DE102010060857A1 - Control and / or regulating means for a light-emitting diode array, circuit arrangement with such a control and / or regulating means and method for operating such a circuit arrangement - Google Patents

Abstract

The invention relates to a control and / or regulating means (c) for a light-emitting diode field (1, 2, 3) with at least two first outputs (A11, A12, A13) from which control signals for controlling the light-emitting diode field (1, 2, 3) can be tapped are and with a first measurement signal input (E1), to which a sensor signal of a current sensor (V2) can be applied, the control and / or regulating means (C) having a second measurement signal input (E2), to which a sensor signal of a voltage sensor (V1) can be applied and that the control and / or regulating means (C) has at least one second output (A2), at which control and / or regulating signals for controlling and / or regulating a current source (I) can be tapped.

Description

The invention relates to a control and / or regulating means for a light-emitting diode array, a circuit arrangement with such a control and / or regulating means and a method for operating such a circuit arrangement.

From the German patent specification with the publication number DE 10 2006 005 521 B3 is a control and / or regulating means for a light-emitting diode array, a circuit arrangement with such a control and / or regulating means and a method for operating such a circuit arrangement known.

The known control and / or regulating means for a light-emitting diode array has at least two first outputs at which control signals for controlling controllable switching elements of the light-emitting diode array can be tapped off. In addition, a first measurement signal input is provided, to which a sensor signal of a current sensor can be applied. Furthermore, the known control and / or regulating means has a second output, to which a control or regulating signal can be applied, with which a voltage source is controlled or regulated.

The in the patent DE 10 2006 005 521 B3 The disclosed circuit arrangement comprises a light-emitting diode array, a control and / or regulating means for the light-emitting diode array having the aforementioned features, a controllable voltage source and in series with the light-emitting diode array a measuring resistor for measuring the current through the light emitting diode array. In this case, the light emitting diode array comprises at least two series circuits, which comprise at least one light emitting diode and a controllable switching element and wherein control inputs of the controllable switching elements are connected to at least two first outputs of the control and / or regulating means. The controllable voltage source is connected to the second output of the control and / or regulating means. Furthermore, a current sensor is provided with which the measurement of the current through the measuring resistor is possible. The current sensor is connected to the first measurement signal input of the control and / or regulating means.

In the patent DE 10 2006 005 521 B3 Furthermore, a method for operating the circuit arrangement is disclosed.

With the disclosed operating method, it is initially possible to determine a threshold voltage for each series connection of the light-emitting diode array which must be provided by the voltage source in order to achieve a current intensity corresponding to a predetermined, desired brightness of the at least one light-emitting diode of the series connection through the series connection. For determining the threshold voltage of a series circuit, only the controlled switching element is driven to close, which is arranged in the series circuit whose threshold voltage is to be determined. The remaining controlled switching elements remain in an open state. One after the other, the desired threshold voltages of each series circuit can be determined by closing the controlled switching elements.

With the disclosed operating method, it is further possible to set the voltage source so that at least the threshold voltage is applied across the light-emitting diode array, which is the highest of the threshold voltages determined. This ensures that the LEDs of the series circuit with the highest threshold voltage carry the current that is necessary to achieve the desired brightness of the LEDs.

In order then no brightness is achieved by the light emitting diodes of the other series circuits with lower threshold voltages, which is greater than the desired brightness, the controllable switching elements of the other series circuits during a clock period for a pulse duration of a control pulse of the control and / or regulating means for closing driven. By adjusting the pulse duration, an average brightness of the light diodes can be achieved, which corresponds to the desired brightness. It is also disclosed to increase the voltage of the voltage source above the maximum threshold voltage. Then all controllable switching elements for selected pulse durations are driven to close, including the controllable switching element of the series circuit with the maximum threshold voltage. In each switching operation at the end of a pulse duration decreases in the disclosed method, the current through the LED array, since the disconnected series circuit can not absorb electricity at a constant voltage.

After each switching operation at the end of a pulse duration is due to inductances of the circuit arrangement, especially in the voltage source, which is often formed by a voltage converter, not to expect a sudden change in current. Rather, the current steadily drops until the energy stored in the inductors is dissipated. The steady decrease of the total current through the light emitting diode array leads, since at the end of the pulse duration, a series circuit no longer receives power, to a sudden increase in the currents through the remaining series circuits. The fewer series circuits remain to receive the current, the higher the current increase through the remaining series connections.

The short-circuit current then supplied by series circuits is significantly higher than the currents required to achieve the desired brightness. In addition, the current can rise so much that the LEDs of the series circuits are destroyed, which can be prevented by that in the series circuits resistors are arranged, which limit the current. However, these resistors result in a high loss line.

This is where the present inventions begin.

The invention was based on the problem of providing a control and / or regulating means for a light-emitting diode array, a circuit arrangement with such a control and / or regulating means and a method for operating such a circuit arrangement, with which it is possible to increase the current after switching off one of the To avoid series connections of the LED array in the remaining switched series circuits.

With regard to the control and / or regulating means, this problem is solved in that the control and / or regulating means has a second measuring signal input to which a sensor signal of a voltage sensor can be applied and in that the control and / or regulating means has at least one second output, on which control and / or regulating signals for controlling and / or regulating a current source can be tapped off.

The problem is solved with respect to the circuit arrangement in that the control and / or regulating means is designed according to the invention that the circuit arrangement has at least one current source which is connected to the at least one second output of the control and / or regulating means and in series with Light emitting diode array is arranged and that the circuit arrangement comprises a voltage sensor, with which the voltage across the light emitting diode array or the voltage across the series circuit of the light emitting diode array and the measuring resistor can be detected.

With regard to the method, the object is achieved in that in a circuit arrangement according to the invention control and / or regulating means the controllable switching element at least one series connection of the LED array during a clock period for a determined by the control and / or regulating means pulse duration by a control pulse at the control input the controllable switching element for closing drives. Shortly before or at the latest at the same time the current source is controlled by the control and / or regulating means according to the invention so that the current is reduced by the amount of current through the switched-off series circuit.

By reducing the current just before the end of the pulse duration, small overshoots in the current can be avoided, which can arise due to inductances.

The inventions are based on the common idea that the desired total current can be made available by means of a controllable or controllable current source, which is necessary in order to achieve the currents in the series circuits of the light-emitting diode field which ensure the desired average brightness of the light-emitting diodes. Resistors for limiting the currents through the series connection are therefore not required in size, as they are necessary in the prior art. Nevertheless, resistances can also be arranged in the series circuits of the light-emitting diode array.

An advantage of using a current source instead of the voltage source used in the prior art is also that a faster and therefore more dynamic operation of the circuit arrangement according to the invention is possible because of the at least significantly lower influence of the inductors.

Another advantage of using the power source is that the LEDs get the desired current regardless of the temperature.

In the prior art, the temperature-dependent current through the series circuits must be periodically measured and the threshold voltage corrected, since the forward voltages of the light-emitting diodes have a negative temperature coefficient. If there were no correction of the threshold voltage in the prior art, the maximum allowable currents of the LEDs could be exceeded at higher temperatures and the power loss of the resistors, which are in series with the LEDs and the LEDs increase significantly.

With no correction of the threshold voltage in the prior art, this voltage at low temperatures could no longer be sufficient to supply the light emitting diodes with the highest threshold voltages with the desired current.

According to the invention, it is possible that the power supply of more than one power source takes place. If multiple power sources are used, the power sources can each Take over power supply of parts of the LED array, for example, a series circuit.

Advantageously, the at least one current source can be switched off.

The measuring resistor of a circuit arrangement according to the invention may be a discrete resistance component. The measuring resistor can also be part of another component, for example a transistor.

The measuring resistor may be part of a parallel connection of a plurality of branches, wherein a measuring resistor and / or a controllable switch, for example a transistor, may be arranged in each branch of the parallel connection. Control terminals of the controllable switches can be connected to third control outputs of the control and / or regulating means according to the invention. By means of such a parallel connection, measuring range switches are possible.

If only one light-emitting diode is arranged in the series circuits, the anodes or the cathodes of the light-emitting diode can lie on one node.

In a method according to the invention, the control and / or regulating means can simultaneously trigger the controllable switching elements of at least one group of series circuits of the light emitting diode array for a pulse duration determined by the control and / or regulating means by control pulses at the control inputs of the controllable switching elements. In the group of series connections, series circuits with similar characteristics, in particular with identical or similar forward voltages and / or rated currents, are advantageously combined. The grouping makes it possible to simplify the regulation or the control of the controllable switches by the control and / or regulating means. It must then not be set individually for each controllable switching element switching times.

During a clock period, the controllable switching elements of one or more series circuits and / or one or more groups of series circuits can be closed by control pulses at the control inputs of the controllable switching elements for different pulse durations determined by the control and / or regulating means.

The control pulses may be at the beginning of a clock period, at the end of a clock period or in a period between the beginning and the end of a clock period.

The pulse duration of one or more control pulses within one clock period may be at least partially shorter than the clock period or as long as the clock period.

In a method according to the invention, in order to determine the pulse durations of the control pulses for achieving a desired average current through a series circuit, the following procedure can be adopted:
During different periods, a controlled switching element is closed by means of the control and / or regulating means. During the periods in which the controlled switching elements are closed, the control and / or regulating means drives the at least one current source for changing the current flowing through the light-emitting diode array and the measuring resistor connected in series therewith. The current is detected by the current sensor. As soon as a desired instantaneous value of the current is detected by means of the current sensor during the periods in which the controlled switching elements are closed, the voltage sensor detects first voltages across the light-emitting diode array or the voltages across the series connection of the light-emitting diode array and the measuring resistor and and / or regulatory means communicated. The desired instantaneous value of the current may preferably be the rated current of the light-emitting diodes, for example in the amount of 500 mA. The control and / or regulating means then stores the first voltages communicated by the voltage sensor.

Advantageously then by the control and / or regulating means from the stored first voltages, the desired instantaneous values of the current and / or predetermined characteristics of the components in the series circuits of the light emitting diode array and possibly the measuring resistor, the forward voltage of the light emitting diode of the series circuits or the summed forward voltages of LEDs of the series circuits determined.

Then, with known forward voltages of the light-emitting diodes or of the summed forward voltages of the light-emitting diodes of the series circuits, the current distribution of the current supplied by the current source to the individual series circuits of the light-emitting diode array is calculated with the aid of characteristic curves of the light-emitting diodes stored in the control and / or regulating means. From the current distribution then the average current can be determined, which is necessary to achieve the desired brightness. Accordingly, the duty cycles and pulse durations for each series connection of the light-emitting diode array can then be determined by the control and / or regulating means.

This can be done, for example, in such a way that, after the first voltages communicated by the voltage sensor have been stored, differential resistances of the series circuits of the light-emitting diode array or the summed differential resistances of the series circuits are determined from a series connection of the light-emitting diode array and the measuring resistor.

For this purpose, one controlled switching element can be closed for each series connection of the light-emitting diode array during different periods by means of the control and / or regulating means. During the periods in each of which a controlled switching element is closed, the control and / or regulating means drives the at least one current source for changing the current flowing through the light-emitting diode array and the measuring resistor connected in series therewith. The current is detected by the current sensor. As soon as a second desired instantaneous value of the current is detected by the current sensor during the periods in which the controlled switching elements are closed, the voltage sensor detects second voltages across the light-emitting diode array or the voltages across the series connection of the light-emitting diode array and the measuring resistor and the control - and / or regulatory means communicated.

The second desired instantaneous value of the current may preferably be the nominal current of the light-emitting diodes increased by a first value. The first value, which is increased by the second instantaneous instantaneous value of the current with respect to the rated current, may be a value which, according to Ohm's law, is equal to the manufacturer's reference voltage for the forward voltage or the sum of the forward voltages Series connections and the differential resistance specified by the manufacturer can be determined. The control and / or regulating means then stores the second voltages communicated by the voltage sensor.

From the voltage difference of the first and the second voltage divided by the current difference of the first instantaneous value of the current and the second instantaneous value of the current, the differential resistance results in the working range of interest of the light-emitting diodes.

On the basis of this differential resistance of individual light-emitting diodes or each series connection of the light-emitting diode array can be identified by comparing with typical values, for example from the manufacturer's specifications, the error-free operation of the light emitting diodes or the series circuits. Since the measurements can also be carried out during the operation of the circuit arrangement, it is possible to set up a monitoring of the light-emitting diodes or of the series circuits of the light-emitting diode array.

For the following description of the determination of the current distribution, the current to be supplied by the current source and the pulse durations of the control pulses with which the controllable switching elements are driven during operation, the following considerations apply: When the series connection of the light-emitting diode array for which the highest first voltage has been determined is operated with the first instantaneous value for the current, the controlled current source with closed controllable switching elements of all series circuits is thus set so that the current flowing in said series connection current corresponds to the first instantaneous value, flow in the other series circuits of the LED array, for the lower first voltages were detected, higher currents.

To determine these higher currents, the first voltages of the series circuits of the light-emitting diode array are subtracted from the determined highest first voltage of all series circuits of the light-emitting diode array. This difference is divided by the differential resistance of the respective series connection. The quotient indicates the current by which the current through the respective series connection is greater than the first instantaneous value of the current through the series connection with the highest first voltage. The sums of the quotients and the first instantaneous value thus yield the desired higher currents which the other series circuits conduct when, with closed controllable switching elements, the current through the series connection with the highest first voltage through the current source is set to reach the first instantaneous value , If the currents through the individual series circuits are known, the sum of the currents results in the current to which the current source must be set.

The pulse durations then result from the ratios of the first instantaneous value to the ascertained higher currents.

Reference to the accompanying drawings, the invention is explained in more detail below.

Showing:

1 a block diagram of the circuit arrangement according to the invention and.

2 a course of currents in the circuit arrangement according to the invention during a clock period.

The in the 1 illustrated circuit arrangement according to the invention comprises a light-emitting diode array of three series circuits D1, R1, S1, D2, R2, S2, D3, R3, S3. Each series connection 1 . 2 . 3 comprises a light emitting diode D1, D2, D3, a resistor R1, R2, R3 and a switch S1, S2, S3. Corresponding to the indices of the designations of the components is subsequently of the first series circuit 1 , the second series connection 2 and the third series connection 3 to be spoken.

The series connections 1 . 2 . 3 are connected in parallel. The light-emitting diodes D1, D2, D3 are arranged within the series circuits so that their anodes abut against a common node. The controllable switching elements S1, S2, S3 also have a common node. The resistors R1, R2, R3 are arranged between the diodes D1, D2, D3 and the controllable switching elements S1, S2, S3.

In addition to the light-emitting diode array, the circuit arrangement according to the invention comprises a current source I, which is connected upstream of the anode-side node. The current source I is a controllable current source.

Downstream of the switch element-side node is a parallel circuit, in which measuring resistors are arranged. In a first branch of the parallel circuit, a controllable switching element S4 is arranged. The controllable switching element is advantageously a transistor whose emitter collector path forms a first measuring resistor and thus the measuring resistor of the first branch of the parallel circuit. In a second branch, a measuring resistor R4 is arranged. In a third branch, a series circuit of a measuring resistor R5 and a controllable switching element S5 is arranged. The parallel circuit is connected via ground to the current source I.

In the circuit arrangement, a voltage sensor V1 and a current sensor V2 is provided. The voltage sensor V1 detects the voltage between the anode-side node and the ground potential. The current sensor V2 detects the current through the light-emitting diode array via the detour of measuring the voltage which drops across the parallel connection of the measuring resistors.

In addition, an inventive control and / or regulating means C is provided in a circuit arrangement according to the invention. The control and / or regulating means C has several inputs and several outputs. About these inputs and outputs is the control and / or regulating means C with the controllable current source I, the controllable switching elements S1, S2, S3 of the light emitting diode array, the controllable switching elements S4, S5 of the parallel connection of the measuring resistors, the voltage sensor V1 and the current sensor V2 connected.

In detail, the connections between the components or components and the inputs or outputs of the control and / or regulating means are produced as follows:
A first input of the control and / or regulating means C is connected to the current sensor V2. Via the first input E1, the control and / or regulating means C can be supplied with the current intensity detected by the current sensor V2 or with an equivalent voltage thereto.

A second input E2 of the control and / or regulating means is connected to the voltage sensor V1. Via this input E2, a signal can be supplied to the control and / or regulating means which indicates the voltage between the anode-side node and the ground potential.

First outputs A11, A12, A13 of the control and / or regulating means are connected to control terminals of the controllable switching elements S1, S2, S3 of the series circuits 1 . 2 . 3 connected to the LED array. Control pulses can be applied to the switching elements via these first outputs A11, A12, A13 in order to close them.

A second output A2 is connected to the controllable current source I. Via this second output A2, a signal can be given by the control and / or regulating means to the controllable current source I in order to set the current supplied by the current source I.

The control and / or regulating means, which may be a microcontroller or an Asic, is set up such that the light-emitting diodes D1, D2, D3 have a desired brightness. For this purpose, owing to tolerances of the characteristics of the light-emitting diodes, in particular of different forward voltages of the light-emitting diodes, different currents are present in the series circuits 1 . 2 . 3 necessary. The current source is adjusted by the control and / or regulating means C so as to provide a current sufficiently large enough to supply power to the series circuit whose LED has the highest forward voltage. This is, for example, the light-emitting diode D3 in the third series circuit 3 , The first series connection 1 on the other hand should the light emitting diode D1 with the lowest forward voltage and the second series circuit 2 have a light emitting diode D2 with a medium forward voltage.

The current supplied by the controllable current source I is divided at the anode-side node the respective currents through the series circuits 1 . 2 . 3 flow. The current distribution depends on the components of the series circuits 1 . 2 . 3 from. Among these components are also the LEDs D1, D2, D3 with their different forward voltages. The currents are distributed in such a way that the series connection with the light-emitting diode with the lowest forward voltage, ie the first series connection, carries the largest current, while the series connection with the light-emitting diode D3 with the largest forward voltage, namely the third series circuit 3 the lowest current.

In order for the third LED D3 with the highest flux voltage to deliver the desired brightness, the current of the controllable current source I must be set so that the current required to provide the desired brightness is provided by the third series connection 3 and thus flows through the third light emitting diode D3.

However, this leads to currents in the other two series circuits 1 . 2 which are larger than the currents required to provide the desired brightness through the LEDs D1 and D2. The light-emitting diodes D1 and D2 or the series circuits 1 and 2 are therefore turned on and off. This results in a current through the first and the second series circuit 1 . 2 which corresponds on average to the current which is necessary to produce the desired brightness.

Switching on and off takes place at such a high frequency that it is invisible to the human eye.

In the example of 2 a clock period T is shown. Within the clock period T, the controllable switching element S3 in the third series circuit 3 switched on for a pulse duration T3. Analogously, the controllable switches S1, S2 of the first and the second series circuit 1 . 2 for pulse durations T1, T2 is turned on, wherein the pulse duration T2 is smaller than the pulse duration T3 and the pulse duration T1 is smaller than the pulse duration T2. The pulse durations T1, T2, T3 are selected such that on average of the clock period T, a current through the series circuit 1 . 2 . 3 flows, which supplies the desired brightness of the LEDs on average. The controllable current source I is controlled so that at the end of the respective pulse durations T1, T2, T3, the current Iges supply of the controllable current source I is reduced by the current consumption of the switched off at the end of the pulse duration T1, T2, T3 series connection. Thus, the controllable current source I supplies exactly the current Iges, which is necessary for the supply of the switched series circuits.

LIST OF REFERENCE NUMBERS

I

controllable power source

V1

voltage sensor

V2

current sensor

D1

LED of the first series connection

R1

Resistor of the first series connection

S1

controllable switch of the first series connection

D2

LED of the second series circuit

R2

Resistor of the second series connection

S2

controllable switch of the second series circuit

D3

LED of the third series connection

R3

Resistor of the third series connection

S3

controllable switch of the third series connection

C

Control and / or regulating means

S4

controllable switch in the first branch of the parallel connection of measuring resistors

R4

Resistor in the second branch of the parallel connection of measuring resistors

S5

controllable switch in the third branch of the parallel connection of measuring resistors

R5

Resistor in the third branch of the parallel connection of measuring resistors

T

clock period

T1

pulse duration

T2

pulse duration

T3

pulse duration

I1

Current through series connection 1

I2

Current through series connection 2

I3

Current through series connection 3

owned

Total current through the LED field

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 102006005521 B3 [0002, 0004, 0005]

Claims (10)

Control and / or regulating means (C) for a light-emitting diode array ( 1 . 2 . 3 ) having at least two first outputs (A11, A12, A13) at which control signals for controlling controllable switching elements (S1, S2, S3) of the light-emitting diode array ( 1 . 2 . 3 ) and can be tapped with a first measuring signal input (E1), to which a sensor signal of a current sensor (V2) can be applied, characterized in that the control and / or regulating means (C) has a second measuring signal input (E2) to which a sensor signal a voltage sensor (V1) can be applied and that the control and / or regulating means (C) has at least one second output (A2) at which control and / or regulating signals for controlling and / or regulating a current source (I) can be tapped off , Circuit arrangement with a light-emitting diode array ( 1 . 2 . 3 ), a control and / or regulating means (C) for the light-emitting diode array ( 1 . 2 . 3 ) and in series with the light-emitting diode array with a measuring resistor (S4, R4, R5) for measuring the current through the light-emitting diode array ( 1 . 2 . 3 ), wherein the light-emitting diode array ( 1 . 2 . 3 ) at least two series circuits ( 1 . 2 . 3 ), which comprise at least one light emitting diode (D1, D2, D3) and a controllable switching element (S1, S2, S3), wherein control inputs of the controllable switching elements with at least two first outputs (A11, A12, A13) of the control and / or Control means (C) are connected, characterized in that the control and / or regulating means (C) is designed according to claim 1, that the circuit arrangement comprises at least one current source (I) connected to the at least one second output (A2) of the control - and / or control means (C) is connected and in series with the light-emitting diode array ( 1 . 2 . 3 ) and that the circuit arrangement has a voltage sensor (V1) with which the voltage across the light-emitting diode array ( 1 . 2 . 3 ) or the voltage across the series circuit ( 1 . 2 . 3 ) from the light-emitting diode array ( 1 . 2 . 3 ) and the measuring resistor (S4, R4, R5) can be detected. Method for operating a circuit arrangement having the features of claim 2, characterized in that the control and / or regulating means (C) the controllable switching element (S1, S2, S3) at least one series circuit ( 1 . 2 . 3 ) of the light-emitting diode array ( 1 . 2 . 3 ) during a clock period for one of the control and / or regulating means (C) determined pulse duration by a control pulse at the control input of the controllable switching element (S1, S2, S3) for closing drives and that the control and / or regulating means (C) short before or at the latest at the same time as the end of a pulse duration, the current source (I) is triggered in such a way that the current is reduced by the amount of current through the series connection ( 1 . 2 . 3 ), whose controllable switching element (S1, S2, S3) at the end of the pulse duration by the control and / or regulating means (C) is driven to open. Method according to Claim 3, characterized in that the control and / or regulating means (C) comprise the controllable switching elements (S1, S2, S3) of at least one group of series circuits ( 1 . 2 . 3 ) of the light-emitting diode array ( 1 . 2 . 3 ) during a clock period simultaneously for a of the control and / or regulating means (C) determined pulse duration by control pulses to the control inputs of the controllable switching elements (S1, S2, S3) for closing drives. Method according to Claim 3 or 4, characterized in that, during one clock period, the controllable switching elements (S1, S2, S3) of one or more series circuits ( 1 . 2 . 3 ) and / or one or more groups of series circuits ( 1 . 2 . 3 ) for different pulse durations determined by the control and / or regulating means (C) by control pulses at the control inputs of the controllable switching elements (S1, S2, S3). Method according to one of claims 3 to 5, characterized in that the control pulses are at the beginning of a clock period, at the end of a clock period or in a period between the beginning and the end of a clock period. Method according to one of claims 3 to 6, characterized in that the pulse duration of one or more control pulses within a clock period are at least partially shorter than the clock period or the same length as the clock period. Method according to one of Claims 3 to 7, characterized in that the pulse durations of the control pulses for achieving a desired average current through a series circuit ( 1 . 2 . 3 ) during a clock period by means of the control and / or regulating means (C) one controlled switching element (S1, S2, S3) is closed after the other, - that during the periods in which the controlled switching elements (S1, S2, S3) are closed by the control and / or regulating means (C) the at least one current source (I) for changing the by the light emitting diode array ( 1 . 2 . 3 ) and the series-connected measuring resistor (S4, R4, R5) flowing current is detected, wherein the current from the current sensor (V2) is detected, that, as soon as during the periods in which the controlled switching elements (S1, S2, S3) are closed, by means of the current sensor (V2), a desired instantaneous value of the current is detected, with the voltage sensor (V1), the voltages across the light emitting diode array ( 1 . 2 . 3 ) or the voltages across the series circuit ( 1 . 2 . 3 ) from the light-emitting diode array ( 1 . 2 . 3 ) and the measuring resistor (S4, R4, R5) are determined and communicated to the control and / or regulating means (c), and - that the communicated voltages are stored by the control and / or regulating means (C). A method according to claim 8, characterized in that by the control and / or regulating means (C) from the stored voltages, the desired instantaneous values of the current and predetermined characteristics of the components in the series circuits ( 1 . 2 . 3 ) of the light-emitting diode array and, if appropriate, of the measuring resistor, the forward voltage of the light-emitting diode of the series circuits or the summed forward voltages of the light-emitting diodes of the series circuits are determined. A method according to claim 9, characterized in that then calculated at known Flussspannungen of the LEDs with the aid of stored in the control and / or regulating means characteristics of the LEDs, the current distribution of the current supplied by the current source to the individual series circuits of the light emitting diode array.

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