Lighting device

Abstract

To further improve the efficiency of a lighting device.SOLUTION: The invention relates to a lighting device (1) that includes a multi-LED chip (2). The multi-LED chip (2) has a plurality of LED light sources (2') as well as a plurality of regulating elements (2"). Each LED light source (2') is assigned a regulating element (2") connected in series for regulating the current consumption of the respective LED light sources (2') and together with the regulating element (2") forms controllable sections (2a, 2b, 2c). Each LED light source (2') is designed to be individually switchable. The lighting device (1) includes an electrical control unit (3). The electrical control unit (3) has a step-down converter (3a) with a voltage input (3aVin), a feedback input (3aFB) and a voltage output (3aVout) and a microcontroller (3b) with a signal input (3bSin) and a signal output (3bSout).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] (Related Application Description) This application claims priority to European Patent Application No. 22206132.7 (DAS Code: BF77), filed November 8, 2022, the entire contents of which are incorporated herein by reference.

[0002] The invention particularly relates to a lighting device (light emitting device) comprising a multi-LED chip, the multi-LED chip comprising a number of LED light sources as well as a number of regulating elements, each LED light source being assigned one regulating element connected in series for regulating the current consumption of the respective LED light source, forming together with the regulating element an adjustable section, each LED light source being configured to be individually switchable, the lighting device further comprising an electrical control unit, the electrical control unit comprising a step-down converter (buck converter) with a voltage input, a feedback input and a voltage output, as well as a microcontroller with a signal input and a signal output, the step-down converter converting an input DC voltage applied to the voltage input into a lower output DC voltage, the voltage output being configured to be switched by the step-down converter ... voltage output being configured to be switched by the step-down converter, the voltage output being configured to be switched by the step-down converter, the voltage output being configured to be switched by the step-down converter, the voltage output being configured to be switched by the step-down converter, the voltage output being configured to be switched by the step-down converter, the voltage output being configured to be switched by the step-down converter, the voltage output being configured to be switched by the step-down converter, the voltage output being configured to be switched by the step-down converter, the voltage output being configured to be switched by the step-down converter a voltage output unit connected to the multi-LED chip for powering the sections of the multi-LED chip, a voltage value of the output DC voltage being determined by a feedback loop in which a predetermined voltage portion of the output DC voltage is fed back to the feedback input unit and the output DC voltage is generated depending on the fed back voltage portion, the microcontroller is configured to receive an input signal via the signal input unit and convert it into an output signal, using the output signal a light image to be emitted by the multi-LED chip can be predefined, each light image to be emitted being associated with a configuration of the adjustment state of the section, and the signal output unit is connected to the multi-LED chip for transmitting the output signal. [Background technology]

[0003] Lighting devices of this kind are increasingly being used. To ensure correct operation of the lighting device, it has been usual up until now to simply set the operating voltage provided for each component of the lighting device as a fixed voltage, i.e. the operating voltage is sufficient to be able to fully power all operating modes of the lighting device. Up until now, the efficiency of such lighting devices has been achieved by optimizing the selection of the components used, the efficiency of the light source as well as the efficiency of the downstream optical system and the utilization of the emitted light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] European Patent Application Publication No. 3255959 [Patent Document 2] International Publication No. 2021 / 251375 [Patent Document 3] German Patent Application Publication No. 102015219100 [Non-patent literature]

[0005] [Non-Patent Document 1] Driver Fet ET AL: “Rsd Csd D Rs Cs Ds N-FET Induc tor V IN V OUT DC / DC BOOk OF kNOWLEDGE Practical tips for the User”, 30. Dezember 2014 (2014-12-30), XP055813172, found in the Internet: URL:https: / / www.schukat.com / schukat / pdf.nsf / EC53E983176DF812C1257E6200395568 / $file / Recom_Book of_Knowledge_English.pdf [found on 2021-06-11] Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to further improve the efficiency of such lighting devices. [Means for solving the problem]

[0007] The object is achieved in the lighting device as described at the beginning by the following configuration: the multi-LED chip according to the invention is further configured to derive for each light image an adjustment state of the sections that matches the respective light image, distinguishing between sections that should be activated and those that should not be activated, calculate the required minimum operating voltage for each section to be activated from the adjustment state derived for each light image, taking into account the voltage losses of the adjustment element, determine the highest minimum operating voltage by comparing the minimum operating voltages of the sections to be activated for each light image, determine this as a target operating voltage for the corresponding light image, and transmit this target operating voltage to a microcontroller, the microcontroller being configured to manipulate the voltage feedback of the voltage portion to the feedback input in such a way that only the target operating voltage is output as output voltage to the voltage output.

[0008] That is, according to the first aspect of the present invention, A lighting device - the lighting device comprises a multi-LED chip, the multi-LED chip having a number of LED light sources as well as a number of adjustment elements, each of the LED light sources being assigned one series-connected adjustment element for adjusting the current consumption of the respective LED light source and forming, together with the adjustment element, an adjustable section, each of the LED light sources being configured to be individually switchable, - the lighting device comprises an electrical control unit, the electrical control unit having a step-down converter with a voltage input, a feedback input and a voltage output, and a microcontroller with a signal input and a signal output, the step-down converter is configured to convert an input DC voltage applied to the voltage input to a lower output DC voltage and output it via the voltage output, the voltage output being connected to the multi-LED chip for powering the section of the multi-LED chip, a voltage value of the output DC voltage being determined by a feedback loop, in which a predetermined voltage portion of the output DC voltage is fed back to the feedback input, and the output DC voltage is generated in dependence on the fed back voltage portion; the microcontroller is configured to receive an input signal via the signal input unit and convert it into an output signal, and by using the output signal, a light image to be emitted by the multi-LED chip can be predefined, each of the light images to be emitted being associated with a configuration of an adjustment state of the section, and the signal output unit is connected to the multi-LED chip for transmitting the output signal; the multi-LED chip is further configured to derive for each of the light images the adjustment states of the sections that match each of the light images, distinguish between the sections that should be activated and those that should not be activated, calculate from the adjustment states derived for each of the light images a necessary minimum operating voltage for each of the sections that should be activated, taking into account the voltage losses of the adjustment elements, detect the maximum of the minimum operating voltages by comparing the minimum operating voltages of the sections that should be activated for each of the light images, determine it as a target operating voltage for the corresponding light image, and transmit the target operating voltage to the microcontroller, the microcontroller being configured to operate a voltage feedback of the voltage portion to the feedback input depending on the target operating voltage transmitted by the multi-LED chip, such that only the target operating voltage is output as an output voltage to the voltage output. A lighting device is provided, characterized in that More specifically, in the first aspect, A lighting device - the lighting device comprises a multi-LED chip, the multi-LED chip having a number of LED light sources as well as a number of adjustment elements, each of the LED light sources being assigned one series-connected adjustment element for adjusting the current consumption of the respective LED light source and forming, together with the adjustment element, an adjustable section, each of the LED light sources being configured to be individually switchable, - the lighting device comprises an electrical control unit, the electrical control unit having a step-down converter with a voltage input, a feedback input and a voltage output, and a microcontroller with a signal input and a signal output, the step-down converter is configured to convert an input DC voltage applied to the voltage input to a lower output DC voltage and output it via the voltage output, the voltage output being connected to the multi-LED chip for powering the section of the multi-LED chip, a feedback loop being provided, a voltage portion of the output DC voltage being fed back to the feedback input and the output DC voltage being generated in dependence on the fed back voltage portion, the feedback loop being used to determine a voltage value of the output DC voltage; the microcontroller is configured to receive an input signal via the signal input unit and convert it into an output signal, and by using the output signal, a light image to be emitted by the multi-LED chip can be predefined, each of the light images to be emitted being associated with a configuration of an adjustment state of the section, and the signal output unit is connected to the multi-LED chip for transmitting the output signal; the multi-LED chip is further adapted to derive for each of the light images the adjustment states of the sections adapted to each of the light images, to distinguish between the sections to be activated and those to be not activated, to calculate from the adjustment states derived for each of the light images the necessary minimum operating voltage for each of the sections to be activated, taking into account the voltage losses of the adjustment elements, to detect the maximum of the minimum operating voltages by comparison of the minimum operating voltages of the sections to be activated for each of the light images, to determine it as a target operating voltage for the corresponding light image, and to transmit the target operating voltage to the microcontroller, the microcontroller being adapted to operate the voltage feedback of the voltage portion to the feedback input depending on the target operating voltage transmitted by the multi-LED chip, in such a way that only the target operating voltage is output as an output voltage to the voltage output, the microcontroller being connected to a switchable resistor network by the microcontroller for manipulating a voltage feedback of the voltage portion to the feedback input, the lighting device including the resistor network, the switchable resistor network being connected to the feedback input and thus to a voltage feedback of the voltage portion; the resistor network being configured as an R2R network; It is characterized by: According to a second aspect of the present invention, there is provided an automobile floodlight including the lighting device. Furthermore, according to a third aspect of the present invention, there is provided an automobile including the lighting device. According to a fourth aspect of the present invention, there is provided a vehicle including the vehicle floodlight. According to a further fifth aspect of the present invention there is provided a method for energy efficient operation of a lighting device comprising: - the lighting device comprises a multi-LED chip, the multi-LED chip having a number of LED light sources as well as a number of adjustment elements, each of the LED light sources being assigned one series-connected adjustment element for adjusting the current consumption of the respective LED light source and forming, together with the adjustment element, an adjustable section, each of the LED light sources being configured to be individually switchable, - the lighting device comprises an electrical control unit, the electrical control unit having a step-down converter with a voltage input, a feedback input and a voltage output, and a microcontroller with a signal input and a signal output, the step-down converter is configured to convert an input DC voltage applied to the voltage input to a lower output DC voltage and output it via the voltage output, the voltage output being connected to the multi-LED chip for powering the section of the multi-LED chip, a voltage value of the output DC voltage being determined by a feedback loop, in which a predetermined voltage portion of the output DC voltage is fed back to the feedback input, and the output DC voltage is generated in dependence on the fed back voltage portion; the microcontroller is configured to receive an input signal via the signal input unit and convert it into an output signal, and by using the output signal, a light image to be emitted by the multi-LED chip can be predefined, each of the light images to be emitted being associated with a configuration of an adjustment state of the section, and the signal output unit is connected to the multi-LED chip for transmitting the output signal; The method includes the steps of: a) receiving the output signal by the multi-LED chip; b) deriving the light image to be emitted in each case from the output signals and calculating the adjustment state of the sections that matches said light image; c) calculating the minimum operating voltage required for each of said sections based on the regulation state detected in step b and taking into account the voltage losses of said regulating elements; d) detecting a target operating voltage by determining a maximum of the minimum operating voltages of the sections; e) communicating said target operating voltage to said microcontroller; f) manipulating, by the microcontroller, a voltage feedback of the voltage portion to the feedback input in dependence on the transmitted target operating voltage, so that only the target operating voltage is output as an output voltage to the voltage output. A method is provided comprising: More specifically, in the fifth aspect, A method for energy-efficient operation of a lighting device, - the lighting device comprises a multi-LED chip, the multi-LED chip having a number of LED light sources as well as a number of adjustment elements, each of the LED light sources being assigned one series-connected adjustment element for adjusting the current consumption of the respective LED light source and forming, together with the adjustment element, an adjustable section, each of the LED light sources being configured to be individually switchable, - the lighting device comprises an electrical control unit, the electrical control unit having a step-down converter with a voltage input, a feedback input and a voltage output, and a microcontroller with a signal input and a signal output, the step-down converter is configured to convert an input DC voltage applied to the voltage input to a lower output DC voltage and output it via the voltage output, the voltage output being connected to the multi-LED chip for powering the section of the multi-LED chip, a feedback loop being provided, a voltage portion of the output DC voltage being fed back to the feedback input and the output DC voltage being generated in dependence on the fed back voltage portion, the feedback loop being used to determine a voltage value of the output DC voltage; the microcontroller is configured to receive an input signal via the signal input and convert it into an output signal, with the output signal being able to predefine a light image to be emitted by the multi-LED chip, each of the light images to be emitted being associated with a configuration of an adjustment state of the section, and the signal output is connected to the multi-LED chip for transmitting the output signal; the microcontroller being connected to a switchable resistor network by the microcontroller for manipulating a voltage feedback of the voltage portion to the feedback input, the lighting device including the resistor network, the switchable resistor network being connected to the feedback input and thus to a voltage feedback of the voltage portion; the resistor network being configured as an R2R network; The method includes the steps of: a) receiving the output signal by the multi-LED chip; b) deriving the light image to be emitted in each case from the output signals and calculating the adjustment state of the sections that matches said light image; c) calculating the minimum operating voltage required for each of said sections based on the regulation state detected in step b and taking into account the voltage losses of said regulating elements; d) detecting a target operating voltage by determining a maximum of the minimum operating voltages of the sections; e) communicating said target operating voltage to said microcontroller; f) manipulating, by the microcontroller, a voltage feedback of the voltage portion to the feedback input in dependence on the transmitted target operating voltage, so that only the target operating voltage is output as an output voltage to the voltage output. It is characterized by: It should be noted that the reference numerals in the drawings used in the claims of this application are intended solely to facilitate understanding of the present invention and are not intended to limit the present invention to the forms shown in the drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] In the present invention, the following configurations are possible. (Form 1) A lighting device - the lighting device comprises a multi-LED chip, the multi-LED chip having a number of LED light sources as well as a number of adjustment elements, each of the LED light sources being assigned one series-connected adjustment element for adjusting the current consumption of the respective LED light source and forming, together with the adjustment element, an adjustable section, each of the LED light sources being configured to be individually switchable, - the lighting device comprises an electrical control unit, the electrical control unit having a step-down converter with a voltage input, a feedback input and a voltage output, and a microcontroller with a signal input and a signal output, the step-down converter is configured to convert an input DC voltage applied to the voltage input to a lower output DC voltage and output it via the voltage output, the voltage output being connected to the multi-LED chip for powering the section of the multi-LED chip, a voltage value of the output DC voltage being determined by a feedback loop, in which a predetermined voltage portion of the output DC voltage is fed back to the feedback input, and the output DC voltage is generated in dependence on the fed back voltage portion; the microcontroller is configured to receive an input signal via the signal input unit and convert it into an output signal, and by using the output signal, a light image to be emitted by the multi-LED chip can be predefined, each of the light images to be emitted being associated with a configuration of an adjustment state of the section, and the signal output unit is connected to the multi-LED chip for transmitting the output signal; Further, the multi-LED chip is configured to derive for each of the light images the adjustment states of the sections that match each of the light images, distinguish between the sections that should be activated and those that should not be activated, calculate from the adjustment states derived for each of the light images a required minimum operating voltage for each of the sections to be activated, taking into account the voltage loss of the adjustment element, detect the maximum of the minimum operating voltages by comparing the minimum operating voltages of the sections to be activated for each of the light images, determine it as a target operating voltage for the corresponding light image, and transmit the target operating voltage to the microcontroller, wherein the microcontroller is configured to operate a voltage feedback of the voltage portion to the feedback input unit depending on the target operating voltage transmitted by the multi-LED chip, such that only the target operating voltage is output as an output voltage to the voltage output unit. (Form 2) In the lighting device described in form 1, it is preferable that the microcontroller is connected to a resistor network switchable by the microcontroller to manipulate the voltage feedback of the voltage portion to the feedback input portion, and that the switchable resistor network is connected to the feedback input portion and therefore to the voltage feedback portion of the voltage portion. (Form 3) In the lighting device according to aspect 2, the resistor network is preferably configured as an R2R network. (Form 4) In the lighting device described in aspect 3, it is preferable that the R2R network has four switching stages, and each of the switching stages is connected to the microcontroller for controlling the switching stages. (Form 5) In the lighting device according to any one of the first to fourth aspects, it is preferable that the output voltage is fed back to the feedback input section via a voltage divider. (Form 6) In the lighting device described in form 5, it is preferable that the voltage divider is connected to ground and the resistor network is engaged at a junction point between the resistors of the voltage divider and is also connected to ground. (Form 7) In the lighting device according to any one of the first to sixth aspects, it is preferable that the lighting device further has an application-specific IC, the application-specific IC being connected to the signal output unit of the microcontroller and configured to convert the output signal into a control signal for controlling the LED light source of the multi-LED chip. (Form 8) In the lighting device according to any one of the first to seventh aspects, the output voltage is preferably between 3V and 5V, particularly between 3.5V and 4.5V. (Form 9) In the lighting device described in any one of forms 1 to 8, it is preferable that the input signal contains information regarding the current light image as well as the light image to be subsequently emitted, based on which the corresponding target operating voltage of the subsequent light image is derived in advance by the microcontroller in order to pre-set the target operating voltage adapted to this light image already directly at the time of switching to the subsequent light image. (Form 10) In the lighting device according to any one of the first to ninth aspects, it is preferable that the microcontroller is configured to store a target voltage value preset by the multi-LED chip for the repeated light image, and to set and maintain the stored target voltage value corresponding to the preset light image until another light image is preset or until the multi-LED chip outputs a target voltage value for the corresponding light image that is different from the stored target voltage value. (Form 11) A vehicle floodlight including the lighting device according to any one of aspects 1 to 10. (Form 12) An automobile including the lighting device according to any one of aspects 1 to 10 and / or the automobile floodlight according to aspect 11. (Form 13) A method for energy-efficient operation of a lighting device, - the lighting device comprises a multi-LED chip, the multi-LED chip having a number of LED light sources as well as a number of adjustment elements, each of the LED light sources being assigned one series-connected adjustment element for adjusting the current consumption of the respective LED light source and forming, together with the adjustment element, an adjustable section, each of the LED light sources being configured to be individually switchable, - the lighting device comprises an electrical control unit, the electrical control unit having a step-down converter with a voltage input, a feedback input and a voltage output, and a microcontroller with a signal input and a signal output, the step-down converter is configured to convert an input DC voltage applied to the voltage input to a lower output DC voltage and output it via the voltage output, the voltage output being connected to the multi-LED chip for powering the section of the multi-LED chip, a voltage value of the output DC voltage being determined by a feedback loop, in which a predetermined voltage portion of the output DC voltage is fed back to the feedback input, and the output DC voltage is generated in dependence on the fed back voltage portion; the microcontroller is configured to receive an input signal via the signal input unit and convert it into an output signal, and by using the output signal, a light image to be emitted by the multi-LED chip can be predefined, each of the light images to be emitted being associated with a configuration of an adjustment state of the section, and the signal output unit is connected to the multi-LED chip for transmitting the output signal; The method includes the steps of: a) receiving the output signal by the multi-LED chip; b) deriving the light image to be emitted in each case from the output signals and calculating the adjustment state of the sections that matches said light image; c) calculating the minimum operating voltage required for each of said sections based on the regulation state detected in step b and taking into account the voltage losses of said regulating elements; d) detecting a target operating voltage by determining a maximum of the minimum operating voltages of the sections; e) communicating said target operating voltage to said microcontroller; f) manipulating, by the microcontroller, a voltage feedback of the voltage portion to the feedback input section depending on the transmitted target operating voltage, so that only the target operating voltage is output as an output voltage to the voltage output section.

[0010] The number of sections (circuit parts or strings) is at least two, but in practice the number of sections can be significantly more and can be any natural number between 2 and 500, in particular between 30 and 100. The specific number of sections depends on which resolution is to be achieved by the respective lighting device, with each section representing at least one pixel of the emitted light image. For simplified control of the individual LED light sources, the number of sections can also be a large number, 2n, where n corresponds to the number of digits in the binary number.

[0011] According to the invention, the operating voltage of the multi-LED chip is variably adapted to the requirements of the multi-LED chip or the light distribution to be emitted. In this way, it is possible to provide only the voltage required for operation and to avoid excess voltage parts that would otherwise appear as loss voltage in the multi-LED chip or be properly regulated out by the regulation components of the multi-LED chip (and thus converted into loss heat). In this way, a better efficiency of the lighting device is achieved.

[0012] The regulating element can be, for example, a linear regulator with an adjustable resistance. Alternatively, a switch with a resistive component and / or a combination of switches is also conceivable (possibly constituted by a transistor). In particular, the microcontroller can be connected to a switchable resistor network by the microcontroller in order to manipulate the voltage feedback of the voltage part to the feedback input, the switchable resistor network being connected to the feedback input and thus to the voltage feedback of the voltage part. In this way, a particularly robust and low-cost possibility is created for manipulating the voltage feedback and the voltage output resulting therefrom.

[0013] Advantageously, the resistor network can be configured as an R2R network, which in particular has four switching stages, each of which can be connected to a microcontroller for controlling the switching stages, so that already 16 (2x2x2x2) different switching states and the corresponding output voltages can be realized.

[0014] Furthermore, the output voltage can be fed back to the feedback input via a voltage divider, this type of feedback being particularly robust and low cost, with the voltage divider being connected to ground and a resistor network engaging a node between the resistors of the voltage divider and also being connected to ground.

[0015] Furthermore, the lighting device may have an application-specific IC, in which the application-specific IC is connected to a signal output of the microcontroller and configured to convert its output signal into a control signal for controlling the LED light source of the multi-LED chip.

[0016] In particular, the output voltage can take values ​​between 3V and 5V, in particular between 3.5V and 4.5V.

[0017] Furthermore, the input signal contains information about the current light image as well as about the light image to be subsequently emitted, on the basis of which the corresponding target operating voltage of the subsequent light image can be derived in advance by the microcontroller in order to pre-set a target operating voltage that is directly adapted to this light image already at the time of the changeover to the subsequent light image, thereby minimizing time delays and, in particular, possible readjustments that may be necessary in the emission, if, for example, the subsequent light image requires a higher target operating voltage and during the transition or otherwise still in the short term, a too low target operating voltage of the previous light image would still be applied until the higher target operating voltage is set.

[0018] In particular, the microcontroller can be configured to store target voltage values ​​preset by the multi-LED chip for a recurring light image, and to preset and maintain the stored target voltage value corresponding to the preset light image until another light image is preset or until the multi-LED chip outputs a target voltage value for the corresponding light image that differs from the stored target voltage value. The stored value is then overwritten and the changed target value takes over. To call up the stored target voltage value, for example, a look-up table can be used. Additionally or alternatively, the target voltage value can also be detectable via calculation.

[0019] The repeated light images, for which the target voltage values ​​are stored, can be, for example, the x most frequent light images or light functions assigned to these light images, where x is a natural number and can take a value between 3 and 20. The light functions can be, for example, a low beam function, a high beam function, a parking light function, a cornering light function, etc.

[0020] The invention further relates to a motor vehicle floodlight comprising a lighting device according to the invention.

[0021] The invention likewise relates to a motor vehicle which comprises a lighting device according to the invention and / or which comprises a motor vehicle floodlight according to the invention.

[0022] The invention further relates to a method for energy-efficient operation of a lighting device, in which the lighting device comprises a multi-LED chip, the multi-LED chip having a number of LED light sources as well as a number of regulating elements, each LED light source being assigned one series-connected regulating element for regulating the current consumption of the respective LED light source and forming together with the regulating element an adjustable section, each LED light source being configured to be individually switchable, the lighting device further comprising an electrical control unit, the electrical control unit comprising a step-down converter (buck converter) with a voltage input, a feedback input and a voltage output, and a microcontroller with a signal input and a signal output, the step-down converter converting an input DC voltage applied to the voltage input into a lower output DC voltage, the step-down converter being configured to convert ... the microcontroller is configured to receive an input signal via a signal input unit and convert it into an output signal, using the output signal a light image to be emitted by the multi-LED chip can be predefined, each light image to be emitted being associated with a configuration of an adjustment state of a section, and the signal output unit is connected to the multi-LED chip for transmitting the output signal.

[0023] The method includes the steps of: a) receiving an output signal by a multi-LED chip; b) deriving from the output signals the light image to be emitted in each case and calculating the adjustment state of the sections that matches this light image; c) calculating the minimum operating voltage required for each section based on the regulation state detected in step b, taking into account the voltage losses of the regulating elements; d) detecting a target operating voltage by determining a maximum minimum operating voltage among the minimum operating voltages of the sections; e) communicating the target operating voltage to a microcontroller; f) manipulating, by the microcontroller, the voltage feedback of the voltage portion to the feedback input section depending on the transmitted target operating voltage, so that only the target operating voltage is output as output voltage to the voltage output section.

[0024] All technical features of the lighting device described herein may of course also be realised in the above method and vice versa.

[0025] The invention will now be explained in more detail on the basis of illustrative, non-limiting embodiments, which are specifically illustrated in the drawings. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 illustrates an exemplary embodiment of a lighting device according to the present invention. [Diagram 2] FIG. 2 is a schematic diagram of an exemplary step-down converter usable with the present invention. [Figure 3a] FIG. 2 illustrates an exemplary light image that can be generated by the lighting device. [Figure 3b] FIG. 2 illustrates an exemplary light image that can be generated by the lighting device. [Figure 4] FIG. 1 illustrates an exemplary embodiment of the present invention having an R2R network. [Diagram 5] FIG. 5 is a detailed diagram of an R2R network having four switching stages, including an indication of connection to the embodiment of FIG. [Figure 6] 6A-6C show example output voltages for different switching states of the switching stage of FIG. 5. EXAMPLES

[0027] In the accompanying drawings, like reference numbers refer to like elements unless otherwise stated.

[0028] FIG. 1 shows a diagram of an exemplary embodiment of a lighting device 1 according to the invention. The lighting device 1 comprises a multi-LED chip 2, which has a number of LED light sources 2′ as well as a number of adjustment elements 2″, where each LED light source 2′ is assigned a series-connected adjustment element 2″ for adjusting the current consumption (current intake) of the respective LED light source 2′, which together with the adjustment element 2″ form adjustable sections (circuit parts) 2a, 2b, 2c. Each LED light source 2′ is configured to be individually switchable. In this way, complex light images can be generated. In the diagram of FIG. 1, only three sections are explicitly shown. Of course, this number can be basically varied and can be selected by a person skilled in the art according to the respective intended use of the lighting device 1.

[0029] The lighting device 1 further includes an electrical control unit 3. The control unit 3 further includes a step-down converter (buck converter) 3a with a voltage input 3aVin, a feedback input 3aFB, and a voltage output 3aVout. The control unit 3 further includes a microcontroller 3b with a signal input 3bSin and a signal output 3bSout.

[0030] The step-down converter 3a is configured to convert the input DC voltage Vin applied to the voltage input section 3aVin into a lower output DC voltage Vout and output it via the voltage output section 3aVout. An example of such a step-down converter is shown in FIG. 2. Further looking at FIG. 1, it can be seen that the voltage output section 3aVout is connected to the multi-LED chip 2 to power the sections 2a, 2b, and 2c of the multi-LED chip 2, in which the voltage value of the DC output voltage Vout is determined by a feedback loop in which a certain voltage portion Vfb (see FIG. 2) of the output DC voltage Vout is fed back to the feedback input section 3aFB, and the output DC voltage Vout is generated depending on the fed back voltage portion Vfb.

[0031] The microcontroller 3b is configured to receive an input signal Sin via the signal input 3bSin and convert it into an output signal Sout. The input signal Sin can come, for example, from a control device of a vehicle's communication bus and be input to the control unit 3. The output signal Sout is used to pre-configure the light images 4a, 4b to be emitted by the multi-LED chip 2, where each light image 4a, 4b to be emitted (see Fig. 3a, 3b; "on" stands for the on state of the LEDs, "off" stands for the off state of the LEDs) is associated with the configuration of the adjustment state of the sections 2a, 2b, 2c, and the signal output 3bSout is connected to the multi-LED chip 2 for transmitting the output signal Sout. For the signal transmission, various communication systems can be used, such as, for example, bus systems, in particular CAN, GMSL and / or LVDS.

[0032] Furthermore, a data interface 3bDat is provided, for example for making settings in the multi-LED chip 2 or for reading out status parameters. This data interface 3bDat may for example comprise a UART, SPI or I2C interface. The status parameters may for example comprise temperature parameters or output parameters. The data interface 3bDat advantageously allows for bidirectional data communication, whereby data can be transmitted from the microcontroller 3b to the multi-LED chip 2 directly or indirectly via the circuit 6 described below.

[0033] Furthermore, the multi-LED chip 2 is configured to derive for each light image 4a, 4b (see Figures 3a, 3b) an adjustment state of the sections 2a, 2b, 2c that matches each light image 4a, 4b, distinguishing between sections 2a, 2b, 2c that should be activated and those that should not be activated, calculate from the adjustment state derived for each light image 4a, 4b the required minimum operating voltages Vmin2a, Vmin2b, Vmin2c taking into account the voltage losses of the adjustment element 2" for each section 2a, 2b, 2c that should be activated, and detect the maximum minimum operating voltage Vmin2a, Vmin2b, Vmin2c by comparing the minimum operating voltages Vmin2a, Vmin2b, Vmin2c of the sections 2a, 2b, 2c that should be activated for each light image 4a, 4b.

[0034] The required minimum operating voltage of the individual sections can for example be calculated on the basis of voltage measurements in a certain partial area of ​​the section, which partial area can for example comprise the LED light source 2' itself or the assigned regulating element 2".

[0035] This maximum minimum operating voltage can also be determined as a target operating voltage Vsoll for the corresponding light image and transmitted to the microcontroller 3b, which causes the output voltage Vout to take this target operating voltage. To this end, the microcontroller 3b is configured to depend on the target operating voltage Vsoll transmitted by the multi-LED chip 2 and manipulate the voltage feedback of the voltage portion Vfb to the feedback input section 3aFB in such a way that only the target operating voltage Vsoll is output to the voltage output section 3aVout as the output voltage Vout. In this way, it can be avoided that excessive voltage values ​​have to be consumed in the regulating element 2'', so that the lighting device 1 has increased efficiency. In this case, the target operating voltage Vsoll is transmitted from the multi-LED chip 2 to the microcontroller 3b via a separate line or via the data interface 3bDat. It is also possible for the microcontroller 3b to query the target operating voltage Vsoll and thus trigger the detection of the maximum minimum operating voltage. This can be done at regular time intervals or, preferably, always after or simultaneously with the presetting of a new light image 4a, 4b to be emitted.

[0036] Figures 3a and 3b show exemplary light images that can be generated by an embodiment of a lighting device 1 according to the invention. The lighting device 1 has a number 105 sections arranged in a matrix with 7 rows and 15 columns. The resolution is thus 7x15, and the total number of "pixels" of the light image is 105. Figures 3a and 3b show different light distributions. In both light images, not all LED light sources 2' or sections are switched on. For different light images, different target operating voltages are usually obtained, for example due to temperature differences or manufacturing tolerances within a number of LED light sources 2' of a multi-LED chip 2.

[0037] 4 shows an exemplary embodiment of the present invention having an R2R network. The microcontroller 3b is connected to a switchable resistor network 7 by the microcontroller 3b to manipulate the voltage feedback of the voltage portion Vfb to the feedback input 3aFB, where the switchable resistor network 7 is connected to the feedback input 3aFB and thus to the voltage feedback of the voltage portion Vfb. The resistor network 7 is configured as an R2R network.

[0038] The resistor network 7 can also consist of several resistors connected in parallel with each other and with the resistor RU, each of which can be assigned an electronic switch, for example a switching transistor, which can activate or deactivate the respective resistor in the resistor network. If a resistor or resistors are deactivated by the respectively assigned switching transistor, a voltage feedback operation of the voltage part Vfb is performed. The switching transistors assigned to the resistors can then be controlled by the microcontroller 3b.

[0039] Alternatively, the microcontroller 3b can be connected to an adjustable resistor for manipulating the voltage feedback of the voltage part Vfb to the feedback input 3aFB, the adjustable resistor being connected to the feedback input 3aFB and thus to the voltage feedback of the voltage part Vfb. Such an adjustable resistor is preferably configured as a transistor connected to the microcontroller 3b, whereby the resistance value of the transistor is adjustable via the microcontroller 3b. The adjustable resistor can then be used instead of the resistor RU.

[0040] Figure 5 shows a detailed view of an R2R network with four switching stages, including an indication of connection to the embodiment of Figure 4. Here, the R2R network has four switching stages S1, S2, S3, S4 connected to a microcontroller 3b for controlling the switching stages S1, S2, S3, S4, respectively, with a resistor network engaged with resistor RU and connected to ground and to a reference voltage URef.

[0041] The technical function of such resistor networks will not be described in detail here, as it is well known to those skilled in the art. The microcontroller 3b selectively sets the connections of the R2R network (Bit0-Bit3 to S1-S4) to +5V or GND via push-pull connections and couples the output voltage to RU.

[0042] By combination of switch positions S1 to S4, a total of 16 different states can be produced, which can be fed back to the step-down converter 3a via the feedback field FB, so that the output voltage Vout can be manipulated in 16 stages by such a resistor network according to FIG.

[0043] The output voltage Vout, or a portion thereof, is fed back to the feedback input 3aFB via a voltage divider 8. The voltage divider 8 is connected to ground, and a resistor network 7 is engaged at a junction point P (see FIG. 4) between resistors RO and RU of the voltage divider 8, and is also connected to ground.

[0044] According to FIG. 1, the lighting device 1 preferably further comprises an application-specific integrated circuit (e.g. ASIC or FPGA) 6, which is connected to the signal output 3bSout of the microcontroller 3b and configured to convert its output signal Sout into control signals Sa, Sb, Sc for controlling the LED light source 2' of the multi-LED chip 2.

[0045] The output voltage Vout can take values ​​between 3V and 5V, in particular between 3.5V and 4.5V, for example.

[0046] Advantageously, the input signal Sin contains information about the current light image 4a, 4b as well as about the light image 4a, 4b to be subsequently emitted, on the basis of which the corresponding target operating voltage Vsoll of the subsequent light image 4a, 4b can be derived in advance by the microcontroller 3b in order to pre-set a target operating voltage Vsoll that is directly adapted to this light image 4a, 4b already at the time of the changeover to the subsequent light image 4a, 4b. This makes it possible to minimize time delays, and in particular possible readjustments that may be necessary in the emission, if, for example, the subsequent light image requires a higher target operating voltage Vsoll and during the transition, or else still in the short term, too little target operating voltage Vsoll of the previous light image would still be applied until the higher target operating voltage is set.

[0047] Furthermore, the microcontroller 3b can be configured to store the target voltage value Vsoll preset by the multi-LED chip 2 for the repeated light images 4a, 4b, and to preset and maintain the saved target voltage value Vsaved (see FIG. 1) corresponding to the preset of the light image 4a, 4b until another light image 4a, 4b is preset or until the multi-LED chip 2 outputs a target voltage value Vsoll for the corresponding light image 4a, 4b that is different from the saved target voltage value Vsaved.

[0048] FIG. 6 shows exemplary output voltages for different switching states of the switching stages S1-S4 of FIG. 5. In period C, the R2R network is activated, all switches S1-S4 are active, so that the voltage values ​​measured at the switching inputs S1-S4 respectively have the voltage value of URef, here for example a value of 5V. In this way the potential of the nodal point P (see FIG. 4) is raised to a maximum. Due to the connection of the feedback to the feedback input 3aFB, the output voltage Vout then has a minimum value and a value of 4.39V. In period D, the switch S1 representing the least significant bit (also called bit 0) is deactivated. Thereby the voltage of the nodal point P (see FIG. 4) rises with as small a voltage jump as possible. In period E, all the remaining switch combinations are made until at the end of period E all switches S1-S4 are turned off. A maximum output voltage in the form of 5.24V is then achieved.

[0049] The invention further comprises a vehicle floodlight comprising at least one lighting device 1 according to the invention. The invention further comprises a vehicle comprising at least one lighting device 1 according to the invention and / or at least one vehicle floodlight according to the invention.

[0050] The invention further relates to a method for energy-efficient operation of a lighting device 1, in particular a lighting device of the above-mentioned type, the lighting device 1 comprising a multi-LED chip 2, the multi-LED chip 2 comprising a number of LED light sources 2′ as well as a number of regulating elements 2″, each LED light source 2′ being assigned one series-connected regulating element 2″ for regulating the current consumption of the respective LED light source 2′ and constituting together with said regulating elements 2″ adjustable sections 2a, 2b, 2c, each LED light source 2′ being configured to be individually switchable, the lighting device 1 further comprising an electrical control unit 3, the electrical control unit 3 comprising a step-down converter (buck converter) 3a with a voltage input 3aVin, a feedback input 3aFB and a voltage output 3aVout, and a microcontroller 3b with a signal input 3bSin and a signal output 3bSout, the step-down converter 3a converting an input DC voltage Vin applied to the voltage input 3aVin into a lower output DC voltage Vout, , and is configured to output the output DC voltage Vout via the voltage output unit 3aVout, the voltage output unit 3aVout being connected to the multi-LED chip 2 in order to supply the sections 2a, 2b, 2c of the multi-LED chip 2, the voltage value of the output DC voltage Vout being determined by a feedback loop, in which a predetermined voltage portion Vfb of the output DC voltage Vout is fed back to the feedback input unit 3aFB, and the output DC voltage Vout is generated depending on the fed back voltage portion Vfb, the microcontroller 3b being configured to receive an input signal Sin via the signal input unit 3bSin and convert it into an output signal Sout, using which light images 4a, 4b to be emitted by the multi-LED chip 2 can be preset, each light image 4a, 4b to be emitted being associated (correlated) with a configuration form (configuration) of the adjustment state of the sections 2a, 2b, 2c, and the signal output unit 3bSout being connected to the multi-LED chip 2 in order to transmit the output signal Sout.

[0051] The method includes the following steps: a) receiving an output signal Sout from the multi-LED chip 2; b) deriving the light image 4a, 4b to be emitted in each case from the output signal Sout and calculating the adjustment state of the sections 2a, 2b, 2c that matches the light image 4a, 4b; c) calculating the minimum operating voltages Vmin2a, Vmin2b, Vmin2c required for each section 2a, 2b, 2c based on the regulation state detected in step b and taking into account the voltage losses of the regulating element 2″; d) detecting a target operating voltage Vsoll by determining the maximum of the minimum operating voltages Vmin2a, Vmin2b, Vmin2c of the sections 2a, 2b, 2c; e) transmitting the target operating voltage Vsoll to the microcontroller 3b; f) A step in which, depending on the transmitted target operating voltage Vsoll, the microcontroller 3b manipulates the voltage feedback of the voltage portion Vfb to the feedback input section 3aFB, so that only the target operating voltage Vsoll is output as the output voltage Vout to the voltage output section 3aVout.

[0052] The present invention is not limited to the embodiments shown, but is defined by the entire scope of protection of the claims. Individual features of the invention or embodiments can also be taken and combined with each other. Reference signs added to the claims are exemplary and do not limit the claims, but are merely intended to make the claims easier to understand.

[0053] The disclosures of the above patent documents and non-patent documents are incorporated herein by reference. Furthermore, within the framework of the entire disclosure of the present invention (including the scope of claims), modifications and adjustments of the embodiments are possible based on the basic technical ideas. Furthermore, within the framework of the entire disclosure of the present invention, various combinations or selections of various disclosed elements (including each element of each claim, each element of each embodiment, each element of each drawing, etc.) are possible. In other words, the present invention naturally includes various modifications and corrections that a person skilled in the art would be able to make according to the entire disclosure including the scope of claims and the technical ideas. In particular, with regard to the numerical ranges described in this specification, any numerical value or subrange included in the range should be interpreted as being specifically described even if not otherwise specified. [Explanation of symbols]

[0054] 1 Lighting device 2 Multi LED Chip 2' LED light source 2” Adjustment element Section 2a Section 2b Section 2c 3. Control Unit 3a Down Step Converter 3aVin Voltage input section 3aFB Feedback input section 3aVout Voltage output section 3b Microcontroller 3bSin Signal input section 3bSout Signal output section 3bDat Data Interface 4a light image 4b light image 6 Circuit 7 Resistor Network 8 Voltage Divider RO resistor RU resistor P Node FB Feedback area S1 Switching stage / switch S2 Switching stage / switch S3 Switching Stage / Switch S4 Switching Stage / Switch Vin Input DC voltage Vout Output DC voltage Vfb voltage part Vsoll Target operating voltage Vsaved The saved target voltage value Sin input signal Sout Output signal Sa control signal Sb Control signal Sc control signal URef Reference voltage Period A B period C period D Period E Period

Claims

1. A lighting device the lighting device (1) comprises a multi-LED chip (2) having a number of LED light sources (2') as well as a number of adjustment elements (2"), each of which is assigned one series-connected adjustment element (2") for adjusting the current consumption of the respective LED light source (2') and which together with said adjustment element (2") constitute adjustable sections (2a, 2b, 2c), each of which is configured to be individually switchable, the lighting device (1) comprises an electrical control unit (3) having a step-down converter (3a) with a voltage input (3aVin), a feedback input (3aFB) and a voltage output (3aVout), as well as a microcontroller (3b) with a signal input (3bSin) and a signal output (3bSout); The step-down converter (3a) is configured to convert an input DC voltage (Vin) applied to the voltage input unit (3aVin) into a lower output DC voltage (Vout) and output the lower output DC voltage (Vout) via the voltage output unit (3aVout), the voltage output unit (3aVout) being connected to the multi-LED chip (2) to power the sections (2a, 2b, 2c) of the multi-LED chip (2), a feedback loop being provided, a predetermined voltage portion (Vfb) of the output DC voltage (Vout) is fed back to the feedback input unit (3aFB) and the output DC voltage (Vout) is generated depending on the fed back voltage portion (Vfb), and the voltage value of the output DC voltage (Vout) is determined using the feedback loop, the microcontroller (3b) is configured to receive an input signal (Sin) via the signal input (3bSin) and convert it into an output signal (Sout), by means of which light images (4a, 4b) to be emitted by the multi-LED chip (2) can be predefined, each of the light images (4a, 4b) to be emitted being associated with a configuration form of an adjustment state of the sections (2a, 2b, 2c), and the signal output (3bSout) is connected to the multi-LED chip (2) to transmit the output signal (Sout); Furthermore, the multi-LED chip (2) derives for each of the light images (4a, 4b) the adjustment states of the sections (2a, 2b, 2c) that match each of the light images (4a, 4b), distinguishes between the sections (2a, 2b, 2c) that should be activated and those that should not be activated, calculates from the adjustment states derived for each of the light images (4a, 4b) a required minimum operating voltage, taking into account the voltage losses of the adjustment element (2'') for each of the sections (2a, 2b, 2c) that should be activated, and by comparing the minimum operating voltages of the sections (2a, 2b, 2c) that should be activated for each of the light images (4a, 4b), and detecting a maximum of the minimum operating voltage, determining it as a target operating voltage (Vsoll) for the corresponding light image (4a, 4b), and transmitting the target operating voltage (Vsoll) to the microcontroller (3b), the microcontroller (3b) being configured to operate a voltage feedback of the voltage portion (Vfb) to the feedback input unit (3aFB) depending on the target operating voltage (Vsoll) transmitted by the multi-LED chip (2) so that only the target operating voltage (Vsoll) is output to the voltage output unit (3aVout) as an output voltage (Vout); the microcontroller (3b) is connected to a switchable resistor network (7) by the microcontroller (3b) for manipulating a voltage feedback of the voltage portion (Vfb) to the feedback input (3aFB), the lighting device (1) comprising the resistor network (7), the switchable resistor network (7) being connected to the feedback input (3aFB) and thus to a voltage feedback of the voltage portion (Vfb), the resistor network (7) being configured as an R2R network; A lighting device characterized by:

2. the R2R network has four switching stages (S1, S2, S3, S4), each of the switching stages (S1, S2, S3, S4) being connected to the microcontroller (3b) for controlling the switching stages (S1, S2, S3, S4); The lighting device according to claim 1 .

3. The output voltage (Vout) is fed back to the feedback input section (3aFB) via a voltage divider (8); The lighting device according to claim 1 .

4. said voltage divider (8) being connected to ground, said resistor network (7) being engaged at a node (P) between the resistors (RO, RU) of said voltage divider (8) and also connected to ground; The lighting device according to claim 3 .

5. the lighting device (1) further includes an application-specific IC (6), the application-specific IC (6) being connected to the signal output unit (3bSout) of the microcontroller (3b) and configured to convert the output signal (Sout) into control signals (Sa, Sb, Sc) for controlling the LED light source (2') of the multi-LED chip (2); The lighting device according to claim 1 .

6. the output voltage (Vout) is between 3V and 5V, or between 3.5V and 4.5V; The lighting device according to claim 1 .

7. the input signal (Sin) contains information about the current light image (4a, 4b) as well as about the light image (4a, 4b) to be subsequently emitted, on the basis of which, by communication with the multi-LED chip (2), the corresponding target operating voltage (Vsoll) of the subsequent light image (4a, 4b) is derived in advance by the microcontroller (3b) in order to pre-set the target operating voltage (Vsoll) adapted to this light image (4a, 4b) already directly at the time of the changeover to the subsequent light image (4a, 4b), The lighting device according to claim 1 .

8. the microcontroller (3b) is configured to store a target voltage value (Vsoll) preset by the multi-LED chip (2) for the repeated light image (4a, 4b) and to preset and maintain the saved target voltage value (Vsaved) corresponding to the preset of the light image (4a, 4b) until another light image (4a, 4b) is preset or until the multi-LED chip (2) outputs a target voltage value (Vsoll) for the corresponding light image (4a, 4b) which is different from the saved target voltage value (Vsaved); The lighting device according to claim 1 .

9. A vehicle floodlight comprising a lighting device according to any one of claims 1 to 8.

10. A vehicle comprising a lighting device according to any one of claims 1 to 8.

11. A vehicle comprising the vehicle floodlight of claim 9.

12. A method for energy-efficient operation of a lighting device, the lighting device (1) comprises a multi-LED chip (2) having a number of LED light sources (2') as well as a number of adjustment elements (2"), each of which is assigned one series-connected adjustment element (2") for adjusting the current consumption of the respective LED light source (2') and which together with said adjustment element (2") constitute adjustable sections (2a, 2b, 2c), each of which is configured to be individually switchable, the lighting device (1) comprises an electrical control unit (3) having a step-down converter (3a) with a voltage input (3aVin), a feedback input (3aFB) and a voltage output (3aVout), as well as a microcontroller (3b) with a signal input (3bSin) and a signal output (3bSout); The step-down converter (3a) is configured to convert an input DC voltage (Vin) applied to the voltage input unit (3aVin) into a lower output DC voltage (Vout) and output the lower output DC voltage (Vout) via the voltage output unit (3aVout), the voltage output unit (3aVout) being connected to the multi-LED chip (2) to power the sections (2a, 2b, 2c) of the multi-LED chip (2), a feedback loop being provided, a predetermined voltage portion (Vfb) of the output DC voltage (Vout) is fed back to the feedback input unit (3aFB) and the output DC voltage (Vout) is generated depending on the fed back voltage portion (Vfb), and the voltage value of the output DC voltage (Vout) is determined using the feedback loop, the microcontroller (3b) is configured to receive an input signal (Sin) via the signal input (3bSin) and convert it into an output signal (Sout), by means of which light images (4a, 4b) to be emitted by the multi-LED chip (2) can be predefined, each of the light images (4a, 4b) to be emitted being associated with a configuration of an adjustment state of the sections (2a, 2b, 2c), and the signal output (3bSout) is connected to the multi-LED chip (2) for transmitting the output signal (Sout); the microcontroller (3b) is connected to a switchable resistor network (7) by the microcontroller (3b) for manipulating a voltage feedback of the voltage portion (Vfb) to the feedback input (3aFB), the lighting device (1) comprising the resistor network (7), the switchable resistor network (7) being connected to the feedback input (3aFB) and thus to a voltage feedback of the voltage portion (Vfb), The resistor network (7) is configured as an R2R network; The method includes the steps of: a) receiving the output signal (Sout) by the multi-LED chip (2); b) deriving the light image (4a, 4b) to be emitted in each case from said output signal (Sout) and calculating the adjustment state of said sections (2a, 2b, 2c) which matches said light image (4a, 4b); c) calculating the minimum operating voltage required for each of said sections (2a, 2b, 2c) based on the regulation state detected in step b and taking into account the voltage losses of said regulating element (2"); d) detecting a target operating voltage (Vsoll) by determining the maximum of the minimum operating voltages of the sections (2a, 2b, 2c); e) communicating said target operating voltage (Vsoll) to said microcontroller (3b); f) depending on the transmitted target operating voltage (Vsoll), the microcontroller (3b) operates a voltage feedback of the voltage portion (Vfb) to the feedback input section (3aFB) so that only the target operating voltage (Vsoll) is output as an output voltage (Vout) at the voltage output section (3aVout); The method comprising:

Images