EP1449408A1 - Circuit for an led array - Google Patents

Circuit for an led array

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Publication number
EP1449408A1
EP1449408A1 EP02803750A EP02803750A EP1449408A1 EP 1449408 A1 EP1449408 A1 EP 1449408A1 EP 02803750 A EP02803750 A EP 02803750A EP 02803750 A EP02803750 A EP 02803750A EP 1449408 A1 EP1449408 A1 EP 1449408A1
Authority
EP
European Patent Office
Prior art keywords
led
led array
circuit arrangement
array according
current
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.)
Granted
Application number
EP02803750A
Other languages
German (de)
French (fr)
Other versions
EP1449408B1 (en
EP1449408B2 (en
Inventor
Simon BLÜMEL
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.)
Ams Osram International GmbH
Original Assignee
Osram Opto Semiconductors 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
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Priority claimed from DE10242365.2A external-priority patent/DE10242365B4/en
Application filed by Osram Opto Semiconductors GmbH filed Critical Osram Opto Semiconductors GmbH
Publication of EP1449408A1 publication Critical patent/EP1449408A1/en
Publication of EP1449408B1 publication Critical patent/EP1449408B1/en
Application granted granted Critical
Publication of EP1449408B2 publication Critical patent/EP1449408B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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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]
    • H05B45/40—Details of LED load circuits
    • H05B45/44—Details of LED load circuits with an active control inside an LED matrix
    • H05B45/46—Details of LED load circuits with an active control inside an LED matrix having LEDs disposed in parallel lines
    • 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]
    • H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
    • 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]
    • H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
    • H05B45/52—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits in a parallel array of LEDs
    • 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]
    • H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
    • H05B45/54—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits in a series array of LEDs
    • 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
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S362/00—Illumination
    • Y10S362/80—Light emitting diode

Definitions

  • the present invention relates to a circuit arrangement for an LED array, in particular for a light signal device, with two or more LED chains connected in parallel, in each of which at least one LED (light-emitting diode, light-emitting diode) is arranged, with two or more LEDs that are connected in series.
  • the anode sides of the LED chains can each be coupled to the positive pole of a supply voltage, and the cathode sides can each be coupled to the negative pole of the supply voltage.
  • a variation in the forward voltage of LEDs can be due to the manufacturing process.
  • a fine grouping of the LEDs with regard to the forward voltage is conceivable. This is associated with comparatively high costs, since appropriate logistics and warehousing are required.
  • the forward voltage of an LED is temperature-dependent, whereby different temperature dependencies can occur between individual LEDs. A change in temperature can therefore lead to a change in the forward voltages.
  • an electrical resistor is connected in series with each LED chain in conventional circuits. Overall, this resistance leads to a flatter UI characteristic of the LED chain in question, so that a certain limitation of the current in the LED chain is achieved.
  • the size of this resistor and thus the voltage drop across it increases, which worsens the efficiency of the overall system.
  • a change in the forward voltage of an LED chain can also be caused by the failure of individual LEDs, for example by a short circuit of an LED.
  • the current is set using resistors connected in series, this leads to a strong redistribution of the currents in the LED chains.
  • the present invention has for its object a
  • circuit arrangement for an LED array with two or more LED chains connected in parallel, in each of which at least one LED is arranged, where two or more LEDs are connected in series and the anode sides of the LED chains are each connected to the positive pole a supply voltage and the cathode sides can each be coupled to the negative pole of the supply voltage, it is provided that for each LED chain a control arrangement for controlling a predetermined current distribution on the individual LED chains is connected in series.
  • the control arrangements preferably each include a current amplification circuit for impressing the current into the respective LED chain.
  • the current amplification circuits can each have a control input for regulating the current in the LED chain, the control inputs of the current amplification circuits being connected to one another.
  • a combination of a transistor with an emitter resistor is provided as the control arrangement, the collector-emitter path or the emitter resistor being connected in series with the respective LED chain.
  • the base connections of the transistors which represent the above-mentioned control inputs, are particularly preferably connected to one another and are at the same potential during operation.
  • the emitter resistor is used in particular to adjust the current distribution on the LED chains.
  • the value is the Emitter resistances are inversely proportional to the corresponding emitter current, which approximately corresponds to the collector current or the current in the associated LED chain (except for interrupted LED chains, as will be explained in more detail below).
  • a control circuit applies a predetermined current to the base connections of the transistors.
  • separate control circuits are provided for the individual LED chains.
  • a common control circuit is provided for a plurality of the LED chains, preferably for all LED chains.
  • the drive circuit which applies a predetermined current to the base connections of the transistors is in each case formed as a series circuit comprising a diode and a resistor, which connects the collector and base connections of the transistors.
  • the diodes ensure that the operating conditions for the transistors are met and, on the other hand, prevent a redistribution of the currents in the LED chains via the common connection of the base connections.
  • a change in the forward voltage of an LED chain which can be caused, for example, by a temperature change or by a short circuit in an LED, is intercepted by means of the control circuit by a corresponding change in the associated collector base voltage, so that the collector current and so that the current in the LED chain does not change or changes only to a small extent.
  • the collector base voltage at the associated transistor increases. Since only the respective base current of the transistors flows through the resistors of the drive circuit, which is typically typically a factor of 100 to 250 smaller than the collector current, the resistors can be dimensioned in such a way that even with a small change in the current through the resistor, a sufficient level high voltage to compensate for the different forward voltages in the individual LED chains across the resistor.
  • the fault case opposite to a short circuit of an LED is a failure of an LED which interrupts the LED chain. This can be caused, for example, by an overload of the LED, so that the LED "burns out”.
  • the intended current distribution is kept constant even in the event of extreme changes in the forward voltages.
  • the collector currents or the currents in the LED chains typically fluctuate only by a few mA.
  • neither an interruption in an LED chain nor a short circuit in an LED chain leads to a breakdown of the current distribution. A costly grouping of the LED components according to forward voltages is not necessary.
  • the values of the resistances in the drive circuit in the first embodiment of the invention are preferably in the range between 100 ohms and 1000 ohms. This means that even relatively small currents can generate sufficiently high compensating voltages to compensate for different forward voltages of the LED chains.
  • the drive circuit which applies a predetermined current to the base connections of the transistors in the control arrangements, is operated in the reverse direction Zener diode formed, which is preferably connected in series with a resistor and / or a fuse.
  • the Zener diode is connected to the base connections on the transistor side.
  • the base current for the transistors is conducted via a single common current path.
  • the supply of the basic connections of the transistors is conducted via a single common current path.
  • 10 transistors can be realized by a current path next to the array, in which the drive circuit, for example the zener diode, is installed. This reduces the circuitry for an LED array compared to the first embodiment.
  • the zener diode should have a zener voltage, which is about
  • I V is greater than the large forward voltage of the LED chains. This ensures a stable operating state for the transistors.
  • an LED chain is interrupted in the second embodiment of the invention, for example because an LED burns out, no more current flows through the defective LED chain, and the voltage between the collector and the base of the associated transistor breaks down.
  • the base of the transistor of the defective chain is still at the same potential due to the common electrical connection of the transistor base connections, the transistor of the defective chain is operated as a diode.
  • the compensation currents required for this flow through the Zener diode and the common connection of the transistor bases.
  • the current distribution predetermined by the dimensioning of the emitter resistances is retained for the other intact LED chains, the currents in the LED chains being approximately equal to the emitter current and, in turn, inversely proportional to the emitter resistances.
  • the fuse is designed in series with the zener diode as a melting resistor. In particular, this prevents the transistors from being destroyed if the array is overloaded.
  • the value of the resistance in series with the zener diode is preferably in the range between 100 ohms and 1000 ohms, so that the required compensation voltages can in turn be generated with relatively small currents.
  • a fuse for example a melting resistor, connected in series with the LED chains.
  • a fuse for example a melting resistor
  • individual faulty LED chains are switched off in a defined manner when the current in the LED chain is too high.
  • the predetermined current distribution in the remaining LED chains is also maintained in the event of an associated interruption of an LED chain.
  • the LED array can be configured flexibly, and in particular a predetermined current can be set for each LED chain without any particular effort. As a rule, a uniform current distribution is desired, which can easily be achieved by using the same emitter resistors.
  • FIG. 1 shows a schematic circuit diagram of a first exemplary embodiment of the invention in accordance with the first embodiment
  • FIG. 2 shows a schematic circuit diagram of a second exemplary embodiment of the invention according to the first embodiment
  • FIG. 3 shows a schematic circuit diagram of a third exemplary embodiment of the invention according to the first embodiment
  • FIG. 4 shows a schematic circuit diagram of a fourth exemplary embodiment of the invention according to the second
  • Figure 5 is a schematic circuit diagram of a fifth embodiment of the invention according to the second embodiment.
  • a plurality of LEDs 2 connected in series to form LED chains Three chains LK1, LK2, LK3 are shown, each with four LEDs 2, wherein a circuit arrangement according to the invention can of course also comprise a different number of LEDs in the LED chains or a different number of LED chains. This is illustrated by the dashed lines in the supply voltage lines (see below), the connection of the transistor base connections (see below) and the LED chains. Furthermore, the number and / or type of LEDs in the individual LED chains can vary from chain to chain.
  • a melting resistor Ful, Fu2, Fu3 can be connected in series with the LED chains LK1, LK2, LK3.
  • the LED Chains LK1, LK2, LK3 are connected on the anode side to the positive pole of a supply voltage U v and on the cathode side each with a control arrangement RA1, RA2, RA3.
  • the control arrangements RA1, RA2, RA3 each include an npn transistor T1, T2, T3, the collector terminals C1, C2, C3 of which each have the cathode side of the associated LED chain LK1, LK2, L3 or the melting resistor Ful which may be connected between them. Fu2, Fu3 is connected.
  • the emitter connection El, E2, E3 is connected to the negative pole of a supply voltage U v via an emitter resistor R12, R22, R32.
  • the transistors T1, T2, T3 in the arrangement shown are designed as commercially available • npn transistors. Between the cathode side or the melting resistance of each LED chain and the respective base connection B1, B2, B3 of the associated transistor T1, T2, T3, there is a control circuit in the form of a series circuit comprising a diode D1, D2, D3 and an electrical resistor Rll, R21, R31 switched.
  • the base connections B1, B2, B3 of the transistors T1, T2, T3 are connected to one another.
  • the running index x denotes the number of the LED chain here and below.
  • the following description also applies generally to an LED array with N LED chains, where x is between 1 and N.
  • the current Ix which - apart from the much lower base current in each case corresponds to the current in the respective LED chain LKx, is regulated in such a way that a voltage of approximately 0.65 is applied to the base-emitter path of the associated transistor Tx V occurs.
  • the current is set via the transistors T1, T2, T3 in such a way that the voltage drop across the emitter resistors is approx. 65 V below the common base potential. Since the voltage between the base and emitter of 0.65V is (almost) the same for transistors T1, T2, T3, the same voltages must drop across the respective emitter resistors R12, R22, R32.
  • the currents II, 12, 13 in the LED chains are thus regulated so that the voltages U12, U22, U32 are the same. Overall, the distribution of the currents on the LED chains is thus determined by the emitter resistors R12, R22, R32, the ratio of the currents being equal to the ratio of the reciprocal emitter resistance values.
  • the emitter current which is made up of the associated base and collector currents, was equated with the collector current, ie the base current, which is much lower in comparison, was neglected.
  • a change in the forward voltage of an LED chain LKx e.g. by short-circuiting an LED, is intercepted by a corresponding change in the associated collector base voltage.
  • the setting of the emitter current Ix and thus the current in the LED chain LKx explained above remains almost unaffected by this, so that the collector current or the current in the LED chain does not change or changes only slightly.
  • the power supply to the base inputs B1, B2, B3 of the transistors Tl, T2, T3 is realized in each case by means of a control circuit in the form of a series connection of a diode D1, D2, D3 and a resistor R11, R21, R31.
  • the diodes D1, D2, D3 have a double function: on the one hand, they set the operating condition of the transistors
  • Tl, T2, T3, ie the required voltage at the respective collector base section Cx-Bx safely, on the other hand they suppress cross currents between the individual LED chains LK1, LK2, LK3.
  • the latter means that there is no current through the common electrical connection of the transistor bases B1, B2, B3, for example due to potential differences in the individual LED chains LK1, LK2, LK3, which can be caused, for example, by different forward voltages or a short-circuited LED , can flow from one LED chain to another LED chain.
  • the diodes D1, D2, D3 are dimensioned so that on them
  • LEDs could also be used here, which can additionally serve as an optical indicator for different forward voltages in the individual chains.
  • the base current of the transistors T1, T2, T3 flows through the electrical resistors R11, R21, R31 and is typically 100 to 250 times smaller than the collector current.
  • These resistors R11, R21, R31 are preferably so dimensionally
  • the resistors R11, R21, R31 preferably have values in the range from 100 ohms to 1000 ohms.
  • the equalizing currents flow through the control circuits of the remaining chains to maintain the voltage at the emitter resistor of the interrupted LED chain.
  • the resistors R11, R21, R31 do not necessarily have to have the same value. The same resistance values are advantageous for optimum reliability and the symmetry of the arrangement.
  • a fuse Fux is preferably connected in series with an LED chain LKx, which additionally prevents excessive current in an LED chain.
  • the fuse blows and thus switches off the LED chain in a defined manner. This breaks the LED chain.
  • the fuses Ful, Fu2, Fu3 can for example be designed as a melting resistor. Commercially available melting resistors can be used that burn out from a defined output and thus permanently interrupt the flow of electricity.
  • a further advantage of the first embodiment of the invention or of the exemplary embodiment shown in FIG. 1 is that a partial stream is branched off for regulation in each LED chain LKx. This increases the reliability and stability of the system.
  • the tolerance of the base currents is 2%, so that overall a comparatively high precision of the current distribution is achieved.
  • circuit arrangement according to FIG. 1 can be expanded by any number of LED chains in the manner shown.
  • the circuit shown in FIG. 1 can also be constructed in an analogous manner with pnp transistors.
  • a corresponding second exemplary embodiment of the invention is shown in FIG. 2.
  • the third exemplary embodiment of the invention shown in FIG. 3 shows an LED array of a size that is used, for example, in signal technology.
  • Corresponding circuits can be used, for example, for traffic signals such as traffic lights or warning lights or for train signals.
  • the circuit corresponds essentially to Figure 2.
  • a total of 120 LEDs 2 in 20 LED chains LK1, ..., LK20 with 6 LEDs each are connected in parallel.
  • the currents in the LED chains of the LED array are additionally controlled by a monitoring circuit 4, which is not described in more detail here.
  • Figure 4 shows a fourth embodiment according to the second embodiment of the invention.
  • several LEDs 2 are also connected in series to form LED chains LKl, LK2, LK3 and the LED chains LKl, LK2, LK3 on the anode side with the positive pole of a supply voltage and on the cathode side via an optional fuse Ful, Fu2, Fu3 each connected to a control arrangement RA1, RA2, RA3.
  • the control arrangements RA1, RA2, RA3 each in turn comprise a transistor Tx, the collector connection Cx of which leads to the corresponding LED chain LKx.
  • the emitter connection Ex is connected to the negative pole of the supply voltage via an emitter resistor Rx2.
  • the base connections B1, B2, B3 of the transistors T1, T2, T3 are connected to one another as in the previous exemplary embodiments and are therefore at the same potential.
  • a common control circuit A which controls the base current for the transistors T1, T2 , T3 generated.
  • a series circuit comprising a Zener diode Dz operated in the reverse direction and a resistor Rz serves as the control circuit.
  • This series connection can optionally include a fuse FuB, for example a melting resistor. This is dimensioned in such a way that it burns out with a predetermined number of interrupted LED chains, each of which leads to an increase in the base current as described. This switches off the entire LED array. Such a mode of operation can be useful, for example, if the remaining number of intact LED chains no longer meets the safety requirements.
  • the fuses Ful, Fu2, Fu3 are also optional and serve as additional protection of the LED chains against excessive currents as described above.
  • the resistor Rz connected in series with the zener diode Dz preferably has a value between 100 ohms and 1000 ohms.
  • the emitter resistors R12, R22, R32 must also have the same value. In special applications, however, different emitter resistances may also be required, for example when combining LEDs of different colors, which usually differ in terms of their specified operating current.
  • FIG. 5 shows a fifth embodiment of the invention according to the second embodiment.
  • the control arrangements RA1, RA2, RA3 are implemented with pnp transistors T1, T2, T3 instead of with npn transistors.
  • control arrangements are arranged between the positive pole of the supply voltage and the anode sides of the LED chains.
  • the control circuit is designed as a series connection of a Zener diode Dz and a resistor Rz and optionally an optional fuse FuB, the Zener diode being connected on the anode side to the negative pole of the supply voltage via the resistor Rz.
  • the first or the second embodiment of the invention can be more advantageous.
  • the first embodiment is characterized by a particular stability, since usually all LED chains contribute to the current for the control. Furthermore, this first embodiment has the higher overall efficiency compared to the second embodiment.
  • the second embodiment requires less circuitry and can be switched off particularly easily via the common connection between the control circuit and the control arrangement, for example as described by means of the fuse FuB.

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

Abstract

The invention relates to a circuit for an LED array, comprising at least two parallel LED chains (LK1, LK2, LK3), in which at least one LED (2) is respectively arranged, at least two LEDs (2) being mounted in series. The anode side of the LED chains (LK1, LK2, LK3) can be respectively coupled to the plus pole of a supply voltage (UV) and the cathode side can be respectively coupled to the minus pole of the supply voltage (UV). A regulating device (RA1, RA2, RA3), used to regulate a provided current distribution between the individual LED chains, is respectively mounted in series with each LED chain (LK1, LK2, LK3).

Description

Beschreibungdescription
Schaltungsanordnung für ein LED-ArrayCircuit arrangement for an LED array
Die vorliegende Erfindung bezieht sich auf eine Schaltungsanordnung für ein LED-Array, insbesondere für eine Lichtsignaleinrichtung, mit zwei oder mehr parallel geschalteten LED-Ketten, in denen jeweils mindestens eine LED (light emit- ting diode, Lichtemissiondiode) angeordnet ist, wobei bei zwei oder mehr LEDs diese in Serie geschaltet sind. Die Anodenseiten der LED-Ketten sind jeweils an dem Pluspol einer Versorgungsspannung, die Kathodenseiten jeweils an dem Minuspol der VersorgungsSpannung ankoppelbar.The present invention relates to a circuit arrangement for an LED array, in particular for a light signal device, with two or more LED chains connected in parallel, in each of which at least one LED (light-emitting diode, light-emitting diode) is arranged, with two or more LEDs that are connected in series. The anode sides of the LED chains can each be coupled to the positive pole of a supply voltage, and the cathode sides can each be coupled to the negative pole of the supply voltage.
Bei derartigen LED-Arrays können aufgrund der steilen U-I- Kennlinie von LEDs bereits kleine Änderungen der Durchlassspannung eine große Stromänderung bewirken und so zu einer erheblichen Abweichung der Stromstärke in den einzelnen LED- Ketten des LED-Arrays von einer vorgegebenen Sollstromstärke führen.In such LED arrays, even small changes in the forward voltage can cause a large current change due to the steep U-I characteristic curve of LEDs and thus lead to a considerable deviation of the current strength in the individual LED chains of the LED array from a predetermined target current strength.
Eine Variation der Durchlassspannung von LEDs kann einerseits fertigungsbedingt sein. Zur Lösung des oben geschilderten Problems ist eine feine Gruppierung der LEDs hinsichtlich der Duchlassspannung denkbar. Dies ist mit vergleichsweise hohen Kosten verbunden, da eine entsprechende Logistik und Lagerhaltung erforderlich ist.A variation in the forward voltage of LEDs can be due to the manufacturing process. To solve the problem described above, a fine grouping of the LEDs with regard to the forward voltage is conceivable. This is associated with comparatively high costs, since appropriate logistics and warehousing are required.
Andererseits ist die DurchlassSpannung einer LED tempera- turabhängig, wobei zwischen einzelnen LEDs wiederum unterschiedliche Temperaturabhängigkeiten auftreten können. Eine Temperaturänderung kann daher zu einer Änderung der Durchlassspannungen führen. Um einer damit verbundenen Ände- rung der Stromstärke in den LED-Ketten entgegenzuwirken, ist bei herkömmlichen Schaltungen beispielsweise zu jeder LED- Kette ein elektrischer Widerstand in Serie geschaltet. Dieser Widerstand führt insgesamt zu einer flacheren U-I-Kennlinie der betreffenden LED-Kette, so dass eine gewisse Limitierung des Stroms in der LED-Kette erreicht wird. Mit steigenden Genauigkeitsanforderungen bei der Einhaltung einer vorgegebenen Stromverteilung auf die einzelnen LED-Ketten wächst allerdings die Größe dieses Widerstands und damit die daran abfal- lende Spannung, wodurch der Wirkungsgrad des Gesamtsystems verschlechtert wird.On the other hand, the forward voltage of an LED is temperature-dependent, whereby different temperature dependencies can occur between individual LEDs. A change in temperature can therefore lead to a change in the forward voltages. To make an associated change To counteract the current in the LED chains, an electrical resistor is connected in series with each LED chain in conventional circuits. Overall, this resistance leads to a flatter UI characteristic of the LED chain in question, so that a certain limitation of the current in the LED chain is achieved. However, with increasing accuracy requirements while maintaining a given current distribution on the individual LED chains, the size of this resistor and thus the voltage drop across it increases, which worsens the efficiency of the overall system.
Weiterhin kann eine Veränderung der Durchlassspannung einer LED-Kette auch durch den Ausfall einzelner LEDs, beispiels- weise durch Kurzschluss einer LED, hervorgerufen werden. Dies führt bei einer Stromeinstellung mittels seriell geschalteter Widerstände zu einer starken Umverteilung der Ströme in den LED-Ketten.Furthermore, a change in the forward voltage of an LED chain can also be caused by the failure of individual LEDs, for example by a short circuit of an LED. When the current is set using resistors connected in series, this leads to a strong redistribution of the currents in the LED chains.
Der vorliegenden Erfindung liegt die Aufgabe zugrunde, eineThe present invention has for its object a
Schaltungsanordnung für ein LED-Array der genannten Art zu schaffen, bei der eine vorgegebene Verteilung der Ströme auf die einzelnen LED-Ketten auch bei unterschiedlichen DurchlassSpannungen oder einer Veränderung der Durchlassspannungen in den einzelnen LED-Ketten möglichst weitgehend aufrechterhalten wird. Insbesondere soll auch bei einem Kurzschluss einer LED oder der Unterbrechung einer LED-Kette die vorgegebene Stromverteilung möglichst unverändert bleiben.To create a circuit arrangement for an LED array of the type mentioned, in which a predetermined distribution of the currents to the individual LED chains is maintained as much as possible even with different forward voltages or a change in the forward voltages in the individual LED chains. In particular, the given current distribution should remain as unchanged as possible even in the event of a short circuit of an LED or the interruption of an LED chain.
Diese Aufgabe wird durch eine Schaltungsanordnung gemäß Patentanspruch 1 gelöst. Vorteilhafte Weiterbildungen der Erfindung sind Gegenstand der abhängigen Ansprüche. Erfindungsgemäß bei einer Schaltungsanordnung für ein LED- Array mit zwei oder mehr parallel geschalteten LED-Ketten, in denen jeweils mindestens eine LED angeordnet ist, wobei bei zwei oder mehr LEDs diese seriell geschaltet sind und wobei die Anodenseiten der LED-Ketten jeweils an dem Pluspol einer Versorgungsspannung und die Kathodenseiten jeweils an dem Minuspol der VersorgungsSpannung ankoppelbar sind, vorgesehen, dass zu jeder LED-Kette jeweils eine Regelungsanordnung zur Regelung einer vorgegebenen Stromverteilung auf die einzelnen LED-Ketten in Serie geschaltet ist.This object is achieved by a circuit arrangement according to claim 1. Advantageous developments of the invention are the subject of the dependent claims. According to the invention in a circuit arrangement for an LED array with two or more LED chains connected in parallel, in each of which at least one LED is arranged, where two or more LEDs are connected in series and the anode sides of the LED chains are each connected to the positive pole a supply voltage and the cathode sides can each be coupled to the negative pole of the supply voltage, it is provided that for each LED chain a control arrangement for controlling a predetermined current distribution on the individual LED chains is connected in series.
Vorzugsweise umfassen dabei die Regelungsanordnungen jeweils eine Stromverstärkungsschaltung zur Einprägung des Stroms in die jeweilige LED-Kette. Die Stromverstärkungsschaltungen können dabei jeweils einen Regelungseingang zur Regelung des Stroms in der LED-Kette aufweisen, wobei die Regelungseingän- ge der Stromverstärkungsschaltungen miteinander verbunden sind.The control arrangements preferably each include a current amplification circuit for impressing the current into the respective LED chain. The current amplification circuits can each have a control input for regulating the current in the LED chain, the control inputs of the current amplification circuits being connected to one another.
Unter LEDs sind bei der Erfindung Lichtemissionsdioden jederIn the invention, among LEDs, light emitting diodes are everyone
Art, inbesondere in Form von LED-Bauelementen, zu verstehen.Kind, in particular in the form of LED components to understand.
Bei einer bevorzugten Ausgestaltung der Erfindung ist als Regelungsanordnung jeweils eine Kombination eines Transistors mit einem Emitterwiderstand vorgesehen, wobei die Kollektor- Emitter-Strecke bzw. der Emitterwiderstand in Serie zu der jeweiligen LED-Kette geschaltet ist. Besonders bevorzugt sind dabei die Basisanschlüsse der Transistoren, die die obengenannten Regelungseingänge darstellen, miteinander verbunden und befinden sich im Betrieb auf gleichem Potential.In a preferred embodiment of the invention, a combination of a transistor with an emitter resistor is provided as the control arrangement, the collector-emitter path or the emitter resistor being connected in series with the respective LED chain. The base connections of the transistors, which represent the above-mentioned control inputs, are particularly preferably connected to one another and are at the same potential during operation.
Der Emitterwiderstand dient insbesondere zur Einstellung der Stromverteilung auf die LED-Ketten. Dabei ist der Wert der Emitterwiderstände jeweils umgekehrt proportional zum entsprechenden Emitterstrom, der näherungsweise dem Kollektorstrom bzw. dem Strom in der zugehörigen LED-Kette entspricht (ausgenommen unterbrochene LED-Ketten, wie im Folgenden noch genauer erläutert wird) .The emitter resistor is used in particular to adjust the current distribution on the LED chains. The value is the Emitter resistances are inversely proportional to the corresponding emitter current, which approximately corresponds to the collector current or the current in the associated LED chain (except for interrupted LED chains, as will be explained in more detail below).
Bei einer bevorzugten Weiterbildung der vorliegenden Erfindung beaufschlagt eine Ansteuerschaltung die Basisanschlüsse der Transistoren mit einem vorbestimmten Strom. Bei einer er- sten Ausführungsform der Erfindung sind dabei für die einzelnen LED-Ketten jeweils gesonderte Ansteuerschaltungen vorgesehen. Bei einer zweiten Ausführungsform der Erfindung ist eine gemeinsame Ansteuerschaltung für eine Mehrzahl der LED- Ketten, vorzugsweise für alle LED-Ketten, vorgesehen.In a preferred development of the present invention, a control circuit applies a predetermined current to the base connections of the transistors. In a first embodiment of the invention, separate control circuits are provided for the individual LED chains. In a second embodiment of the invention, a common control circuit is provided for a plurality of the LED chains, preferably for all LED chains.
Vorzugsweise ist bei der ersten Ausführungsform der Erfindung die die Basisanschlüsse der Transistoren mit einem vorbestimmten Strom beaufschlagende Ansteuerschaltung jeweils als Serienschaltung aus einer Diode und einem Widerstand gebil- det, die jeweils Kollektor- und Basisanschluss der Transistoren verbindet. Die Dioden stellen einerseits sicher, dass die Betriebsbedingungen für die Transistoren erfüllt sind und verhindern andererseits eine Umverteilung der Ströme in den LED-Ketten über die gemeinsame Verbindung der Basisanschlüs- se.In the first embodiment of the invention, the drive circuit which applies a predetermined current to the base connections of the transistors is in each case formed as a series circuit comprising a diode and a resistor, which connects the collector and base connections of the transistors. On the one hand, the diodes ensure that the operating conditions for the transistors are met and, on the other hand, prevent a redistribution of the currents in the LED chains via the common connection of the base connections.
Eine Veränderung in der Durchlassspannung einer LED-Kette, die beispielsweise durch eine Temperaturänderung oder durch den Kurzschluss einer LED hervorgerufen sein kann, wird mit- tels der Ansteuerschaltung durch eine entsprechende Veränderung der zugehörigen Kollektor-Basis-Spannung abgefangen, so dass sich der Kollektorstrom und damit der Strom in der be- treffenden LED-Kette nicht bzw. nur in geringem Umfang ändert .A change in the forward voltage of an LED chain, which can be caused, for example, by a temperature change or by a short circuit in an LED, is intercepted by means of the control circuit by a corresponding change in the associated collector base voltage, so that the collector current and so that the current in the LED chain does not change or changes only to a small extent.
Fällt beispielsweise in einer LED-Kette eine LED durch Kurz- schluss aus, so verringert sich die DurchläseSpannung derIf, for example, an LED in a LED chain fails due to a short circuit, the forward voltage of the
LED-Kette. Dies wird mittels der zugehörigen Regelungsanordnung dadurch kompensiert, dass sich die Kollektor-Basis- Spannung am zugehörigen Transistor erhöht . Da über die Widerstände der Ansteuerschaltung nur der jeweilige Basisstrom der Transistoren fließt, der etwa typischerweise um einen Faktor 100 bis 250 kleiner als der Kollektorstrom ist, können die Widerstände jeweils so dimensioniert werden, dass schon bei einer geringen Änderung des Stroms durch den Widerstand eine ausreichend hohe Spannung zum Ausgleich der unterschiedlichen Durchlassspannungen in den einzelnen LED-Ketten an dem Widerstand abfällt.LED chain. This is compensated for by means of the associated control arrangement in that the collector base voltage at the associated transistor increases. Since only the respective base current of the transistors flows through the resistors of the drive circuit, which is typically typically a factor of 100 to 250 smaller than the collector current, the resistors can be dimensioned in such a way that even with a small change in the current through the resistor, a sufficient level high voltage to compensate for the different forward voltages in the individual LED chains across the resistor.
Den zu einem Kurzschluss einer LED entgegengesetzten Fehlerfall stellt ein Ausfall einer LED dar, der die LED-Kette un- terbricht. Dies kann beispielsweise durch eine Überlastung der LED verursacht sein, so dass die LED "durchbrennt".The fault case opposite to a short circuit of an LED is a failure of an LED which interrupts the LED chain. This can be caused, for example, by an overload of the LED, so that the LED "burns out".
In der zugehörigen LED-Kette fließt dann kein Strom mehr, die Spannung zwischen Kollektor und Basis des zugehörigen Transi- stors bricht zusammen. Die Basis des Transistors der defekten Kette liegt aufgrund der gemeinsamen elektrischen Verbindung der Transistorbasisanschlüsse nach wie vor auf demselben Potential. Der Transistor der defekten LED-Kette wird also als Diode betrieben, wobei die hierfür erforderlichen Ausgleichs- ströme über die intakten LED-Ketten und die Verbindung der Tranistorbasisanschlüsse fließen. Die durch die Dimensionierung der Emitterwiderstände vorgegebene Stromverteilung bleibt für die übrigen intakten LED-Ketten erhalten, wobei die Ströme in den intakten LED-Ketten annähernd gleich den jeweiligen Emitterströmen und wiederum jeweils umgekehrt proportional zu den entsprechenden Emitterwiderständen sind.No current then flows in the associated LED chain, the voltage between the collector and the base of the associated transistor breaks down. The base of the transistor of the defective chain is still at the same potential due to the common electrical connection of the transistor base connections. The transistor of the defective LED chain is therefore operated as a diode, the compensation currents required for this flowing through the intact LED chains and the connection of the transistor base connections. The current distribution predetermined by the dimensioning of the emitter resistances is retained for the other intact LED chains, whereby the currents in the intact LED chains are approximately equal to the respective emitter currents and in turn are inversely proportional to the corresponding emitter resistances.
In entsprechender Weise werden auch alle weiteren Betriebsbzw. Fehler-Zustände bezüglich der DurchlassSpannungen der LED-Ketten zwischen den Extremfällen eines Kurzschlusses und einer Unterbrechung einer LED bzw. LED-Kette kompensiert, so dass die Stromverteilung in den LED-Ketten (abgesehen von ei- ner unterbrochenen LED-Kette) weitgehend aufrechterhalten wird.In a corresponding manner, all other Betriebsbzw. Error states with regard to the forward voltages of the LED chains between the extreme cases of a short circuit and an interruption of an LED or LED chain are compensated so that the current distribution in the LED chains (apart from an interrupted LED chain) is largely maintained ,
Insbesondere wird bei der erfindungsgemäßen Schaltungsanordnung die vorgesehene Stromverteilung auch bei extremen Ände- rungen der Durchlassspannungen konstant gehalten. Die Kollektorströme bzw. die Ströme in den LED-Ketten schwanken dabei typischerweise nur noch um wenige mA. Vorteilhafterweise führt weder eine Unterbrechung einer LED-Kette noch ein Kurzschluss in einer LED-Kette zum Zusammenbruch der Stromvertei- lung. Eine kostenträchtige Gruppierung der LED-Bauelemente nach Durchlassspannungen ist nicht erforderlich.In particular, in the circuit arrangement according to the invention, the intended current distribution is kept constant even in the event of extreme changes in the forward voltages. The collector currents or the currents in the LED chains typically fluctuate only by a few mA. Advantageously, neither an interruption in an LED chain nor a short circuit in an LED chain leads to a breakdown of the current distribution. A costly grouping of the LED components according to forward voltages is not necessary.
Vorzugsweise liegen die Werte der Widerstände in der Ansteuerschaltung bei der ersten Ausführungsform der Erfindung im Bereich zwischen 100 Ohm und 1000 Ohm. Damit können bereits durch relativ kleine Ströme ausreichend hohe Ausgleichsspannungen zur Kompensation unterschiedlicher Durchlassspannungen der LED-Ketten erzeugt werden.The values of the resistances in the drive circuit in the first embodiment of the invention are preferably in the range between 100 ohms and 1000 ohms. This means that even relatively small currents can generate sufficiently high compensating voltages to compensate for different forward voltages of the LED chains.
Bei einer bevorzugten zweiten Ausführungsform der Erfindung ist die Ansteuerschaltung, die die Basisanschlüsse der Transistoren in den Regelungsanordnungen mit einem vorbestimmten Strom beaufschlagt, als eine in Sperrrichtung betriebene Zenerdiode ausgebildet, die vorzugsweise mit einem Widerstand und/oder einer Sicherung in Reihe geschaltet ist . Transistor- seitig ist die Zenerdiode mit den Basisanschlüssen verbunden.In a preferred second embodiment of the invention, the drive circuit, which applies a predetermined current to the base connections of the transistors in the control arrangements, is operated in the reverse direction Zener diode formed, which is preferably connected in series with a resistor and / or a fuse. The Zener diode is connected to the base connections on the transistor side.
5 Die Zenerdiode und der Widerstand stellen eine gemeinsame5 The Zener diode and the resistor form a common one
Stromversorgung für die jeweiligen Transistorbasisanschlüsse dar. Die Differenz zwischen der DurchläseSpannung der jeweiligen LED-Kette und der an der Ansteuerschaltung abfallenden Spannung liegt am jeweiligen Transistor einer Regelungsanord-Power supply for the respective transistor base connections. The difference between the forward voltage of the respective LED chain and the voltage drop across the control circuit lies at the respective transistor of a control arrangement.
10 nung als Kollektor-Basis-Spannung an. Eine Veränderung der Durchlassspannung einer LED-Kette wird durch eine entsprechende Veränderung der zugehörigen Kollektor-Basis-Spannung kompensiert, so dass sich der Kollektorstrom und damit der entsprechende Strom in der LED-Kette nicht bzw. nur sehr ge-10 voltage as the collector base voltage. A change in the forward voltage of an LED chain is compensated for by a corresponding change in the associated collector base voltage, so that the collector current and thus the corresponding current in the LED chain are not or only very
L5 ringfügig ändert .L5 changes slightly.
Bei dieser zweiten Ausführungform wird der Basisstrom für die Transistoren über einen einzigen gemeinsamen Strompfad geführt . Hierbei kann die Versorgung der Basisanschlüsse derIn this second embodiment, the base current for the transistors is conducted via a single common current path. The supply of the basic connections of the
10 Transistoren durch einen Strompfad neben dem Array realisiert werden, in den die Ansteuerschaltung, beispielsweise die Zenerdiode, eingebaut ist. Dies reduziert den Schaltungsaufwand für ein LED-Array gegenüber der ersten Ausführungsform. Die Zenerdiode sollte eine Zenerspannung aufweisen, die etwa10 transistors can be realized by a current path next to the array, in which the drive circuit, for example the zener diode, is installed. This reduces the circuitry for an LED array compared to the first embodiment. The zener diode should have a zener voltage, which is about
,5 I V größer ist als die große Durchlassspannung der LED- Ketten. Damit ist für die Transistoren ein stabiler Betriebszustand gewährleistet..5 I V is greater than the large forward voltage of the LED chains. This ensures a stable operating state for the transistors.
Bei der ersten Ausführungsform ist demgegenüber die für dieIn contrast, in the first embodiment, that for the
!0 Regelungsanordnungen erforderlich Spannung geringer, so dass diese Ausführungsform vor allem bei längeren LED-Ketten ein energetisch vorteilhafteres Gesamtsystem darstellt. Fällt bei der zweiten Ausführungsform der Erfindung in einer LED-Kette eine LED durch Kurzschluss aus, so verringert sich die Durchlassspannung der LED-Kette. Dies wird mittels der zugehörigen Regelungsanordnung dadurch kompensiert, dass sich die Kollektor-Basis-Spannung am zugehörigen Transistor erhöht. Die jeweiligen Kollektorströme bzw. Ströme in den LED- Ketten bleiben damit annähernd konstant .! 0 control arrangements require lower voltage, so that this embodiment represents an energetically more advantageous overall system, especially with longer LED chains. If, in the second embodiment of the invention, an LED in an LED chain fails due to a short circuit, the forward voltage of the LED chain is reduced. This is compensated for by means of the associated control arrangement in that the collector base voltage at the associated transistor increases. The respective collector currents or currents in the LED chains thus remain approximately constant.
Wird bei der zweiten Ausführungsform der Erfindung hingegen eine LED-Kette unterbrochen, beispielsweise, weil eine LED durchbrennt, so fließt durch die defekte LED-Kette kein Strom mehr, die Spannung zwischen Kollektor und Basis des zugehörigen Transistors bricht zusammen. Die Basis des Transistors der defekten Kette liegt aufgrund der gemeinsamen elektri- sehen Verbindung der Transistorbasisanschlüsse nach wie vor auf demselben Potential, der Transistor der defekten Kette wird als Diode betrieben. Die hierfür erforderlichen Ausgleichsströme fließen über die Zenerdiode und die gemeinsame Verbindung der Transistorbasen. Die durch die Dimensionierung der Emitterwiderstände vorgegebene Stromverteilung bleibt für die übrigen intakten LED-Ketten erhalten, wobei die Ströme in den LED-Ketten annähernd gleich dem Emitterstrom und wiederum umgekehrt proportional zu den Emitterwiderständen sind.If, however, an LED chain is interrupted in the second embodiment of the invention, for example because an LED burns out, no more current flows through the defective LED chain, and the voltage between the collector and the base of the associated transistor breaks down. The base of the transistor of the defective chain is still at the same potential due to the common electrical connection of the transistor base connections, the transistor of the defective chain is operated as a diode. The compensation currents required for this flow through the Zener diode and the common connection of the transistor bases. The current distribution predetermined by the dimensioning of the emitter resistances is retained for the other intact LED chains, the currents in the LED chains being approximately equal to the emitter current and, in turn, inversely proportional to the emitter resistances.
Damit werden auch mit der zweiten Ausführungsform der Erfindung die obengenannten Vorteile der ersten Ausführungsform erreicht .The above-mentioned advantages of the first embodiment are thus also achieved with the second embodiment of the invention.
Bei einer vorteilhaften Weiterbildung der Erfindung ist die Sicherung in Serie zur Zenerdiode als Schmelzwiderstand ausgeführt. Das verhindert insbesondere, dass bei Überlastung des Arrays die Transistoren zerstört werden. Vorzugsweise liegt der Wert des Widerstands in Serie zur Zenerdiode im Bereich zwischen 100 Ohm und 1000 Ohm, so dass wiederum mit relativ kleinen Strömen die erforderlichen Ausgleichsspannungen erzeugt werden können.In an advantageous development of the invention, the fuse is designed in series with the zener diode as a melting resistor. In particular, this prevents the transistors from being destroyed if the array is overloaded. The value of the resistance in series with the zener diode is preferably in the range between 100 ohms and 1000 ohms, so that the required compensation voltages can in turn be generated with relatively small currents.
Weiterhin ist es bei beiden Ausführungsformen der Erfindung vorteilhaft, eine seriell zu den LED-Ketten geschaltete Sicherung, zum Beispiel einen Schmelzwiderstand, vorzusehen. Auf diese Weise werden einzelne fehlerhafte LED-Ketten bei zu hohem Strom in der LED-Kette definiert abgeschaltet. Wie oben beschrieben wird auch bei der damit einhergehenden Unterbrechung einer LED-Kette die vorgegebene Stromverteilung in den verbleibenden LED-Ketten aufrechterhalten.Furthermore, in both embodiments of the invention, it is advantageous to provide a fuse, for example a melting resistor, connected in series with the LED chains. In this way, individual faulty LED chains are switched off in a defined manner when the current in the LED chain is too high. As described above, the predetermined current distribution in the remaining LED chains is also maintained in the event of an associated interruption of an LED chain.
Da die Ströme in den LED-Ketten umgekehrt proportional zu den jeweiligen Emitterwiderständen sind, ist das LED-Array flexibel ausgestaltbar, wobei insbesondere ohne besonderen Aufwand für jede LED-Kette ein vorgegebener Strom eingestellt werden kann. In der Regel wird eine gleichmäßige Stromverteilung ge- wünscht sein, was durch gleiche Emitterwiderstände ohne weiteres realisierbar ist.Since the currents in the LED chains are inversely proportional to the respective emitter resistances, the LED array can be configured flexibly, and in particular a predetermined current can be set for each LED chain without any particular effort. As a rule, a uniform current distribution is desired, which can easily be achieved by using the same emitter resistors.
Weitere Vorteile, Weiterbildungen und Ausführungsformen der Erfindung, insbesondere für eine Lichtsignaleinrichtung, er- geben sich aus den im Folgenden unter Bezugnahme auf die Figuren erläuterten Ausführungsbeispielen.Further advantages, developments and embodiments of the invention, in particular for a light signal device, result from the exemplary embodiments explained below with reference to the figures.
Es zeigen:Show it:
Figur 1 einen schematischen Schaltplan eines ersten Ausführungsbeispiels der Erfindung gemäß der ersten Aus- führungsform, Figur 2 einen schematischen Schaltplan eines zweiten Ausführungsbeispiels der Erfindung gemäß der ersten Ausführungsform,FIG. 1 shows a schematic circuit diagram of a first exemplary embodiment of the invention in accordance with the first embodiment, FIG. 2 shows a schematic circuit diagram of a second exemplary embodiment of the invention according to the first embodiment,
Figur 3 einen schematischen Schaltplan eines dritten Ausführungsbeispiels der Erfindung gemäß der ersten Ausführungsform,FIG. 3 shows a schematic circuit diagram of a third exemplary embodiment of the invention according to the first embodiment,
Figur 4 einen schematischen Schaltplan eines vierten Aus- führungsbeispiels der Erfindung gemäß der zweitenFIG. 4 shows a schematic circuit diagram of a fourth exemplary embodiment of the invention according to the second
Ausführungsform, undEmbodiment, and
Figur 5 einen schematischen Schaltplan eines fünften Ausführungsbeispiels der Erfindung gemäß der zweiten Ausführungsform.Figure 5 is a schematic circuit diagram of a fifth embodiment of the invention according to the second embodiment.
Gleiche oder gleichwirkende Elemente sind in den Figuren mit denselben Bezugszeichen versehen.The same or equivalent elements are provided with the same reference numerals in the figures.
Bei dem in Figur 1 gezeigten Schaltplan ist jeweils eineIn the circuit diagram shown in Figure 1 there is one
Mehrzahl von LEDs 2 seriell zu LED-Ketten geschaltet. Dargestellt sind drei Ketten LK1, LK2 , LK3 mit je vier LEDs 2, wobei eine erfindungsgemäße Schaltungsanordnung selbstverständlich auch eine andere Anzahl von LEDs in den LED-Ketten oder eine andere Anzahl von LED-Ketten umfassen kann. Dies ist durch die gestrichelten Linien in den Versorgungsspannungs- leitungen (s.u.), der Verbindung der Transistorbasisanschlüsse (s.u.) bzw. der LED-Ketten verdeutlicht. Weiterhin kann auch die Abzahl und/oder der Typ der LEDs in den einzelnen LED-Ketten von Kette zu Kette variieren.A plurality of LEDs 2 connected in series to form LED chains. Three chains LK1, LK2, LK3 are shown, each with four LEDs 2, wherein a circuit arrangement according to the invention can of course also comprise a different number of LEDs in the LED chains or a different number of LED chains. This is illustrated by the dashed lines in the supply voltage lines (see below), the connection of the transistor base connections (see below) and the LED chains. Furthermore, the number and / or type of LEDs in the individual LED chains can vary from chain to chain.
Optional kann zu den LED-Ketten LK1, LK2 , LK3 ein Schmelzwiderstand Ful, Fu2, Fu3 in Serie geschaltet sein. Die LED- Ketten LK1, LK2 , LK3 sind anodenseitig jeweils mit dem Pluspol einer Versorgungsspannung Uv und kathodenseitig jeweils mit einer Regelungsanordnung RAl, RA2 , RA3 verbunden.Optionally, a melting resistor Ful, Fu2, Fu3 can be connected in series with the LED chains LK1, LK2, LK3. The LED Chains LK1, LK2, LK3 are connected on the anode side to the positive pole of a supply voltage U v and on the cathode side each with a control arrangement RA1, RA2, RA3.
Die Regelungsanordnungen RAl, RA2 , RA3 umfassen jeweils einen npn-Transistor Tl, T2, T3 , dessen Kollektoranschluss Cl, C2 , C3 jeweils mit der Kathodenseite der zugehörigen LED-Kette LK1, LK2 , L3 bzw. mit dem gegebenenfalls dazwischen geschalteten Schmelzwiderstand Ful, Fu2 , Fu3 verbunden ist. Der Emitteranschluss El, E2 , E3 ist jeweils über einen Emitterwiderstand R12, R22, R32 an dem Minuspol einer Versorgungsspannung Uv angeschlossen.The control arrangements RA1, RA2, RA3 each include an npn transistor T1, T2, T3, the collector terminals C1, C2, C3 of which each have the cathode side of the associated LED chain LK1, LK2, L3 or the melting resistor Ful which may be connected between them. Fu2, Fu3 is connected. The emitter connection El, E2, E3 is connected to the negative pole of a supply voltage U v via an emitter resistor R12, R22, R32.
Die Transistoren Tl , T2 , T3 sind in der dargestellten Anord- nung als handelsübliche • npn-Transistoren ausgeführt. Zwischen der Kathodenseite bzw. dem Schmelzwiderstand jeder LED-Kette und dem jeweiligen Basisanschluss Bl, B2 , B3 des zugehörigen Transistors Tl, T2 , T3 ist jeweils eine Ansteuerschaltung in Form einer Serienschaltung aus einer Diode Dl, D2 , D3 und ei- nem elektrischen Widerstand Rll, R21, R31 geschaltet.The transistors T1, T2, T3 in the arrangement shown are designed as commercially available • npn transistors. Between the cathode side or the melting resistance of each LED chain and the respective base connection B1, B2, B3 of the associated transistor T1, T2, T3, there is a control circuit in the form of a series circuit comprising a diode D1, D2, D3 and an electrical resistor Rll, R21, R31 switched.
Die Basisanschlüsse Bl, B2 , B3 der Transistoren Tl, T2 , T3 sind miteinander verbunden.The base connections B1, B2, B3 of the transistors T1, T2, T3 are connected to one another.
Im Betrieb fällt an den Widerständen Rx2 bei einer Bestromung mit der Stromstärke Ix eine Spannung Ux2=Rx2*Ix ab. Der Laufindex x bezeichnet hier und im Folgenden die Nummer der LED-Kette. Im gezeigten Beispiel gilt also für die linke LED- Kette x=l, für die mittlere x=2 und für rechte LED-Kette LK3 x=3. Die folgende Beschreibung gilt auch allgemein für ein LED-Array mit N LED-Ketten, wobei dann x zwischen 1 und N liegt . Der Strom Ix, der - abgesehen von dem jeweils sehr viel geringeren Basisstrom dem Strom in der jeweiligen LED-Kette LKx entspricht, wird dabei so geregelt, dass an der Basis- Emitter-Strecke des zugehörigen Transistors Tx eine Spannung von ca. 0,65 V auftritt.During operation, a voltage Ux2 = Rx2 * Ix drops across the resistors Rx2 when energized with the current strength Ix. The running index x denotes the number of the LED chain here and below. In the example shown, the left LED chain x = 1, the middle x = 2 and the right LED chain LK3 x = 3. The following description also applies generally to an LED array with N LED chains, where x is between 1 and N. The current Ix, which - apart from the much lower base current in each case corresponds to the current in the respective LED chain LKx, is regulated in such a way that a voltage of approximately 0.65 is applied to the base-emitter path of the associated transistor Tx V occurs.
Da die Basiseingänge Bl, B2 , B3 der Transistoren Tl, T2 , T3 untereinander elektrisch verbunden sind und auf gleichem Potential liegen, wird über die Transistoren Tl, T2 , T3 der Strom so eingestellt, dass die an den Emitterwiderständen abfallende Spannung ca. 0,65 V unter dem gemeinsamen Basispotential liegt. Da die Spannung zwischen Basis und Emitter von 0,65V bei den Transistoren Tl, T2 , T3 (nahezu) gleich ist, müssen dazu an den jeweiligen Emitterwiderständen R12 , R22, R32 die gleichen Spannungen abfallen. Die Ströme II, 12, 13 in den LED-Ketten werden damit so geregelt, dass die Spannungen U12, U22, U32 gleich sind. Insgesamt wird damit die Verteilung der Ströme auf die LED-Ketten durch die Emitterwiderstände R12 , R22, R32 festgelegt, wobei das Ver- hältnis der Ströme gleich dem Verhältnis der reziproken Emitterwiderstandswerte ist .Since the base inputs B1, B2, B3 of the transistors T1, T2, T3 are electrically connected to one another and are at the same potential, the current is set via the transistors T1, T2, T3 in such a way that the voltage drop across the emitter resistors is approx. 65 V below the common base potential. Since the voltage between the base and emitter of 0.65V is (almost) the same for transistors T1, T2, T3, the same voltages must drop across the respective emitter resistors R12, R22, R32. The currents II, 12, 13 in the LED chains are thus regulated so that the voltages U12, U22, U32 are the same. Overall, the distribution of the currents on the LED chains is thus determined by the emitter resistors R12, R22, R32, the ratio of the currents being equal to the ratio of the reciprocal emitter resistance values.
Bei dieser Betrachtung wurde jeweils der Emitterstrom, der sich aus dem zugehörigen Basis- und Kollektorstrom zusammen- setzt, mit dem Kollektorstrom gleichgesetzt, also der im Vergleich wesentlich geringere Basisstrom vernachlässigt.In this analysis, the emitter current, which is made up of the associated base and collector currents, was equated with the collector current, ie the base current, which is much lower in comparison, was neglected.
Soll ein Gesamtstrom gleichmäßig auf alle LED-Ketten LK1, LK2, LK3 aufgeteilt werden, so müssen alle Emitterwiderstände R12, R22, R32 denselben Widerstandswert aufweisen. Eine unterschiedlichen Bestromung der verschiedenen Ketten kann ohne besonderen Aufwand durch unterschiedliche Werte für die Emitterwiderstände R12 , R22, R32 realisiert werden. Damit kann vorteilhafterweise die Bestromung der LED-Ketten je nach Anforderung angepaßt werden, ohne dass weitere, gegebenenfalls aufwändigere Änderungen der Schaltung erforderlich sind.If a total current is to be distributed evenly across all LED chains LK1, LK2, LK3, then all emitter resistors R12, R22, R32 must have the same resistance value. Different energization of the different chains can be realized without special effort by different values for the emitter resistors R12, R22, R32. In order to the current supply to the LED chains can advantageously be adapted as required without further, possibly more complex changes to the circuit being required.
Eine Veränderung der DurchläseSpannung einer LED-Kette LKx, z.B. durch Kurzschluss einer LED, wird durch eine entsprechende Veränderung der zugehörigen Kollektor-Basis-Spannung abgefangen. Die oben erläuterte Einstellung des Emitterstroms Ix und damit des Stroms in der LED-Kette LKx bleibt hiervon nahezu unberührt, so dass dass sich der Kollektorstrom bzw. der Strom in der LED-Kette nicht oder nur geringfügig ändert.A change in the forward voltage of an LED chain LKx, e.g. by short-circuiting an LED, is intercepted by a corresponding change in the associated collector base voltage. The setting of the emitter current Ix and thus the current in the LED chain LKx explained above remains almost unaffected by this, so that the collector current or the current in the LED chain does not change or changes only slightly.
Wird im Extremfall einer Unterbrechung einer LED-Kette LKx der Strom in der LED-Kette bzw. der Kollektorstrom auf Null reduziert, so wird die Spannung Ux2 am zugehörigen Emitterwiderstand Rxl durch eine entsprechende Änderung des Basisstroms aufrechterhalten. Dies wird über die gemeinsame elektrische Verbindung der Transistorbasisanschlüsse ermöglicht. Die Näherung, dass der Basisstrom gegenüber dem Kollektorstrom vernachlässigt werden kann, gilt in diesem Ausnahmefall nicht mehr.If, in the extreme case of an interruption of an LED chain LKx, the current in the LED chain or the collector current is reduced to zero, the voltage Ux2 at the associated emitter resistor Rxl is maintained by a corresponding change in the base current. This is made possible by the common electrical connection of the transistor base connections. The approximation that the base current can be neglected compared to the collector current no longer applies in this exceptional case.
Die Stromversorgung der Basiseingänge Bl, B2 , B3 der Transi- stören Tl, T2 , T3 ist jeweils mittels einer Ansteuerschaltung in Form einer Serienschaltung einer Diode Dl, D2 , D3 und eines Widerstands Rll, R21, R31 realisiert.The power supply to the base inputs B1, B2, B3 of the transistors Tl, T2, T3 is realized in each case by means of a control circuit in the form of a series connection of a diode D1, D2, D3 and a resistor R11, R21, R31.
Den Dioden Dl, D2 , D3 kommt hierbei eine Doppelfunktion zu: Einerseits stellen sie die Betriebsbedingung der TransistorenThe diodes D1, D2, D3 have a double function: on the one hand, they set the operating condition of the transistors
Tl, T2, T3, d.h. die erforderliche Spannung an der jeweiligen Kollektor-Basis-Strecke Cx-Bx sicher, andererseits unterdrük- ken sie Querströme zwischen den einzelnen LED-Ketten LK1, LK2, LK3. Letzteres bewirkt, dass über die gemeinsame elektrische Verbindung der Transistorbasen Bl, B2 , B3 kein Strom, beispielsweise aufgrund von Potentialunterschieden in den einzelnen LED-Ketten LKl, LK2 , LK3 , die etwa wegen unter- 5 schiedlicher DurchlassSpannungen oder einer kurzgeschlossener LED verursacht sein können, von einer LED-Kette in eine andere LED-Kette fließen kann.Tl, T2, T3, ie the required voltage at the respective collector base section Cx-Bx safely, on the other hand they suppress cross currents between the individual LED chains LK1, LK2, LK3. The latter means that there is no current through the common electrical connection of the transistor bases B1, B2, B3, for example due to potential differences in the individual LED chains LK1, LK2, LK3, which can be caused, for example, by different forward voltages or a short-circuited LED , can flow from one LED chain to another LED chain.
Die Dioden Dl, D2 , D3 sind so dimensioniert, dass an ihnenThe diodes D1, D2, D3 are dimensioned so that on them
LO eine Spannung abfällt, die für einen stabilen Betriebszustand der Transistoren Tl, T2 , T3 ausreicht. Beispielsweise könnten hier auch LEDs zum Einsatz kommen, die zusätzlich als optischer Indikator für unterschiedliche Durchlassspannungen in den einzelnen Ketten dienen können.LO a voltage drops, which is sufficient for a stable operating state of the transistors T1, T2, T3. For example, LEDs could also be used here, which can additionally serve as an optical indicator for different forward voltages in the individual chains.
L5L5
Über die elektrischen Widerstände Rll, R21, R31 fließt der Basisstrom der Transistoren Tl, T2, T3 , der typischerweise um einem Faktor 100 bis 250 kleiner als der Kollektorstrom ist. Diese Widerstände Rll, R21, R31 sind vorzugsweise so dimen-The base current of the transistors T1, T2, T3 flows through the electrical resistors R11, R21, R31 and is typically 100 to 250 times smaller than the collector current. These resistors R11, R21, R31 are preferably so dimensionally
20 sioniert, dass bereits eine sehr kleine Veränderung des Basisstroms durch den Widerstand Rxl, beispielsweise im Bereich unter 1 mA, eine ausreichend große Änderung der Spannung an dem Widerstand Rxl bewirkt, wodurch unterschiedliche Durchlassspannungen oder eine Änderung der DurchlassSpannungen bei20 states that even a very small change in the base current through the resistor Rxl, for example in the range below 1 mA, causes a sufficiently large change in the voltage across the resistor Rxl, which results in different forward voltages or a change in the forward voltages
25 den einzelnen LED-Ketten LKl, LK2 , LK3 ausgeglichen werden. Die Widerstände Rll, R21, R31 weisen dazu vorzugsweise Werte im Bereich von 100 Ohm bis 1000 Ohm auf.25 the individual LED chains LKl, LK2, LK3 can be compensated. For this purpose, the resistors R11, R21, R31 preferably have values in the range from 100 ohms to 1000 ohms.
Bei der Unterbrechung einer LED-Kette fließen über die An- 30 Steuerschaltungen der verbleibenden Ketten auch die Aus- gleichströme zur Aufrechterhaltung der Spannung am Emitterwiderstand der unterbrochenen LED-Kette. Die Widerstände Rll, R21, R31 müssen prinzipiell nicht zwangsläufig denselben Wert aufweisen. Für eine optimale Zuverlässigkeit und die Symmetrie der Anordnung sind gleiche Widerstandswerte vorteilhaft .If an LED chain is interrupted, the equalizing currents flow through the control circuits of the remaining chains to maintain the voltage at the emitter resistor of the interrupted LED chain. In principle, the resistors R11, R21, R31 do not necessarily have to have the same value. The same resistance values are advantageous for optimum reliability and the symmetry of the arrangement.
Bei der gezeigten Schaltung ist, insbesondere durch die Emitterwiderstände R12, R22, R32, eine ausreichende Stabilität der Schaltung gegenüber fertigungsbedingten Schwankungen der Stromverstärkungsfaktoren, d.h. dem Verhältnis von Kollektor- ström zu Basisstrom, der Transistoren Tl, T2 , T3 gewährleistet .In the circuit shown, in particular due to the emitter resistors R12, R22, R32, there is sufficient stability of the circuit against production-related fluctuations in the current gain factors, i.e. the ratio of collector current to base current, which ensures transistors T1, T2, T3.
In einer weiteren Variante, die insbesondere bei erhöhten Sicherheitsanforderungen vorteilhaft ist, ist vorzugsweise je- weils eine Sicherung Fux in Serie zu eine LED-Kette LKx geschaltet, welcher zusätzlich einen zu großen Strom in einer LED-Kette unterbindet. Im Fehlerfall, wenn beispielsweise in einer LED-Kette LKx der doppelte Sollstrom fließt, brennt die Sicherung durch und schaltet so die LED-Kette definiert ab. Damit wird die LED-Kette unterbrochen. Wie bereits beschrieben ist es hierbei von Vorteil, dass bei einer solchen Unterbrechung die Stromverteilung in den noch intakten LED-Ketten aufrechterhalten bleibt. Die Sicherungen Ful, Fu2 , Fu3 können zum Beispiel als Schmelzwiderstand ausgeführt sein. Dabei können handelsübliche Schmelzwiderstände eingesetzt werden, die ab einer definierten Leistung durchbrennen und so dauerhaft den Stromfluss unterbrechen.In a further variant, which is particularly advantageous in the case of increased security requirements, a fuse Fux is preferably connected in series with an LED chain LKx, which additionally prevents excessive current in an LED chain. In the event of a fault, for example when the double set current flows in an LED chain LKx, the fuse blows and thus switches off the LED chain in a defined manner. This breaks the LED chain. As already described, it is advantageous that the current distribution in the still intact LED chains is maintained in the event of such an interruption. The fuses Ful, Fu2, Fu3 can for example be designed as a melting resistor. Commercially available melting resistors can be used that burn out from a defined output and thus permanently interrupt the flow of electricity.
Ein weiterer Vorteil der ersten Ausführungsform der Erfindung bzw. des in Figur 1 dargestellten Ausführungsbeispiels besteht darin, dass bei jeder LED-Kette LKx ein Teilstrom zur Regelung abgezweigt wird. Dadurch wird die Zuverlässigkeit und Stabilit des Systems erhöht. Bei Verwendung von Emitter- widerständen R12, R22, R32 mit 1% Toleranz beträgt die Toleranz der Basisströme 2%, so dass insgesamt eine vergleichweise hohe Präzision der Stromverteilung erzielt wird.A further advantage of the first embodiment of the invention or of the exemplary embodiment shown in FIG. 1 is that a partial stream is branched off for regulation in each LED chain LKx. This increases the reliability and stability of the system. When using emitter resistors R12, R22, R32 with 1% tolerance, the tolerance of the base currents is 2%, so that overall a comparatively high precision of the current distribution is achieved.
Wie bereits erläutert ist die Schaltungsanordnung gemäß Figur 1 um eine beliebige Anzahl an LED-Ketten in der dargestellten Weise erweiterbar.As already explained, the circuit arrangement according to FIG. 1 can be expanded by any number of LED chains in the manner shown.
Die in Figur 1 gezeigte Schaltung kann in analoger Weise auch mit pnp-Transistoren aufgebaut werden. Ein entsprechendes zweites Ausführungsbeispiel der Erfindung ist in Figur 2 dargestellt. Hierbei sind die Regelungsanordnungen RAl, RA2 , RA3 mit den Transistoren Tl, T2, T3, den Emitterwiderständen R12 , R22, R32 und den Ansteuerschaltungen aus den Widerständen Rll, R21, R31 und den Dioden Dl, D2 , D3 zwischen den Anodenseiten der LED-Ketten LKl, LK2 , LK3 und dem Pluspol der Versorgungsspannung Uv angeordnet .The circuit shown in FIG. 1 can also be constructed in an analogous manner with pnp transistors. A corresponding second exemplary embodiment of the invention is shown in FIG. 2. Here, the control arrangements RA1, RA2, RA3 with the transistors T1, T2, T3, the emitter resistors R12, R22, R32 and the control circuits made up of the resistors R11, R21, R31 and the diodes Dl, D2, D3 between the anode sides of the LED Chains LKl, LK2, LK3 and the positive pole of the supply voltage U v arranged.
Das in Figur 3 gezeigte dritte Ausführungsbeispiel der Erfin- düng zeigt ein LED-Array in einer Größe, die beispielsweise in der Signaltechnik eingesetzt wird. Entsprechende Schaltungen können zum Beispiel für VerkehrsSignale wie Ampeln oder Warnleuchten oder für Bahnsignale verwendet werden.The third exemplary embodiment of the invention shown in FIG. 3 shows an LED array of a size that is used, for example, in signal technology. Corresponding circuits can be used, for example, for traffic signals such as traffic lights or warning lights or for train signals.
Die Schaltung entspricht im wesentlichen Figur 2. Im Unterschied dazu sind insgesamt 120 LEDs 2 in 20 LED-Ketten LK1,...,LK20 mit je 6 LEDs parallel geschaltet. Die Ströme in den LED-Ketten des LED-Arrays werden zusätzlich durch eine hier nicht näher beschriebene Überwachungsschaltung 4 kon- trolliert.The circuit corresponds essentially to Figure 2. In contrast, a total of 120 LEDs 2 in 20 LED chains LK1, ..., LK20 with 6 LEDs each are connected in parallel. The currents in the LED chains of the LED array are additionally controlled by a monitoring circuit 4, which is not described in more detail here.
Bei Arrays dieser Größe ist es von besonderer Bedeutung, einen möglichst hohen Wirkungsgrad zu erzielen. Die eingangs beschriebene Möglichkeit nach dem Stand der Technik, unterschiedliche Durchlassspannungen der LED-Ketten des Arrays mittels rein ohmscher Serienwiderstände zu kompensieren, würde hier zu einer sehr hohen Verlustleistung und in der Folge zu aufwändigen Kühlmaßnahmen führen.With arrays of this size, it is particularly important to achieve the highest possible efficiency. The beginning The described possibility according to the prior art to compensate for different forward voltages of the LED chains of the array by means of purely ohmic series resistors would lead to a very high power loss and consequently to complex cooling measures.
Figur 4 zeigt ein viertes Ausführungsbeispiel gemäß der zweiten Ausführungsform der Erfindung. Wie bei dem in Figur 1 dargestellten Ausführungsbeispiel sind auch hier jeweils meh- rere LEDs 2 seriell zu LED-Ketten LKl, LK2 , LK3 geschaltet und die LED-Ketten LKl, LK2 , LK3 anodenseitig mit dem Pluspol einer VersorgungsSpannung und kathodenseitig über eine optionale Sicherung Ful, Fu2 , Fu3 jeweils mit einer Regelungsanordnung RAl, RA2, RA3 verbunden.Figure 4 shows a fourth embodiment according to the second embodiment of the invention. As in the exemplary embodiment shown in FIG. 1, several LEDs 2 are also connected in series to form LED chains LKl, LK2, LK3 and the LED chains LKl, LK2, LK3 on the anode side with the positive pole of a supply voltage and on the cathode side via an optional fuse Ful, Fu2, Fu3 each connected to a control arrangement RA1, RA2, RA3.
Die Regelungsanordnungen RAl, RA2 , RA3 umfassen wiederum jeweils einen Transistor Tx, dessen Kollektoranschluss Cx zu der entsprechenden LED-Kette LKx führt. Der Emitteranschluss Ex ist jeweils über einen Emitterwiderstand Rx2 mit dem Mi- nuspol der Versorgungsspannung verbunden.The control arrangements RA1, RA2, RA3 each in turn comprise a transistor Tx, the collector connection Cx of which leads to the corresponding LED chain LKx. The emitter connection Ex is connected to the negative pole of the supply voltage via an emitter resistor Rx2.
Die Basisanschlüsse Bl, B2 , B3 der Transistoren Tl, T2 , T3 sind wie bei den bisherigen Ausführungsbeispielen miteinander verbunden und liegen somit auf demselben Potential.The base connections B1, B2, B3 of the transistors T1, T2, T3 are connected to one another as in the previous exemplary embodiments and are therefore at the same potential.
Im Unterschied zu den in Figur 1 bis 3 gezeigten Ausführungs- beispielen gemäß der ersten Ausführungsform der Erfindung ist bei dem in Figur 4 gezeigten Ausführungsbeispiel nach der zweiten Ausfürungsform der Erfindung eine gemeinsame Ansteu- erschaltung A vorgesehen, die den Basisstrom für die Transistoren Tl, T2, T3 erzeugt. Als Ansteuerschaltung dient eine Serienschaltung aus einer in Sperrrichtung betriebenen Zenerdiode Dz und einem Widerstand Rz . Optional kann diese Serienschaltung eine Sicherung FuB, zum Beispiel einen Schmelzwiderstand umfassen. Diese ist so dimensioniert, dass sie bei einer vorgegebenen Zahl von unter- brochenen LED-Ketten, die jeweils wie beschrieben zu einem Anstieg des Basisstroms führen, durchbrennt. Damit wird das gesamte LED-Array abgeschaltet. Eine solche Funktionsweise kann beispielsweise sinnvoll sein, wenn die verbleibende Anzahl von intakten LED-Ketten den Sicherheitsanforderungen nicht mehr genügt.In contrast to the exemplary embodiments shown in FIGS. 1 to 3 according to the first embodiment of the invention, in the exemplary embodiment shown in FIG. 4 according to the second embodiment of the invention, a common control circuit A is provided, which controls the base current for the transistors T1, T2 , T3 generated. A series circuit comprising a Zener diode Dz operated in the reverse direction and a resistor Rz serves as the control circuit. This series connection can optionally include a fuse FuB, for example a melting resistor. This is dimensioned in such a way that it burns out with a predetermined number of interrupted LED chains, each of which leads to an increase in the base current as described. This switches off the entire LED array. Such a mode of operation can be useful, for example, if the remaining number of intact LED chains no longer meets the safety requirements.
Die Sicherungen Ful, Fu2 , Fu3 sind ebenfalls optional und dienen wie oben beschrieben der zusätzlichen Absicherung der LED-Ketten gegen zu hohe Ströme.The fuses Ful, Fu2, Fu3 are also optional and serve as additional protection of the LED chains against excessive currents as described above.
Der in Serie zur Zenerdiode Dz geschaltete Widerstand Rz besitzt vorzugsweise einen Wert zwischen 100 Ohm und 1000 Ohm.The resistor Rz connected in series with the zener diode Dz preferably has a value between 100 ohms and 1000 ohms.
Für eine gleichmäßige Basisstromaufteilung in allen Ketten müssen auch hier die Emitterwiderstände R12, R22, R32 den gleichen Wert aufweisen. Bei speziellen Anwendungen können aber auch unterschiedliche Emitterwiderstände erforderlich sein, zum Beispiel bei der Kombination von LEDs unterschiedlicher Farben, die sich in der Regel hinsichtlich ihres spezifizierten Betriebsstroms unterscheiden.For an even base current distribution in all chains, the emitter resistors R12, R22, R32 must also have the same value. In special applications, however, different emitter resistances may also be required, for example when combining LEDs of different colors, which usually differ in terms of their specified operating current.
Die Zenerdiode ist so dimensioniert, dass die daran abfallende Spannung einen stabilen Betriebszustand der Transistoren sicherstellt. Vorzugsweise ist die Zenerspannung der Zener- diode Dz etwa 1 V größer als die höchste DurchlassSpannung der LED-Ketten. Figur 5 zeigt eine fünftes Ausführungsbeispiel der Erfindung gemäß der zweiten Ausführungsform. Im Unterschied zu dem in Figur 4 dargestellten Ausführungsbeispiel sind die Regelungsanordnungen RAl, RA2, RA3 mit mit pnp-Transistoren Tl, T2 , T3 statt mit npn-Transistoren realisiert.The zener diode is dimensioned so that the voltage drop across it ensures a stable operating state of the transistors. The Zener voltage of the Zener diode Dz is preferably about 1 V higher than the highest forward voltage of the LED chains. Figure 5 shows a fifth embodiment of the invention according to the second embodiment. In contrast to the exemplary embodiment shown in FIG. 4, the control arrangements RA1, RA2, RA3 are implemented with pnp transistors T1, T2, T3 instead of with npn transistors.
Entsprechend sind die Regelungsanordnungen jeweils zwischen dem Pluspol der Versorgungsspannung und den Anodenseiten der LED-Ketten angeordnet. Die Ansteuerschaltung ist wie in Figur 4 als Serienschaltung einer Zenerdiode Dz und eines Widerstands Rz und gegebenenfalls einer optionalen Sicherung FuB ausgeführt, wobei die Zenerdiode anodenseitig über den Widerstand Rz mit dem Minuspol der VersorgungsSpannung verbunden ist .Accordingly, the control arrangements are arranged between the positive pole of the supply voltage and the anode sides of the LED chains. As in FIG. 4, the control circuit is designed as a series connection of a Zener diode Dz and a resistor Rz and optionally an optional fuse FuB, the Zener diode being connected on the anode side to the negative pole of the supply voltage via the resistor Rz.
Je nach Anforderung kann die erste oder die zweite Aufüh- rungsform der Erfindung vorteilhafter sein. Dabei zeichnet sich die erste Ausführungsform durch eine besondere Stabilität aus, da in der Regel alle LED-Ketten zum Strom für die Regelung beitragen. Weiterhin besitzt diese erste Ausführungsform gegenüber der zweiten Ausführungsform den höheren Gesamtwirkungsgrad.Depending on the requirements, the first or the second embodiment of the invention can be more advantageous. The first embodiment is characterized by a particular stability, since usually all LED chains contribute to the current for the control. Furthermore, this first embodiment has the higher overall efficiency compared to the second embodiment.
Die zweite Ausführunsform erfordert aufgrund der gemeinsamen Ansteuerschaltung für die LED-Ketten einen geringeren schaltungstechnischen Aufwand und ist besonders leicht über die gemeinsame Verbindung zwischen Ansteuerschaltung und Regelungsanordnung abschaltbar, beispielsweise wie beschrieben mittels der Sicherung FuB.Due to the common control circuit for the LED chains, the second embodiment requires less circuitry and can be switched off particularly easily via the common connection between the control circuit and the control arrangement, for example as described by means of the fuse FuB.
Die Erläuterung der Erfindung anhand der Ausführungsbeispiele ist selbstverständlich nicht als Einschränkung hierauf zu verstehen. The explanation of the invention on the basis of the exemplary embodiments is of course not to be understood as a restriction thereon.

Claims

Patentansprüche claims
1. Schaltungsanordnung für ein LED-Array mit zwei oder mehr 5 parallel geschalteten LED-Ketten (LKl, LK2 , LK3) , in denen jeweils mindestens eine LED (2) angeordnet ist, wobei bei zwei oder mehr LEDs (2) diese in Serie geschaltet sind, bei der jeweils die Anodenseiten der LED-Ketten (LKl, LK2 , LK3) an dem Pluspol einer VersorgungsSpannung (Uv) und die Katho-1. Circuit arrangement for an LED array with two or more 5 LED chains (LKl, LK2, LK3) connected in parallel, in each of which at least one LED (2) is arranged, with two or more LEDs (2) these being in series are switched, in which the anode sides of the LED chains (LKl, LK2, LK3) at the positive pole of a supply voltage (U v ) and the cathode
L0 denseiten an dem Minuspol der Versorgungsspannung (Uv) ankoppelbar sind, d a d u r c h g e k e n n z e i c h n e t, dass zu jeder LED-Kette (LKl, LK2 , LK3) jeweils eine Regelungsanordnung (RAl, RA2 , RA3) zur Regelung einer vorgegebenenL0 denseiten can be coupled to the negative pole of the supply voltage (U v ), characterized in that for each LED chain (LKl, LK2, LK3) each have a control arrangement (RAl, RA2, RA3) for controlling a given one
15 Stromverteilung auf die einzelnen LED-Ketten (LKl, LK2 , LK3) in Serie geschaltet ist.15 current distribution on the individual LED chains (LKl, LK2, LK3) is connected in series.
2. Schaltungsanordnung für ein LED-Array nach Anspruch 1, d a d u r c h g e k e n n z e i c h n e t, dass 0 die Regelungsanordnungen (RAl, RA2 , RA3) jeweils eine Stromverstärkungsschaltung zur Einprägung eines Stroms in die LED- Ketten (LKl, LK2 , LK3) gemäß der vorgegebenen Stromverteilung umfassen.2. Circuit arrangement for an LED array according to claim 1, so that the control arrangements (RAl, RA2, RA3) each comprise a current amplification circuit for impressing a current into the LED chains (LKl, LK2, LK3) according to the predetermined current distribution.
5 3. Schaltungsanordnung für ein LED-Array nach Anspruch 1 oder 2 , d a d u r c h g e k e n n z e i c h n e t, dass die Stromverstärkungsschaltungen jeweils einen Regelungseingang zur Regelung des Stroms in der zugehörigen LED-Kette 0 aufweisen, wobei die Regelungseingänge miteinander verbunden sind. 5 3. Circuit arrangement for an LED array according to claim 1 or 2, characterized in that the current amplification circuits each have a control input for regulating the current in the associated LED chain 0, the control inputs being connected to one another.
4. Schaltungsanordnung für ein LED-Array nach einem der Ansprüche 1 bis 3, d a d u r c h g e k e n n z e i c h n e t, dass die Regelungsanordnungen (RAl, RA2 , RA3) jeweils einen vor- zugsweise bipolaren Transistor (Tl, T2 , T3) enthalten, dessen Kollektoranschluss (Cl, C2 , C3) jeweils mit der Kathodenseite der zugehörigen LED-Kette (LKl, LK2 , LK3) verbunden ist, und dessen Emitteranschluss (El, E2 , E3) jeweils über einen Emitterwiderstand (R12, R22, R32) mit dem Minuspol der Versor- gungsspannung (Uv) verbindbar ist, wobei die Basisanschlüsse (Bl, B2, B3) der Transistoren (Tl, T2 , T3) miteinander verbunden sind, und wobei eine Ansteuerschaltung die Basisanschlüsse (Bl, B2, B3) der Transistoren (Tl, T2 , T3) mit einem vorbestimmten Strom beaufschlagt.4. Circuit arrangement for an LED array according to one of claims 1 to 3, characterized in that the control arrangements (RAl, RA2, RA3) each contain a preferably bipolar transistor (Tl, T2, T3), the collector connection (Cl, C2 , C3) is connected to the cathode side of the associated LED chain (LKl, LK2, LK3), and its emitter connection (El, E2, E3) is connected to the negative pole of the supply voltage via an emitter resistor (R12, R22, R32) (U v ) can be connected, the base connections (B1, B2, B3) of the transistors (Tl, T2, T3) being connected to one another, and a control circuit connecting the base connections (B1, B2, B3) of the transistors (Tl, T2, T3) with a predetermined current.
5. Schaltungsanordnung für ein LED-Array nach einem der Ansprüche 1 bis 3, d a d u r c h g e k e n n z e i c h n e t, dass die Regelungsanordnungen (RAl, RA2 , RA3) jeweils einen vor- zugsweise bipolaren Transistor (Tl, T2 , T3) enthalten, dessen Kollektoranschluss (Cl, C2 , C3) jeweils mit der Anodenseite der zugehörigen LED-Kette (LKl, LK2 , LK3) verbunden ist und dessen Emitteranschluss (El, E2 , E3) jeweils über einen Emitterwiderstand (R12, R22, R32) mit dem Pluspol der Versor- gungsspannung (U) verbindbar ist, wobei die Basisanschlüsse (Bl, B2, B3) der Transistoren (Tl, T2 , T3) miteinander verbunden sind, und wobei eine Ansteuerschaltung die Basisanschlüsse (Bl, B2, B3) der Transistoren (Tl, T2 , T3) mit einem vorbestimmten Strom beaufschlagt .5. Circuit arrangement for an LED array according to one of claims 1 to 3, characterized in that the control arrangements (RAl, RA2, RA3) each contain a preferably bipolar transistor (Tl, T2, T3), the collector connection (Cl, C2 , C3) is connected to the anode side of the associated LED chain (LKl, LK2, LK3) and its emitter connection (El, E2, E3) each has an emitter resistor (R12, R22, R32) with the positive pole of the supply voltage ( U) can be connected, the base connections (B1, B2, B3) of the transistors (Tl, T2, T3) being connected to one another, and a control circuit connecting the base connections (B1, B2, B3) of the transistors (Tl, T2, T3) supplied with a predetermined current.
6. Schaltungsanordnung für ein LED-Array nach Anspruch 4 oder 5 , d a d u r c h g e k e n n z e i c h n e t, dass als Ansteuerschaltung jeweils eine Serienschaltung einer Diode (Dl, D2 , D3) und eines Widerstands (Rll, R21, R31) vorgesehen ist, die zwischen dem jeweiligen Kollektoranschluss (Cl, C2 , C3) und dem jeweiligen Basisanschluss (Bl, B2 , B3) des Transistors (Tl, T2 , T3) einer Regelungsanordnung (RAl, RA2, RA3) angeordnet ist.6. Circuit arrangement for an LED array according to claim 4 or 5, characterized in that A series connection of a diode (D1, D2, D3) and a resistor (R11, R21, R31) is provided as the control circuit, which is connected between the respective collector connection (Cl, C2, C3) and the respective base connection (B1, B2, B3) of the transistor (T1, T2, T3) of a control arrangement (RA1, RA2, RA3) is arranged.
7. Schaltungsanordnung für ein LED-Array nach Anspruch 3 oder 4 , d a d u r c h g e k e n n z e i c h n e t, dass die Ansteuerschaltung eine an den Pluspol der Versorgungs- Spannung (Uv) anschließbare, in Sperrrichtung zu der Versorgungsspannung (Uv) betriebene Zenerdiode (Dz) umfasst, deren Anode mit den Steuereingängen bzw. mit den Basisanschlüssen (Bl, B2, B3) verbunden ist.7. Circuit arrangement for an LED array according to claim 3 or 4, characterized in that the control circuit comprises a Zener diode (Dz) which can be connected to the positive pole of the supply voltage (U v ) and is operated in the reverse direction to the supply voltage (U v ) Anode is connected to the control inputs or to the basic connections (B1, B2, B3).
8. Schaltungsanordnung für ein LED-Array nach Anspruch 3 oder 5 , d a d u r c h g e k e n n z e i c h n e t, dass die Ansteuerschaltung eine an den Minuspol der Versorgungsspannung (Uv) anschließbare, in Sperrrichtung zu der Versorgungsspannung (Uv) betriebene Zenerdiode (Dz) umfasst, deren Kathode mit den Steuereingängen bzw. mit den Basisanschlüssen (Bl, B2, B3) verbunden ist.8. Circuit arrangement for an LED array according to claim 3 or 5, characterized in that the control circuit comprises a connectable to the negative pole of the supply voltage (U v ), in the reverse direction to the supply voltage (U v ) operated Zener diode (Dz), the cathode of which the control inputs or with the basic connections (B1, B2, B3).
9. Schaltungsanordnung für ein LED-Array nach einem der Ansprüche 7 oder 8, d a d u r c h g e k e n n z e i c h n e t, dass in Serie zu der Zenerdiode (Dz) eine Sicherung (FuB) , vor- zugsweise ein Schmelzwiderstand, geschaltet ist.9. Circuit arrangement for an LED array according to one of claims 7 or 8, d a d u r c h g e k e n n z e i c h n e t that a fuse (FuB), preferably a melting resistor, is connected in series with the Zener diode (Dz).
10. Schaltungsanordnung für ein LED-Array nach einem der Ansprüche 7, 8 oder 9, d a d u r c h g e k e n n z e i c h n e t, dass in Serie zu der Zenerdiode (Dz) ein Widerstand (Rz) geschaltet ist.10. Circuit arrangement for an LED array according to one of claims 7, 8 or 9, characterized in that a resistor (Rz) is connected in series with the Zener diode (Dz).
5 11. Schaltungsanordnung für ein LED-Array nach Anspruch 10, d a d u r c h g e k e n n z e i c h n e t, dass der Wert des Widerstands (Rz) in Serie zur Zenerdiode (Dz) zwischen 100 Ohm und 1000 Ohm liegt.5 11. Circuit arrangement for an LED array according to claim 10, d a d u r c h g e k e n n z e i c h n e t that the value of the resistance (Rz) in series with the Zener diode (Dz) is between 100 ohms and 1000 ohms.
.0.0
12. Schaltungsanordnung für ein LED-Array nach einem der Ansprüche 4 bis 11, d a d u r c h g e k e n n z e i c h n e t, dass die Emitterwiderstände (R12, R22, R32) zur Einstellung der Ströme in den jeweiligen LED-Ketten (LKl, LK2 , LK3) dienen.12. Circuit arrangement for an LED array according to one of claims 4 to 11, d a d u r c h g e k e n n z e i c h n e t that the emitter resistors (R12, R22, R32) serve to adjust the currents in the respective LED chains (LKl, LK2, LK3).
L5L5
13. Schaltungsanordnung für ein LED-Array nach einem der Ansprüche 4 bis 12, d a d u r c h g e k e n n z e i c h n e t, dass die Werte der Emitterwiderstände (R12, R22, R32) zwischen 20 1 Ohm und 100 Ohm liegen und vorzugsweise etwa 10 Ohm betragen.13. Circuit arrangement for an LED array according to one of claims 4 to 12, so that the values of the emitter resistances (R12, R22, R32) are between 20 1 ohms and 100 ohms and are preferably about 10 ohms.
14. Schaltungsanordnung für ein LED-Array nach einem der Ansprüche 1 bis 13, 5 d a d u r c h g e k e n n z e i c h n e t, dass seriell zu den LED-Ketten (LKl, LK2 , LK3) jeweils eine Sicherung (Ful, Fu2, Fu3) , vorzugsweise ein Schmelzwiderstand, geschaltet ist .14. Circuit arrangement for an LED array according to one of claims 1 to 13, 5 characterized in that a fuse (Ful, Fu2, Fu3), preferably a melting resistor, is connected in series with the LED chains (LKl, LK2, LK3) ,
0 15. Schaltungsanordnung für ein LED-Array nach einem der Ansprüche 1 bis 14, d a d u r c h g e k e n n z e i c h n e t, dass das LED-Array eine Lichtsignaleinrichtung ist. 15. Circuit arrangement for an LED array according to one of claims 1 to 14, so that the LED array is a light signal device.
EP02803750A 2001-11-26 2002-11-26 Circuit for an led array Expired - Fee Related EP1449408B2 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10440786B1 (en) 2018-05-09 2019-10-08 Infineon Technologies Ag Control circuit and techniques for controlling a LED array

Families Citing this family (88)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20040141329A1 (en) * 2003-01-20 2004-07-22 Walter Fleischmann Lighting system for aircraft cabins
JP2005257790A (en) * 2004-03-09 2005-09-22 Olympus Corp Illuminator and image projection device using the same
JP4241487B2 (en) * 2004-04-20 2009-03-18 ソニー株式会社 LED driving device, backlight light source device, and color liquid crystal display device
EP2299781A3 (en) * 2004-09-13 2011-05-04 Semiconductor Energy Laboratory Co, Ltd. Light emitting layer device
JP4438599B2 (en) * 2004-10-26 2010-03-24 住友電気工業株式会社 Optical transmitter
JP2007005014A (en) * 2005-06-21 2007-01-11 Toshiba Matsushita Display Technology Co Ltd Illumination device and liquid crystal display device
EP2367400B1 (en) 2005-06-28 2020-03-18 Seoul Viosys Co., Ltd Light emitting device for AC power operation
JP4585398B2 (en) * 2005-07-25 2010-11-24 サンクス株式会社 Display device and detection sensor having the device
US7872430B2 (en) * 2005-11-18 2011-01-18 Cree, Inc. Solid state lighting panels with variable voltage boost current sources
DE102005056255A1 (en) * 2005-11-25 2007-06-06 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Circuit device with overhead buck transistor
US7738229B2 (en) * 2006-01-10 2010-06-15 Bayco Products, Ltd. Microprocessor-controlled multifunctioning light with intrinsically safe energy limiting
KR100678774B1 (en) 2006-01-13 2007-02-02 한국 고덴시 주식회사 Apparatus and method for driving of light emitting diode array module
WO2007087327A2 (en) * 2006-01-25 2007-08-02 Cree Led Lighting Solutions, Inc. Circuit for lighting device, and method of lighting
US20070290629A1 (en) * 2006-06-16 2007-12-20 Koren Pinhas P Modular illumination system
US20080007885A1 (en) * 2006-07-05 2008-01-10 Texas Instruments Incorporated System for improving LED illumination reliability in projection display systems
WO2008012958A1 (en) * 2006-07-24 2008-01-31 Sharp Kabushiki Kaisha Back light device, and display device using same
EP2087772B1 (en) * 2006-10-31 2017-09-06 Philips Lighting Holding B.V. Light source comprising light-emitting clusters
CN100562200C (en) * 2006-12-15 2009-11-18 鸿富锦精密工业（深圳）有限公司 Solar streetlight control circuit
CN101652861B (en) * 2007-01-22 2013-01-23 科锐公司 Fault tolerant light emitters, systems incorporating fault tolerant light emitters and methods of fabricating fault tolerant light emitters
JP2010517274A (en) * 2007-01-22 2010-05-20 クリー レッド ライティング ソリューションズ、インコーポレイテッド Illumination device using array of light-emitting elements interconnected externally and method of manufacturing the same
EP1965609A3 (en) * 2007-02-27 2011-06-15 Lumination, LLC LED chain failure detection
US8703492B2 (en) * 2007-04-06 2014-04-22 Qiagen Gaithersburg, Inc. Open platform hybrid manual-automated sample processing system
US8049709B2 (en) 2007-05-08 2011-11-01 Cree, Inc. Systems and methods for controlling a solid state lighting panel
KR100930818B1 (en) 2007-08-31 2009-12-09 엘지이노텍 주식회사 Power supply
US9079022B2 (en) * 2007-09-27 2015-07-14 Led Intellectual Properties, Llc LED based phototherapy device for photo-rejuvenation of cells
TWI369777B (en) 2007-10-04 2012-08-01 Young Lighting Technology Corp Surface light source of backlight module in a flat panel display
US8004216B2 (en) * 2008-05-02 2011-08-23 The United States Of America As Represented By The Secretary Of The Navy Variable intensity LED illumination system
DE102008039526B4 (en) 2008-08-23 2016-07-14 Hella Kgaa Hueck & Co. Method for powering an LED array and circuit arrangement for carrying out the method and a lighting unit
US8773336B2 (en) 2008-09-05 2014-07-08 Ketra, Inc. Illumination devices and related systems and methods
US10210750B2 (en) 2011-09-13 2019-02-19 Lutron Electronics Co., Inc. System and method of extending the communication range in a visible light communication system
US9509525B2 (en) 2008-09-05 2016-11-29 Ketra, Inc. Intelligent illumination device
US9276766B2 (en) 2008-09-05 2016-03-01 Ketra, Inc. Display calibration systems and related methods
US7977887B2 (en) * 2008-09-09 2011-07-12 Delphi Technologies, Inc. Low leakage current LED drive apparatus with fault protection and diagnostics
CN201282580Y (en) * 2008-09-28 2009-07-29 张荣民 Drive circuit for high-power LED
TWI401990B (en) * 2008-12-31 2013-07-11 Genesis Photonics Inc Electronic device, constant current unit and stable current method
FR2948440B1 (en) * 2009-07-21 2011-08-26 Thales Sa SECURED LIGHT-EMITTING DIODE LIGHT BOX
CN101695207B (en) * 2009-08-31 2014-07-23 裘麒龙 LED tube circuit
US8344632B2 (en) * 2009-12-15 2013-01-01 Silicon Touch Technology Inc. Light emitting device
US20120319603A1 (en) 2010-03-01 2012-12-20 Hella Kgaa Method to supply power to an led array as well as the circuit arrangement for implementing the method
TWM390632U (en) * 2010-06-07 2010-10-11 Unity Opto Technology Co Ltd Light-emitting diode protection structure
NL2005418C2 (en) * 2010-09-29 2012-04-02 Europ Intelligence B V Intrinsically safe led display.
US9386668B2 (en) 2010-09-30 2016-07-05 Ketra, Inc. Lighting control system
USRE49454E1 (en) 2010-09-30 2023-03-07 Lutron Technology Company Llc Lighting control system
WO2012086662A1 (en) 2010-12-24 2012-06-28 Semiconductor Energy Laboratory Co., Ltd. Lighting device
US8552440B2 (en) 2010-12-24 2013-10-08 Semiconductor Energy Laboratory Co., Ltd. Lighting device
CN102022655A (en) * 2010-12-24 2011-04-20 鸿富锦精密工业（深圳）有限公司 LED serial-parallel circuit and LED illumination device
CN103262656B (en) 2010-12-28 2016-08-24 株式会社半导体能源研究所 Luminescence unit, light-emitting device and illuminator
US9516713B2 (en) 2011-01-25 2016-12-06 Semiconductor Energy Laboratory Co., Ltd. Light-emitting device
JP5925511B2 (en) 2011-02-11 2016-05-25 株式会社半導体エネルギー研究所 Light emitting unit, light emitting device, lighting device
US8735874B2 (en) 2011-02-14 2014-05-27 Semiconductor Energy Laboratory Co., Ltd. Light-emitting device, display device, and method for manufacturing the same
US8772795B2 (en) 2011-02-14 2014-07-08 Semiconductor Energy Laboratory Co., Ltd. Light-emitting device and lighting device
WO2012164511A1 (en) 2011-06-03 2012-12-06 Osram Ag A method of driving led lighting sources and related device
US9232587B2 (en) 2011-09-30 2016-01-05 Advanced Analogic Technologies, Inc. Low cost LED driver with integral dimming capability
US8779696B2 (en) 2011-10-24 2014-07-15 Advanced Analogic Technologies, Inc. Low cost LED driver with improved serial bus
DE102012000605B4 (en) 2011-10-27 2016-01-07 Diehl Aerospace Gmbh Lighting device for an AC power supply
RU2474920C1 (en) * 2011-11-14 2013-02-10 Вячеслав Николаевич Козубов Method to generate light-emitting matrices
JP5845108B2 (en) 2012-02-23 2016-01-20 ルネサスエレクトロニクス株式会社 Power device
DE102012206888A1 (en) * 2012-04-26 2013-10-31 Zumtobel Lighting Gmbh LED array
JP5522643B2 (en) * 2012-07-13 2014-06-18 シャープ株式会社 Light emitting device
JP6155703B2 (en) * 2013-03-04 2017-07-05 セイコーエプソン株式会社 Light source device and projector
US9345097B1 (en) 2013-08-20 2016-05-17 Ketra, Inc. Interference-resistant compensation for illumination devices using multiple series of measurement intervals
US9651632B1 (en) 2013-08-20 2017-05-16 Ketra, Inc. Illumination device and temperature calibration method
USRE48955E1 (en) 2013-08-20 2022-03-01 Lutron Technology Company Llc Interference-resistant compensation for illumination devices having multiple emitter modules
US9578724B1 (en) 2013-08-20 2017-02-21 Ketra, Inc. Illumination device and method for avoiding flicker
US9769899B2 (en) 2014-06-25 2017-09-19 Ketra, Inc. Illumination device and age compensation method
US9332598B1 (en) 2013-08-20 2016-05-03 Ketra, Inc. Interference-resistant compensation for illumination devices having multiple emitter modules
US9247605B1 (en) 2013-08-20 2016-01-26 Ketra, Inc. Interference-resistant compensation for illumination devices
USRE48956E1 (en) 2013-08-20 2022-03-01 Lutron Technology Company Llc Interference-resistant compensation for illumination devices using multiple series of measurement intervals
US9360174B2 (en) 2013-12-05 2016-06-07 Ketra, Inc. Linear LED illumination device with improved color mixing
US9237620B1 (en) * 2013-08-20 2016-01-12 Ketra, Inc. Illumination device and temperature compensation method
US9736895B1 (en) 2013-10-03 2017-08-15 Ketra, Inc. Color mixing optics for LED illumination device
US9392663B2 (en) 2014-06-25 2016-07-12 Ketra, Inc. Illumination device and method for controlling an illumination device over changes in drive current and temperature
US10161786B2 (en) 2014-06-25 2018-12-25 Lutron Ketra, Llc Emitter module for an LED illumination device
US9557214B2 (en) 2014-06-25 2017-01-31 Ketra, Inc. Illumination device and method for calibrating an illumination device over changes in temperature, drive current, and time
US9736903B2 (en) 2014-06-25 2017-08-15 Ketra, Inc. Illumination device and method for calibrating and controlling an illumination device comprising a phosphor converted LED
JP6355046B2 (en) * 2014-07-29 2018-07-11 パナソニックＩｐマネジメント株式会社 Lighting device and lighting fixture
EP2979954B1 (en) * 2014-07-29 2020-12-23 Pintsch GmbH Led unit for light signal emitter, light signal emitter with such a unit and method for monitoring a led strand of a led unit
US9510416B2 (en) 2014-08-28 2016-11-29 Ketra, Inc. LED illumination device and method for accurately controlling the intensity and color point of the illumination device over time
US9392660B2 (en) 2014-08-28 2016-07-12 Ketra, Inc. LED illumination device and calibration method for accurately characterizing the emission LEDs and photodetector(s) included within the LED illumination device
US9237623B1 (en) 2015-01-26 2016-01-12 Ketra, Inc. Illumination device and method for determining a maximum lumens that can be safely produced by the illumination device to achieve a target chromaticity
US9485813B1 (en) 2015-01-26 2016-11-01 Ketra, Inc. Illumination device and method for avoiding an over-power or over-current condition in a power converter
US9237612B1 (en) 2015-01-26 2016-01-12 Ketra, Inc. Illumination device and method for determining a target lumens that can be safely produced by an illumination device at a present temperature
WO2017180527A1 (en) 2016-04-11 2017-10-19 Cooper Technologies Company Fail-safe led system
US20180031190A1 (en) * 2016-07-28 2018-02-01 Richard Nicolai Scalable direct line voltage led luminaire tape
CN106704888A (en) * 2017-03-17 2017-05-24 南京养元素电子科技有限公司 LED illumination device with high reliability
US11272599B1 (en) 2018-06-22 2022-03-08 Lutron Technology Company Llc Calibration procedure for a light-emitting diode light source
CN109058799A (en) * 2018-10-25 2018-12-21 深圳市虹晟源光电科技有限公司 A kind of LED light bar
CA3136613A1 (en) * 2019-04-08 2020-10-15 Agrify Corporation Device for limiting current

Family Cites Families (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3030058A1 (en) * 1980-08-08 1982-03-11 Vdo Adolf Schindling Ag, 6000 Frankfurt Low powered LED display - with leds which are connected in series-parallel with constant voltage devices compensating for current variations
US5149190A (en) * 1989-05-24 1992-09-22 Bay Industrial And Mine Tech Inc. Portable safety device
US5144117A (en) * 1990-02-27 1992-09-01 Alps Electric Co., Ltd. Illumination type optical recorded information reading device
US5278432A (en) 1992-08-27 1994-01-11 Quantam Devices, Inc. Apparatus for providing radiant energy
JPH07262810A (en) * 1994-03-18 1995-10-13 Sony Tektronix Corp Luminous device
DE19618010C1 (en) 1996-05-04 1997-07-03 Hella Kg Hueck & Co Flashing light indicator system with light-emitting diodes for motor vehicle
US6150771A (en) * 1997-06-11 2000-11-21 Precision Solar Controls Inc. Circuit for interfacing between a conventional traffic signal conflict monitor and light emitting diodes replacing a conventional incandescent bulb in the signal
DE19728763B4 (en) * 1997-07-07 2007-10-31 Reitter & Schefenacker Gmbh & Co. Kg Circuit device for protecting current-driven light sources, in particular LEDs, for signaling or lighting purposes
US7038398B1 (en) * 1997-08-26 2006-05-02 Color Kinetics, Incorporated Kinetic illumination system and methods
DE19749333A1 (en) † 1997-09-19 1999-03-25 Garufo Gmbh Light signal consisting of LEDs connected to voltage via current source
JP3461272B2 (en) * 1997-09-22 2003-10-27 キヤノン株式会社 Image reading method and apparatus
DE19804891A1 (en) 1998-02-07 1999-09-02 Mannesmann Vdo Ag Circuit for vehicle display lighting
US6461019B1 (en) * 1998-08-28 2002-10-08 Fiber Optic Designs, Inc. Preferred embodiment to LED light string
ATE339077T1 (en) * 1999-08-19 2006-09-15 Schott Ag LIGHTING CONTROL DEVICE
US6351079B1 (en) * 1999-08-19 2002-02-26 Schott Fibre Optics (Uk) Limited Lighting control device
DE19950135A1 (en) * 1999-10-18 2001-04-19 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh Control circuit for LED array has master string with given number of LEDs in string and control circuit also controls semiconducting switch of slave string
US6762563B2 (en) * 1999-11-19 2004-07-13 Gelcore Llc Module for powering and monitoring light-emitting diodes
US6161910A (en) 1999-12-14 2000-12-19 Aerospace Lighting Corporation LED reading light
US6480399B2 (en) * 2000-03-02 2002-11-12 Power Integrations, Inc. Switched mode power supply responsive to current derived from voltage across energy transfer element input
DE10017878A1 (en) * 2000-04-11 2001-10-25 Hella Kg Hueck & Co Control device for a lamp of a motor vehicle provided with a number of light-emitting diodes
US6628252B2 (en) * 2000-05-12 2003-09-30 Rohm Co., Ltd. LED drive circuit
US6621235B2 (en) * 2001-08-03 2003-09-16 Koninklijke Philips Electronics N.V. Integrated LED driving device with current sharing for multiple LED strings

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO03047314A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10440786B1 (en) 2018-05-09 2019-10-08 Infineon Technologies Ag Control circuit and techniques for controlling a LED array

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WO2003047314A1 (en) 2003-06-05
US20050077838A1 (en) 2005-04-14
JP4488489B2 (en) 2010-06-23
EP1449408B1 (en) 2007-08-15
CN1596560A (en) 2005-03-16
TWI235349B (en) 2005-07-01
DE50210722D1 (en) 2007-09-27
EP1449408B2 (en) 2011-08-31
TW200300545A (en) 2003-06-01
US7317287B2 (en) 2008-01-08
JP2005510891A (en) 2005-04-21
CN1596560B (en) 2011-04-06

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