EP2744302A1 - Method and device for operating a lighting device of a motor vehicle - Google Patents

Abstract

The method involves connecting semiconductor light sources (22) of illumination device (10) in parallel to each other and turning ON the semiconductor light sources by supply of energy through current source (32), such that all the switched light sources are powered by a common power source with energy. A predeterminable total operating current is provided through the current source corresponding to the number of switched-ON light sources. Independent claims are included for the following: (1) electrical control and/or regulating device for operating lighting device; and (2) illumination device of motor vehicle.

Description

The present invention relates to a method for operating a lighting device of a motor vehicle, wherein a plurality of semiconductor light sources of the lighting device are connected in parallel to each other and switched semiconductor light sources are powered by at least one power source with energy. Moreover, the invention relates to an electrical control and / or regulating device for operating a lighting device of a motor vehicle according to the preamble of claim 9 and a lighting device of a motor vehicle according to the preamble of claim 11.

Various lighting devices for motor vehicles are known from the prior art. How to distinguish between headlights and lights. Headlamps are in the front of a vehicle arranged. They serve in addition to road safety by visualizing the vehicle for other road users in particular the illumination of the road ahead of the vehicle, especially in the form of low beam, high beam, fog light or any other, eg. Adaptive light distribution to the view for the driver of the vehicle improve.

Lights are mainly used for traffic safety by visualizing the vehicle for other road users. Thus, front lights in the front of the vehicle, for example, as a position light, flashing or daytime running lights and tail lights in the rear of the vehicle, for example, as a brake light, tail light or flashing light used. The front lights can be integrated in a headlight, but they can also be designed as separate lights and arranged in the front of the vehicle. A luminaire can fulfill one or more luminaire functions. In a tail light usually several lighting functions are integrated.

Headlamps may have at least one incandescent lamp, halogen lamp or gas discharge lamp as a light source, for example; Luminaires can be used as light source e.g. Have light bulbs. But headlights and lights are also more and more with semiconductor light sources, in particular light emitting diodes (LEDs), operated as a light source. To generate a light distribution of a desired width and light intensity, a plurality of semiconductor light sources can also be combined into an array and operated in a matrix-like manner. It is possible that temporarily only a part of the semiconductor light sources arranged in the array is operated simultaneously.

A so-called semiconductor chip comprises one or more Semiconductor light sources. The semiconductor light sources or the semiconductor chips are preferably operated in the prior art in a plurality of paths connected in parallel with each path comprising at least one semiconductor light source. For electrical power supply, the semiconductor light sources are operated either by a current source per semiconductor chip (comprising one or more light-emitting diodes) or per path or by a common voltage source for all paths, in the latter case switching elements are arranged in the paths and the operating current per path by opening or closing the switching elements is regulated, wherein the operating current results by averaging. For this purpose, a high sampling rate for determining the current current values and an integrator for averaging is required in the control circuit.

From the DE 10 2008 021 534 A1 is a lighting device of a motor vehicle is known which has a plurality of parallel paths connected to each other, wherein in each path, a series connection of a plurality of light-emitting diodes is arranged. The lighting device is operated by a common voltage source for all paths and by a current source per path, using a control arrangement for regulating the operating voltage. The control arrangement operates at a high sampling rate and includes an integrator for averaging.

The object of the invention is to design a lighting device of the type mentioned in such a way and to further develop that it can be operated very efficiently. The circuit complexity and the required installation space should be as low as possible.

To solve this problem, a method for operating a lighting device of the aforementioned type is proposed, in which all switched semiconductor light sources are powered by a common power source with energy, wherein a predetermined total operating current is provided by the power source corresponding to the number of semiconductor light sources turned on.

By the method according to the invention, on the one hand, the circuit complexity is reduced by supplying a plurality of semiconductor light sources, for example all semiconductor light sources of an LED array, with energy by a single current source. The semiconductor light sources individually assigned power sources are no longer necessary. On the other hand, the necessary sum operating current for operating all switched semiconductor light sources can be determined in a control and / or regulating device and then the current source can be switched so that each semiconductor light source can be operated properly with a suitable constant current. In this case, the control and / or regulating device provides a sum operating current for all semiconductor light sources or for all paths connected in parallel with one another. The sum operating current generated by the current source can therefore be predetermined by signals of the control and / or regulating device, depending on the number of semiconductor light sources that are switched on. The total operating current can thus be controlled or regulated with a reduced number of components and a much greater sampling rate than previously required. In particular, in the invention can be dispensed with an integrator for averaging. The lower drive frequency also increases the energy efficiency of the components used.

In this case, the sum operating current is divided automatically into the semiconductor light sources or paths with semiconductor light sources, which are preferably connected in parallel with one another. The electrical properties of the semiconductor light sources or of the paths in which the semiconductor light sources are arranged can be set in different ways. As a result, the individual operating current resulting in the semiconductor light sources or the paths is automatically adjusted. The invention is based on the idea to replace the hitherto customary complicated control of the individual operating currents in the individual semiconductor light sources or paths by a single, common for all semiconductor light sources and paths total current control. In this case, only one common current source is required for all paths or all semiconductor light sources whose operating current is controlled and / or regulated, and an integrator can be dispensed with. As a result of the reduced circuit complexity, a clear cost and space reduction and improved efficiency are achieved.

In a preferred embodiment, it is provided that all switched semiconductor light sources are operated with an identical operating current. If the semiconductor light sources are arranged in a plurality of parallel paths, the individual operating currents in the individual paths are the same. For this purpose, the illumination device may preferably be designed such that in each case an equal number of semiconductor light sources, preferably all of the same type, is arranged in a plurality of parallel paths of the illumination device. Semiconductor light sources of the same type preferably have the same electrical properties. Thus, the paths have the same electrical properties. As an electrical property, in particular the ohmic resistance of the path or the semiconductor light sources arranged therein is considered here. This ensures that the sum of the operating current generated by the power source evenly divided on all paths. Due to the identical operating current intensity for the paths or the semiconductor light sources, it can be achieved that all switched semiconductor light sources radiate with the same brightness, which leads to a particularly homogeneous light distribution and color of the light generated by the illumination device.

According to the invention, it is further provided that at least one of the semiconductor light sources or at least one of the paths connected in parallel to one another is assigned a switch, by means of which the current flow through the semiconductor light source can be switched on and off. Preferably, all semiconductor light sources or all paths associated with a separate switch. The switches are preferably designed as electrically controllable switches, in particular as transistors or thyristors. The switches are preferably controlled by means of an electrical drive signal of an electrical control and / or regulating device of the illumination device. In one path, the switches are preferably arranged in series with the at least one semiconductor light source arranged in the path. The control and / or regulating device can switch on as many semiconductor light sources or paths of the illumination device as semiconductor light sources are necessary or desired for realizing a desired light distribution or light function of the illumination device. The control and regulating device is thus aware of the Number of activated paths or the switched semiconductor light sources and can adjust the total operating current by means of control or simplified control in a particularly simple manner. The total operating current of the current source is determined and set by the control and / or regulating device in such a way that it is ensured that an operating current flows through each semiconductor light source or through all the semiconductor light sources arranged in a path, which for proper operation of the semiconductor light source (s). in the required or desired manner, ie for generating the desired light distribution and the desired light color, etc., is necessary.

Furthermore, it is provided that the operating current intensity for operating at least one of the semiconductor light sources or the semiconductor light sources of at least one of the paths is adjusted by means of an ohmic resistor arranged in series with the at least one semiconductor light source. In this case, different types of semiconductor light sources with different electrical properties can also be used in the illumination device. The different electrical properties of the semiconductor light sources can also result due to manufacturing tolerances. The different electrical properties of the semiconductor light sources can be taken into account by selecting and arranging a suitable resistor, preferably an ohmic resistor, in series with the semiconductor light sources or in a path of the semiconductor light sources and compensating their effects. Also, a different number of semiconductor light sources in the individual paths can be taken into account by the arrangement of suitable resistors. At least one of the ohmic

Resistors may also be temperature-dependent changeable, for example, to take into account a change in resistance of the semiconductor light source (s) in a path which increases during operation of the semiconductor light source and the associated heating. At the beginning of operation, the ohmic resistance may be greater and smaller by heating, so that the sum of ohmic resistance and resistance of the semiconductor light sources and thus the current in the path or by the semiconductor light source (s) of the path from the beginning over the total operating time remains approximately constant. The ohmic resistors are preferably selected in series with the semiconductor light sources or in the paths such that equal operating currents are established in the individual paths of the illumination device.

However, it is also conceivable that the semiconductor light sources are tolerated so that the total operating current strength is automatically and substantially evenly distributed over the individual paths within a tolerable value range.

It is further provided that the operating current intensity for operating at least one of the semiconductor light sources of a path is adjusted by means of path-wise pulse width modulation. For this purpose, a switching element is arranged in each of the parallel paths. These are, for example, a switching element which can be activated by means of a control signal of the control or regulating device and which can preferably switch at a relatively high frequency. In particular, the switching element is designed as a transistor or as a thyristor or as a network with a plurality of such switching elements. Preferably, the current is determined in each path and in the control and / or Control device evaluated. The determination of the current intensity in a path can be easily determined on the basis of the number and arrangement of the activated or deactivated semiconductor light sources, which are known to the control or regulating device, without requiring a constant current measurement with a high sampling rate. Subsequently, the switching element arranged in the path is correspondingly activated so that the current is alternately switched on or off and the desired individual operating current in the path is established by averaging the on or off periods. A pulse width modulation of the sum of the operating current of the current source is also conceivable, then a common switching element is provided for all paths, which is controlled by means of a corresponding drive signal from the control or regulating device in dependence on the number and arrangement of the activated or deactivated semiconductor light sources.

When setting the duty cycle of the pulse width modulation in the individual paths, a light request of the illumination device for the individual semiconductor light sources can be taken into account. In this case, for example, an operating current in the paths is pulse width modulated as a function of the light requirement by a control algorithm by means of the switching elements arranged in the paths. If the total operating current is also controlled by pulse width modulation, the two duty cycles (the total operating current control and the individual operating current control of the individual paths) can be superimposed. Furthermore, it is conceivable that individual paths and the semiconductor light sources arranged therein can be selectively switched on or off depending on the desired light function.

• Eine gemeinsame Stromquelle für alle parallel geschalteten Pfade und die darin angeordneten aktivierten Halbleiterlichtquellen.
• Keine aufwendige Regelung des Summenbetriebsstroms mit hoher Abtastrate erforderlich; der Summenbetriebsstrom wird in Abhängigkeit von der Anzahl der aktivierten Halbleiterlichtquellen gesteuert oder mit geringerer Ansteuerfrequenz geregelt.
• Zusätzlich zur Einstellung des Summenbetriebsstroms Einstellen des individuellen Betriebsstroms pro Pfad für die darin angeordneten Halbleiterlichtquelle(n).
• Einstellen des individuellen Betriebsstroms mittels pfadweiser Pulsweitenmodulation.
• Als Alternative Einstellen des individuellen Betriebsstroms pro Pfad mittels pfadweiser Anpassung der elektrischen Eigenschaften, insbesondere des ohmschen Widerstands, des Pfads durch Anordnen eines geeigneten Widerstands in dem Pfad.

Important aspects of the invention are therefore the following:

• A common power source for all parallel paths and the activated semiconductor light sources arranged therein.
• No complex control of the summation operating current with a high sampling rate required; the total operating current is controlled as a function of the number of activated semiconductor light sources or regulated with a lower driving frequency.
• In addition to adjusting the sum operating current, adjusting the individual operating current per path for the semiconductor light source (s) disposed therein.
• Setting the individual operating current by means of path-wise pulse width modulation.
• Alternatively, adjusting the individual operating current per path by adapting the electrical properties, in particular the ohmic resistance, of the path by placing a suitable resistance in the path.

Figur 1

eine schematische Darstellung einer erfindungsgemäßen Beleuchtungseinrichtung in einer Seitenansicht;

Figur 2

eine Schaltungsanordnung zum Betreiben mehrerer Halbleiterlichtquellen der Beleuchtungseinrichtung aus Figur 1 in einer ersten Ausführungsform;

Figur 3

eine Schaltungsanordnung zum Betreiben mehrerer Halbleiterlichtquellen der Beleuchtungseinrichtung aus Figur 1 in einer zweiten Ausführungsform; und

Figur 4

eine Schaltungsanordnung zum Betreiben mehrerer Halbleiterlichtquellen der Beleuchtungseinrichtung aus Figur 1 in einer dritten Ausführungsform.

Preferred embodiments of the present invention are illustrated in the figures described below. Show it:

FIG. 1

a schematic representation of a lighting device according to the invention in a side view;

FIG. 2

a circuit arrangement for operating a plurality of semiconductor light sources of the illumination device FIG. 1 in a first embodiment;

FIG. 3

a circuit arrangement for operating a plurality of semiconductor light sources of Lighting device off FIG. 1 in a second embodiment; and

FIG. 4

a circuit arrangement for operating a plurality of semiconductor light sources of the illumination device FIG. 1 in a third embodiment.

FIG. 1 shows a lighting device according to the invention in section and in a simplified representation. The lighting device is designated in its entirety by the reference numeral 10. The lighting device 10 may be designed as a headlight or as a lamp, preferably for use in a motor vehicle. In the example of FIG. 1 the lighting device 10 is designed as a headlight.

The lighting device 10 comprises a housing 12 which is preferably made of plastic. In a light exit direction 14, the housing 12 has a light exit opening, which is closed by a translucent cover 16. The cover 16 may be formed as a clear disc without optically active elements or at least partially with optically active elements (not shown) as a diffuser. The cover 16 is made of plastic or glass.

Inside the housing 12, a light module 18 is arranged. The light module 18 serves to generate a desired light distribution which has a certain horizontal and vertical extent and a certain illuminance value distribution in the illuminated area. In the illustrated example of a Headlamps 10 this produces, for example, a low beam, high beam or fog light. In the case of a luminaire, the illumination device 10 could serve in the front region of a vehicle, for example for generating a position light, flashing light or daytime running light or in the rear region of a vehicle. For generating a brake light, flashing light or a tail light.

The light module 18 has a printed circuit board 20, which in the illustrated example is equipped with three semiconductor light sources 22. The semiconductor light sources 22 are preferably designed as light-emitting diodes (LEDs). They are preferably of the same type, that is they have almost the same electrical and optical properties. The electrical properties relate to, for example, the operating current, the operating voltage or the ohmic resistance and / or its temperature dependence. The optical properties relate, for example, the illuminance (lux), the light intensity (candela), the luminous flux (candela-sr, lumens) and / or the light color (color temperature in Kelvin). The selected number of semiconductor light sources 22 and their arrangement on the circuit board 20 are exemplary and may be provided as desired differently. The semiconductor light sources 22 can form a so-called array in one or more rows and / or columns, preferably a so-called 1x3 array (1 column, 3 rows or 3 columns, 1 row), wherein the semiconductor light sources 22 of the 1x3- Arrays can preferably be switched individually and controlled. Any other number and arrangement of the LEDs 22 is also conceivable.

The light module 18 also includes an optical array 24 having a plurality of primary optics for converging the light beams emitted from the semiconductor light sources 22.

The primary optics are formed, for example, as attachment optics 26. The attachment optics 26 may be connected to each other so that the primary optics 24 forms a unit, or they may be formed separately and separately from each other, so that the primary optics 24 is formed in several parts. The attachment optics 26 are preferably solid and consist of a transparent material, in particular plastic or glass. Preferably, each semiconductor light source 22 is assigned its own optical attachment 26. A majority of the light emitted by one of the semiconductor light sources 22 is coupled into the corresponding optical attachment 26 via a light input surface. A portion of the injected light passes directly to the light output surface and is decoupled via this from the optical attachment 26. Another part of the injected light reaches lateral interfaces of the optical attachment 26 and is totally reflected at this, to then meet on the light output surface and be decoupled via this. Due to the total reflection at the boundary surfaces of the attachment optics 26 as well as by refraction at the light entry surfaces and / or light exit surfaces of the attachment optics 26, the light beams emitted by the semiconductor light sources 22 and coupled into the attachment optics 26 are bundled. The optical array 24 generates the desired light distribution of the light module 18 either alone or in cooperation with other optical elements, for example a projection lens (not shown) be associated with multiple reflectors or be assigned a differently configured optical array 24.

On a semiconductor light sources 22 opposite side of the circuit board 20 is a heat sink 28 for Heat dissipation arranged. This is preferably formed substantially more massive than the circuit board 20. The heat sink 28 preferably comprises cooling fins or cooling pins 28a for surface enlargement. In addition, an active cooling element, for example in the form of a fan, may be provided in order to improve the cooling effect achievable by the heat sink 28. The heat sink 28 dissipates the heat generated during operation of the LEDs 22 from the LEDs 22 in order to avoid overheating.

The light module 18 is operated by a control and / or regulating device 30. The control and / or regulating device 30 is assigned a current source 32. This can be an integral part of the control and / or regulating device 30 (cf. FIG. 1 ), but it may also be a separate device outside the control and / or regulating device 30 inside or outside the housing 12 of the illumination device 10. The current source 32 is ideally characterized by the fact that it always tries, regardless of a connected electrical load, to provide the same amperage available. Between the power source 32 and the printed circuit board 20, an electrical supply line 34 is disposed, between the control and / or regulating device 30 and the circuit board 20, a signal line 36 is additionally arranged, via the drive signals for the light module 18 and the LEDs 22 and other components the LED circuitry can be transmitted. The lines 34 and 36 serve to operate the semiconductor light sources 22 according to the inventive method. But it is also conceivable that the lines 34 and 36 are formed as a common line, via which both the drive signals and the supply energy are transmitted.

FIG. 2 shows a circuit arrangement for operating the semiconductor light sources 22 of the illumination device 10 FIG. 1 in a first embodiment. Exemplary are in FIG. 2 three semiconductor light sources 22 shown. The semiconductor light sources 22 are each connected individually in a separate path 38 in parallel with each other and are electrically supplied by the power source 32 via the supply line 34. Each path 38 could also include more than one semiconductor light source 22 in series with, or in parallel with, the LED 22 shown. Each path 38 may comprise an arbitrarily configured electrical network of a plurality of parallel and / or serially connected LEDs 22.

In the paths 38, a switching element 40 in each case is arranged in series with the at least one semiconductor light source 22. The switching elements 40 are preferably designed as electrically controllable switching elements, particularly preferably semiconductor switching elements, in particular transistors or thyristors or as networks of such switching elements. The switching elements 40 are preferably arranged on the printed circuit board 20. Each switching element 40 can be controlled and switched separately via its own signal line 36 by the control and / or regulating device 30 in order to switch on or off a predetermined number of semiconductor light sources 22 in the light module 18. If only two of the three LEDs 22 are required to implement a given light function, the control unit 30 can control the switch 40 in one of the paths 38 in such a way that the switch 40 opens, the current flow through the corresponding path 38 is interrupted and the LED 22 arranged therein is disabled.

The number of LEDs 22 to be activated may be, for example, due to requirements for a to be achieved Light distribution of the light module 18 or due to the operation of the lighting device 10 in a particular country, with different legal requirements apply to a light distribution in different countries.

In the in FIG. 2 In the embodiment shown, the semiconductor light sources 22 have almost identical electrical properties, so that the sum operating current provided by the current source 32 is divided equally into the paths 38. Thus, in each of the switched paths 38, the same current flows. Also, the optical properties of the semiconductor light sources 22 are preferably almost equal, so that the semiconductor light sources 22 all shine with a largely equal intensity and the same light color. For this reason, in this first embodiment a symmetrization of the paths 38, for example via resistors 42 (cf. FIGS. 3 and 4 ), not necessary.

Thus, the lighting device 10 and the light module 18 regardless of the number of active LEDs 22 and paths 38 always bright and / or with the same color lights, the control and / or regulating device 30 must the sum operating current corresponding to the number of active LEDs Set 22 or paths 38. The total operating current is controlled or regulated to a current that is needed for the LEDs 22 switched on. Actuation of the switches 40 in the paths 38 can thus also have effects on the sum operating current. The control and / or regulating device 30 controls the individual switches 40 and at the same time predefines the current source 32 as to which current intensity is to be made available as a sum operating current. By this procedure, a path-wise adjustment of the respective operating current by means of pulse width modulation can be achieved by the switches 40 be used for the realization of a pulse width modulation, that is, with a certain duty cycle on and off.

In order therefore to be able to operate all the semiconductor light sources 22 switched on independently of a number of currently switched-on semiconductor light sources 22 with the same current intensity, the total operating current flowing via the operating line 34 must be adjustable depending on the number of currently switched semiconductor light sources 22. In the lighting device 10 according to the invention, therefore, the sum operating current can be controlled or regulated according to the number of semiconductor light sources 22 to be operated. For this purpose, the current source 32 can be controlled by the control and / or regulating device 30 in such a way that it provides the respectively required total operating current. Due to the activation of the switching elements 40, the control and / or regulating device 30 has information regarding the currently active semiconductor light sources 22 and can accordingly set the required magnitude of the total operating current. If the sum operating current is regulated, such a control can be realized substantially simply due to the knowledge of the number of active LEDs 22 and the resulting total operating current required. In particular, the operating frequency of the control can be significantly reduced because the scheme still works sufficiently quickly and reliably with a much higher sampling rate than in known controls. In addition, it is possible to dispense with an integrator for averaging. Thus, for example, it is conceivable that via the knowledge existing in the control and / or regulating device about the required total operating current, a desired value for the control can be newly specified as soon as an LED 22 is switched on or off.

For controlling or controlling the sum operating current, for example, in the operating line 34, a pulse width modulation device (not shown) may be arranged, which may vary the sum operating current by means of pulse width modulation. In this case, the duty cycle of the pulse width modulation is adjusted so that sets a desired total operating current over the time average. This preferably corresponds to the number of active semiconductor light sources 22.

FIG. 3 shows a circuit arrangement for operating the semiconductor light sources 22 in a second embodiment. Unlike the first embodiment ( FIG. 2 ) is in each path 38 in addition to the at least one semiconductor light source 22 and the switching element 40 in addition an ohmic resistor 42 is arranged. The resistors 42 serve to electrically balance the paths 38 so that the ohmic resistance of a path 38, which results from the aggregation of the individual resistances of the components arranged in the path 38, assumes a specific value. Preferably, it is attempted that the ohmic resistance of a path 38 corresponds to the ohmic resistance of the remaining paths 38. In this case, for example when operating the semiconductor light sources 22, different types of semiconductor light sources 22 or also manufacturing tolerances of the semiconductor light sources 22, which can lead to different resistances of the LEDs 22, are taken into account. A different number of semiconductor light sources 22 in the individual paths 38 can also be taken into account in this way. The values of the ohmic resistors 42 are chosen so that a desired individual operating current in the individual paths 38 sets. Preferably, the resistance values of the resistors 42 are selected such that the same operating current is established in all paths 38.

The electrical resistors 42 may also have a temperature-dependent ohmic resistance value and be designed as NTC or PTC resistors. As a result, heating of the semiconductor light sources 22 and an associated change in the resistance of the semiconductor light sources 22 can be compensated for, for example, during operation of the illumination device 10, so that regardless of the current operating temperature, the desired individual current strength always flows through the respective path 38, that is, the current regardless of the operating temperature of the LEDs 22 is kept constant.

FIG. 4 shows a circuit arrangement for operating the semiconductor light sources 22 in a third embodiment. In this case, each of the switching elements 40 serves in addition to the switching on and off of the corresponding path 38 and the LEDs 22 arranged therein as a switching device for a path-wise pulse width modulation. In this case, in each of the paths 38, an individual pulse width modulation can be realized in order to set the operating current per path 38 individually and to be able to divide the total operating current provided by the current source 32 in the desired manner onto the individual paths 38. In this case, the duty cycle of the pulse width modulation in each path 38 is set such that the desired current intensity in the path 38 is set over the time average. In this case, the pulse width modulation can be controlled or regulated. When controlling the individual operating current, the current in each path 38 must be detected separately and fed to a path-individual control. For this purpose, in this embodiment at each path 38 a measuring line 44th provided via which the control and / or regulating device 30 determines the respective current in the respective path 38 and supplies the determined current to the control algorithm. In this case, the sampling rate for detecting the current current can be selected to be significantly larger (the current value is detected less frequently) than in the prior art. This is possible since the control and / or regulating device 30 has additional knowledge with regard to the number of active LEDs 22 and the resulting sum operating current resulting therefrom. In this case, brightness requirements on the individual semiconductor light sources 22 can be met by the duty cycle of the pulse width modulation in the individual paths 38 being set individually. It is also possible that the duty cycle of the pulse width modulation in the paths 38 superimposed on the duty cycle of the pulse width modulation for setting the total operating current.

Claims (13)

A method of operating a lighting device (10) of a motor vehicle, wherein a plurality of semiconductor light sources (22) of the illumination device (10) are connected in parallel to each other and turned-on semiconductor light sources (22) are supplied by at least one current source (32) with power, characterized in that all the switched- Semiconductor light sources (22) are powered by a common power source (32), wherein by the power source (32) corresponding to the number of semiconductor light sources (22) turned on a predetermined total operating current is provided. A method according to claim 1, characterized in that all switched semiconductor light sources (22) are operated with an identical operating current. A method according to claim 1 or 2, characterized in that at least one of the semiconductor light sources (22) is associated with a switch (40) through which the semiconductor light source (22) is turned on and off. A method according to claim 3, characterized in that the switch (40) by an electrical control and / or regulating device (30) of the illumination device (10) is actuated. Method according to one of Claims 1 to 4, characterized in that the operating current intensity for operating at least one of the semiconductor light sources (22) is adjusted by means of an electrical resistor (42) arranged in series with the semiconductor light source (22). Method according to one of claims 1 to 5, characterized in that the operating current for operating at least one of the semiconductor light sources (22) is adjusted by means of pulse width modulation. A method according to claim 6, characterized in that the operating current intensity for operating at least one of the semiconductor light sources (22) is regulated by means of the pulse width modulation. A method according to claim 6 or 7, characterized in that the electrical control and / or regulating device (30) of the illumination device (10) adjusts or regulates the pulse width modulation. Electrical control and / or regulating device (30) for operating a lighting device (10) of a motor vehicle, wherein the lighting device (10) comprises a plurality of semiconductor light sources (22) connected in parallel, characterized in that the control and / or regulating device (30) for controlling a common current source (32), which serves to supply power to all switched-semiconductor light sources (22), is designed such that the current source (32) corresponding to the number of switched semiconductor light sources (22) provides a predetermined total operating current available. Control and / or regulating device (30) according to claim 9, characterized in that the control and / or regulating device (30) comprises means for carrying out a method according to one of claims 4 or 8. Illumination device (10) of a motor vehicle, comprising a plurality of semiconductor light sources (22) connected in parallel, characterized in that the illumination device (10) comprises a control and / or regulating device (30) for controlling a common current source (32) which is energized for supplying power to all Semiconductor light sources (22) is used, such that the current source (32) corresponding to the number of switched semiconductor light sources (22) provides a predetermined total operating current available. Lighting device (10) according to claim 11, characterized in that in each case an equal number of semiconductor light sources (22), preferably of the same type, in a plurality of mutually parallel paths (38) of the illumination device (10) is arranged. Lighting device according to claim 11 or 12, characterized in that the illumination device (10) comprises means for carrying out a method according to one of claims 2 to 8.

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