DE102010003244A1 - Method and circuit arrangement for operating a plurality of LEDs - Google Patents

Method and circuit arrangement for operating a plurality of LEDs

Info

Publication number
DE102010003244A1
DE102010003244A1 DE201010003244 DE102010003244A DE102010003244A1 DE 102010003244 A1 DE102010003244 A1 DE 102010003244A1 DE 201010003244 DE201010003244 DE 201010003244 DE 102010003244 A DE102010003244 A DE 102010003244A DE 102010003244 A1 DE102010003244 A1 DE 102010003244A1
Authority
DE
Germany
Prior art keywords
led
led2
led1
current
duty cycle
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
DE201010003244
Other languages
German (de)
Inventor
Knut Asmussen
Ralf Hying
Oskar Schallmoser
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Osram GmbH
Original Assignee
Osram GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Osram GmbH filed Critical Osram GmbH
Priority to DE201010003244 priority Critical patent/DE102010003244A1/en
Publication of DE102010003244A1 publication Critical patent/DE102010003244A1/en
Application status is Ceased legal-status Critical

Links

Images

Classifications

    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR
    • H05B33/00Electroluminescent light sources
    • H05B33/02Details
    • H05B33/08Circuit arrangements not adapted to a particular application
    • H05B33/0803Circuit arrangements not adapted to a particular application for light emitting diodes [LEDs] comprising only inorganic semiconductor materials
    • H05B33/0806Structural details of the circuit
    • H05B33/0821Structural details of the circuit in the load stage
    • H05B33/0824Structural details of the circuit in the load stage with an active control inside the LED load configuration
    • H05B33/083Structural details of the circuit in the load stage with an active control inside the LED load configuration organized essentially in string configuration with shunting switches
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR
    • H05B33/00Electroluminescent light sources
    • H05B33/02Details
    • H05B33/08Circuit arrangements not adapted to a particular application
    • H05B33/0803Circuit arrangements not adapted to a particular application for light emitting diodes [LEDs] comprising only inorganic semiconductor materials
    • H05B33/0806Structural details of the circuit
    • H05B33/0809Structural details of the circuit in the conversion stage
    • H05B33/0815Structural details of the circuit in the conversion stage with a controlled switching regulator
    • H05B33/0818Structural details of the circuit in the conversion stage with a controlled switching regulator wherein HF AC or pulses are generated in the final stage
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR
    • H05B33/00Electroluminescent light sources
    • H05B33/02Details
    • H05B33/08Circuit arrangements not adapted to a particular application
    • H05B33/0803Circuit arrangements not adapted to a particular application for light emitting diodes [LEDs] comprising only inorganic semiconductor materials
    • H05B33/0842Circuit arrangements not adapted to a particular application for light emitting diodes [LEDs] comprising only inorganic semiconductor materials with control
    • H05B33/0845Circuit arrangements not adapted to a particular application for light emitting diodes [LEDs] comprising only inorganic semiconductor materials with control of the light intensity
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00Energy efficient lighting technologies
    • Y02B20/30Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
    • Y02B20/34Inorganic LEDs
    • Y02B20/341Specially adapted circuits
    • Y02B20/346Switching regulators
    • Y02B20/347Switching regulators configured as a current source

Abstract

The present invention relates to a method of operating a plurality of LEDs (LED1, LED2, LED3) on a circuit arrangement having a supply terminal for coupling to a supply voltage (V CC ); a reference potential terminal for coupling to a reference potential; at least a first parallel connection of at least one first LED (LED1) and a first short-circuit switch (KS1) for short-circuiting the at least one first LED (LED1); at least one second parallel connection of at least one second LED (LED2) and a second short-circuit switch (KS2) for short-circuiting the at least one second LED (LED2); a current source (I Q ), wherein the series circuit of the current source (I Q ), the at least one first and the at least one second parallel connection between the supply terminal and the reference potential terminal is coupled; and a control device (10), the at least one first output (A1) for driving the first short-circuit switch (KS1); a second output (A2) for driving the second short-circuit switch (KS2); and at least one input (St) for supplying at least one first control signal for setting an instantaneous brightness output of the at least one first LED (LED1) and a second control signal for setting a momentary brightness output of the at least one second LED (LED2); wherein the instantaneous current (I) of the current source (I Q ) is varied by the control device (10) as a function of the instantaneous brightness output to be set of the at least one first LED (LED1) and / or the at least one second LED (LED2). It also relates to a corresponding circuit arrangement for operating a plurality of LEDs (LED1, LED2, LED3).

Description

  • Technical area
  • The present invention relates to a method for operating a plurality of LEDs on a circuit arrangement having a supply terminal for coupling to a supply voltage, a reference potential terminal for coupling to a reference potential, at least a first parallel connection of at least one first LED and a first shorting switch for short-circuiting the at least one first LED, at least one second parallel connection of at least one second LED and a second shorting switch for shorting the at least one second LED, a current source, wherein the series circuit of the current source, the at least one first and the at least one second parallel circuit between the supply terminal and the reference potential terminal is coupled , And a control device, the at least one first output for driving the first short-circuit switch, a second output for driving the second short-circuit switch and min at least one input for supplying at least one first control signal for setting an instantaneous brightness output of the at least one first LED and a second control signal for setting a momentary brightness output of the at least one second LED. It also relates to a corresponding circuit arrangement for operating a plurality of LEDs.
  • State of the art
  • The present invention is described using the example of so-called AFS (Advanced Forward Lighting Systems) systems, although it can also be used in other areas, as is obvious to the person skilled in the art. In AFS systems, for example, a large number of surface elements of a travel path or an environment with LEDs are to be illuminated differently depending on the time of day. Individual surface elements must be illuminated dimmed, others, for example, in dangerous situations, briefly even with very high brightness.
  • It is known to dim LEDs by appropriate control by means of a PWM (Pulse Width Modulation) signal. To set a lower brightness output, therefore, the duty cycle, ie. H. the duty cycle, reduced, increased to set a higher brightness output. Only when the brightness requirement is high, the duty cycle is increased to 100%. In normal operation, therefore, the duty cycle is significantly lower. With the reduction of the duty cycle is accompanied by a reduction of the efficiency of the circuit arrangement.
  • Presentation of the invention
  • The object of the present invention is therefore to develop a generic method or a generic circuit arrangement such that an increase in the efficiency is made possible.
  • This object is achieved by a method having the features of patent claim 1 and by a circuit arrangement having the features of patent claim 13.
  • The present invention is based on the finding that the higher the instantaneous current flowing through the LED, the lower the efficiency of an LED relative to the instantaneous current flowing through the LED. In the prior art, the LEDs are powered by a power source that continuously supplies a constant current. The brightness output currently to be set is achieved solely by driving the short circuit switch connected in parallel to the LED with a signal which has a duty cycle which leads to the setting of the instantaneous brightness output.
  • The present invention now goes to the solution of the above-described object, the way to vary the current supplied by the current source instantaneous current. According to the invention, therefore, the instantaneous current of the current source is varied by the control device, specifically as a function of the instantaneous brightness output to be set of the at least one first LED and / or the at least one second LED. By this procedure, operation of the LEDs is possible with the lowest possible current at the highest possible duty cycle. This results in a significantly increased efficiency and as a result in a lower thermal load of the circuit arrangement. As a result, on the one hand cooling measures can be reduced, on the other hand an increase in the service life of the components involved is thereby achieved.
  • Although the present invention is fundamentally independent of the fact that the short-circuiting switches are driven with a PWM signal, it is nevertheless preferred if a first PWM signal is provided at the first output of the control device, which has a first duty cycle, and second output of the control device, a second PWM signal having a second duty cycle. Since these signals are coupled to the short circuit switch, the respective LED is therefore operated with the respective inverse duty cycle.
  • In a preferred embodiment, the smaller of the at least two duty cycles is first determined on this basis. Subsequently, the smaller of the at least two duty cycles is reduced and the instantaneous current of the current source is lowered in such a way that the at least one LED operated with the smaller duty cycle outputs its brightness which is currently to be set. Finally, the at least one other duty cycle is reduced in such a way that the at least one LED operated with the at least one other duty cycle outputs its brightness to be currently set. By this measure, it is ensured that both LEDs on the one hand give their currently set brightness, on the other hand, the LEDs can be operated with the lowest possible power, which is turned off on the smaller of the at least two duty cycles, since it can not be lowered below 0% , Preferably, the smaller of the two Dutty cycles is lowered to a Dutty cycle of at most 10%, preferably at most 5%, more preferably to 0%. This results in a minimization of the current flowing through the LED and in accordance with a maximization of the efficiency of the circuit arrangement.
  • Preferably, the reduction of the Dutty cycles and the corresponding reduction of the instantaneous current of the current source takes place in stages, in particular in predefinable stages. It takes place in particular such that the brightness emitted by the LEDs does not change.
  • In order to take account of varying brightness requirements, it is preferred if the determination step, that is to say the step in which the smaller of the at least two Dutty cycles is determined, is repeated at predefinable time intervals. This ensures that the LEDs are operated for as long a period as possible with an optimal ratio of dutty cycle and instantaneous current.
  • A preferred embodiment of the method according to the invention is characterized in that, moreover, it is determined whether a brightness output of the at least one LED to be set can be achieved with the current instantaneous current at a third predefinable Dutty cycle, in particular a Dutty cycle of 0%. If the result of this determination is "no", the instantaneous current is increased according to the invention. So even if a Dutty cycle of 0% at the short circuit switch is no longer sufficient to achieve a high set brightness output of at least one LED, the instantaneous current is raised again. This allows a dynamic adjustment of the instantaneous current, both downwards and upwards. The LEDs are thus operated so that on the one hand the brightness to be set can be realized, on the other hand, this is done with the lowest possible instantaneous current.
  • Preferably, the increase of the instantaneous current takes place in one step, wherein the step is selected so that at a fourth predetermined Dutty cycle, in particular a Dutty cycle of at most 20%, preferably 0%, the brightness output of the at least one LED to be set is achievable. The increase in one step enables a quick response to a momentary brightness request, for example in a dangerous situation. On the other hand, this is done in such a way that the brightness output to be set is achieved at the lowest possible instantaneous current of the current source.
  • If a time duration in which the maximum instantaneous current flows exceeds a predefinable time duration, the maximum instantaneous current is the rated current of the at least one LED. This ensures that the LED will not be damaged even if it has to emit high brightness over a longer period of time. If, however, a time period in which the maximum instantaneous current flows does not exceed a predefinable time duration, then the maximum instantaneous current may be the maximum pulse current of the at least one LED. As a result, particularly high levels of brightness can be achieved, in particular at certain points, whereby it is again ensured that the LEDs affected thereby and the components of the circuit arrangement are not damaged. Such high brightnesses have not been achieved in the prior art, since the components involved, in particular driver and power source, were not designed to continuously supply the maximum pulse current of the at least one LED. Only the variation of the current provided by the current source enables the provision of a particularly high current over a short limited period of time.
  • As a result of the above-mentioned increase of the instantaneous current, the at least one other duty cycle is advantageously increased such that at least one LED whose short-circuit switch is operated with the at least one other duty cycle outputs its currently set brightness. This ensures that all LEDs output their currently set brightness.
  • While in the preferred embodiments presented above, the aim was to achieve a brightness to be set with the largest possible duty cycle and the lowest possible instantaneous current of the current source, another preferred embodiment of the invention takes into account the fact that, if the instantaneous current already exists, the current source a brightness requirement occurs, which by means of a given duty cycle in this minimum instantaneous current can not be set because it is lower.
  • According to the invention, therefore, it is further provided that it is determined whether a brightness output of the at least one LED to be set can be achieved with the current duty cycle at a minimum instantaneous current of the current source. If this is not the case, since the brightness output which can be set in the current duty cycle is above the brightness output to be set, the duty cycle is increased according to the invention, with which the short-circuit switch of the relevant LED is operated. The invention therefore enables an extremely large dynamic range of the brightness to be emitted by the LEDs, which could not be achieved according to the prior art procedure.
  • Further preferred embodiments emerge from the subclaims.
  • The preferred embodiments presented with reference to the method according to the invention and their advantages apply correspondingly, as far as applicable, to the circuit arrangement according to the invention. The corresponding steps are realized by appropriate design of the control device.
  • Short description of the drawing (s)
  • Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. Show it:
  • 1 a schematic representation of an embodiment of a circuit arrangement according to the invention;
  • 2 the time course of various signals from 1 in a method known from the prior art;
  • 3 the time course of various signals from 1 a first embodiment of a method according to the invention; and
  • 4 the time course of various signals from 1 a second embodiment of a method according to the invention.
  • Preferred embodiment of the invention
  • 1 shows a schematic representation of an embodiment of a circuit arrangement according to the invention. This comprises a plurality of LEDs, in this case LED1, LED2, LED3, wherein each LED a short-circuiting switch is connected in parallel, in the present case the LED1 of the short-circuiting switch KS1, the LED2 of the short-circuiting switch KS2 and the LED3 of the short-circuiting switch KS3. Although in the present case only one LED is connected in parallel with each short-circuit switch, it goes without saying that each short-circuit switch can also have an LED string comprising a plurality of serially coupled LEDs connected in parallel.
  • A current source I Q is connected in series with these parallel circuits, the combination of current source I Q and the several parallel circuits being coupled between a supply voltage V CC and a reference potential. The current source I Q is designed to deliver a rated current I 0 . The current current provided by the current source I Q is denoted by I. The current source I Q preferably comprises a switching regulator and a freewheeling diode and thus operates very low loss.
  • The circuit arrangement further comprises a control device 10 with an input St to which control signals for setting a momentary brightness output of the LED1, LED2, LED3 are supplied. The individual control signals can be provided serially at the input St. Alternatively, a plurality of such inputs St may be provided. The control device 10 In this case has three outputs, namely an output A1 for driving the first short-circuit switch KS1, an output A2 for driving the second short-circuit switch KS2 and an output A3 for driving the third short-circuit switch KS3. The signals provided at the outputs A1 to A3 are in each case PWM signals which are distinguished by a respective current duty cycle, that is to say a momentary duty cycle.
  • The signal provided at output A1 is designated S1, the signal provided at output A2 is S2, and the signal provided at output A3 is designated S3. The duty cycle of the signal S1 is D1, that of the signal S2 is D2 and that of the signal S3 is D3. The control device 10 moreover has an output A4 which is coupled to a control input of the current source and over which the instantaneous current I output by the current source I Q can be adjusted.
  • 2 shows a schematic representation of the time course of the current I, as well as the signals S 1 . S 2 and S 3 ,
  • Here is the signal S 1 complementary to the signal S1, the signal S 2 complementary to the signal S2, and the signal S 3 complementary to the signal S3. The representation of the signals S 1 . S 2 and S 3 The reason is that they reflect the sequence according to which the respective LED emits light.
  • In 2 the circuit arrangement according to the prior art is operated (without connection between the control device 10 and current source I Q ). The current source I Q continuously supplies the rated current I 0 . For example, the duty cycle of the signal S1 is 50%, the duty cycle of the signal S2 is 90% (corresponding to the duty cycle of the signal S 2 10%), the duty cycle of signal S3 is 70% (corresponding to the duty cycle of the signal S 3 30%).
  • In the presentation of 3 is the circuit of 1 operated according to the inventive method. The LEDs should emit the same brightness as in the procedure according to 2 , For this purpose, the control device 10 designed to have the smallest duty cycle of the signals S1, S2 and S3 of 2 to investigate. This is present at signal S1 (50%). The control device 10 is further designed to reduce the smallest duty cycle, in this case S1, as far as possible, that is in the present case to 0%. At the same time, the instantaneous current I of the current source I Q is correspondingly lowered, that is to say below I 0/2 , that is, according to the efficiency characteristics of the LEDs, to less than half of the rated current I 0 , which results in the efficiency advantage of the present invention. In the example the typical value is 0.4 · I 0 .
  • The duty cycle S 1 is to achieve the desired brightness output of the LED1 now 100%. The duty cycles of the further signals S2, S3 are adjusted accordingly. After adjustment, the duty cycle S2 is therefore 80%, corresponding to the duty cycle of the signal S 2 20%, and the duty cycle S3 40%, the duty cycle of the signal S 3 corresponding to 60%.
  • Will the circuit of 1 with the signals according to 3 operated, the LEDs LED1, LED2, LED3 output the same brightness as when they are in accordance with the signals from 2 operate. Thereby, however, that the current I in the procedure according to 3 only half as high as the procedure after 2 , the LEDs LED1, LED2, LED3 are operated in a working area, which is characterized by a higher efficiency than according to the procedure of 2 ,
  • The reduction of the Dutty cycles and the corresponding reduction of the instantaneous current I of the current source I Q can take place in stages, in particular in predefinable stages. In order to respond to instantaneous fluctuations in the desired brightness output, the test of whether a reduction of the instantaneous current I is possible is repeated at predeterminable time intervals.
  • If it is determined that at the instantaneous instantaneous current I and a predefinable dutty cycle of the signals S1, S2, S3, a brightness output to be set can no longer be achieved, the instantaneous current I is increased again. The increase is preferably such that the smallest Dutty cycle of the signals S1, S2, S3 is 0%. The other Dutty cycles are adjusted accordingly.
  • If it is determined that with the current Dutty cycles at a minimum instantaneous current I of the current source I Q a brightness output of at least one LED to be set is no longer achievable, since the brightness output adjustable with the current Dutty cycle is above the brightness output to be set, the duty Cycles, with which the short circuit of the LEDs are operated, again increased accordingly.
  • In the control device 10 It can be provided that the above-mentioned checking steps are carried out at predeterminable time intervals or when the control signals at the input St. change. If the brightness emitted by the LEDs is fed to a control circuit, the control device can 10 Perform the set verification step, if there is a change in the control of the short-circuit switch KS1 to KS3 due to the control circuit.
  • 4 shows the operation of the circuit of 1 according to a further embodiment of the method according to the invention. Shown are the sake of simplicity, only the time course of the instantaneous current I and the signals S 1 and S 2 , The duty cycle of the signal S 3 during the periods T1 and T3 100%. How out 4 It can be seen that the duty cycle of the signals S 1 and S 2 during the period T1 60%, the instantaneous current I corresponds to its nominal value I 0 . Accordingly, the LEDs LED1 and LED2 emit an average brightness during the period T1, the LED3 a maximum brightness which can be emitted over a longer period of time. At time t 1 , a particularly high brightness output of the LED1 is desired. This is achieved here by the fact that the duty cycle of the signal S 1 during the period T2 is raised to 100% and at the same time the instantaneous current I is raised to the maximum pulse current I P. However, the operation of the circuit arrangement with the maximum pulse current I P is possible only during a time period T max , without the risk of damaging elements of the circuit arrangement. In the present case, the period T2 is smaller than the period T max , so that the circuit arrangement can be operated safely with the maximum pulse current I P.
  • Since, during the period T2, the LED 2 is to emit the same brightness as during the period T1, the duty cycle of the signal becomes S 2 Reduced in relation to nominal current to maximum pulse current taking into account the efficiency characteristic of LED2. At the time t 2 , operation of the LED 1 is desired again with the brightness as in the period T1. Therefore, in the period T3, the instantaneous current I is lowered back to the rated current I 0 , or, if the operation of the LED3 allows this, even further.
  • The duty cycles of the signals S 1 and S 2 are adjusted again accordingly, that is the duty cycle of the signal S 1 to deliver the desired brightness in the period T3, the duty cycle of the signal S 2 again to the duty cycle according to period T1, if it is desired that the LED2 continuously outputs the same brightness during the periods T1 to T3.
  • The period T max may be, for example, between 1 ms and 100 ms, preferably 20 ms.

Claims (13)

  1. A method of operating a plurality of LEDs (LED1, LED2, LED3) on a circuit arrangement having a supply terminal for coupling to a supply voltage (V CC ); a reference potential terminal for coupling to a reference potential; at least a first parallel connection of at least one first LED (LED1) and a first short-circuit switch (KS1) for short-circuiting the at least one first LED (LED1); at least one second parallel connection of at least one second LED (LED2) and a second short-circuit switch (KS2) for short-circuiting the at least one second LED (LED2); a current source (I Q ), wherein the series circuit of the current source (I Q ), the at least one first and the at least one second parallel connection between the supply terminal and the reference potential terminal is coupled; and a control device ( 10 ), the at least one first output (A1) for driving the first short-circuit switch (KS1); a second output (A2) for driving the second short-circuit switch (KS2); and at least one input (St) for supplying at least one first control signal for setting an instantaneous brightness output of the at least one first LED (LED1) and a second control signal for setting a momentary brightness output of the at least one second LED (LED2); characterized by the following step: varying the instantaneous current (I) of the current source (I Q ) by the control device ( 10 ) as a function of the instantaneous brightness output to be set of the at least one first LED (LED1) and / or the at least one second LED (LED2).
  2. Method according to Claim 1, characterized by the following steps: a) provision of a first PWM signal (S1) having a first duty cycle at the first output (A1) of the control device ( 10 ); and b) providing a second PWM signal (S2) having a second duty cycle at the second output (A2) of the control device (FIG. 10 ).
  3. Method according to claim 2, characterized by the following steps: c) determining the smaller of the at least two duty cycles; d) reducing the smaller of the at least two duty cycles and lowering the instantaneous current (I) of the current source (I Q ) such that the at least one LED (LED1, LED2, LED3) whose short-circuit switch (KS1, KS2, KS3) with the operated smaller duty cycle, their currently set brightness outputs; and e) reducing the at least one other duty cycle in such a way that the at least one LED (LED1, LED2, LED3), whose short-circuit switch (KS1, KS2, KS3) is operated with the at least one other duty cycle, its currently set brightness emits.
  4. A method according to claim 3, characterized in that in step d) the smaller of the two duty cycles is reduced to a duty cycle of at most 10%, preferably at most 5%, more preferably to 0%.
  5. Method according to one of claims 3 or 4, characterized in that the reduction of the duty cycle and the corresponding reduction of the instantaneous current (I) of the current source (I Q ) stepwise, in particular in predeterminable stages, takes place.
  6. Method according to one of claims 3 to 5, characterized in that step c) is repeated at predetermined time intervals.
  7. Method according to one of claims 2 to 6, characterized by the following steps: f) determining whether with the current instantaneous current (I) at a third predetermined duty cycle, in particular a duty cycle of 0%, a brightness output to be set the at least one LED (LED1, LED2, LED3) can be achieved; and g) if the answer to step f) is no: increasing the instantaneous current (I).
  8. Method according to claim 9, characterized, the increase of the instantaneous current (I) takes place in one step, the step being selected that at a fourth predetermined duty cycle, in particular a duty cycle of at most 20%, preferably 0%, the brightness output of the at least one LED (LED1, LED2, LED3) to be set is achievable.
  9. Method according to one of claims 7 or 8, characterized in that the maximum instantaneous current (I) of the rated current (I 0 ) of the at least one LED (LED1, LED2, LED3) is, if a period in which the maximum instantaneous current (I) flows, a predetermined period of time (T max ) exceeds.
  10. Method according to one of claims 7 to 9, characterized in that the maximum instantaneous current (I) is the maximum pulse current (I P ) of the at least one LED (LED1, LED2, LED3), if a period of time in which the maximum instantaneous current (I ) flows, does not exceed a predetermined period of time (T max ).
  11. Method according to one of claims 7 to 10, characterized by the following step: h) increasing the at least one other duty cycle in such a way that at least one LED (LED1, LED2, LED3), whose short-circuit switch (KS1, KS2, KS3) is operated with the at least one other duty cycle, outputs its current brightness to be set.
  12. Method according to one of the preceding claims, characterized by the following steps: i) determining whether with the current duty cycle at a minimum instantaneous current (I) of the current source (I Q ) a brightness output of the at least one LED to be set (LED1, LED2, LED3) is achievable; and j) if the answer to step i) is no, since the brightness output adjustable at the current duty cycle is above the brightness output to be adjusted: increasing the duty cycle with which the short circuit switch (KS1, KS2, KS3) of the at least one LED (LED1, LED2, LED3) is operated.
  13. Circuit arrangement for operating a plurality of LEDs (LED1, LED2, LED3) with - a supply terminal for coupling to a supply voltage (V CC ); A reference potential terminal for coupling to a reference potential; - At least a first parallel connection of at least a first LED (LED1) and a first short-circuit switch (KS1) for shorting the at least one first LED (LED1); - At least a second parallel connection of at least one second LED (LED2) and a second short-circuit switch (KS2) for shorting the at least one second LED (LED2); - A current source (I Q ), wherein the series circuit of the current source (I Q ), the at least a first and the at least one second parallel connection between the supply terminal and the reference potential terminal is coupled; and a control device ( 10 ) comprising: - at least one first output (A1) for driving the first short circuit switch (KS1); - A second output (A2) for driving the second short-circuit switch (KS2); and - at least one input (St) for supplying at least one control signal for setting an instantaneous brightness of the at least one first (LED1) and one instantaneous brightness of the at least one second LED (LED2); characterized in that the current source (I Q ) comprises a control input for varying the instantaneous current (I) which it can provide, the control device ( 10 ) further comprises a third output (A4) coupled to the control input of the current source (I Q ).
DE201010003244 2010-03-25 2010-03-25 Method and circuit arrangement for operating a plurality of LEDs Ceased DE102010003244A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE201010003244 DE102010003244A1 (en) 2010-03-25 2010-03-25 Method and circuit arrangement for operating a plurality of LEDs

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE201010003244 DE102010003244A1 (en) 2010-03-25 2010-03-25 Method and circuit arrangement for operating a plurality of LEDs
PCT/EP2011/052181 WO2011117024A1 (en) 2010-03-25 2011-02-15 Method and circuit arrangement for operating a multiplicity of leds

Publications (1)

Publication Number Publication Date
DE102010003244A1 true DE102010003244A1 (en) 2011-09-29

Family

ID=43929146

Family Applications (1)

Application Number Title Priority Date Filing Date
DE201010003244 Ceased DE102010003244A1 (en) 2010-03-25 2010-03-25 Method and circuit arrangement for operating a plurality of LEDs

Country Status (2)

Country Link
DE (1) DE102010003244A1 (en)
WO (1) WO2011117024A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014090640A1 (en) * 2012-12-12 2014-06-19 Osram Gmbh Current compensation device and lighting apparatus with the same
DE102016207732A1 (en) * 2016-05-04 2017-11-09 Bayerische Motoren Werke Aktiengesellschaft Lighting device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013170397A1 (en) * 2012-05-16 2013-11-21 钰瀚科技股份有限公司 Lighting device driving method and device based on light emitting diode

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050243022A1 (en) * 2004-04-30 2005-11-03 Arques Technology, Inc. Method and IC driver for series connected R, G, B LEDs
WO2009029553A2 (en) * 2007-08-24 2009-03-05 Cirrus Logic, Inc. Multi-led control
DE102007044476A1 (en) * 2007-09-18 2009-03-19 Osram Gesellschaft mit beschränkter Haftung Lighting unit and method for controlling the lighting unit
DE102007053481A1 (en) * 2007-11-09 2009-05-14 Diehl Aerospace Gmbh Method for producing mixed light colors

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2972780A1 (en) * 2005-04-08 2006-10-12 Eldolab Holding B.V. Methods and apparatuses for operating groups of high-power leds
US20080001547A1 (en) * 2005-09-20 2008-01-03 Negru Sorin L Driving parallel strings of series connected LEDs
BRPI0820090A2 (en) * 2007-12-07 2015-06-30 Koninkl Philips Electronics Nv LED lamp, and, LED lamp power management method and system
TWI459858B (en) * 2008-06-24 2014-11-01 Eldolab Holding Bv Control unit for an led assembly and lighting system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20050243022A1 (en) * 2004-04-30 2005-11-03 Arques Technology, Inc. Method and IC driver for series connected R, G, B LEDs
WO2009029553A2 (en) * 2007-08-24 2009-03-05 Cirrus Logic, Inc. Multi-led control
DE102007044476A1 (en) * 2007-09-18 2009-03-19 Osram Gesellschaft mit beschränkter Haftung Lighting unit and method for controlling the lighting unit
DE102007053481A1 (en) * 2007-11-09 2009-05-14 Diehl Aerospace Gmbh Method for producing mixed light colors

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014090640A1 (en) * 2012-12-12 2014-06-19 Osram Gmbh Current compensation device and lighting apparatus with the same
DE102016207732A1 (en) * 2016-05-04 2017-11-09 Bayerische Motoren Werke Aktiengesellschaft Lighting device

Also Published As

Publication number Publication date
WO2011117024A1 (en) 2011-09-29

Similar Documents

Publication Publication Date Title
US8125159B2 (en) LED driving device with variable light intensity
EP2760254B1 (en) Adjusting color temperature in a dimmable LED lighting system
EP2468071B1 (en) Control unit for a led assembly and lighting system
US8400079B2 (en) LED drive circuit, dimming device, LED illumination fixture, LED illumination device, and LED illumination system
DE10013215B4 (en) Control circuit for light emitting diodes
US7352135B2 (en) Lighting controller for lighting device for vehicle
EP2471342B1 (en) METHOD AND APPARATUS FOR CONTROLLING DIMMING LEVELS OF LEDs
TWI459858B (en) Control unit for an led assembly and lighting system
US7126290B2 (en) Light dimmer for LED and incandescent lamps
JP5198456B2 (en) Switching optical element and operation method thereof
US8410720B2 (en) Solid state lighting circuit and controls
US8339053B2 (en) LED dimming apparatus
KR20100019503A (en) Driver device for leds
US20140292201A1 (en) Driver Circuit for Efficiently Driving a Large Number of LEDs
US7855520B2 (en) Light-emitting diode driving circuit and secondary side controller for controlling the same
EP2596680B1 (en) Triac dimming systems for solid-state loads
RU2481752C2 (en) System and method to control led lamp power supply
DE102008010320B4 (en) Light-emitting device for a vehicle
US8471495B2 (en) Light-emitting diode driving apparatus and light-emitting diode lighting controlling method
WO2011077909A1 (en) Led drive circuit
JP2009009817A (en) Illumination apparatus
US8890419B2 (en) System and method providing LED emulation of incandescent bulb brightness and color response to varying power input and dimmer circuit therefor
WO2013011924A1 (en) Led illumination device
JP4943892B2 (en) Light control device and lighting fixture using the same
JP2011119738A (en) Light-emitting apparatus

Legal Events

Date Code Title Description
R081 Change of applicant/patentee

Owner name: OSRAM GMBH, DE

Free format text: FORMER OWNER: OSRAM GESELLSCHAFT MIT BESCHRAENKTER HAFTUNG, 81543 MUENCHEN, DE

Effective date: 20111130

Owner name: OSRAM AG, DE

Free format text: FORMER OWNER: OSRAM GESELLSCHAFT MIT BESCHRAENKTER HAFTUNG, 81543 MUENCHEN, DE

Effective date: 20111130

R016 Response to examination communication
R016 Response to examination communication
R002 Refusal decision in examination/registration proceedings
R081 Change of applicant/patentee

Owner name: OSRAM GMBH, DE

Free format text: FORMER OWNER: OSRAM AG, 81543 MUENCHEN, DE

Effective date: 20130129

R003 Refusal decision now final

Effective date: 20130316

R081 Change of applicant/patentee

Owner name: OSRAM GMBH, DE

Free format text: FORMER OWNER: OSRAM GMBH, 81543 MUENCHEN, DE

Effective date: 20130827