DE20220356U1 - Lighting unit comprising light emitting diodes, includes microprocessor and circuitry determining intensity from characteristic curve - Google Patents

Abstract

LED intensity is determined from a curve by the control stage (3). The characteristic curve is laid down in a stage (4) of the main circuit (X).

Description

PB 2145/GM 21 March 2003

Applicant: INSTA ELEKTRO GMBH 58511 Lüdenscheid

Lighting equipment

The present invention is based on a lighting device designed according to the preamble of the main claim.

Such lighting devices are designed to provide lighting in the lighting area allocated to them as required. To avoid unnecessary glare for people in the lighting area, the light from such lighting devices is often not emitted directly to the outside, but rather via a reflector.

A lighting device corresponding to the generic term of the main claim has become known from DE 201 02 147 LM. Such a lighting device has several lamps designed as LEDs that are connected to a power supply. In order to be able to specifically control the individual lamps to achieve certain lighting effects, such a lighting device is provided with an electronic circuit arrangement that has a control stage. These days, such electronic circuit arrangements are usually provided with a microcontroller. Due to the manufacturing process or the material properties of LEDs, differences in their luminosity occur when the power supply is identical. Such effects are further intensified by the unavoidable aging process, which is unacceptable, particularly when there are high demands on the quality of illumination (the same or consistent luminosity while maintaining the desired light color).

Based on such an embodiment, the present invention is based on the object of creating a lighting device in which a high quality of illumination, i.e. in which an equal or constant luminosity over a long operating period, is automatically realized in a simple manner.

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According to the invention, the object is achieved by the features specified in the characterizing part of the main claim.

A particularly advantageous feature of such a design is that the luminosity of each connected LED or each connected LED circuit of the lighting device can be adjusted according to the required

Illumination requirements can be easily set during manufacture or initial commissioning, and that this setting, once made, e.g. with regard to luminosity, is automatically retained for a particularly long period of operation.

Another advantage is that such a lighting device can be manufactured particularly cost-effectively.

Further advantageous embodiments of the subject matter according to the invention are specified in the subclaims and are explained in more detail with reference to an embodiment shown in the drawings, in which:

Fig. 1: a block diagram of a stand-alone device
lighting device;

Fig. 2: a block diagram of a group device
lighting equipment.

As can be seen from the figures, such a lighting device essentially consists of a power supply 1 to which several lighting means designed as LEDs 2 are connected, whereby these can be specifically controlled via a control stage 3.

As can be seen in particular from Fig. 1, the lighting device designed as a single device further comprises a circuit arrangement X on which a microcontroller Y is arranged. The microcontroller Y contains a characteristic curve stage 4 and an operating hour counter 5 as well as a start stage 6. The

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Start level 6 is programmable and, once programmed, contains the individual start current values for the connected LEDs 2, which are determined, for example, at the time of production or the initial installation of the lighting device and then programmed in. For each individual LED 2 or each connected LED circuit, there is therefore an individually coordinated start current value for a previously determined luminosity in start level 6. Each lighting device is therefore individually coordinated with regard to the conditions prevailing due to the connected LEDs 2 with regard to the start current values. The characteristic curve stored in characteristic curve level 4 is designed as a degradation characteristic curve. Depending on the operating time of the connected LEDs 2 recorded in the operating hours counter 5, the characteristic curve stored in characteristic curve level 4 is traversed so that the inevitable signs of aging of the LEDs 2 in terms of decreasing luminosity are effectively compensated for. In addition, a dimming stage 7 is arranged on the circuit arrangement X so that the luminosity of the connected LEDs 2 can be conveniently and easily set or changed directly by the user according to his wishes or needs. In addition, a command transmitter 8 is connected to the circuit arrangement X, via which the programming of the start stage 6 and the influencing of the dimming stage 7 can be carried out, e.g. via a bus system. Furthermore, the characteristic curve or curves to be read into the characteristic curve stage 4 can also be entered via the command transmitter 8. As already described above, aging processes of the connected LEDs 2 are effectively compensated for in an automatic manner by the characteristic curve stage 4, operating hour counter 5 and start stage 6 combined to form an adaptation arrangement.

As can be seen in particular from Fig. 2, the circuit arrangement X of the second embodiment designed as a group device additionally has, with respect to the components described above in accordance with the first embodiment, a coupling stage 9 and a decoupling stage 10, in which the power supply 1 is looped through via a supply line 11. The coupling stage 9 is also connected on the input side to the command transmitter 8 and is also connected on the input side to a master unit 12 of the operating hours counter 5.

Connection. On the output side, as already described, the decoupling stage 10 is connected, which in turn is connected on the output side to the start stage 6, to the dimming stage 7 and to a slave unit 13 of the operating hours counter 5 as well as the connected LEDs 2.

In the two exemplary embodiments shown, the circuit arrangement X is designed in such a way that only a single characteristic curve for a specific LED type or a specific LED circuit, which consists of several similar LEDs 2, is stored in the characteristic curve level 4. If several different LED types or LED circuits are installed in the lighting device, a separate circuit arrangement X must be installed for each different LED type or LED circuit. Of course, with an appropriate design of the circuit arrangement X or characteristic curve level 4, it is also possible to store several characteristic curves for different LED types or LED circuits in a single circuit arrangement X.

In order to be able to carry out automatic degradation compensation in such lighting devices, the power supply 1 is required as a basic requirement. In the two embodiments described in Fig. 1 and Fig. 2, a converter is used as the power supply 1, which converts the mains voltage into a low voltage that is appropriate for requirements. This ensures that all components of a lighting device can be supplied with a low voltage that is safe for people. As can also be seen from Fig. 1 and Fig. 2, the low voltage is used both to supply the LEDs 2 or the LED circuits and for the other components of the lighting device. In order to clarify the process of automatic degradation compensation, the initial commissioning of such a lighting device is examined in more detail. In order to be able to integrate the lighting device as flexibly as possible, e.g. into an existing lighting management system, it must first be possible to provide the connected LEDs 2 or the connected LED circuit with an individual starting value with regard to their luminosity. This is implemented in the start stage 6. In the starting stage 6, the limit values within which the luminosity of the LEDs 2 should be set are determined from the outside, e.g. via a bus system. This applies to both the

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Maximum and minimum values of the luminosity of the connected LEDs 2 or the connected LED circuit. The maximum and minimum values are also the key values within which the time-controlled, automatic degradation compensation can then move. As already described, only one characteristic curve is stored in characteristic curve level 4, which counteracts the age-related loss of luminosity of the LEDs 2 that occurs in the respective application. This ensures that the LEDs 2 automatically have an almost constant luminosity throughout their entire operating time. The values determined in characteristic curve level 4 go to control level 3. In the embodiments described in Fig. 1 and Fig. 2, this is designed as a PWM-controlled modulator that acts directly on the LEDs 2 or the LED circuit. The operating hour counter 5 is provided for time control for the automatic degradation compensation. This means that depending on the operating time, the voltage supply for the connected LEDs 2 or the connected LED circuit is automatically adjusted again and again according to the characteristic curve so that a constant luminosity of the LED 2 is maintained over the entire operating time.

As can be seen in particular from Fig. 2, the operating hours counter 5 is provided with a master unit 12 and a slave unit 13. This is necessary in order to allow each lighting device in a lighting system made up of several lighting devices to be automatically adjusted in accordance with the degradation characteristic at the same time. Each individual lighting device in the lighting system is therefore controlled synchronously to compensate for the loss of luminosity due to age and is then adjusted. This can be carried out particularly advantageously if the operating hours counter 5 of a lighting device in the lighting system is configured as a master unit 12 and the operating hours counters 5 of the other lighting devices in the lighting system are configured as slave units 13. The concept is thus designed such that almost any number of other circuit arrangements X designed as slave units 13 can be operated via a circuit arrangement X designed as a master unit 12.

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In order to be able to adapt the luminosity to individual circumstances, each lighting device in the lighting system is provided with its own dimmer stage 7. Commands directed to the dimmer stage 7 cause the control stage 3 to change its output signal accordingly in order to achieve the desired dimming value setting of the connected LEDs 2 or the connected LED circuit. As already indicated above, the operating hours counter 5, the programmable start stage 6 and the dimmer stage 7 are connected to one another via a bus system. In order to be able to dispense with additional control lines, the supply line 11 is also used to transmit commands or to exchange information in the embodiment shown in Fig. 2. A typical operating signal thus reaches the coupling stage 9 via the external command transmitter 8. Here, the incoming commands or control signals are modulated onto the low voltage of the supply line 11 so that all lighting devices in the lighting system can be operated simultaneously with the same information level. The coupling stage 9 shown in Fig. 2 is provided with an additional input. The signal line connected to this additional input couples the synchronization signals of the operating hours counter 5 of one circuit arrangement X, configured as the master unit 12, to the supply line 11 belonging to the bus system, in order to then be able to make these available to the operating hours counters 5 of the other circuit arrangements X, configured as the slave unit 13. The supply line 11 therefore contains both the low voltage for the connected components and the control signals for the entire lighting system. In order to be able to make the modulated control signals available again, e.g. for the dimmer stage 7, these must again be separated from the low voltage. This takes place in the decoupling stage 10, at whose output the control signals are now available again in their original form for forwarding. The dimmer stage 7, the programmable start stage 6, the characteristic curve stage 4, as well as the operating hours counter 5 can thus extract the information or commands addressed to them from the modulated data stream or control signals of the supply line 11 and then execute the corresponding functions.

Claims (13)

1. Lighting device with a plurality of light sources designed as LEDs which are connected to a power supply and which can be specifically controlled by an electronic circuit arrangement containing a microcontroller via a control stage, characterized in that the intensity of the illuminance provided by the control stage ( 3 ) for at least one LED ( 2 ) is dependent on the time of at least one characteristic curve which is stored in a characteristic curve stage ( 4 ) belonging to the circuit arrangement (X). 2. Lighting device according to claim 1, characterized in that at least one characteristic curve stored in the characteristic curve stage ( 4 ) is designed as a degradation characteristic curve. 3. Lighting device according to claim 1 or 2, characterized in that at least one characteristic curve is traversed as a function of time of the stored operating time of at least one LED ( 2 ), the operating time being recorded in an operating hour counter ( 5 ) belonging to the circuit arrangement (X). 4. Lighting device according to one of claims 1 to 3, characterized in that a plurality of different characteristic curves are stored in the characteristic curve stage ( 4 ) of the circuit arrangement (X) according to the number of different types of LEDs ( 2 ) to be controlled. 5. Lighting device according to one of claims 1 to 4, characterized in that a plurality of lighting devices, each with a plurality of lighting means designed as LEDs ( 2 ), can be controlled by the circuit arrangement (X). 6. Lighting device according to one of claims 1 to 5, characterized in that at least the characteristic curve stage ( 4 ) and the operating hour counter ( 5 ) are implemented by a microcontroller (Y) belonging to the circuit arrangement (X). 7. Lighting device according to claim 6, characterized in that the operating hour counter ( 5 ) in the microcontroller (Y) is designed as an internal RC oscillator. 8. Lighting device according to one of claims 1 to 7, characterized in that when using several circuit arrangements (X), one of the circuit arrangements (X) is configured as a master unit ( 12 ) and the remaining circuit arrangements (X) are each configured as a slave unit ( 13 ). 9. Lighting device according to one of claims 1 to 8, characterized in that a command transmitter ( 8 ) is connected to the circuit arrangement (X) and comprises a starting stage ( 6 ) in which at least one individual starting current value for at least one LED ( 2 ) is stored. 10. Lighting device according to one of claims 1 to 9, characterized in that the circuit arrangement (X) is provided with a controllable dimming stage ( 7 ). 11. Lighting device according to one of claims 1 to 10, characterized in that the control stage ( 3 ), the characteristic curve stage ( 4 ), the operating hour counter ( 5 ) and the start stage ( 6 ) are combined to form an adaptation arrangement on the circuit arrangement (X). 12. Lighting device according to one of claims 1 to 11, characterized in that the circuit arrangement (X) contains a coupling stage ( 9 ) and a coupling-out stage ( 10 ), and that the coupling stage ( 9 ) is connected on the input side to the command transmitter ( 8 ), and that on the other hand the coupling-out stage ( 10 ) is connected to the coupling stage ( 9 ). 13. Lighting device according to claim 12, characterized in that the supply line ( 11 ) emanating from the power supply ( 1 ) is used to transmit the internal and external data necessary for functional implementation.