instructions may vary depending on the CPU design. The program instructions may be coded by a programming language, which may be a high-level programming language, such as C, Java, etc., or a low-level programming language, such as a machine language, or an assembler. The electronic digital computer may also have an operating system, which may provide system services to a computer program written with the program instructions.

The processing unit 204 may also be implemented as one or more integrated circuits, such as application-specific integrated circuits ASIC. Other hardware embodiments are also feasible, such as a circuit built of separate logic components. A hybrid of these different implementations is also feasible. When selecting the method of implementation, a person skilled in the art will consider the requirements set for the size and power consumption of the apparatus, the necessary processing capacity, production costs, and production volumes, for example.

It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.