WO2008098617A1 - Circuit et procédé pour faire fonctionner au moins une del - Google Patents

Circuit et procédé pour faire fonctionner au moins une del Download PDF

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Publication number
WO2008098617A1
WO2008098617A1 PCT/EP2007/051468 EP2007051468W WO2008098617A1 WO 2008098617 A1 WO2008098617 A1 WO 2008098617A1 EP 2007051468 W EP2007051468 W EP 2007051468W WO 2008098617 A1 WO2008098617 A1 WO 2008098617A1
Authority
WO
WIPO (PCT)
Prior art keywords
circuit arrangement
led
switch
led4
led3
Prior art date
Application number
PCT/EP2007/051468
Other languages
German (de)
English (en)
Inventor
Ralf Hying
Peter Niedermeier
Original Assignee
Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH
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 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH filed Critical Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH
Priority to PCT/EP2007/051468 priority Critical patent/WO2008098617A1/fr
Publication of WO2008098617A1 publication Critical patent/WO2008098617A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/10—Controlling the intensity of the light
    • H05B45/12—Controlling the intensity of the light using optical feedback
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • H05B45/375—Switched mode power supply [SMPS] using buck topology
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • Y—GENERAL 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Definitions

  • the present invention relates to a circuit arrangement for operating at least one LED, wherein the circuit arrangement comprises a DC-DC converter, which comprises an input with a first and a second input terminal for applying an input voltage, and an output with a first and second output terminals for providing an output voltage, wherein at least one LED is coupled between the first and second output terminals. It also relates to a corresponding method for operating at least one LED.
  • the problem underlying the present invention results in particular from the use of LEDs in microdisplay applications for front and rear projection. It is necessary to switch the current and thus the light in the ⁇ s range on and off. The current and thus the brightness of the light emitted by the LED should be adjustable. It should be noted that the currents of the LEDs used for these applications are sometimes more than 1 A.
  • linear power amplifiers have hitherto been used for this purpose.
  • these are characterized by high power loss and a resulting low efficiency.
  • This enlarges the in view of the high flowing currents already existing problems in the derivation of the resulting heat.
  • Direct operation of the LEDs at the output of a DC-DC converter, for example a step-down converter is currently not possible with reasonable effort since the switch of the step-down converter would have to be controlled in the MHz range in order to switch the light on and off in the ⁇ s range, in particular in the range below 1 microseconds to allow.
  • the object of the present invention is therefore to provide a circuit arrangement and a method for operating at least one LED, in which the at least one LED can be operated in a cost effective manner and with the lowest possible power loss such that the switching on and off of the LEDs With switching times of up to ⁇ 1 ⁇ s is possible.
  • the present invention is based on the realization that the above object can be achieved if, in series with the at least one LED, an electronic switch is arranged with which the circuit in the branch in which the at least one LED is arranged is closed and opened can. As a result, the control of the at least one LED is separated from the behavior of the buck converter. The switching on and off of the LEDs takes place un ⁇ depending on the switching time of the switch of the DC-DC Transducer or circulating parasitic inductances.
  • a circuit arrangement according to the invention further comprises a drive device for opening and closing the first switch.
  • an ohmic resistor is arranged in series with the LEDs and the electronic switch, with which the current flowing in this branch can be adjusted.
  • the switching on and off is no longer indirectly dependent on the switch of the DC-DC converter, resulting in the extremely high An Kunststofffrequenzen for this switch, but they result directly from appropriate control of the serial to the LEDs arranged switch.
  • This measure therefore makes it possible to solve the problem underlying the invention, the use of a DC-DC converter and thereby results - in comparison to the linear power amplifiers used in the prior art - in a high efficiency, low power loss and low heat.
  • In order to regulate the current through the LEDs provided at the transition from ⁇ of the DC-DC converter voltage can be varied by appropriate control of the DC-DC converter.
  • the LEDs of the parallel-connected series circuit are designed, light different color.
  • the LEDs of the parallel-connected series circuit are designed, light different color.
  • the circuit arrangement further comprises a first regulating or control device for controlling or controlling the actual value of the output voltage to a desired value which can be predetermined by a nominal value setting device. Can thereby be within certain limits the brightness of the light emitted by the LEDs ⁇ SET len.
  • the first Regelvor ⁇ device comprises a voltage measuring device for measuring the actual value of the output voltage.
  • This measure takes into account the fact that the LED voltage is not constant and changes with both the current and the manufacturing batch.
  • Using a voltage measuring ⁇ device can thus be ensured that the correct voltage difference between the output voltage, which is provided on the DC-DC converter, and the voltage dropping at the at least one LED voltage is set, this difference the current through the at least one LED and thus determines the brightness of the light emitted by it.
  • the circuit arrangement further comprises a setpoint variation device that is designed to vary the setpoint value that can be predetermined by the setpoint specification device.
  • a setpoint variation device that is designed to vary the setpoint value that can be predetermined by the setpoint specification device.
  • This measure makes it possible to set the desired value as a function of a signal, in particular a signal. a video signal, to vary. Therefore especially preferred environmentally setpoint variation apparatus sums an input for supplying a video signal, wherein the target ⁇ value varying means is adapted to determine the predetermined setpoint in response to the video signal, in particular depending on the brightness of a color component ⁇ riieren to va.
  • the voltage provided at the output of the DC-DC converter can be sensibly varied, ie, for example, adapted to the required brightness, the power loss converted in the ohmic resistance is further reduced, which results in an even higher degree of efficiency.
  • the setpoint variation device preferably also has an input for supplying an information signal about the switching state of the first switch, wherein the setpoint variation device is designed to vary the setpoint value as a function of the switching state of the at least one first switch.
  • a preferred development further comprises a second control device for controlling at least one property of the light emitted by the at least one LED to a predefinable setpoint value.
  • the second control device in this case comprises a light sensor for sensing at least one property of the min ⁇ least one LED emitted by the light.
  • the first control device has a time constant that is greater by at least a factor of 10 than the second control device. Also by this procedure can be particularly fast on and off swinging realisie ⁇ reindeer.
  • Figure 1 shows a schematic representation of the structure of a first embodiment of a circuit arrangement according to the invention.
  • Fig. 2 is a schematic representation of the structure of a second embodiment of an inventive ⁇ SEN circuitry
  • FIG. 3 is a schematic representation of the construction of a third exemplary embodiment of a circuit arrangement according to the invention.
  • FIG. Figure 4 is a schematic illustration of the construction of a fourth embodiment of an inventive ⁇ SEN circuitry.
  • Fig. 5 is a schematic illustration of the construction of a fifth embodiment of an inventive ⁇ SEN circuitry.
  • Fig. 1 shows a first embodiment of an inventive ⁇ circuit arrangement.
  • an input voltage U e in is applied to an input with a first El and a second input terminal E 2.
  • a capacitor Ci is arranged, which provides the input voltage U e in to a DC-DC converter 10.
  • this is designed as a buck converter and comprises a switch S1, a diode D1, an inductance L1 and a capacitor C2, the capacitor C2, ie at the output of the DC-DC converter 16, having a first A1 and a second A1 Output terminal A2 is formed, the output voltage U zw , the so-called intermediate circuit voltage, to a Se- rienscrien comprising an ohmic resistance R, four LEDs LEDl to LED4 and an electronic switch S2 is provided.
  • the voltage dropping across the four LEDs LED1 to LED4 is denoted by U LED .
  • the switch S2 is driven by a drive device 12 for opening and closing the switch S2.
  • the first series ⁇ circuit comprises an ohmic resistance Rl, four LEDs of a first color, at which the voltage U LED i drops, and a switch S21
  • the second series circuit comprises a resistor R2, four LEDs a two ⁇ th color, at which the voltage U LED2 drops, and egg ⁇ NEN switch S22
  • the third series circuit comprises a resistor R3, four LEDs of a third color, where the voltage U LED3 drops, and a switch S23.
  • the number of LEDs per branch may vary, as well as the color combinations may vary, ie a respective series circuit may have LEDs of only one color, but may also be a composite of LEDs of different colors.
  • Fig. 3 shows a third embodiment of a circuit arrangement according OF INVENTION ⁇ dung.
  • the latter has a regulating device 14 for regulating the actual value of the voltage U zw to a desired value specified by a nominal value setting device 16.
  • the voltage is regulated by appropriate control of the switch Sl of the DC-DC converter 16.
  • a set value variation device 18 which on the one hand has an input V for supplying a video signal, wherein the setpoint variation device 18 is designed to set the desired value predefinable by the setpoint setting device 16 as a function of the video signal, in particular as a function of the brightness a Farban ⁇ part, to vary.
  • the setpoint varying device 18 also has an input I for supplying an information signal on the switching state of the switch S2, wherein the setpoint varying device 18 is designed to vary the predetermined by the set value setting device 16 target value as a function of the switching state of the switch S2.
  • the information signal I is preferably coupled out at the output of the drive device 12.
  • the embodiment shown in FIG. 5 has a second control device 20, which in the present case is taken over by the same component, in particular a microcontroller, which also assumes the function of the control device 12 and of the first control device 14. It includes a light sensor 22 for sensing at least one property of the light emitted by the LEDs.
  • a light sensor 22 for sensing at least one property of the light emitted by the LEDs.
  • One Ver ⁇ compensates for the time constants of the first 14 and the second control device 20, it is particularly preferred if the first control device 14 a at least the Factor 10 has greater time constant than the second control device 20th

Landscapes

  • Circuit Arrangement For Electric Light Sources In General (AREA)
  • Led Devices (AREA)

Abstract

L'invention concerne un circuit pour faire fonctionner au moins une DEL (LED1 ; LED2 ; LED3 ; LED4), ce circuit comprenant : un convertisseur CC-CC (10), qui comporte une entrée avec un premier (E1) et un second (E2) branchements d'entrée pour appliquer une tension d'entrée (Uein), et une sortie avec un premier (A1) et un second (A2) branchements de sortie pour fournir une tension de sortie (UZW) ; et au moins une DEL (LED1 ; LED2 ; LED3 ; LED4), qui est couplée entre le premier (A1) et le second (A2) branchements de sortie. Le circuit comprend en outre : au moins une résistance ohmique (R1 ; R2 ; R3) et un premier commutateur (S1), qui sont couplés en série avec la DEL au moins unique (LED1 ; LED2 ; LED3 ; LED4) entre le premier (A1) et le second (A2) branchements de sortie ; et un dispositif d'asservissement (12) pour ouvrir et fermer le premier commutateur (S1). L'invention concerne en outre un procédé correspondant pour faire fonctionner au moins une DEL.
PCT/EP2007/051468 2007-02-15 2007-02-15 Circuit et procédé pour faire fonctionner au moins une del WO2008098617A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/EP2007/051468 WO2008098617A1 (fr) 2007-02-15 2007-02-15 Circuit et procédé pour faire fonctionner au moins une del

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2007/051468 WO2008098617A1 (fr) 2007-02-15 2007-02-15 Circuit et procédé pour faire fonctionner au moins une del

Publications (1)

Publication Number Publication Date
WO2008098617A1 true WO2008098617A1 (fr) 2008-08-21

Family

ID=38109911

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2007/051468 WO2008098617A1 (fr) 2007-02-15 2007-02-15 Circuit et procédé pour faire fonctionner au moins une del

Country Status (1)

Country Link
WO (1) WO2008098617A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1036907C2 (en) * 2009-04-28 2010-10-29 Ind Solutions B V Device for driving a light source.
WO2011084805A1 (fr) * 2010-01-05 2011-07-14 3M Innovative Properties Company Procédé, appareil et système permettant de fournir un courant pulsé à une charge
EP2563095A3 (fr) * 2011-08-22 2013-03-27 Panasonic Corporation Dispositif d'éclairage, dispositif d'éclairage de phare et unité de phare et véhicule en disposant

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000037904A1 (fr) * 1998-12-18 2000-06-29 Koninklijke Philips Electronics N.V. Luminaire a diodes electroluminescentes
US20020101198A1 (en) * 2000-12-18 2002-08-01 Kemp William Harry LED lamp with color and brightness controller for use in wet, electrically hazardous bathing environments
US20060022607A1 (en) * 2004-07-30 2006-02-02 Au Optronics Corp. Device for driving light emitting diode strings

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000037904A1 (fr) * 1998-12-18 2000-06-29 Koninklijke Philips Electronics N.V. Luminaire a diodes electroluminescentes
US20020101198A1 (en) * 2000-12-18 2002-08-01 Kemp William Harry LED lamp with color and brightness controller for use in wet, electrically hazardous bathing environments
US20060022607A1 (en) * 2004-07-30 2006-02-02 Au Optronics Corp. Device for driving light emitting diode strings

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1036907C2 (en) * 2009-04-28 2010-10-29 Ind Solutions B V Device for driving a light source.
WO2011084805A1 (fr) * 2010-01-05 2011-07-14 3M Innovative Properties Company Procédé, appareil et système permettant de fournir un courant pulsé à une charge
CN102695997A (zh) * 2010-01-05 2012-09-26 3M创新有限公司 将脉冲电流供应至负载的方法、设备和系统
EP2563095A3 (fr) * 2011-08-22 2013-03-27 Panasonic Corporation Dispositif d'éclairage, dispositif d'éclairage de phare et unité de phare et véhicule en disposant
US8766540B2 (en) 2011-08-22 2014-07-01 Panasonic Corporation Lighting device, headlamp lighting device, and headlamp unit and vehicle having same

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