DE102020114075A1 - Control circuit and method for controlling a plurality of LED arrangements and lighting device connected in parallel to one another for a motor vehicle with such a control circuit - Google Patents

Abstract

The invention relates to an electrical control circuit (4) for controlling a plurality of LED arrangements (2.1, 2.2, 2.3, 2.i) connected in parallel to one another. A supply voltage (UBatt) is applied to the control circuit (4). The LED arrangements (2.1, 2.2, 2.3, 2.i) are connected to control outputs (10a, 10b). The control circuit (4) comprises: - a common controllable current source (12) which provides an individual operating current (I_1; I_2; I_3; I_i) for the LED arrangements (2.1, 2.2, 2.3, 2.i), - several switching elements (S_1, S_2, S_3, S_i), one of which is assigned to one of the LED arrangements (2.1, 2.2, 2.3, 2.i) which are assigned to the respective switching element (S_1, S_2, S_3, S_i) LED arrangement (2.1; 2.2; 2.3; 2.i) switch flowing operating current (I_1; I_2; I_3; I_i), and a control unit (14) for controlling the current source (12) in such a way that it generates the operating current (I_1; I_2; I_3; I_i) for at least one selected LED arrangement (2.1; 2.2; 2.3; 2.i) and for controlling the switching elements (S_1, S_2, S_3, S_i) in such a way that the current source (12) provided operating current (I_1; I_2; I_3; I_i) through which at least one selected LED arrangement (2.1; 2.2; 2.3; 2.i) flows.

Description

The present invention relates to an electrical control circuit for controlling a plurality of LED arrangements connected in parallel to one another. The control circuit has two supply voltage inputs to which a supply voltage is applied, at least two control outputs for connecting the LED arrangements and at least one current source for providing an operating current for the LED arrangements via the control outputs.

The invention also relates to a lighting device for a motor vehicle, comprising a plurality of LED arrangements connected in parallel to one another and a control circuit for controlling the LED arrangements. The lighting device can be designed as a headlight or as any light, in particular as a rear light.

Finally, the invention also relates to a method for controlling a plurality of LED arrangements connected in parallel to one another by means of a control circuit. A supply voltage is applied to two supply voltage inputs of the control circuit, the LED arrangements are connected to at least two control outputs of the control circuit, and an operating current for the LED arrangements is provided by at least one current source of the control circuit.

An electrical control circuit, a lighting device and a control method of the type mentioned are, for example. From DE 10 2008 021 534 A1 known. Similar prior art is also in DE 100 27 478 A1 as well as the DE 103 18 780 A1 known.

The known lighting devices each have a plurality of LED arrangements, each LED arrangement comprising a plurality of LEDs connected in series. The LED arrangements are controlled by a control circuit. A supply voltage, preferably a battery voltage of a motor vehicle, is applied to the control circuit via two supply voltage inputs. The control circuit has its own separate current source for each LED arrangement, which provides an individual, impressed operating current for the respective LED arrangement. Each of the LED arrangements is connected to the control circuit via two control outputs. A first control output for each of the LED arrangements is connected to the associated current source and a second control output is connected to ground. The control circuit thus has at least one separate control output of its own for each of the LED arrangements.

The control circuits known from the prior art and the lighting devices equipped with them are relatively complex, large-scale and expensive due to the large number of current sources and control outputs. The present invention is based on the object of making control circuits and lighting devices for motor vehicles equipped therewith simpler, smaller and more cost-effective.

• - eine gemeinsame ansteuerbare Stromquelle, die ausgebildet ist, einen individuellen Betriebsstrom für zumindest einige der durch die Steuerschaltung gesteuerten LED-Anordnungen bereitzustellen,
• - mehrere Schaltelemente, wobei jeweils ein Schaltelement einer der LED-Anordnungen zugeordnet ist, für welche die Stromquelle den Betriebsstrom bereitstellt, und die Schaltelemente ausgebildet sind, den in der dem jeweiligen Schaltelement zugeordneten LED-Anordnung fließenden Betriebsstrom zu schalten, und
• - eine Steuereinheit zur Steuerung der Stromquelle derart, dass diese den Betriebsstrom für mindestens eine ausgewählte LED-Anordnung bereitstellt, und zur Steuerung der Schaltelemente derart, dass der von der Stromquelle bereitgestellte Betriebsstrom durch die mindestens eine ausgewählte LED-Anordnung fließt.

To solve this problem, a control circuit having the features of claim 1 is proposed. In particular, on the basis of the control circuit of the type mentioned at the outset, it is proposed that the control circuit comprise:

• a common controllable current source which is designed to provide an individual operating current for at least some of the LED arrangements controlled by the control circuit,
• Several switching elements, one switching element being assigned to one of the LED arrangements for which the current source provides the operating current, and the switching elements are designed to switch the operating current flowing in the LED arrangement assigned to the respective switching element, and
• a control unit for controlling the current source in such a way that it provides the operating current for at least one selected LED arrangement, and for controlling the switching elements in such a way that the operating current provided by the current source flows through the at least one selected LED arrangement.

The control circuit is preferably designed to control the LED arrangements of a lighting device in successive clock phases of a repetitive control cycle. At least one other LED arrangement is activated in each clock phase. At the end of a control cycle, all LED arrangements have preferably been activated at least once, wherein the activation of an LED arrangement can also include operation of the LED arrangement with an operating current of 0 A. Thus, by controlling the LED arrangements, the intensity (or brightness) of the LED Arrangements of emitted light are set and the LED arrangements can be switched on or off. The successive control cycles are preferably run through at a frequency that does not allow the human eye to differentiate between switched on LED arrangement (higher intensity) in a first control cycle and switched off or dimmed LED arrangement (lower intensity) in a subsequent control cycle. Rather, the duration of a control cycle is selected to be so short that the human eye or the brain averages the various brightness values in successive control cycles to form an average. The frequency of the control cycles is thus preferably above 75 Hz, ie a control cycle lasts less than 13 ms. This leaves, for example, four parallel LED arrangements to be controlled independently of one another, a duration for a clock phase of approximately 3.3 ms. These are only exemplary values that can be deviated from in practice.

The control of one or more LED arrangements of the lighting device preferably comprises, on the one hand, providing the operating current required for the operation or a desired intensity of the emitted light of the currently activated LED arrangements) via the common power source and, on the other hand, the flow of current in the LED To control arrangements via the switching elements in such a way that the operating current provided by the current source flows through the LED arrangement (s) currently activated in the respective clock phase. In a clock phase, an LED arrangement or several LED arrangements can be controlled and operated with the operating current provided by the current source. The invention has the advantage that the control circuit only has a common current source for providing an individual operating current for several LED arrangements of the lighting device that are to be controlled. As a result, the control circuit and the lighting device provided with it can be implemented in a simpler and more cost-effective manner. In addition, the use of only one common power source can result in an increase in the efficiency of the control circuit.

Each of the activated LED arrangements can emit light which is used to generate a specific light or lighting function of the lighting device or a part thereof. For example, it would be conceivable that one or more of the LED arrangements are designed to generate a low beam, a high beam, a daytime running light, a position light and / or a flashing light. One or more LED arrangements can also be designed to generate several light or lighting functions, which can be implemented by controlling the LED arrangement (s) with different operating currents. In the event that only one of the light or lighting functions (e.g. daytime running lights) is active for a certain period of time, the control method according to the invention with the repetitive control cycles and the sequential clock phase of a control cycle can also be temporarily suspended. In this case, the at least one LED arrangement that generates the long-term light or lighting function can then be operated with the corresponding operating current for the desired period of time (for example over several control cycles). A resumption of the control cycles with the clock phases is only necessary again when an additional light or lighting function is added.

The control circuit can control several LED arrangements of the lighting device according to the method according to the invention and operate one or more other LED arrangements of the lighting device in a different way, for example according to a method known from the prior art with a separate power source for each of the other operating LEDs Arrangements. According to an advantageous development of the invention, however, it is proposed that the one common current source of the control circuit is designed to supply all of the LED arrangements of the lighting device controlled by the control circuit with the individual operating current. In this sense, it is also proposed that a switching element be arranged in each of the LED arrangements of the lighting device that are supplied with the individual operating current by the current source.

According to a preferred embodiment of the invention, it is proposed that the control circuit have two common control outputs for all of the LED arrangements supplied with the individual operating current from the current source. One of the control outputs is preferably grounded and the operating current provided by the common current source is preferably applied to the other control output.

It is advantageously provided that the control unit is designed to control the current source and the switching elements in a synchronized manner. As soon as the common current source is set in a clock phase to provide a desired operating current, the switching elements are controlled in the same clock phase so that the provided operating current flows through the LED arrangement (s) to be controlled in this clock phase.

It is proposed that the clock phases of a control cycle are executed sequentially. In this sense, the control unit is designed to sequentially control the current source and the switching elements assigned to the LED assemblies for each of the LED assemblies to which a switching element is assigned. The control unit is preferably designed, in one of several repetitive control cycles, in each case by sequentially controlling the current source and the switching elements for each of the LED arrangements to which a switching element is assigned, the operating current in the respective currently controlled LED arrangement (s). set individually.

Furthermore, it is proposed that the control unit for controlling the current source specifies a current setpoint value which is dependent on the operating current for the currently controlled LED arrangement (s). The current source then either supplies the current setpoint as the operating current or the current source has a control function in order to regulate the supplied operating current to the current setpoint as part of a regulation. For this purpose it can be advantageous if the currently supplied operating current is recorded, for example by means of a current sensor. This can be arranged in the control circuit at the control output at which the operating current supplied by the common current source is applied.

Each of the LED arrangements preferably comprises at least one LED or a laser diode. The LED arrangements can also include any other semiconductor light sources. The LEDs can, for example, be white LEDs that emit white light. It would also be conceivable that the LEDs are red, yellow and / or blue LEDs, which together form RGB LEDs. In this case, LEDs of one color are preferably arranged in each case in an LED arrangement. In the event that at least one of the LED arrangements comprises several LEDs or laser diodes, these are preferably connected in series. The individual LED arrangements can differ from one another in terms of the number and / or the type or type (e.g. RGB LEDs, conventional white LEDs or high-power LEDs) of the LEDs or laser diodes. This can result in different operating currents that are required for proper operation of the LED arrangements. It is also conceivable that different types or types of LEDs or laser diodes are arranged within an LED arrangement. Furthermore, it is not ruled out that a plurality of LEDs or laser diodes are also connected in parallel to one another within an LED arrangement.

The switching elements assigned to the LED arrangements are preferably each connected in series with the at least one LED or laser diode of the corresponding LED arrangement. In this way, the flow of current through the LED arrangements can be controlled, in particular interrupted or switched through, by the switching elements.

According to an advantageous embodiment of the invention, it is proposed that a parallel connection of an output capacitor and a further switching element be connected in parallel with the LED arrangements of the lighting device, the control unit being designed to also control the further switching element assigned to the output capacitor. The output capacitor or the entire parallel circuit can be part of the control circuit or be arranged outside the control circuit. The output capacitor can be used - if necessary - to reduce the operating current more quickly between one clock phase and the next. For this purpose, the output capacitor can be discharged to the current value of the following (smaller) operating current amplitude if required. To discharge the output capacitor, the further switching element is closed so that the capacitor can (partially) discharge via ground.

The control unit is particularly preferably designed to control (or close) the further switching element assigned to the output capacitor following the control of a switching element which is assigned to one of the LED arrangements. The further control element is therefore preferably activated at the end of each clock phase of a control cycle.

The object on which the present invention is based is also achieved by a lighting device for a motor vehicle having the features of claim 14. In particular, it is proposed that the lighting device, in addition to the LED arrangements connected in parallel to one another, have a control circuit according to the invention for controlling the LED arrangements. The lighting device is preferably designed as a motor vehicle headlight or as any motor vehicle light, in particular as a rear light, which realizes various lighting functions (e.g. rear light, brake light, rear fog light, reversing light, flashing light). At least one of the LED arrangements can be assigned to each of these lighting functions. All these lighting functions can be implemented in the lighting device according to the invention by a common power source.

• - die Stromquelle eine gemeinsame ansteuerbare Stromquelle ist, durch die ein individueller Betriebsstrom für zumindest einige der durch die Steuerschaltung gesteuerten LED-Anordnungen bereitgestellt wird, wobei die Stromquelle durch eine Steuereinheit der Steuerschaltung gesteuert wird, um den individuellen Betriebsstrom jeweils für mindestens eine ausgewählte LED-Anordnung bereitzustellen, und
• - jeweils ein Schaltelement einer der LED-Anordnungen zugeordnet ist, für welche die Stromquelle den Betriebsstrom bereitstellt, und die Schaltelemente durch die Steuereinheit gesteuert werden, damit der von der Stromquelle bereitgestellte Betriebsstrom durch die mindestens eine ausgewählte LED-Anordnung fließt.

Furthermore, the object on which the present invention is based is achieved by a control method having the features of claim 15. In particular, based on the control method of the type mentioned above, it is proposed that

• - The current source is a common controllable current source by means of which an individual operating current is provided for at least some of the LED arrangements controlled by the control circuit, the current source being controlled by a control unit of the control circuit in order to generate the individual operating current for at least one selected LED. Provide arrangement, and
• - In each case a switching element is assigned to one of the LED arrangements for which the current source provides the operating current, and the switching elements are controlled by the control unit so that the operating current provided by the current source flows through the at least one selected LED arrangement.

• 1 eine erfindungsgemäße Steuerschaltung in einer bevorzugten Ausführungsform;
• 2 eine Steuerung von LED-Anordnungen gemäß einem erfindungsgemäßen Verfahren in einer bevorzugten Ausführungsform;
• 3 eine Steuerung von LED-Anordnungen gemäß einem erfindungsgemäßen Verfahren in einer alternativen Ausführungsform;
• 4 eine erfindungsgemäße Beleuchtungseinrichtung in einer bevorzugten Ausführungsform.

Further features and advantages of the present invention are explained in more detail below with reference to the figures. Individual features shown in the figures and described below can also be essential to the invention on their own, even if this is not expressly mentioned. In addition, the individual features shown in the figures and described below can be combined with one another in any way, even if this is not shown or is expressly mentioned. Show it:

• 1 a control circuit according to the invention in a preferred embodiment;
• 2 a control of LED arrangements according to a method according to the invention in a preferred embodiment;
• 3 a control of LED arrangements according to a method according to the invention in an alternative embodiment;
• 4th a lighting device according to the invention in a preferred embodiment.

In 4th is a lighting device according to the invention for motor vehicles in the form of a headlight, in particular for cars or trucks, in its entirety with the reference number 101 designated. Corresponding headlights can, however, also be used in trains, trams, boats, ships or airplanes. Of course, the lighting device 101 also be designed as a motor vehicle light, in particular as a rear light. The following statements relating to headlights therefore apply equally to motor vehicle lights.

The headlight 101 includes a housing 102 , which is preferably made of plastic. In one light exit direction 103 has the headlight housing 102 a light exit opening through a transparent cover plate 104 is locked. The cover panel 104 is made of colorless plastic or glass. The disc 104 can be designed as a so-called clear pane without optically effective profiles. Alternatively, the disc 104 be provided at least in some areas with optically effective profiles (for example cylinder lenses or prisms) which cause the light passing through to be scattered, preferably in the horizontal direction. The headlight 101 is intended for installation on an attachment side of a motor vehicle. Two of the headlights shown 101 , which are arranged on different attachment sides of the motor vehicle, form a motor vehicle lighting device according to the invention. This includes the headlights installed on different attachment sides 101 preferably mirror-symmetrical to one another with regard to their general geometrical external appearance.

Inside the headlight housing 102 are two light modules in the example shown 105 , 106 arranged. The light modules 105 , 106 are fixed or relative to the housing 102 movably arranged. Through a relative movement of the light modules 105 , 106 to the housing 102 A dynamic cornering light function can be implemented in the horizontal direction. When the light modules move 105 , 106 Headlight range control can be implemented around a horizontal axis, i.e. in the vertical direction. Of course, in the headlight housing 102 also more or less than the two light modules shown 105 , 106 be provided. One or more of the light modules 105 , 106 of the headlight 101 can have a lighting means according to the invention as a light source, which is explained in detail below.

The light module 105 can be designed to generate different light distributions, e.g. a low beam, a high beam and a partial high beam or parts thereof (e.g. a low beam base light, a low beam spot, a high beam base light, a high beam spot, etc.). It is conceivable that the light distributions of the light modules 105 , 106 to the resulting light distribution of the headlight 101 add to. It is also conceivable that the light distributions of the light modules differ from one another Attachment sides of the motor vehicle arranged headlights 101 to the resulting light distribution of the lighting arrangement comprising both headlights 101 add to.

On the outside of the headlight housing 102 is a control device 107 in a control unit housing 108 arranged. Of course, the control unit can 107 also at any other point on the headlight 101 be arranged. In particular, for each of the light modules 105 , 106 a separate control device can be provided, the control devices being an integral part of the light modules 105 , 106 could be. Of course, the control unit can 107 also away from the headlight 101 , for example. Be arranged in the engine compartment of the motor vehicle. The control unit 107 serves to control and / or regulate the light modules 105 , 106 or of subcomponents of the light modules 105 , 106 , such as the light sources of the light modules 105 , 106 . The control of the light modules 105 , 106 or the subcomponents by the control unit 107 takes place via connecting lines 110 , in the 4th are shown only symbolically by a dashed line. Over the lines 110 can also supply the light modules 105 , 106 done with electrical energy. The lines 110 are from inside the headlight 101 through an opening in the headlight housing 102 in the control unit housing 108 and there to the circuit of the control unit 107 connected. If control units are an integral part of the light modules 105 , 106 are provided, the lines 110 and can be the opening in the headlight housing 102 omitted. The control unit 107 comprises a plug element 109 for connecting a connection cable to a higher-level control unit (eg in the form of a so-called body controller unit) and / or an energy source (eg in the form of the vehicle battery).

The light modules 105 , 106 the lighting device 101 can have several LED arrangements arranged parallel to one another, as exemplified in FIG 1 are shown and with the reference numerals 2.1 , 2.2 , 2.3 , 2.i (together reference numerals 2 ) are designated. The light modules are used to generate one or more light functions, such as, for example, low beam, high beam, fog light, etc. Of course, the LED arrangements 2 also part of one or more inside the housing 102 be arranged light modules, which are used to generate one or more light functions, such as daytime running lights, position lights, flashing lights, etc. Finally, it would also be conceivable that some of the LED arrangements 2.1 , 2.2 , 2.3 , 2.i Part of a light module 105 , 106 and another part of the LED arrays 2.1 , 2.2 , 2.3 , 2.i Part of a light module of the lighting device 101 is that also in the housing 102 be arranged and can be used to generate any lighting function. The LED arrangements 2 are preferably controlled by a common electrical control circuit 4th can be controlled.

Any of the LED arrangements 2 comprises one or more semiconductor light sources 6th , e.g. LEDs or laser diodes. When multiple semiconductor light sources 6th in an LED array 2 are provided, they are preferably connected in series. In the LED arrangements 2 can each have the same number of semiconductor light sources 6th be provided. But it is also conceivable that the LED arrangements 2 a different number of semiconductor light sources 6th exhibit. The semiconductor light sources 6th can be of the same type or of the same type (e.g. LEDs, OLEDs, conventional laser diodes, VCSELs, normal white LEDs, high-power LEDs, RGB LEDs, etc.) or of different types. In addition, at least some of the semiconductor light sources 6th in an LED array 2 also be connected in parallel. Furthermore, in the LED arrangements 2 further electrical components can also be arranged, preferably in series with the semiconductor light sources 6th switched.

The electrical control circuit 4th has two supply voltage inputs 8a , 8b to which a supply voltage, for example a battery voltage U _{Batt of} a vehicle battery or a voltage made available by a superordinate control unit (for example in the form of a so-called body controller unit), is applied. The control circuit 4th is preferably in the control unit 107 the lighting device 101 arranged. Furthermore, the control circuit comprises 4th at least two control outputs, in this case exactly two control outputs 10a , 10b , for connecting the LED arrangements 2 . It is at one of the control outputs 10a preferably an operating voltage for the LED arrangements 2 on and the other control output 10b lies on earth.

Furthermore, the control circuit 4th a common electrically controllable power source 12th to provide an operating current I_1, I_2, I_3, I_i (together I) for the LED arrangements 2.1 , 2.2 , 2.3 , 2.i via the control outputs 10a , 10b on. In particular, the power source 12th be caused by control, an individual operating current I_1, I_2, I_3, I_i for at least some of the by the control circuit 4th controlled LED arrangements 2.1 , 2.2 , 2.3 , 2.i provide. The power source 12th can be a known bridge circuit (for example in the form of an H-bridge) and / or a known DC voltage converter (for example in the form of a single-ended primary inductor converter; SEPIC) and / or a have up converter known per se (so-called boost or step-up converter) and / or a step-down converter known per se (so-called buck or step-down converter).

In the branches of the LED arrays 2 for which the power source 12th provides the operating current I_1, I_2, I_3, I_i is each a switching element S_1 , S_2 , S_3 , S_i (together S) arranged or the corresponding LED arrangements 2.1 , 2.2 , 2.3 , 2.i assigned. By actuating or controlling the switching elements S_1 , S_2 , S_3 , S_i can be in the respective branch or through the respective LED arrangement 2.1 , 2.2 , 2.3 , 2.i flowing operating current I_1, I_2, I_3, I_i can be switched. In particular, the current flow can be interrupted or switched through by the switching elements S. The switching elements S are preferably designed as electrically controllable semiconductor switches, for example as transistors. Advantageously, the switching elements S used are MOSFETs with a particularly low resistance R _DSon between the drain and source in the switched-through state. The MOSFETs used preferably also have a minimal parasitic capacitance. Alternatively, the switching elements S can also be designed as bipolar transistors or as other types of controllable switches.

Finally, the control circuit comprises 4th a control unit 14th to control the power source 12th via a control signal CTRL_Current and to control the switching elements S via one or more control signals CTRL_Switches. The control unit 14th can comprise a processing unit with a processor, in particular a microcontroller. A computer program (so-called control program) can run on this, which is programmed to carry out the control method according to the invention, and which enables the control method to be carried out by the control circuit 4th caused when it runs on the processor or microcontroller. The power source 12th and the control unit 14th can be integrated in a common ASIC. The control unit 14th can have a DAC (Digital Analog Converter) that sends a current setpoint value to the H-bridge of the current source 12th gives. Due to the time-critical application, this is preferably done via DMA functionality (Direct Memory Access) of the control unit 14th .

The control of the power source 12th takes place in such a way that this has a suitable operating current I_1; I_2; I_3 or I_i for at least one selected LED arrangement 2.1 ; 2.2 ; 2.3 ; 2.i provides. The switching elements S are controlled in such a way that the current source 12th provided operating current I_1; I_2; I_3 or I_i through the at least one selected LED arrangement 2.1 ; 2.2 ; 2.3 ; 2.i flows. The switching elements S are preferably controlled synchronously with the control of the current source 12th , possibly with a slight time delay to the control of the power source 12th to the power source 12th to give a short time to provide the appropriate operating current I.

The control of the power source 12th preferably includes the specification of a current setpoint. The power source 12th can then provide an operating current I corresponding to the specified setpoint in a controlled manner. Alternatively, the power source 12th regulate the operating current I to the specified setpoint as part of a current control. For this purpose it may be necessary to measure the current operating current I (actual current value), for example by means of a current sensor 22nd to eat. This can be done in the control circuit 4th at the control output 10a (so-called. High-side path) to which the operating voltage is applied.

For example the LED arrangement 2.1 to operate in the first branch with the appropriate operating current I_1, the current source 12th controlled in such a way that it provides the appropriate operating current I_1. The switching elements S_2 , S_3 and S_i who have favourited the LED arrangements 2.2 , 2.3 and 2.i are assigned, are controlled in such a way that they are open and interrupt the flow of current through the corresponding branches. The switching element S_1 that of the LED array 2.1 is assigned, is controlled in such a way that it closes and enables the flow of current through the corresponding branch. The operating current I_1 thus flows through the first branch and the LED arrangement 2.1 . In a corresponding manner, by suitably controlling the current source 12th and the switch S the remaining LED arrangements 2.2 , 2.3 , 2.i operated with the appropriate operating current I_2, I_3, I_i.

The different LED arrangements 2 can be used to generate one or more light functions or lighting functions of the lighting device 101 or part of a light or luminous function. By operating one or more of the LED arrays 2 can thus be used by the lighting device 101 generated resulting light or luminous function can be switched on or off. Possible light or lighting functions of the headlight 101 by one or more of the LED arrays 2 can be generated are, for example, low beam, high beam, daytime running light, position light or flashing light. In the case of a rear light, the light or lighting functions can include, for example, rear light, brake light, rear fog light, reversing light or flashing light.

The control of the power source 12th and the switch S takes place preferably in a plurality of clock phases T_1, T_2 that follow one another in time. T_3, T_i (together T) of a control cycle, as exemplified in 2 is shown. The clock phases T of a control cycle are preferably of the same length; but they can also be of different lengths. During the clock phases T of a control cycle, all LED arrangements are preferably 2 sequentially controlled. But it would also be conceivable that only some of the LED arrangements in one control cycle 2 the lighting device 101 can be controlled.

In the context of the control method according to the invention for the LED arrangements 2 are preferably run through several repetitive control cycles in succession. The successive control cycles are preferably run through at a frequency that does not allow the human eye to pass between the switched-on LED arrangement 2 (or higher intensity) in a first control cycle and switched off or dimmed LED arrangement 2 (or lower intensity) to be differentiated in a subsequent control cycle. The duration of a control cycle is preferably selected to be so short that the human eye or the brain averages the various brightness values in successive control cycles to form an average. The frequency of the control cycles is thus preferably above 75 Hz, ie a control cycle lasts less than 13 ms. This leaves, for example, four parallel LED arrangements to be controlled independently of one another 2 a duration for a clock phase T of about 3.3 ms or less. In the example shown, a control cycle lasts 5 ms, so that with four LED arrangements to be controlled 2 a clock phase T lasts 1.25 ms. Thus, the individual LED arrangements 2 driven at a frequency of 200 Hz. This is also the frequency with which the control cycles are repeated.

In the 2 Light or lighting functions shown, which are used by the various LED arrangements 2 Generated include low beam (LB), high beam (HB), daytime running light (DRL), position light (POS), and turn indicator (TI). Deviating from the example of 2 it would also be conceivable that in a clock phase T several LED arrangements 2 can be controlled or operated at the same time, provided they are operated with an operating current I of the same size. In this way, for example, an LED arrangement 2 for generating a low beam that illuminates a close-up area (below a light-dark border) in the resulting light distribution, at the same time as another LED arrangement 2 to illuminate a long-range area (above the light-dark border) of the resulting light distribution in order to generate a high beam that complies with the rules as a whole. For this it is sufficient to adapt the control method or the control program accordingly. It is also different from the example of 2 conceivable that the LED arrangements 2 operated in a different order than shown.

The amplitudes of the operating current I_1, I_2, I_3, I_i in the various clock phases T preferably differ from one another, depending on the number and type of semiconductor light sources 6th in the LED arrays 2 and depending on the light or lighting function to be generated. With the sequential operation of the LED arrangements 2 within one control cycle it can happen that the from the power source 12th provided operating current I from a clock phase T to the subsequent clock phase T within a short time, preferably immediately, of a higher current value for a first LED arrangement 2 to a lower current value for a different LED arrangement 2 must fall.

The following table shows an example of how the power source is controlled 12th and the switching elements S are reproduced in one control cycle. Of course, the control can also be designed differently. Light function Clock phase Bar duration Current amplitude Current value LB T_1 1.25 ms I_1 800 mA HB T_2 1.25 ms I_2 850 mA DRL / POS T_3 1.25 ms I_3 680 mA TI T_i 1.25 ms I_i 750 mA

Between the control output 10a , at which the operating voltage for the LED arrangements 2 is applied, and ground can be an output capacitor 16 be switched. Furthermore, a further electrically controllable switching element can be used in parallel 18th between the control output 10a and be connected to ground. In the branch of the further switching element 18th can be a resistance 20th be arranged. If the further switching element 18th is closed, a current I_CLR can flow through this branch. This can lead to the faster Discharge of the output capacitor 18th to serve. This also allows for the operation of the LED arrangements 2 harmful current peaks that can be caused by recharging are reduced.

The control method or the control program can also be adapted in such a way that the output capacitor is discharged 18th after or at the end of a clock phase T_i only takes place up to the end value of a smaller current amplitude of the subsequent clock phase T_i + 1. A discharge of the output capacitor can also occur 18th can be completely dispensed with if the current amplitude of the subsequent clock phase T_i + 1 is greater than the current amplitude of the current clock phase T_i.

The further switching element 18th is preferably activated after or at the end of a clock phase T, ie closed. This is exemplified in 3 shown. The activation duration of the further switching element 18th is preferably shorter than the preceding clock phase T. In the example shown, the activation of the further switching element takes time 18th 0.5 ms, so that there is a period of 7 ms and a frequency for controlling the individual LED arrangements 2 of about 143 Hz. Of course, other control durations or time durations of the clock phases T are also conceivable.

The present invention makes it possible to generate independent variable current amplitudes I in successive clock phases T and, by controlling the switching elements S, the corresponding LED arrangements 2 thus to operate variably and independently of each other. This can reduce the number of power sources 12th in the control circuit 4th be limited to a single one. Thus, with the control circuit 4th multiple independent branches with LED arrays 2 be supplied with variable operating current and operating voltage. The invention provides a solution that requires fewer components and can thus be implemented more cheaply. In addition, the control circuit 4th lead to an increase in efficiency as it is in the circuit 4th due to the only one common power source 12th there are fewer losses.

It is also conceivable to adapt the control method or the control program in such a way that the clock phases T are suspended as long as only one light function (eg daytime running lights) is active, ie as long as only one or more LED arrangements 2 can be operated with the appropriate operating current I to generate this light function. In this case, a control cycle would only include the one clock phase T for generating the one light function.

It is also conceivable to adapt the control method or the control program in such a way that the brightness of the LED arrangement currently being controlled is dimmed within one or more clock phases T 2 emitted light, for example by means of a pulse width modulation (PWM) of the operating current I takes place.

This can cause the from the power source 12th provided operating current I in selected clock phases T can be reduced again.

In the lighting facility 101 , preferably in the vicinity of the semiconductor light sources 6th of the LED arrangements 2 , a temperature sensor for detecting an operating temperature of the semiconductor light sources 6th be provided. Preferably each of the LED arrays 2 at least one temperature sensor assigned. If the detected temperature exceeds a predeterminable limit value, the operating current I can be reduced within one or more clock phases T in order to reduce the power consumption. This can either be done by appropriately controlling the power source 12th or by the described PWM.

• - den elektrischen Eigenschaften der Halbleiterlichtquellen 6 der LED-Anordnung 2,
• - der Anzahl der Halbleiterlichtquellen 6 in der LED-Anordnung 2,
• - der Schaltung (seriell und/oder parallel) der Halbleiterlichtquellen 6 der LED-Anordnung 2, und/oder
• - den Helligkeitsanforderungen an das von der LED-Anordnung 2 ausgesandte Licht, und/oder
• - von der Takt-Phase T.

The maximum current amplitude in a specific clock phase T for the currently controlled LED arrangement 2 should be selected depending on one or more of the following criteria:

• - the electrical properties of the semiconductor light sources 6th the LED arrangement 2 ,
• - the number of semiconductor light sources 6th in the LED arrangement 2 ,
• - the circuit (serial and / or parallel) of the semiconductor light sources 6th the LED arrangement 2 , and or
• - the brightness requirements for the LED arrangement 2 emitted light, and / or
• - from the clock phase T.

In the following table, some possible light profiles are shown by way of example, which control the power source accordingly 12th and the switching elements S can be realized. Of course, other combinations are also possible. Light profile / cycle T_1 T_2 T_3 T_i Day DRL Day and flashing DRL TI Day and headlight flasher DRL HB Day and flashing and flasher DRL TI HB night LB POS Night and flashing LB POS TI Night and flasher LB POS HB Night and flashing and flasher LB POS TI HB

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102008021534 A1 [0004]
• DE 10027478 A1 [0004]
• DE 10318780 A1 [0004]

Claims (15)

Electrical control circuit (4) for controlling several LED arrangements (2.1, 2.2, 2.3, 2.i) connected in parallel to one another, the control circuit (4) having two supply voltage inputs (8a, 8b) to which a supply voltage (U _Batt ) is applied, at least two control outputs (10a, 10b) for connecting the LED arrangements (2.1, 2.2, 2.3, 2.i) and at least one current source (12) for providing an operating current (I_1, I_2, I_3, I_i) for the LED arrangements (2.1, 2.2, 2.3, 2.i) via the control outputs (10a, 10b), characterized in that the control circuit (4) comprises: - a common controllable current source (12) which is designed to generate an individual operating current (I_1 ; I_2; I_3; I_i) for at least some of the LED arrangements (2.1, 2.2, 2.3, 2.i) controlled by the control circuit (4), several switching elements (S_1, S_2, S_3, S_i), each with one Switching element (S_1; S_2; S_3; S_i) assigned to one of the LED arrangements (2.1, 2.2, 2.3, 2.i) t for which the current source (12) supplies the operating current (I_1; I_2; I_3; I_i) provides, and the switching elements (S_1, S_2, S_3, S_i) are formed which flow in the LED arrangement (2.1; 2.2; 2.3; 2.i) assigned to the respective switching element (S_1, S_2, S_3, S_i) Operating current (I_1; I_2; I_3; I_i) to switch, and - a control unit (14) for controlling the current source (12) in such a way that it generates the operating current (I_1; I_2; I_3; I_i) for at least one selected LED arrangement ( 2.1; 2.2; 2.3; 2.i) and to control the switching elements (S_1, S_2, S_3, S_i) in such a way that the operating current (I_1; I_2; I_3; I_i) provided by the current source (12) through the at least a selected LED arrangement (2.1; 2.2; 2.3; 2.i) flows. Control circuit (4) after Claim 1 , characterized in that the current source (12) is designed to supply all of the LED arrangements (2.1, 2.2, 2.3, 2.i) controlled by the control circuit (4) with the individual operating current (I_1; I_2; I_3; I_i) . Control circuit (4) after Claim 1 or 2 , characterized in that in each of the LED arrangements (2.1, 2.2, 2.3, 2.i) supplied with the individual operating current (I_1; I_2; I_3; I_i) a switching element (S_1; S_2; S_3 ; S_i) is arranged. Control circuit (4) according to one of the preceding claims, characterized in that the control circuit (4) has two common control outputs (10a, 10b) for all LEDs supplied with the individual operating current (I_1; I_2; I_3; I_i) from the current source (12) Arrangements (2.1, 2.2, 2.3, 2.i). Control circuit (4) according to one of the preceding claims, characterized in that the control unit (14) is designed to control the current source (12) and the switching elements (S_1, S_2, S_3, S_i) in a synchronized manner. Control circuit (4) according to one of the preceding claims, characterized in that the control unit (14) is designed, the power source (12) and the switching elements (S_1, S_2) assigned to the LED arrangements (2.1, 2.2, 2.3, 2.i) , S_3, S_i) for each of the LED arrangements (2.1, 2.2, 2.3, 2.i) to which a switching element (S_1; S_2; S_3; S_i) is assigned to be controlled sequentially. Control circuit (4) after Claim 6 , characterized in that the control unit (14) is designed, in one of several repetitive control cycles, in each case by sequentially controlling the current source (12) and the switching elements (S_1, S_2, S_3, S_i) for each of the LED arrangements (2.1, 2.2, 2.3, 2.i), to which a switching element (S_1; S_2; S_3; S_i) is assigned, the operating current (I_1; I_2; I_3; I_i) in the respective LED arrangement (2.1; 2.2; 2.3; 2. i) set individually. Control circuit (4) according to one of the preceding claims, characterized in that the control unit (14) for controlling the current source (12) specifies a current setpoint (CTRL_Current) which is dependent on the operating current (I_1; I_2; I_3; I_i) for the currently controlled LED arrangement (2.1; 2.2; 2.3; 2.i). Control circuit (4) according to one of the preceding claims, characterized in that each of the LED arrangements (2.1, 2.2, 2.3, 2.i) comprises at least one semiconductor light source (6), in particular an LED or a laser diode. Control circuit (4) according to one of the preceding claims, characterized in that each of the LED arrangements (2.1, 2.2, 2.3, 2.i) comprises several semiconductor light sources (6), in particular LEDs or laser diodes, which are connected in series. Control circuit (4) according to one of the preceding claims, characterized in that the switching elements (S_1, S_2, S_3, S_i) assigned to the LED arrangements (2.1, 2.2, 2.3, 2.i) are each in series with the at least one semiconductor light source ( 6) one of the LED arrangements (2.1, 2.2, 2.3, 2.i) are connected. Control circuit (4) according to one of the preceding claims, characterized in that a parallel connection of an output capacitor (16) and a further switching element (18) is connected in parallel with the LED arrangements (2.1, 2.2, 2.3, 2.i), the Control unit (14) is designed to also control the further switching element (18) assigned to the output capacitor (16). Control circuit (4) after Claim 12 , characterized in that the control unit (14) is designed to control the further switching element (18) assigned to the output capacitor (16) following the control of a switching element (S_1; S_2; S_3; S_i), which is one of the LED arrangements (2.1, 2.2, 2.3, 2.i) is assigned. Lighting device (101) for a motor vehicle, comprising several LED arrangements (2.1, 2.2, 2.3, 2.i) connected in parallel to one another and a control circuit (4) for controlling the LED arrangements (2.1, 2.2, 2.3, 2.i) according to one of the preceding claims. Method for controlling several LED arrangements (2.1, 2.2, 2.3, 2.i) connected in parallel by means of a control circuit (4), a supply voltage (U _Batt ) being applied to two supply voltage inputs (8a, 8b) of the control circuit (4) , the LED arrangements (2.1, 2.2, 2.3, 2.i) are connected to at least two control outputs (10a, 10b) of the control circuit (4), and an operating current (I_1, I_2, I_3, I_i) for the LED arrangements (2.1, 2.2, 2.3, 2.i) is provided by at least one current source (12) of the control circuit (4), characterized in that - the current source (12) is a common controllable current source through which an individual operating current (I_1; I_2; I_3; I_i) is provided for at least some of the LED arrangements (2.1, 2.2, 2.3, 2.i) controlled by the control circuit (4), the current source (12) being provided by a control unit (14) of the control circuit (4 ) is controlled to increase the individual operating current (I_1; I_2; I_ 3; I_i) each for at least one selected LED arrangement (2.1; 2.2; 2.3; 2.i) to be provided, and - in each case a switching element (S_1; S_2; S_3; S_i) of one of the LED arrangements (2.1, 2.2, 2.3, 2 .i) is assigned, for which the current source (12) provides the operating current (I_1; I_2; I_3; I_i) and the switching elements (S_1, S_2, S_3, S_i) are controlled by the control unit (14) so that the the current source (12) provided individual operating current (I_1; I_2; I_3; I_i) through which at least one selected LED arrangement (2.1; 2.2; 2.3; 2.i) flows.

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