DE102020106270A1 - Control and / or regulating means, circuit arrangement and method for controlling and / or monitoring light-emitting diodes in a light-emitting diode field - Google Patents

Abstract

The present invention relates to a control and / or regulating means (1) for a light-emitting diode field (2) - with at least two first outputs (3) at which control signals for controlling first controllable switching elements (S1, S2) of the light-emitting diode field (2) can be tapped - with at least one second output (5) at which control signals for controlling a second controllable switching element (6) can be tapped or at which control and / or regulation signals for controlling and / or regulating a controllable and / or regulatable current source (7 ) can be tapped, - with at least two measurement signal inputs (8), to which sensor signals from at least two voltage sensors (9, 10) can be applied, and - with a third output (11), to which control and / or regulating signals for controlling and / or or control of a controllable voltage source (12) can be tapped, - wherein the control and / or regulation signals for controlling and / or regulating the controllable voltage source (12) as a function of the sensorsi signals of the at least two voltage sensors (9, 10) are determined.

Description

The invention relates to a control and / or regulating means for a light-emitting diode field. A circuit arrangement and a method for operating the circuit arrangement.

Light-emitting diode fields consisting of a large number of light-emitting diodes are currently in the process of replacing the classic incandescent lamps in the headlights of modern motor vehicles. Light-emitting diodes not only offer a high light output and more safety, but also a lot of design freedom and a high energy-saving potential. In addition to creative lighting concepts, new developments offer the possibility of generating different light distributions, e.g. for city or country roads, bad weather or motorway light. For this it is necessary that the brightness and the light output of the individual light-emitting diodes or of several light-emitting diodes combined to form a group can be precisely controlled in the light-emitting diode field.

Due to the parameter spread of the individual light-emitting diodes, the individual light-emitting diodes and also the groups of light-emitting diodes have a different voltage drop. These different voltages can lead to an uneven current and thus to an uneven light distribution over the individual light emitting diodes of a group.

In order to achieve a uniform light distribution is out of the document DE 10 2006 005 521 B3 a control for a light-emitting diode array is known, with a current measurement being carried out in an initialization or test phase for each group of light-emitting diodes, while the voltage is increased in stages until a predetermined target current flows at a threshold voltage. The disadvantage of the known solution is that an additional current measuring device is required for current monitoring of the individual groups, which increases the costs. Furthermore, the voltage must be increased in stages, which increases the duration of the initialization or test phase.

A suitable control of the light-emitting diodes or the groups of light-emitting diodes in the light-emitting diode field is desirable in order to achieve a desired light distribution while at the same time minimizing the losses. Furthermore, it is desirable to recognize and localize a failure of light-emitting diodes, on the one hand to compensate for the failure caused by the remaining intact light-emitting diodes and to be able to intervene promptly in the event of a major failure.

This is where the invention begins.

The invention was based on the problem of improving the known control circuit for a light-emitting diode field in such a way that the parameter spread of the individual light-emitting diodes can be recognized and compensated for using simple means, the recognition being successful within a short period of time.

• - mit wenigstens zwei ersten Ausgängen, an denen Steuersignale zum Steuern von ersten steuerbaren Schaltelementen des Leuchtdiodenfeldes abgreifbar sind,
• - mit wenigstens einem zweiten Ausgang, an welchem Steuersignale zum Steuern eines zweiten steuerbaren Schaltelementes abgreifbar sind oder an welchem Steuer- und/oder Regelungssignale zum Steuern und/oder Regeln einer steuerbaren und/oder regelbaren Stromquelle abgreifbar sind,
• - mit wenigstens zwei Messsignaleingängen, an welchen Sensorsignale von wenigstens zwei Spannungssensoren anlegbar sind, und
• - mit einem dritten Ausgang, an welchem Steuer- und/oder Regelungssignale zum Steuern und/oder Regeln einer regelbaren Spannungsquelle abgreifbar sind,
• - wobei die Steuer- und/oder Regelungssignale zum Steuern und/oder Regeln der regelbaren Spannungsquelle in Abhängigkeit der Sensorsignale der wenigstens zwei Spannungssensoren bestimmt sind.

According to the invention, the object is achieved by a control and / or regulating means for a light-emitting diode field

• - With at least two first outputs, at which control signals for controlling first controllable switching elements of the light-emitting diode field can be tapped,
• - With at least one second output, at which control signals for controlling a second controllable switching element can be tapped or at which control and / or regulating signals for controlling and / or regulating a controllable and / or regulatable current source can be tapped,
• - With at least two measurement signal inputs, to which sensor signals from at least two voltage sensors can be applied, and
• - With a third output, at which control and / or regulation signals for controlling and / or regulating a controllable voltage source can be tapped,
• - wherein the control and / or regulation signals for controlling and / or regulating the controllable voltage source are determined as a function of the sensor signals of the at least two voltage sensors.

The problem is solved with regard 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 controllable voltage source which is connected to the one at least third output of the control and / or regulating means and that the circuit arrangement has at least one first voltage sensor, with which the voltage across the light-emitting diode field can be detected, and with at least one second voltage sensor, with which a supply voltage or the voltage of the controllable voltage source can be detected.

• - mittels des Steuer- und/oder Regelungsmittel werden die ersten steuerbaren Schaltelemente zum Öffnen angesteuert,
• - das zweite steuerbare Schaltelement wird zum Schließen angesteuert, wobei ein Messzweig über dem Messwiderstand zwischen einer Versorgungsspannung und dem Leuchtdiodenfeld geschlossen wird oder die steuerbare und/oder regelbare Stromquelle wird zum Einstellen eines definierten Stromes angesteuert,
• - der zweite Spannungssensor ermittelt die Versorgungsspannung,
• - mittels des Steuer- und/oder Regelungsmittel werden die ersten steuerbaren Schaltelemente zum Schließen und Öffnen angesteuert, derart dass nacheinander jeweils nur ein einer Reihenschaltung zugewiesenes erstes steuerbares Schaltelement geschlossen ist,
• - der erste Spannungssensor ermittelt den Spannungsabfall über der eingeschaltete Reihenschaltung des Leuchtdiodenfeldes,
• - die ermittelten Spannungswerte der Spannungssensoren werden an das Steuer- und/oder Regelungsmittel übermittelt und im Steuer- und/oder Regelungsmittel gespeichert,
• - aus der Differenz der Spannungswerte der beiden Spannungssensoren bestimmt das Steuer- und/oder Regelungsmittel den Spannungsabfall über dem Messwiderstand,
• - aus der Spannungsabfall über dem Messwiderstand und dem Messwiderstand ermittelt das Steuer- und/oder Regelungsmittel den Strom, welcher durch die eingeschaltete Reihenschaltung als Leuchtdiodenstrom fließt,
• - das Wertepaar aus dem ermittelten Leuchtdiodenstrom und dem Spannungsabfall über der eingeschalteten Reihenschaltung wird im Steuer- und/oder Regelungsmittel als Arbeitspunkt der Reihenschaltung innerhalb eines Leuchtdioden-Strom-Spannungs-Kennlinienfeldes bestimmt und mit Hilfe des Arbeitspunktes die für die eingeschaltete Reihenschaltung zutreffende Leuchtdioden-Strom-Spannungs-Kennlinie ermittelt,
• - durch eine Verschiebung des Arbeitspunktes auf der bestimmten Kennlinie wird im Steuer- und/oder Regelungsmittel zu einem gewünschten Leuchtdiodenstrom eine optimale Betriebsspannung für die Reihenschaltung ermittelt.

The object set is achieved by a method for operating a circuit arrangement according to the invention, the method having at least the following steps:

• - by means of the control and / or regulating means, the first controllable switching elements are activated for opening,
• - The second controllable switching element is controlled to close, with a measuring branch is closed via the measuring resistor between a supply voltage and the light-emitting diode field or the controllable and / or regulatable current source is activated to set a defined current,
• - the second voltage sensor determines the supply voltage,
• - by means of the control and / or regulating means, the first controllable switching elements for closing and opening are activated in such a way that only one first controllable switching element assigned to a series circuit is closed, one after the other,
• - the first voltage sensor determines the voltage drop across the switched-on series connection of the light-emitting diode field,
• - the determined voltage values of the voltage sensors are transmitted to the control and / or regulating means and stored in the control and / or regulating means,
• - The control and / or regulating means determines the voltage drop across the measuring resistor from the difference between the voltage values of the two voltage sensors,
• - From the voltage drop across the measuring resistor and the measuring resistor, the control and / or regulating means determines the current that flows through the switched-on series circuit as a light-emitting diode current,
• - The pair of values from the determined LED current and the voltage drop across the switched-on series circuit is determined in the control and / or regulating means as the operating point of the series circuit within a light-emitting diode current-voltage characteristic field and, with the help of the working point, the LED current applicable to the switched-on series circuit -Voltage characteristic determined,
• - By shifting the operating point on the specific characteristic curve, an optimal operating voltage for the series circuit is determined in the control and / or regulating means for a desired light-emitting diode current.

A current measuring device is dispensed with in the circuit arrangement according to the invention. By dispensing with a current measurement, the circuit arrangement can be constructed in a cost-effective manner. It is also possible to dispense with a step-by-step increase in the supply voltage. The determination of the optimal operating voltage for the switched-on series connection can thus take place more quickly than with the known method from the prior art.

A shortening of the determination of the optimal operating voltage is particularly advantageous if the steps are carried out within an initialization or test phase. During the period of the initialization or test phase, the light-emitting diode field is not operated in the form that is necessary for a desired brightness distribution. In the case of a light-emitting diode field in a headlight of a motor vehicle, the surroundings of the vehicle are accordingly not properly illuminated during the initialization or test phase. It is therefore necessary that the duration is kept as short as possible. A period of time which remains virtually unnoticed by an observer is advantageous.

To determine the operating point of the series connection, it can be provided that the light-emitting diode current-voltage characteristic is stored in the control and / or regulating means via a table of values. There is also the possibility that the light-emitting diode current-voltage characteristic is stored in the control and / or regulating means via a mathematical formula. This makes it possible to parameterize the LED current-voltage characteristic.

In the case of a large number of series connections, provision can be made for a variable number of series connections to be connected for each actuation of the first controllable switching elements for closing. Grouping the series connections would further shorten the time for the initialization or test phase. However, it is then not possible to determine an optimal operating voltage for each series connection, but only for the group of series connections that are connected together. In such a case, a balance should be made between the accuracy of the determination and the shortening of the initialization or test phase.

To protect the circuit arrangement, it can be provided that the control and / or regulating means only controls the first controllable switching elements of the light-emitting diode field to close when the supply voltage is in a range that is tolerable for the light-emitting diodes in the light-emitting diode field, this range of values in the Control and / or regulating means is stored. Here it is particularly important to protect the light diodes from overloads. Such overvoltages can occur, for example, when a vehicle battery is bridged by a jump start device. It is also possible that when a vehicle is started, the supply voltage drops briefly and falls below a value of the forward voltage of the light-emitting diodes within a series circuit. The initialization or test phase only starts when the Supply voltage has assumed a tolerable value.

The control and / or regulating means preferably controls the first controllable switching elements separately and independently of one another, so that only one series connection is connected in each case. In addition to the most exact possible determination of the optimal operating voltage, this also enables precise detection of errors within a series connection. It can be provided that an error signal is output if, within the initialization or test phase, the first voltage sensor determines a voltage that is lower or higher than a specified error threshold on a series circuit that is switched on and supplied with voltage.

Furthermore, there is the possibility that after an error has been detected in a series circuit, an error message identifying the series circuit is stored in the control and / or regulating means. The storage of the error message enables the error to be read out, for example when the vehicle is being serviced. In this way, the faulty series connection can then be localized. It is also conceivable that, after a fault has been detected, adjacent series connections are controlled in such a way that they at least partially absorb the missing light output of the defective series connection.

In order to achieve optimal operation of the light-emitting diode array, it can be provided that during operation of the circuit arrangement, outside of the initialization or test phase, the controllable voltage source is set to an operating voltage that corresponds to at least the highest determined optimal operating voltage of a series circuit. This ensures that the operating voltages of the series connections are in a range that the forward voltages of the light-emitting diodes are achieved. At the same time, it is ensured that the light-emitting diode field is not overloaded and that this can lead to defects.

Furthermore, it can be provided that the operating voltage is set higher by a value stored in the control and / or regulating means than corresponds to the highest determined optimal operating voltage of a series connection. In particular, it can be provided that the operating voltage is set 2% to 25% higher than it corresponds to the highest determined optimal operating voltage of a series connection. With this increase in the operating voltage, an overload of the light-emitting diode field is avoided, but at the same time it is achieved that the light-emitting diode field is operated without a doubt. An increase in brightness can also be achieved if this is desired.

There is the possibility that a series circuit, whose required LED current is lower than the LED current that is set due to the set operating voltage, is adjusted in its LED current by clocked activation of the associated first controllable switching element for opening and closing. The series circuit is switched on by opening and closing the associated first controllable switching element just long enough for the desired average light-emitting diode current to flow. An excessively high light-emitting diode current, which would arise due to the excessively high operating voltage, is thus avoided.

• 1 ein Blockschaltbild einer erfindungsgemäßen Schaltungsanordnung mit einem Messwiderstand
• 2 ein Blockschaltbild einer zweiten Ausführungsform der Erfindung mit einer steuerbaren und/oder regelbaren Stromquelle

The invention is explained in more detail below with reference to the accompanying drawings. It shows:

• 1 a block diagram of a circuit arrangement according to the invention with a measuring resistor
• 2 a block diagram of a second embodiment of the invention with a controllable and / or regulatable current source

In the 1 The circuit arrangement according to the invention shown comprises a light-emitting diode field 2 from two series connections I. , II . Any series connection I. , II includes two light emitting diodes D1 , D2 , a resistor R1 , R2 and a first controllable switching element S1 , S2 . According to the indices of the names of the components, the first series connection is followed I. and the second series connection II spoken. The number of light emitting diodes D1 , D2 can be seen as an example and can vary.

The series connections I. , II are connected in parallel. The light emitting diodes D1 , D2 are within the series connections I. , II arranged in series. Their anodes are connected to a common first node. The first controllable switching elements S1 , S2 are at a common second node. The resistances R1 , R2 are between the diodes D1 , D2 and the first controllable switching elements S1 , S2 arranged.

Next to the LED field 2 the circuit arrangement comprises a controllable voltage source 12th upstream of the first node. The adjustable voltage source 12th is derived from the supply voltage of the vehicle electrical system 4th fed.

Between a connection to the supply voltage 4th and a measurement branch is provided for the first node. This includes one Measuring resistor 13th and a second controllable switching element 6th , via which the measuring branch can be switched on.

There are two voltage sensors in the circuit arrangement 9 , 10 intended. The second voltage sensor 9 detects the supply voltage, the first voltage sensor 10 detects the voltage between the first node and the ground potential.

Furthermore, a control and / or regulating means according to the invention is included in the circuit arrangement 1 intended. The control and / or regulating means 1 has several entrances 8th and multiple outputs 3 , 5 , 11 . Via these inputs and outputs 3 , 5 , 8th , 11 is the control and / or regulating means 1 with the adjustable voltage source 12th , the first controllable switching elements S1 , S2 of the LED field 2 , the controllable switching element 6th of the measuring branch and the two voltage sensors 9 , 10 tied together.

The details are the connections between the structural elements or components and the inputs and outputs 3 , 5 , 8th , 11 of the control and / or regulating means 1 manufactured as follows. A first entrance 8th of the control and / or regulating means is with the first voltage sensor 10 tied together. Via this entrance 8th can the control and / or regulating means 1 a signal can be supplied which corresponds to the voltage between the first node and the ground potential.

A second entrance 8th of the control and / or regulating means 1 is with the second voltage sensor 9 tied together. Via the second entrance 8th can the control and / or regulating means 1 the one from the first voltage sensor 9 detected voltage are fed to the supply voltage.

First exits 3 of the control and / or regulating means 1 are with the control connections of the first controllable switching elements S1 , S2 the series connections I. , II of the LED field 2 tied together. The first controllable switching elements S1 , S2 can be controlled to open and close.

A second exit 5 of the control and / or regulating means 1 is with the second controllable switching element 6th of the measuring branch connected. Via this second exit 5 can a control pulse the second controllable switching element 6th opened and closed and the measuring branch switched on or off.

A third exit 11 is with the adjustable voltage source 12th tied together. Via this third exit 11 can of the control and / or regulating means 1 a signal to the controllable voltage source 12th be given to that of the controllable voltage source 12th set the voltage supplied.

The control and / or regulating means 1 is set up so that the light emitting diodes D1 , D2 in the LED field 2 have a desired brightness. Due to tolerances of the parameters of the individual light emitting diodes D1 , D2 have the individual light emitting diodes D1 , D2 as well as the series connections I. , II these light emitting diodes D1 , D2 different voltages in the series connections I. , II . The different voltages lead to different currents in the series connections I. , II which in turn can lead to uneven brightness.

By means of the circuit arrangement, for each series connection I. , II the voltage can be determined individually. If the information about the voltage of each series connection I. , II is present, the controllable voltage source 12th can be optimally adjusted.

About the voltages of the series connections I. , II to be determined, all first controllable switching elements are initially in an initialization or test phase S1 , S2 the series connections I. , II controlled to open. The measuring branch is then switched on and the supply voltage via the second voltage sensor 9 measured. Is the supply voltage in a range that is required for the light emitting diodes D1 , D2 in the LED field 2 is tolerable, this range of values is in the control and / or regulating means 1 stored, controls the control and / or regulating means 1 the first controllable switching element S1 the first series connection I. of the LED field 2 to close. The first voltage sensor 10 determines the voltage drop across this first series connection I. between the first node and the ground potential. From the voltage values of the two voltage sensors 9 , 10 can in the control and / or regulating means 1 the voltage difference and thus the voltage drop across the measuring resistor 13th to be determined. From the voltage drop and the value of the measuring resistor 13th the current can be determined by the first series connection I. flows.

The pair of values from the determined LED current and the voltage drop across the switched on series connection I. , II becomes in the control and / or regulating means 1 as the working point of the series connection I. , II determined within a light-emitting diode current-voltage characteristic field and with the help of the operating point that for the switched-on series circuit I. , II appropriate LED current-voltage characteristic determined. By a Shifting of the operating point on the specific characteristic curve is made in the control and / or regulating means 1 an optimal operating voltage for the series connection to a desired LED current I. , II determined.

The control and / or regulating means 1 controls all first controllable switching elements one after the other S1 , S2 the series connections I. , II to open and close, so that each a first controllable switching element S1 , S2 a series connection I. , II is closed and thus always a series connection I. , II is activated.

From the determined optimal operating voltages of each series connection I. , II becomes an optimal operating voltage for the LED field 2 determined that is at least as large as the highest determined operating voltage of a series connection I. , II . The control and / or regulating means 1 controls the adjustable voltage source 12th in such a way that after the end of the initialization or test phase the optimum operating voltage for the light-emitting diode field 2 is set. To the series connections I. , II to adapt with a lower optimal operating voltage, the known methods of pulse width modulation are used. In this case, when connected in series I. , II whose required light-emitting diode current is lower than the light-emitting diode current that is set on the basis of the set operating voltage, by clocked activation of the associated first controllable switching element S1 , S2 adapted for opening and closing the light emitting diode current. The series connection I. , II is made by opening and closing the associated first controllable switching element S1 , S2 switched on just long enough for the desired mean LED current to flow. An excessively high light-emitting diode current, which would arise due to the excessively high operating voltage, is thus avoided.

2 shows a circuit arrangement as in FIG 1 described with the difference that the second controllable switching element 6th by a controllable and / or adjustable power source 7th is replaced. It is also conceivable that the current source is a constant current source set to a fixed value.

The second exit 5 of the control and / or regulating means 1 is in this case with the controllable and / or adjustable power source 7th tied together. Via this second exit 5 can of the control and / or regulating means 1 a signal to the controllable power source 7th be given to the from the controllable and / or adjustable power source 7th to adjust the supplied current.

Becomes a controllable and / or adjustable power source 7th used, the LED current does not have to be in the control and / or regulating means 1 by forming the difference with the voltage sensors 9 , 10 measured voltages are determined, but is from the controllable and / or regulatable current source 7th imprinted.

The determination of the operating voltage is identical to that in 1 described procedure. About the voltages of the series connections I. , II To be determined, all controllable switching elements are initially determined in an initialization or test phase S1 , S2 the series connections I. , II controlled to open. The supply voltage is then determined by means of the second voltage sensor 9 measured. Is the supply voltage in a range that is required for the light emitting diodes D1 , D2 in the LED field 2 is tolerable, this range of values is in the control and / or regulating means 1 stored, controls the control and / or regulating means 1 the first controllable switching element S1 the first series connection I. of the LED field 2 to close. Via the second exit 5 of the control and / or regulating means 1 a signal is sent to the controllable and / or adjustable power source 7th given to the from the controllable and / or adjustable power source 7th to adjust the supplied current.

The first voltage sensor 10 determines the voltage drop across the first series connection I. between the first node and the ground potential.

The pair of values from the determined LED current and the voltage drop across the switched on series connection I. , II becomes in the control and / or regulating means 1 as the working point of the series connection I. , II determined within a light-emitting diode current-voltage characteristic field and with the help of the operating point that for the switched-on series circuit I. , II appropriate LED current-voltage characteristic determined. By shifting the operating point on the specific characteristic curve, the control and / or regulating means 1 an optimal operating voltage for the series connection to a desired LED current I. , II determined.

The control and / or regulating means 1 controls all first controllable switching elements one after the other S1 , S2 the series connections I. , II to open and close, so that each a first controllable switching element S1 , S2 a series connection I. , II is closed and thus always a series connection I. , II is activated.

From the determined optimal operating voltages of each series connection I. , II becomes an optimal operating voltage for the LED field 2 determined that is at least as large as the highest determined operating voltage of a series connection I. , II . The control and / or regulating means 1 controls the adjustable voltage source 12th in such a way that after the end of the initialization or test phase the optimum operating voltage for the light-emitting diode field 2 is set. To the series connections I. , II to adapt with a lower optimal operating voltage, the known methods of pulse width modulation are used. In this case, when connected in series I. , II whose required light-emitting diode current is lower than the light-emitting diode current that is set on the basis of the set operating voltage, by clocked activation of the associated first controllable switching element S1 , S2 adapted for opening and closing the light emitting diode current. The series connection I. , II is made by opening and closing the associated first controllable switching element S1 , S2 switched on just long enough for the desired mean LED current to flow. An excessively high light-emitting diode current, which would arise due to the excessively high operating voltage, is thus avoided.

List of reference symbols

1

Control and / or regulating means

2

LED field

3

first exits

4th

Supply voltage

5

second exit

6th

second controllable switching elements

7th

controllable and / or adjustable power source

8th

Measurement signal inputs

9, 10

Voltage sensors

11

third exit

12th

adjustable voltage source

13th

Measuring resistor

I.

first series connection

II

second series connection

D1

Light-emitting diode of the first series connection

D2

Light-emitting diode of the second series connection

R1

Resistance of the first series connection

R2

Resistance of the second series connection

S1

first controllable switching element of the first series circuit

S2

first controllable switching element of the second series circuit

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 102006005521 B3 [0004]

Claims (14)

Control and / or regulating means (1) for a light-emitting diode field (2) - With at least two first outputs (3) at which control signals for controlling first controllable switching elements (S1, S2) of the light-emitting diode array (2) can be tapped, - With at least one second output (5) at which control signals for controlling a second controllable switching element (6) can be tapped or at which control and / or regulating signals for controlling and / or regulating a controllable and / or regulatable current source (7) can be tapped are, - With at least two measurement signal inputs (8) to which sensor signals from at least two voltage sensors (9, 10) can be applied, and - With a third output (11), at which control and / or regulation signals for controlling and / or regulating a controllable voltage source (12) can be tapped, - wherein the control and / or regulation signals for controlling and / or regulating the controllable voltage source (12) are determined as a function of the sensor signals of the at least two voltage sensors (9, 10). Circuit arrangement - with a light-emitting diode field (2) and - with a control and / or regulating means (1) for the light-emitting diode field (2), - wherein the light-emitting diode field (2) comprises at least two series circuits (I, II) which contain at least one light-emitting diode ( D1, D2) and a first controllable switching element (S1, S2), - wherein control inputs of the first controllable switching elements (S1, S2) are connected to at least two first outputs (3) of the control and / or regulating means (1), and - with a measuring resistor (13) and a second controllable switching element (6) or a controllable and / or regulatable current source (7) in series with the light-emitting diode field, - with a control input of the second controllable switching element (6) or the controllable and / or regulatable current source (7) is connected to the at least one second output (5) of the control and / or regulating means (1), characterized in that - the control and / or regulating means (1) after Claim 1 is designed, - that the circuit arrangement has at least one controllable voltage source (12) which is connected to at least one third output (11) of the control and / or regulating means (1) and - that the circuit arrangement has at least one first voltage sensor (10) with which the voltage across the light emitting diode field (2) can be detected and with at least one second voltage sensor (9) with which a supply voltage or the voltage of the controllable voltage source (12) can be detected. Method for operating a circuit arrangement having the features of Claim 2 , the method having at least the following steps: - the first controllable switching elements (S1, S2) are controlled to open by means of the control and / or regulating means (1), - the second controllable switching element (6) is controlled to close, wherein a measuring branch is closed across the measuring resistor (13) between a supply voltage and the light-emitting diode field or the controllable and / or regulatable current source is activated to set a defined current, - the second voltage sensor (9) determines the supply voltage, - by means of the control and / or or control means (1), the first controllable switching elements (S1, S2) are controlled for closing and opening such that only one first controllable switching element (S1, S2) assigned to a series circuit (I, II) is closed one after the other, the first voltage sensor (10) determines the voltage drop across the switched-on series connection (I, II) of the light-emitting diode field, the determined voltage values of the voltage sensors (9, 10) are transmitted to the control and / or regulating means (1) and stored in the control and / or regulating means (1), - from the difference between the voltage values of the two voltage sensors (9, 10) the control and / or regulating means (1) determines the voltage drop across the measuring resistor (13), - the control and / or regulating means (1) determines the current from the voltage drop across the measuring resistor (13) and the measuring resistor (13), which flows through the switched-on series circuit (I, II) as a light-emitting diode current, - the pair of values from the determined light-emitting diode current and the voltage drop across the switched-on series circuit (I, II) is used in the control and / or regulating means (1) as the operating point of the series circuit (I , II) is determined within a light-emitting diode current-voltage characteristic field and, with the help of the operating point, the light-emitting diode current voltage applicable to the switched-on series circuit (I, II) s characteristic curve determined, - by shifting the operating point on the specific light-emitting diode current-voltage characteristic curve, an optimal operating voltage for the series circuit (I, II) is determined in the control and / or regulating means (1) for a desired light-emitting diode current. Procedure according to Claim 3 , characterized in that the steps are carried out within an initialization or test phase. Procedure according to Claim 3 until 4th , characterized in that the light-emitting diode current-voltage characteristic is stored in the control and / or regulating means (1) via a table of values. Procedure according to Claim 3 until 4th , characterized in that the light-emitting diode current-voltage characteristic is stored in the control and / or regulating means (1) via a mathematical formula. Procedure according to Claim 3 until 6th , characterized in that each time the first controllable switching elements (S1, S2) are activated, a variable number of series connections (I, II) is switched on for closing. Procedure according to Claim 3 until 7th , characterized in that the control and / or regulating means (1) controls the first controllable switching elements (S1, S2) of the light-emitting diode field (2) to close only when the supply voltage is in a range that is suitable for the light-emitting diodes (D1, D2) can be tolerated in the light-emitting diode field (2), this range of values being stored in the control and / or regulating means (1). Procedure according to Claim 3 until 8th , characterized in that an error signal is output if, within the initialization or test phase, a voltage is determined by the first voltage sensor (10) on a series circuit (I, II) that is switched on and supplied with voltage, which voltage is lower or higher than a specified one Failure threshold. Procedure according to Claim 9 , characterized in that after an error has been detected in a series circuit (I, II), an error message identifying the series circuit (I, II) is stored in the control and / or regulating means (1). Procedure according to Claim 3 until 10 , characterized in that during operation of the circuit arrangement, outside of the initialization or test phase, the controllable voltage source (12) is set to an operating voltage which corresponds to at least the highest determined optimal operating voltage of a series circuit (I, II). Procedure according to Claim 11 , characterized in that the operating voltage is set higher by a value stored in the control and / or regulating means (1) than corresponds to the highest determined optimal operating voltage of a series circuit (I, II). Procedure according to Claim 12 , characterized in that the operating voltage is set 2% to 25% higher than it corresponds to the highest determined optimal operating voltage of a series circuit (I, II). Procedure according to Claim 12 until 13th , characterized in that a series circuit (I, II), the required LED current is lower than the LED current, which is set due to the set operating voltage, by clocked control of the associated first controllable switching element (S1, S2) for opening and closing in their LED current is adjusted.

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