EP0158072A1 - Electronic ballast for multiple fluorescent lamps - Google Patents

Electronic ballast for multiple fluorescent lamps Download PDF

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Publication number
EP0158072A1
EP0158072A1 EP19850102029 EP85102029A EP0158072A1 EP 0158072 A1 EP0158072 A1 EP 0158072A1 EP 19850102029 EP19850102029 EP 19850102029 EP 85102029 A EP85102029 A EP 85102029A EP 0158072 A1 EP0158072 A1 EP 0158072A1
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EP
European Patent Office
Prior art keywords
fluorescent lamps
lamp
ignite
resonant circuit
fluorescent
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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.)
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EP19850102029
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German (de)
French (fr)
Inventor
Ferdinand Dipl.-Ing. Mertens
Fred Dr.-Ing. Hasemann
Norbert Dipl.-Ing. Wittig
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Trilux GmbH and Co KG
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Trilux Lenze GmbH and Co KG
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    • 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
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
    • H05B41/2825—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a bridge converter in the final stage
    • H05B41/2827—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a bridge converter in the final stage using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations

Definitions

  • the invention relates to an electronic ballast for a plurality of fluorescent lamps, with a push-pull switch arrangement which is connected to a DC voltage and consists of two electronic switches and with a plurality of working resonant circuits controlled by the electronic switches, each of which has a fluorescent lamp connected in parallel with the resonant circuit capacitor and in series with the resonant circuit coil.
  • Electronic ballasts which serve to jointly connect two or more fluorescent lamps. ignite and operate. Such ballasts are used in particular in luminaires that contain several fluorescent lamps, which are always switched together. Difficulties arise in the ballasts mentioned that two or more Series resonant circuits are connected in parallel, of which the resonant circuit capacitor is bridged by a fluorescent lamp as soon as it has ignited.
  • the fluorescent lamp that ignites first brings about a reduction in the voltage applied to the working resonant circuits from approximately 900 V to approximately 450 V and a reduction in the oscillation frequency from approximately 80 kHz to approximately 22 kHz.
  • the second fluorescent lamp ignites much worse. At temperatures above approx. 15 ° C it is often observed that the second fluorescent lamp no longer ignites at all.
  • the newer lamp starts before the weaker older lamp.
  • the weaker lamp must therefore be started with a lower ignition voltage. This leads to a high emitter load on the heating wire of the fluorescent lamp and to glow discharges. This results in a higher lamp load and a reduction in lamp life.
  • ballasts are known which only make it possible to start a fluorescent lamp when the second fluorescent lamp has been inserted and is ready for operation. This is to ensure that a lamp is never operated with only one fluorescent lamp.
  • both fluorescent lamps do not work. The user must therefore replace both fluorescent lamps at the same time, especially since he cannot recognize which of the lamps is defective.
  • the invention has for its object to provide an electronic ballast of the type mentioned, which makes it possible to ignite each of these fluorescent lamps with increased voltage at several fluorescent lamps operated in parallel, even if the fluorescent lamps have different properties, such as. different ages, or have to be screwed into their versions one after the other.
  • the additional capacitor transmits an additional pulse to the other fluorescent lamp which has not yet been ignited, so that the lamp which is more unwilling to ignite receives an additional voltage surge. Due to the capacitive coupling, the weaker lamp is pulled along by the stronger one. Another advantage is that in the event that one fluorescent lamp has been unscrewed from its socket, the other fluorescent lamp will work. If the removed fluorescent lamp is then used, a voltage surge occurs on the additional capacitor, which causes the lamp used later to ignite immediately. The fact that the additional capacitor supplies a voltage pulse to the lamp which ignited last, the ignition process is accelerated and it becomes the harmful consequences of glow discharge caused by slow ignition are avoided. The lifespan of the fluorescent lamps is thus considerably increased.
  • the voice circuit coil is triggered when a surge occurs, e.g. when the fluorescent lamp is started, briefly saturated, which reduces its inductance.
  • the lamp when the lamp is started, its resistance and capacity naturally change. So far it has not been possible to exactly determine the function of the additional capacitor when starting the first fluorescent lamp or when turning in a further fluorescent lamp and to uncover the theoretical backgrounds. It is assumed that the capacitance of the additional capacitor temporarily forms a blocking circuit with the resonant circuit inductances and that, in addition to the coupling function which the additional capacitor has, temporary resonance functions also play a role.
  • the capacitance of the additional capacitor is preferably 1/5 to 4/5 of the capacitance of one of the resonant circuit capacitors and is in particular in the range of 1/3 to 2/3 of the capacitance of a resonant circuit capacitor. In these areas, the desired effect of generating a voltage pulse for the subsequently lighting fluorescent lamp is achieved with great certainty.
  • the ballast shown in FIG. 1 has a DC voltage source (not shown) which applies a DC voltage to the supply lines 10, 11.
  • the push-pull switch arrangement comprising the transistors of the same type connected in series, in the present case npn transistors, is placed between the supply lines 10, 11.
  • a series circuit comprising the primary coil 15 of a transformer 16 and a capacitor 17 is connected to the connection point 14 of the two transistors 12 and 13.
  • the resonant circuit coils L 1 and L 2 of the two fluorescent lamps 18 and 19 are connected to the other leg of the capacitor 17.
  • Each resonant circuit coil L 1 and L 2 is connected in series with the associated resonant circuit capacitor C 1 and C 2 .
  • the associated fluorescent lamp 18 or 19 is connected in parallel with the resonant circuit capacitor C 1 or C 2 .
  • One ends of the resonant circuit capacitors C 1 and the fluorescent lamps 18 and 19 are connected to the negative supply line 10.
  • Transistors 12 and 13 are switched in push-pull mode, ie when transistor 12 is conductive, transistor 13 is blocked and when transistor 13 is conductive, transistor 12 is blocked. However, overlap the blocking phases of both transistors slightly.
  • the transistors 12 and 13 are controlled via two secondary windings 20, 21 of the transformer 16.
  • the secondary winding 20 is connected to a control circuit 22, the output of which is connected to the base of the transistor 13.
  • the second secondary coil 21, which is also inductively coupled to the primary coil 15 of the transmitter 16, is connected to a control circuit 23, the output signal of which controls the base of the transistor 12.
  • the two secondary coils 20 and 21 are excited in opposite directions from one another by the primary coil 15 in order to control the transistors 12 and 13 in a push-pull manner, so that the connection point 14 alternately assumes the potentials of the positive and negative poles of the supply voltage when the current in the primary coil 15 oscillates.
  • the oscillating voltage for controlling the transistors 12, 13 is caused by the resonant circuits L 1 , C 1 and L 2 , C 2 .
  • each resonant circuit has a natural frequency of approximately 80 kHz. Since the resonant circuits are undamped, high voltages of approximately 900 V arise at the resonant circuit capacitors C 1 and C 2.
  • the series resonant circuits are damped by the parallel connection of the fluorescent lamps to the resonant circuit capacitors, so that the voltage present at the fluorescent lamps increases approx. 110 V (at 58 W fluorescent lamp Krypton) and the oscillation frequency is reduced to 33 kHz. Accordingly, the frequency at which the transistors 12 and 13 are reversed also changes.
  • the additional capacitor C 3 which has a capacitance of a few nF, is connected between the connection points of L 1 and C 1 and the connection points of L 2 and C2 .
  • This additional capacitor has the effect that, as soon as the first fluorescent lamp ignites, a voltage pulse is transmitted to the second fluorescent lamp, so that the ignition of this second fluorescent lamp is made easier.
  • both fluorescent lamps ignite practically at the same time, so that neither of the fluorescent lamps is supplied with the lower voltage for an extended period of time in the non-ignited state.
  • the resonant circuit components had the following dimensions:
  • the capacitance of the additional capacitor C 3 should be in the order of magnitude of the capacitance of the resonant circuit capacitor, but should be smaller than this.
  • FIG. 2 differs from that of FIG. 1 only in that instead of the common discharge capacitor 17, which supplies both series resonant circuits in FIG. 1, two identical capacitors 17a, 17b are provided, one of which is a capacitor 17a of the first Voice circuit coil L 1 is connected upstream, while the second 17b is connected upstream of the second voice circuit coil L 2 .
  • the capacitor 17 of FIG. 1 as well as the capacitors 17a and 17b of FIG. 2 serve to charge the energy. Their capacitance is considerably larger than that of the other capacitors used and is, for example, 0.33 ⁇ F.
  • the vibrations in the series resonant circuits are influenced by the capacitors 17 and 17a, 17b.
  • two fluorescent lamps with the associated series resonant circuits are present.
  • more than two fluorescent lamps can also be coupled to one another, two fluorescent lamps each being connected to one another by an additional capacitor C 3 .

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Circuit Arrangements For Discharge Lamps (AREA)

Abstract

In order reliably to ignite a plurality of fluorescent lamps (18, 19), each of which has its own oscillator circuit (L1, C1; L2, LC), the ends of the fluorescent lamps (18, 19) connected to the oscillator coils (L1, L2) are connected to one another by an additional capacitor (C3). When the first fluorescent lamp ignites, this results in a voltage pulse being transmitted through the additional capacitor (C3) to the lamp which is less willing to ignite, which is then likewise ignited. This technique avoids the lamp which is less willing to ignite being permanently supplied with a lower supply voltage after ignition of the lamp which was willing to ignite, in which situation it is difficult to ignite or cannot ignite at all. <IMAGE>

Description

Die Erfindung betrifft ein elektronisches Vorschaltgerät für mehrere Leuchtstofflampen, mit einer an einer Gleichspannung liegenden Gegentaktschalteranordnung aus zwei elektronischen Schaltern und mit mehreren von den elektronischen Schaltern angesteuerten Arbeitsschwingkreisen, von denen jeder eine dem Schwingkreiskondensator parallelgeschaltete und mit der Schwingkreisspule in Reihe liegende Leuchtstofflampe aufweist.The invention relates to an electronic ballast for a plurality of fluorescent lamps, with a push-pull switch arrangement which is connected to a DC voltage and consists of two electronic switches and with a plurality of working resonant circuits controlled by the electronic switches, each of which has a fluorescent lamp connected in parallel with the resonant circuit capacitor and in series with the resonant circuit coil.

Es sind elektronische Vorschaltgeräte bekannt, die dazu dienen, zwei oder mehr Leuchtstofflampen gemeinsam zu. zünden und zu betreiben. Solche Vorschaltgeräte werden insbesondere in Leuchten eingesetzt, die mehrere Leuchtstofflampen enthalten, welche stets gemeinsam geschaltet werden. Schwierigkeiten ergeben sich bei den genannten Vorschaltgeräten dadurch, daß zwei oder mehr Reihenschwingkreise parallelgeschaltet sind, von denen jeweils der Schwingkreiskondensator durch eine Leuchtstofflampe, sobald diese gezündet hat, überbrückt wird. Diejenige Leuchtstofflampe, die zuerst zündet, bewirkt eine Verringerung der an den Arbeitsschwingkreisen anstehenden Spannung von etwa 900 V auf etwa 450 V und eine Verringerung der Schwingfrequenz von ca. 80 kHz auf etwa 22 kHz. Infolge dieser veränderten Betriebsbedingungen zündet die zweite Leuchtstofflampe wesentlich schlechter. Bei Temperaturen ab ca. 15 °C wird häufig beobachtet, daß die zweite Leuchtstofflampe überhaupt nicht mehr zündet.Electronic ballasts are known which serve to jointly connect two or more fluorescent lamps. ignite and operate. Such ballasts are used in particular in luminaires that contain several fluorescent lamps, which are always switched together. Difficulties arise in the ballasts mentioned that two or more Series resonant circuits are connected in parallel, of which the resonant circuit capacitor is bridged by a fluorescent lamp as soon as it has ignited. The fluorescent lamp that ignites first brings about a reduction in the voltage applied to the working resonant circuits from approximately 900 V to approximately 450 V and a reduction in the oscillation frequency from approximately 80 kHz to approximately 22 kHz. As a result of these changed operating conditions, the second fluorescent lamp ignites much worse. At temperatures above approx. 15 ° C it is often observed that the second fluorescent lamp no longer ignites at all.

Wenn bei den bekannten Vorschaltgeräten, die zum gleichzeitigen Betreiben mehrerer Leuchtstofflampen geeignet sind, Leuchtstofflampen unterschiedlichen Alters eingesetzt werden, startet die neuere Lampe vor der schwächeren älteren Lampe. Die schwächere Lampe muß also mit einer geringeren Zündspannung gestartet werden. Dies führt zu einer hohen Emitterbelastung des Heizdrahtes der Leuchtstofflampe und zu Glimmentladungen. Dies ergibt eine höhere Lampenbelastung und eine Verringerung der Lampenlebensdauer.If fluorescent lamps of different ages are used in the known ballasts which are suitable for operating several fluorescent lamps at the same time, the newer lamp starts before the weaker older lamp. The weaker lamp must therefore be started with a lower ignition voltage. This leads to a high emitter load on the heating wire of the fluorescent lamp and to glow discharges. This results in a higher lamp load and a reduction in lamp life.

Um zu erreichen, daß die Leuchtstofflampen möglichst genau zum gleichen Zeitpunkt gezündet werden, ist bei den bekannten Vorschaltgeräten unabdingbare Voraussetzung, daß die Leuchtstofflampen untereinander gleiche Charakteristiken haben. Um dies zu gewährleisten, sind Vorschaltgeräte bekannt, die das Starten einer Leuchtstofflampe nur dann ermöglichen, wenn die zweite Leuchtstofflampe eingesetzt und betriebsfähig ist. Damit soll erreicht werden, daß eine Leuchte niemals mit nur einer Leuchtstofflampe betrieben wird. Wenn eine der Leuchtstofflampen defekt ist, funktionieren beide Leuchtstofflampen nicht. Der Benutzer muß daher beide Leuchtstofflampen gleichzeitig auswechseln, zumal er nicht erkennen kann, welche der Lampen defekt ist.In order to ensure that the fluorescent lamps are lit as precisely as possible at the same time, it is an essential requirement in the known ballasts that the fluorescent lamps have the same characteristics as one another. In order to ensure this, ballasts are known which only make it possible to start a fluorescent lamp when the second fluorescent lamp has been inserted and is ready for operation. This is to ensure that a lamp is never operated with only one fluorescent lamp. When a of the fluorescent lamps is defective, both fluorescent lamps do not work. The user must therefore replace both fluorescent lamps at the same time, especially since he cannot recognize which of the lamps is defective.

Der Erfindung liegt die Aufgabe zugrunde, ein elektronisches Vorschaltgerät der eingangs genannten Art zu schaffen, das es ermöglicht, bei mehreren parallel betriebenen Leuchtstofflampen jede dieser Leuchtstofflampen mit erhöhter Spannung zu zünden, selbst wenn die Leuchtstofflampen unterschiedliche Eigenschaften, wie z.B. unterschiedliches Alter, haben oder nacheinander in ihre Fassungen eingedreht werden.The invention has for its object to provide an electronic ballast of the type mentioned, which makes it possible to ignite each of these fluorescent lamps with increased voltage at several fluorescent lamps operated in parallel, even if the fluorescent lamps have different properties, such as. different ages, or have to be screwed into their versions one after the other.

Die Lösung dieser Aufgabe besteht erfindungsgemäß darin, daß die mit den Schwingkreisspulen verbundenen Enden der Leuchtstofflampen durch einen zusätzlichen Kondensator miteinander verbunden sind.The solution to this problem is, according to the invention, that the ends of the fluorescent lamps connected to the resonant circuit coils are connected to one another by an additional capacitor.

Durch den zusätzlichen Kondensator wird, wenn die eine Leuchtstofflampe zündet, ein zusätzlicher Impuls auf die noch nicht gezündete andere Leuchtstofflampe übertragen, so daß die zündunwilligere Lampe einen zusätzlichen Spannungsstoß erhält. Durch die kapazitive Kopplung wird die schwächere Lampe gewissermaßen von der stärkeren mitgezogen. Ein weiterer Vorteil besteht darin, daß in dem Fall, daß eine Leuchtstofflampe aus ihrer Fassung herausgedreht worden ist, die andere Leuchtstofflampe funktioniert. Wird die herausgenommene Leuchtstofflampe anschließend eingesetzt, so entsteht an dem zusätzlichen Kondensator ein Spannungsstoß, der bewirkt, daß die später eingesetzte Lampe sofort zündet. Dadurch, daß der zusätzliche Kondensator an die zuletzt zündende Lampe einen Spannungsimpuls liefert, wird der Zündvorgang beschleunigt und es werden die schädlichen Folgen, die bei schleppender Zündung durch Glimmentladung entstehen, vermieden. Die Lebensdauer der Leuchtstofflampen wird damit beträchtlich erhöht.When the one fluorescent lamp ignites, the additional capacitor transmits an additional pulse to the other fluorescent lamp which has not yet been ignited, so that the lamp which is more unwilling to ignite receives an additional voltage surge. Due to the capacitive coupling, the weaker lamp is pulled along by the stronger one. Another advantage is that in the event that one fluorescent lamp has been unscrewed from its socket, the other fluorescent lamp will work. If the removed fluorescent lamp is then used, a voltage surge occurs on the additional capacitor, which causes the lamp used later to ignite immediately. The fact that the additional capacitor supplies a voltage pulse to the lamp which ignited last, the ignition process is accelerated and it becomes the harmful consequences of glow discharge caused by slow ignition are avoided. The lifespan of the fluorescent lamps is thus considerably increased.

Es ist schwierig, die Funktion des zusätzlichen Kondensators im einzelnen zu ermitteln, weil die Vorgänge, die beim Zünden stattfinden, komplexe Reaktionen mit variierenden Induktivitäten, Kapazitäten und Widerständen sind. Beispielsweise wird die Schwingkreisspule bei einem auftretenden Stromstoß, z.B. beim Starten der Leuchtstofflampe, kurzzeitig in die Sättigung gebracht, wodurch ihre Induktivität sich verringert. Außerdem ändert sich beim Starten der Lampe natürlich deren Widerstand und Kapazität. Es ist bisher nicht gelungen, die Funktion des zusätzlichen Kondensators beim Starten der ersten Leuchtstofflampe bzw. beim nachträglichen Eindrehen einer weiteren Leuchtstofflampe genau zu ermitteln und die theoretischen Hintergründe aufzudecken. Es wird angenommen, daß die Kapazität des zusätzlichen Kondensators mit den Schwingkreisinduktivitäten vorübergehend einen Sperrkreis bildet und daß außer der Kopplungsfunktion, die der zusätzliche Kondensator hat, auch noch vorübergehende Resonanzfunktionen mitwirken.It is difficult to determine the function of the additional capacitor in detail because the processes that take place during ignition are complex reactions with varying inductances, capacitances and resistances. For example, the voice circuit coil is triggered when a surge occurs, e.g. when the fluorescent lamp is started, briefly saturated, which reduces its inductance. In addition, when the lamp is started, its resistance and capacity naturally change. So far it has not been possible to exactly determine the function of the additional capacitor when starting the first fluorescent lamp or when turning in a further fluorescent lamp and to uncover the theoretical backgrounds. It is assumed that the capacitance of the additional capacitor temporarily forms a blocking circuit with the resonant circuit inductances and that, in addition to the coupling function which the additional capacitor has, temporary resonance functions also play a role.

Die Kapazität des zusätzlichen Kondensators beträgt vorzugsweise 1/5 bis 4/5 der Kapazität eines der Schwingkreiskondensatoren und sie liegt insbesondere im Bereich von 1/3 bis 2/3 der Kapazität eines Schwingkreiskondensators. In diesen Bereichen wird die angestrebte Wirkung der Erzeugung eines Spannungsimpulses für die nachfolgend zündende Leuchtstofflampe mit großer Sicherheit erreicht.The capacitance of the additional capacitor is preferably 1/5 to 4/5 of the capacitance of one of the resonant circuit capacitors and is in particular in the range of 1/3 to 2/3 of the capacitance of a resonant circuit capacitor. In these areas, the desired effect of generating a voltage pulse for the subsequently lighting fluorescent lamp is achieved with great certainty.

Im folgenden werden unter Bezugnahme auf die Zeichnungen Ausführungsbeispiele der Erfindung näher erläutert.Exemplary embodiments of the invention are explained in more detail below with reference to the drawings.

Es zeigen:

  • Fig. 1 ein schematisches Schaltbild eines elektronischen Vorschaltgerätes und
  • Fig. 2 eine Modifizierung des Vorschaltgerätes nach Fig. 1.
Show it:
  • Fig. 1 is a schematic diagram of an electronic ballast and
  • 2 shows a modification of the ballast according to FIG. 1.

Das in Fig. 1 dargestellte Vorschaltgerät weist eine (nicht gezeigte) Gleichspannungsquelle auf, die an die Versorgungsleitungen 10,11 eine Gleichspannung legt. Zwischen die Versorgungsleitungen 10,11 ist die Gegentaktschalteranordnung aus den in Reihe geschalteten Transistoren von gleichem Typ - im vorliegenden Fall npn-Transistoren - gelegt. An dem Verbindungspunkt 14 der beiden Transistoren 12 und 13 ist eine Reihenschaltung aus der Primärspule 15 eines Übertragers 16 und einem Kondensator 17 angeschlossen. Mit dem anderen Bein des Kondensators 17 sind die Schwingkreisspulen L1 und L2 der beiden Leuchtstofflampen 18 und 19 verbunden. Jede Schwingkreisspule L1 und L2 ist mit dem zugehörigen Schwingkreiskondensator C1 und C2 in Reihe geschaltet. Dem Schwingkreiskondensator C1 bzw. C2 ist die zugehörige Leuchtstofflampe 18 bzw. 19 parallelgeschaltet. Die einen Enden der Schwingkreiskondensatoren C1 und der Leuchtstofflampen 18 bzw. 19 sind mit der negativen Versorgungsleitung 10 verbunden.The ballast shown in FIG. 1 has a DC voltage source (not shown) which applies a DC voltage to the supply lines 10, 11. The push-pull switch arrangement comprising the transistors of the same type connected in series, in the present case npn transistors, is placed between the supply lines 10, 11. A series circuit comprising the primary coil 15 of a transformer 16 and a capacitor 17 is connected to the connection point 14 of the two transistors 12 and 13. The resonant circuit coils L 1 and L 2 of the two fluorescent lamps 18 and 19 are connected to the other leg of the capacitor 17. Each resonant circuit coil L 1 and L 2 is connected in series with the associated resonant circuit capacitor C 1 and C 2 . The associated fluorescent lamp 18 or 19 is connected in parallel with the resonant circuit capacitor C 1 or C 2 . One ends of the resonant circuit capacitors C 1 and the fluorescent lamps 18 and 19 are connected to the negative supply line 10.

Die Transistoren 12 und 13 werden im Gegentakt geschaltet, d.h. wenn Transistor 12 leitend ist, ist Transistor 13 gesperrt und wenn Transistor 13 leitend ist, ist Transistor 12 gesperrt. Allerdings überschneiden sich die Sperrphasen beider Transistoren geringfügig. Die Steuerung der Transistoren 12 und 13 erfolgt über zwei Sekundärwicklungen 20,21 des Übertragers 16. Die Sekundärwicklung 20 ist an eine Steuerschaltung 22 angeschlossen, deren Ausgang mit der Basis des Transistors 13 verbunden ist. Die zweite Sekundärspule 21, die ebenfalls induktiv mit der Primärspule 15 des Ubertragers 16 gekoppelt ist, ist mit einer Steuerschaltung 23 verbunden, deren Ausgangssignal die Basis des Transistors 12 steuert. Die beiden Sekundärspulen 20 und 21 werden von der Primärspule 15 gegensinnig zueinander erregt, um die Transistoren 12 und 13 im Gegentakt zu steuern, so daß der Verbindungspunkt 14 abwechselnd die Potentiale des positiven und des negativen Pols der Versorgungsspannung annimmt, wenn der Strom in der Primärspule 15 oszilliert.Transistors 12 and 13 are switched in push-pull mode, ie when transistor 12 is conductive, transistor 13 is blocked and when transistor 13 is conductive, transistor 12 is blocked. However, overlap the blocking phases of both transistors slightly. The transistors 12 and 13 are controlled via two secondary windings 20, 21 of the transformer 16. The secondary winding 20 is connected to a control circuit 22, the output of which is connected to the base of the transistor 13. The second secondary coil 21, which is also inductively coupled to the primary coil 15 of the transmitter 16, is connected to a control circuit 23, the output signal of which controls the base of the transistor 12. The two secondary coils 20 and 21 are excited in opposite directions from one another by the primary coil 15 in order to control the transistors 12 and 13 in a push-pull manner, so that the connection point 14 alternately assumes the potentials of the positive and negative poles of the supply voltage when the current in the primary coil 15 oscillates.

Die oszillierende Spannung zur Steuerung der Transistoren 12,13 wird hervorgerufen durch die Schwingkreise L1, C1 und L2, C2. Solange die Leuchtstofflampen 18 und 19 nicht gezündet sind, hat jeder Schwingkreis eine Eigenfrequenz von etwa 80 kHz. Da die Schwingkreise ungedämpft sind, entstehen an den Schwingkreiskondensatoren C1 und C2 hohe Spannungen von etwa 900 V. Nach dem Zünden der Leuchtstofflampen werden die Reihenschwingkreise durch die Parallelschaltung der Leuchtstofflampen zu den Schwingkreiskondensatoren bedämpft, so daß die an den Leuchtstofflampen anstehende Spannung sich auf ca. 110 V (bei 58 W Leuchtstofflampe Krypton) und die Schwingfrequenz sich auf 33 kHz verringert. Demgemäß verändert sich auch die Frequenz, mit der die Transistoren 12 und 13 umgesteuert werden.The oscillating voltage for controlling the transistors 12, 13 is caused by the resonant circuits L 1 , C 1 and L 2 , C 2 . As long as the fluorescent lamps 18 and 19 are not ignited, each resonant circuit has a natural frequency of approximately 80 kHz. Since the resonant circuits are undamped, high voltages of approximately 900 V arise at the resonant circuit capacitors C 1 and C 2. After the fluorescent lamps have been ignited, the series resonant circuits are damped by the parallel connection of the fluorescent lamps to the resonant circuit capacitors, so that the voltage present at the fluorescent lamps increases approx. 110 V (at 58 W fluorescent lamp Krypton) and the oscillation frequency is reduced to 33 kHz. Accordingly, the frequency at which the transistors 12 and 13 are reversed also changes.

Nach der Erfindung ist zwischen die Verbindungspunkte von L1 und C1 und die Verbindungspunkte von L2 und C2 der zusätzliche Kondensator C3 geschaltet, der eine Kapazität von einigen nF hat. Dieser zusätzliche Kondensator bewirkt, daß, sobald die erste Leuchtstofflampe zündet, ein Spannungsimpuls auf die zweite Leuchtstofflampe übertragen wird, so daß dieser zweiten Leuchtstofflampe das Zünden erleichtert wird. Somit zünden beide Leuchtstofflampen praktisch gleichzeitig, so daß keine der Leuchtstofflampen längere Zeit im ungezündeten Zustand mit der niedrigeren Spannung versorgt wird.According to the invention, the additional capacitor C 3 , which has a capacitance of a few nF, is connected between the connection points of L 1 and C 1 and the connection points of L 2 and C2 . This additional capacitor has the effect that, as soon as the first fluorescent lamp ignites, a voltage pulse is transmitted to the second fluorescent lamp, so that the ignition of this second fluorescent lamp is made easier. Thus, both fluorescent lamps ignite practically at the same time, so that neither of the fluorescent lamps is supplied with the lower voltage for an extended period of time in the non-ignited state.

Bei einem praktischen Ausführungsbeispiel der Schaltung nach Fig. 1, bei dem Leuchtstofflampen 18,19 mit einer Leistung von jeweils 50 W verwendet wurden, hatten die Schwingkreiskomponenten die folgenden Bemessungen:

Figure imgb0001
Figure imgb0002
Figure imgb0003
 In a practical embodiment of the circuit according to FIG. 1, in which fluorescent lamps 18, 19 with a power of 50 W each were used, the resonant circuit components had the following dimensions:
Figure imgb0001
Figure imgb0002
Figure imgb0003

Bei Leuchtstofflampen mit einer Leistung von je 32 W ergeben sich folgende Bemessungen:

Figure imgb0004
Figure imgb0005
Figure imgb0006
 For fluorescent lamps with a power of 32 W each, the following dimensions result:
Figure imgb0004
Figure imgb0005
Figure imgb0006

Grundsätzlich sollte die Kapazität des zusätzlichen Kondensators C3 in der Größenordnung der Kapazität des Schwingkreiskondensators liegen, jedoch kleiner sein als dieser.In principle, the capacitance of the additional capacitor C 3 should be in the order of magnitude of the capacitance of the resonant circuit capacitor, but should be smaller than this.

Das Ausführungsbeispiel von Fig. 2 unterscheidet sich von demjenigen der Fig. 1 nur dadurch, daß anstelle des gemeinsamen Entladekondensators 17, der in Fig. 1 beide Reihenschwingkreise versorgt, zwei gleiche Kondensatoren 17a, 17b vorgesehen sind, von denen der eine Kondensator 17a der ersten Schwingkreisspule L1 vorgeschaltet ist, während der zweite 17b der zweiten Schwingkreisspule L2 vorgeschaltet ist. Der Kondensator 17 von Fig. 1 sowie auch die Kondensatoren 17a und 17b von Fig. 2 dienen der Umladung der Energie. Ihre Kapazität ist erheblich größer als diejenige der übrigen verwendeten Kondensatoren und betägt z.B. 0,33 µF. Die Schwingungen in den Reihenschwingkreisen werden durch die Kondensatoren 17 bzw. 17a, 17b kann beeinflußt.The embodiment of FIG. 2 differs from that of FIG. 1 only in that instead of the common discharge capacitor 17, which supplies both series resonant circuits in FIG. 1, two identical capacitors 17a, 17b are provided, one of which is a capacitor 17a of the first Voice circuit coil L 1 is connected upstream, while the second 17b is connected upstream of the second voice circuit coil L 2 . The capacitor 17 of FIG. 1 as well as the capacitors 17a and 17b of FIG. 2 serve to charge the energy. Their capacitance is considerably larger than that of the other capacitors used and is, for example, 0.33 µF. The vibrations in the series resonant circuits are influenced by the capacitors 17 and 17a, 17b.

Bei den dargestellten Ausführungsbeispielen sind jeweils zwei Leuchtstofflampen mit den zugehörigen Reihenschwingkreisen vorhanden. Auf dieselbe Weise können auch mehr als zwei Leuchtstofflampen miteinander gekoppelt werden, wobei jeweils zwei Leuchtstofflampen durch einen zusätzlichen Kondensator C3 untereinander verbunden sind.In the illustrated embodiments, two fluorescent lamps with the associated series resonant circuits are present. In the same way, more than two fluorescent lamps can also be coupled to one another, two fluorescent lamps each being connected to one another by an additional capacitor C 3 .

Claims (3)

1. Elektronisches Vorschaltgerät für mehrere Leuchtstofflampen, mit einer an einer Gleichspannung liegenden Gegentaktschalteranordnung (12,13) aus zwei elektronischen Schaltern und mit mehreren von den elektronsichen Schaltern angesteuerten Arbeitsschwingkreisen (L1,C1;L2,C2), von denen jeder eine dem Schwingkreiskondensator (C1;C2) parallelgeschaltete und mit der Schwingkreisspule (L1;L2) in Reihe liegende Leuchtstofflampe (18;19) aufweist, dadurch gekennzeichnet , daß die mit den Schwingkreisspulen (L1;L2) verbundenen Enden der Leuchtstofflampen (18,19) durch einen zusätzlichen Kondensator (C3) miteinander verbunden sind.1. Electronic ballast for a plurality of fluorescent lamps, with a push-pull switch arrangement (12, 13) connected to a DC voltage, consisting of two electronic switches and with a plurality of working resonant circuits (L 1 , C 1 ; L 2 , C 2 ) controlled by the electronic switches, each of which has a fluorescent lamp (18; 19) connected in parallel with the resonant circuit capacitor (C 1 ; C 2 ) and in series with the resonant circuit coil (L 1 ; L 2 ), characterized in that the ends connected to the resonant circuit coils (L 1 ; L 2 ) the fluorescent lamps (18, 19) are connected to one another by an additional capacitor (C 3 ). 2. Elektronisches Vorschaltgerät nach Anspruch 1, dadurch gekennzeichnet, daß die Kapazität des zusätzlichen Kondensators (C3) 1/5 bis 4/5 der Kapazität eines der Schwingkreiskondensatoren (C1,C2) beträgt.2. Electronic ballast according to claim 1, characterized in that the capacitance of the additional capacitor (C 3 ) 1/5 to 4/5 of the capacitance of one of the resonant circuit capacitors (C 1 , C 2 ). 3. Elektronisches Vorschaltgerät nach Anspruch 2, dadurch gekennzeichnet, daß die Kapazität des zusätzlichen Kondensators 1/3 bis 2/3 der Kapazität eines der Schwingkreiskondensatoren beträgt.3. Electronic ballast according to claim 2, characterized in that the capacitance of the additional capacitor is 1/3 to 2/3 of the capacitance of one of the resonant circuit capacitors.
EP19850102029 1984-04-06 1985-02-23 Electronic ballast for multiple fluorescent lamps Withdrawn EP0158072A1 (en)

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DE19843412942 DE3412942C2 (en) 1984-04-06 1984-04-06 Electronic ballast for several fluorescent lamps
DE3412942 1984-04-06

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WO1999053731A1 (en) * 1998-04-15 1999-10-21 Electro-Mag International, Inc. Ballast instant start circuit

Families Citing this family (2)

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Publication number Priority date Publication date Assignee Title
DE4245092B4 (en) * 1992-12-23 2012-07-26 Tridonic Gmbh & Co Kg Starter circuit for use with parallel driven gas-discharge lighting units - has inverter coupled to series resonance circuit with transformer having symmetrical windings coupled to lamps
DE4243955B4 (en) * 1992-12-23 2010-11-18 Tridonicatco Gmbh & Co. Kg Ballast for at least one parallel-operated pair of gas discharge lamps

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US4259614A (en) * 1979-07-20 1981-03-31 Kohler Thomas P Electronic ballast-inverter for multiple fluorescent lamps
EP0065794A1 (en) * 1981-05-14 1982-12-01 Koninklijke Philips Electronics N.V. Electric arrangement for starting and supplying a gas and/or vapour discharge lamp comprising two preheatable electrodes
EP0093469A2 (en) * 1982-04-20 1983-11-09 Koninklijke Philips Electronics N.V. DC/AC converter for the ignition and the supply with alternating current of a gas and/or vapour discharge lamp
EP0111929A1 (en) * 1982-12-23 1984-06-27 Siemens Aktiengesellschaft Arrangement for switching off an inverter

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US4259614A (en) * 1979-07-20 1981-03-31 Kohler Thomas P Electronic ballast-inverter for multiple fluorescent lamps
EP0065794A1 (en) * 1981-05-14 1982-12-01 Koninklijke Philips Electronics N.V. Electric arrangement for starting and supplying a gas and/or vapour discharge lamp comprising two preheatable electrodes
EP0093469A2 (en) * 1982-04-20 1983-11-09 Koninklijke Philips Electronics N.V. DC/AC converter for the ignition and the supply with alternating current of a gas and/or vapour discharge lamp
EP0111929A1 (en) * 1982-12-23 1984-06-27 Siemens Aktiengesellschaft Arrangement for switching off an inverter

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999053731A1 (en) * 1998-04-15 1999-10-21 Electro-Mag International, Inc. Ballast instant start circuit
US6069455A (en) * 1998-04-15 2000-05-30 Electro-Mag International, Inc. Ballast having a selectively resonant circuit
US6236168B1 (en) 1998-04-15 2001-05-22 Electro-Mag International, Inc. Ballast instant start circuit

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