EP0429716B1 - Electronic ballast for fluorescent lamps - Google Patents
Electronic ballast for fluorescent lamps Download PDFInfo
- Publication number
- EP0429716B1 EP0429716B1 EP89122189A EP89122189A EP0429716B1 EP 0429716 B1 EP0429716 B1 EP 0429716B1 EP 89122189 A EP89122189 A EP 89122189A EP 89122189 A EP89122189 A EP 89122189A EP 0429716 B1 EP0429716 B1 EP 0429716B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- circuit
- preheating
- lln
- inverter
- electronic ballast
- 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.)
- Expired - Lifetime
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Classifications
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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
- H05B41/295—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 and specially adapted for lamps with preheating electrodes, e.g. for fluorescent lamps
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- 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
- Y10S315/00—Electric lamp and discharge devices: systems
- Y10S315/05—Starting and operating circuit for fluorescent lamp
Definitions
- the invention relates to an electronic ballast for at least one fluorescent lamp equipped with heatable electrodes with an inverter to which an operating DC voltage is supplied on the input side and which is connected on the output side to a load circuit having a fluorescent lamp, which is used for the potential-free connection of the fluorescent lamp to the output of the Inverter includes a transformer.
- heating electrodes In the case of fluorescent lamps equipped with heatable electrodes, the electrodes designed as heating coils, hereinafter referred to as heating electrodes for short, must first be preheated sufficiently in order to then be able to ignite the fluorescent lamp safely and free of flickering effects.
- the literature US Pat. No. 3,710,177 brings about the high-frequency heating of the heating electrodes by means of a frequency shift in the switching frequency of the inverter.
- This frequency shift has the task, on the one hand, of ensuring rapid preheating and, on the other hand, of preventing during the preheating time that the fluorescent lamp receives a high voltage causing its ignition prematurely. If necessary, the voltage on the fluorescent lamp can also be reduced during the preheating time at the same time as the frequency shift.
- the preheating time cannot be kept as short as desired.
- preheating times of the order of more than 1.2 seconds result.
- the preheating time delays the switching on of the fluorescent lamp over a time interval which sometimes proves to be annoying.
- the invention has for its object to provide a further solution for an electronic ballast of the type described in the introduction, in which preheating times can be achieved significantly less than 1 second, with relatively little technical effort.
- the invention is based on the knowledge that the preheating of the heating electrodes of the fluorescent lamp can be done much more quickly without the design of the ballast for higher electrical power if the required electrical power is applied by the rectified AC mains voltage. In this way, practically any preheating current for the heating electrodes can be made available. Thanks to the fluorescent lamp controlled by the inverter via a transformer, a DC path can be formed from the series connection of the secondary winding of the transformer with the heating electrodes, which is then switched on during a switch-on process to carry out the desired preheating via switches to the operating DC voltage and at the end of Preheating phase is switched off again.
- This type of direct current preheating can also be used in an extremely advantageous manner on ballasts which simultaneously supply two or more fluorescent lamps to have. All that is required is to connect the secondary windings of the transformers assigned to the individual fluorescent lamps in a suitable manner.
- the block diagram for a ballast assigned to a plurality of fluorescent lamps has a harmonic filter OW to which the AC line voltage Un is applied on the input side.
- a rectifier GL is connected to the harmonic filter OW, and a charging capacitor Co is connected in parallel on the output side.
- the rectified, smoothed mains AC voltage Un is present at the charging capacitor Co in the form of the operating DC voltage Ub.
- the DC operating voltage Ub supplied to the inverter WR is switched over to a high frequency with the aid of a self-controlled switch bridge arrangement and is fed to the load circuit LK on the output side via the coupling capacitor Ck.
- the load circuit has n fluorescent lamps LL1, LL2, ... LLn, each of which has an ignition capacitor C1, C2, ... Cn and on the other hand, the secondary winding of a transformer TR1, TR2, ... Tn are connected in parallel.
- the respective transformers TR1, TR2, ... TRn assigned to a fluorescent lamp LL1, LL2, ... LLn are connected in parallel to the output of the inverter WR with regard to their primary windings.
- the secondary windings of the transformers TR1, TR2, ... TRn are connected in series on the ignition capacitors C1, C2, ... Cn so that a DC path is formed in which the heating electrodes He of all fluorescent lamps LL1, LL2,. .. LLn are connected in series with the secondary windings of the transformers TR1, TR2, ... TRn.
- the common connection point of the heating electrode He of the tube LL1 with the ignition capacitor C1 is connected via the switch S11 and the heating resistor RV to the positive pole of the operating DC voltage Ub.
- the negative pole of the DC operating voltage Ub is at the reference potential.
- the DC path at the common connection point of the ignition capacitor Cn to the lower heating electrode He of the fluorescent lamp LLn is also connected to this reference potential via a switch S12.
- the switches S11 and S12 represent working contacts a1 and a2 of a relay A, the excitation winding of the operating DC voltage Ub can be connected in parallel via the preheating control VH.
- the preheating control VH is a timer which is activated when the ballast is switched on via the operating DC voltage Ub built up at the charging capacitor Co and thus triggers the relay A.
- the thus closing normally open contacts a1 and a2 of the switches S11 and S12 switch on the DC path described via the preheating resistor RV and the DC operating voltage Ub and the preheating current now flows via this DC path and thus over all heating electrodes of the fluorescent lamps LL1, LL2, ... LLn iVH.
- the preheating current iVH is above the falling Relay A is interrupted again after a predetermined short time and the fluorescent lamps LL1, LL2, ... LLn can then be ignited.
- the ignition takes place after the deactivation of the preheating control VH by swinging the self-controlled switch bridge arrangement, the bridge switches S1 and S2 are alternately closed in rhythm with the high-frequency switching frequency.
- the self-controlled switch bridge arrangement has a saturation transmitter SÜ for self-excitation, with the aid of which the positive feedback of the output circuit of the inverter to the control inputs of the bridge switches S11 and S12 is realized.
- the saturation transformer SÜ has an additional secondary winding Wz with a center tap P, which two diodes D1 and D2 are connected in series in opposite directions.
- the blocking circuit SS By means of the blocking circuit SS, the common connection point of the two diodes D1 and D2 can also be connected to the reference potential via a time switching element and the additional secondary winding Wz can thus be short-circuited.
- the blocking circuit SS also responds like the preheating control VH when the ballast is switched on and thus prevents parasitic oscillation of the self-controlled switch bridge arrangement during the preheating phase.
- the blocking circuit SS is activated, as in the preheating control VH, by the operating DC voltage Ub building up at the charging capacitor Co during a switch-on process.
- the blocking circuit SS also has a control output via which it activates the starter circuit ST for a defined oscillation of the self-controlled switch bridge arrangement after the short circuit of the additional secondary winding Wz of the saturation transformer SÜ has been removed.
- the transformers TR1, TR2, ... TRn are designed as stray field transformers whose stray inductances (not shown in FIG. 1) form series resonance circuits with the ignition capacitors C1, C2, ... Cn, which are approximately matched to the high-frequency switching frequency of the inverter.
- the sequence of a switch-on process as far as it concerns the preheating of the heating electrodes of the fluorescent lamps LL1, LL2,... LLn with the preheating current iVH, is shown over time.
- the time diagrams represent the course of the DC operating voltage Ub, the switching behavior of the preheating control VH, the switching behavior of the blocking circuit SS, the time course of the starting pulse I emitted by the starter circuit ST and the course of the preheating current iVH over time t from top to bottom.
- the preheating control VH and the blocking circuit SS are activated at the same time.
- the blocking circuit SS remains activated at the time t2 at the time of switching off the preheating control VH until time t3, at which unavoidable bruises of the working contacts a1 and a2 have subsided when the relay A has dropped out.
- This bounce behavior of the above-mentioned normally open contacts a1 and a2 is shown in the current diagram for the preheating current iVH.
- the blocking circuit SS also switches off and thus releases the inverter WR.
- the blocking circuit SS generates a control pulse for the starter circuit ST when it is switched off, which thus outputs the start pulse I to the inverter WR.
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- Circuit Arrangements For Discharge Lamps (AREA)
Description
Die Erfindung bezieht sich auf ein elektronisches Vorschaltgerät für wenigstens eine mit heizbaren Elektroden ausgerüstete Leuchtstofflampe mit einem Wechselrichter, dem eingangsseitig eine Betriebsgleichspannung zugeführt ist und der ausgangsseitig mit einem eine Leuchtstofflampe aufweisenden Lastkreis in Verbindung steht, der für die potentialfreie Anschaltung der Leuchtstofflampe an den Ausgang des Wechselrichters einen Transformator mitumfaßt.The invention relates to an electronic ballast for at least one fluorescent lamp equipped with heatable electrodes with an inverter to which an operating DC voltage is supplied on the input side and which is connected on the output side to a load circuit having a fluorescent lamp, which is used for the potential-free connection of the fluorescent lamp to the output of the Inverter includes a transformer.
Bei mit heizbaren Elektroden ausgerüsteten Leuchtstofflampen müssen bei einem Einschaltvorgang zunächst die als Heizwendeln gestalteten Elektroden, im folgenden kurz Heizelektroden genannt, ausreichend vorgeheizt werden, um die Leuchtstofflampe anschließend sicher und frei von Flackereffekten zünden zu können.In the case of fluorescent lamps equipped with heatable electrodes, the electrodes designed as heating coils, hereinafter referred to as heating electrodes for short, must first be preheated sufficiently in order to then be able to ignite the fluorescent lamp safely and free of flickering effects.
Beispielsweise durch die Literaturstelle US-PS 3,710,177 wird die Hochfrequenzheizung der Heizelektroden mit Hilfe einer Frequenzverschiebung der Schaltfrequenz des Wechselrichters herbeigeführt. Diese Frequenzverschiebung hat die Aufgabe, einerseits eine schnelle Vorheizung sicherzustellen und andererseits während der Vorheizzeit zu verhindern, daß die Leuchtstofflampe vorzeitig eine ihre Zündung bewirkende hohe Spannung erhält. Gegebenenfalls kann auch gleichzeitig mit der Frequenzverschiebung die Spannung an der Leuchtstofflampe während der Vorheizzeit herabgesetzt werden.For example, the literature US Pat. No. 3,710,177 brings about the high-frequency heating of the heating electrodes by means of a frequency shift in the switching frequency of the inverter. This frequency shift has the task, on the one hand, of ensuring rapid preheating and, on the other hand, of preventing during the preheating time that the fluorescent lamp receives a high voltage causing its ignition prematurely. If necessary, the voltage on the fluorescent lamp can also be reduced during the preheating time at the same time as the frequency shift.
Da die Hochfrequenzleistung des Wechselrichters begrenzt ist, läßt sich die Vorheizzeit nicht beliebig klein halten. In der Regel ergeben sich hierbei Vorheizzeiten in der Größenordnung von mehr als 1,2 Sekunden. Mit anderen Worten wird das Einschalten der Leuchtstofflampe durch die Vorheizzeit über ein Zeitintervall verzögert, das sich mitunter als störend erweist.Since the high-frequency power of the inverter is limited, the preheating time cannot be kept as short as desired. As a rule, preheating times of the order of more than 1.2 seconds result. In other words, the preheating time delays the switching on of the fluorescent lamp over a time interval which sometimes proves to be annoying.
Der Erfindung liegt die Aufgabe zugrunde, für ein elektronisches Vorschaltgerät der einleitend beschriebenen Art eine weitere Lösung anzugeben, bei der Vorheizzeiten wesentlich kleiner als 1 Sekunde erreicht werden können, und zwar bei relativ geringem technischen Aufwand.The invention has for its object to provide a further solution for an electronic ballast of the type described in the introduction, in which preheating times can be achieved significantly less than 1 second, with relatively little technical effort.
Diese Aufgabe wird gemäß der Erfindung durch die im Patentanspruch 1 angegebenen Merkmale gelöst.This object is achieved according to the invention by the features specified in claim 1.
Der Erfindung liegt die Erkenntnis zugrunde, daß das Vorheizen der Heizelektroden der Leuchtstofflampe unter Verzicht auf eine Auslegung des Vorschaltgerätes für eine höhere elektrische Leistung wesentlich schneller dann erfolgen kann, wenn die hierfür erforderliche elektrische Leistung von der gleichgerichteten Netzwechselspannung aufgebracht wird. Auf diese Weise läßt sich praktisch ein beliebig großer Vorheizstrom für die Heizelektroden zur Verfügung stellen. Dank der vom Wechselrichter über einen Transformator angesteuerten Leuchtstofflampe kann aufgrund der hierdurch gegebenen Potentialtrennung ein Gleichstrompfad aus der Reihenschaltung der Sekundärwicklung des Transformators mit den Heizelektroden gebildet werden, der dann bei einem Einschaltvorgang zur Durchführung der gewünschten Vorheizung über Schalter an die Betriebsgleichspannung angeschaltet und am Ende der Vorheizphase wiederum hiervon abgeschaltet wird.The invention is based on the knowledge that the preheating of the heating electrodes of the fluorescent lamp can be done much more quickly without the design of the ballast for higher electrical power if the required electrical power is applied by the rectified AC mains voltage. In this way, practically any preheating current for the heating electrodes can be made available. Thanks to the fluorescent lamp controlled by the inverter via a transformer, a DC path can be formed from the series connection of the secondary winding of the transformer with the heating electrodes, which is then switched on during a switch-on process to carry out the desired preheating via switches to the operating DC voltage and at the end of Preheating phase is switched off again.
Diese Art der Gleichstromvorheizung läßt sich in außerordentlich vorteilhafter Weise auch auf Vorschaltgeräte anwenden, die gleichzeitig zwei und mehr Leuchtstofflampen zu versorgen haben. Hierzu ist es lediglich erforderlich, die Sekundärwicklungen der den einzelnen Leuchtstofflampen zugeordneten Transformatoren in geeigneter Weise in Reihe zu schalten.This type of direct current preheating can also be used in an extremely advantageous manner on ballasts which simultaneously supply two or more fluorescent lamps to have. All that is required is to connect the secondary windings of the transformers assigned to the individual fluorescent lamps in a suitable manner.
Zweckmäßige Ausgestaltungen des Gegenstandes nach dem Patentanspruch 1 sind in den weiteren Patentansprüchen 2 bis 6 angegeben.Expedient embodiments of the subject matter according to claim 1 are specified in the further claims 2 to 6.
In der Zeichnung bedeuten die der näheren Erläuterung der Erfindung dienenden Figuren
- Fig. 1
- das Blockschaltbild eines für mehrere Leuchtstofflampen vorgesehenen Vorschaltgerätes mit einer Gleichstromvorheizung,
- Fig. 2
- die Wirkungsweise der Schaltung nach Fig. 1 näher erläuternde Zeitdiagramme.
- Fig. 1
- the block diagram of a ballast provided for several fluorescent lamps with a DC preheating,
- Fig. 2
- the operation of the circuit of FIG. 1 time diagrams.
Das Blockschaltbild für ein mehreren Leuchtstofflampen zugeordnetes Vorschaltgerät weist ein Oberwellenfilter OW auf, an dem eingangsseitig die Netzwechselspannung Un anliegt. An das Oberwellenfilter OW schließt sich ein Gleichrichter GL an, dem auf der Ausgangsseite ein Ladekondensator Co parallel liegt. Am Ladekondensator Co steht die gleichgerichtete geglättete Netzwechselspannung Un in Form der Betriebsgleichspannung Ub an. Die dem Wechselrichter WR eingangsseitig zugeführte Betriebsgleichspannung Ub wird im Rhythmus einer Hochfrequenz mit Hilfe einer selbstgesteuerten Schalterbrückenanordnung umgeschaltet und ausgangsseitig über den Koppelkondensator Ck dem Lastkreis LK zugeführt.The block diagram for a ballast assigned to a plurality of fluorescent lamps has a harmonic filter OW to which the AC line voltage Un is applied on the input side. A rectifier GL is connected to the harmonic filter OW, and a charging capacitor Co is connected in parallel on the output side. The rectified, smoothed mains AC voltage Un is present at the charging capacitor Co in the form of the operating DC voltage Ub. The DC operating voltage Ub supplied to the inverter WR is switched over to a high frequency with the aid of a self-controlled switch bridge arrangement and is fed to the load circuit LK on the output side via the coupling capacitor Ck.
Der Lastkreis weist n Leuchtstofflampen LL1, LL2, ... LLn auf, denen einerseits jeweils ein Zündkondensator C1, C2, ... Cn und andererseits die Sekundärwicklung eines Transformators TR1, TR2, ... Tn parallel geschaltet sind. Die jeweils einer Leuchtstofflampe LL1, LL2, ... LLn zugeordneten Transformatoren TR1, TR2, ... TRn sind hinsichtlich ihrer Primärwicklungen in Parallelschaltung mit dem Ausgang des Wechselrichters WR verbunden.The load circuit has n fluorescent lamps LL1, LL2, ... LLn, each of which has an ignition capacitor C1, C2, ... Cn and on the other hand, the secondary winding of a transformer TR1, TR2, ... Tn are connected in parallel. The respective transformers TR1, TR2, ... TRn assigned to a fluorescent lamp LL1, LL2, ... LLn are connected in parallel to the output of the inverter WR with regard to their primary windings.
Die Sekundärwicklungen der Transformatoren TR1, TR2, ... TRn sind auf seiten der Zündkondensatoren C1, C2, ... Cn so einander in Serie geschaltet, daß sich hierdurch ein Gleichstrompfad bildet, in dem die Heizelektroden He sämtlicher Leuchtstofflampen LL1, LL2, ... LLn mit den Sekundärwicklungen der Transformatoren TR1, TR2, ... TRn in Reihe geschaltet sind. Der gemeinsame Verbindungspunkt der Heizelektrode He der Röhre LL1 mit dem Zündkondensator C1 ist über den Schalter S11 und den Heizvorwiderstand RV mit dem positiven Pol der Betriebsgleichspannung Ub verbunden. Der negative Pol der Betriebsgleichspannung Ub liegt auf Bezugspotential. Mit diesem Bezugspotential ist der Gleichstrompfad am gemeinsamen Verbindungspunkt des Zündkondensators Cn mit der unteren Heizelektrode He der Leuchtstofflampe LLn ebenfalls über einen Schalter S12 verbunden. Die Schalter S11 und S12 stellen Arbeitskontakte a1 und a2 eines Relais A dar, dessen Erregerwicklung der Betriebsgleichspannung Ub über die Vorheizsteuerung VH parallel anschaltbar ist.The secondary windings of the transformers TR1, TR2, ... TRn are connected in series on the ignition capacitors C1, C2, ... Cn so that a DC path is formed in which the heating electrodes He of all fluorescent lamps LL1, LL2,. .. LLn are connected in series with the secondary windings of the transformers TR1, TR2, ... TRn. The common connection point of the heating electrode He of the tube LL1 with the ignition capacitor C1 is connected via the switch S11 and the heating resistor RV to the positive pole of the operating DC voltage Ub. The negative pole of the DC operating voltage Ub is at the reference potential. The DC path at the common connection point of the ignition capacitor Cn to the lower heating electrode He of the fluorescent lamp LLn is also connected to this reference potential via a switch S12. The switches S11 and S12 represent working contacts a1 and a2 of a relay A, the excitation winding of the operating DC voltage Ub can be connected in parallel via the preheating control VH.
Die Vorheizsteuerung VH ist ein Zeitschaltglied, das bei Einschalten des Vorschaltgerätes über die sich am Ladekondensator Co aufbauende Betriebsgleichspannung Ub aktiviert wird und damit das Relais A zum Ansprechen bringt. Die hierdurch sich schließenden Arbeitskontakte a1 und a2 der Schalter S11 und S12 schalten den geschilderten Gleichstrompfad über den Vorheizwiderstand RV und die Betriebsgleichspannung Ub an und es fließt nunmehr über diesen Gleichstrompfad und damit über sämtliche Heizelektroden der Leuchtstofflampen LL1, LL2, ... LLn der Vorheizstrom iVH.The preheating control VH is a timer which is activated when the ballast is switched on via the operating DC voltage Ub built up at the charging capacitor Co and thus triggers the relay A. The thus closing normally open contacts a1 and a2 of the switches S11 and S12 switch on the DC path described via the preheating resistor RV and the DC operating voltage Ub and the preheating current now flows via this DC path and thus over all heating electrodes of the fluorescent lamps LL1, LL2, ... LLn iVH.
Entsprechend der Einstellung der Zeitschaltung der Vorheizsteuerung VH wird der Vorheizstrom iVH über das abfallende Relais A nach einer vorgegebenen kurzen Zeit wieder unterbrochen und es können dann die Leuchtstofflampen LL1, LL2, ... LLn gezündet werden. Die Zündung erfolgt im Anschluß an die Deaktivierung der Vorheizsteuerung VH durch Anschwingen der selbstgesteuerten Schalterbrückenanordnung, deren Brückenschalter S1 und S2 wechselweise im Rhythmus der hochfrequenten Schaltfrequenz geschlossen werden.According to the setting of the timing of the preheating control VH, the preheating current iVH is above the falling Relay A is interrupted again after a predetermined short time and the fluorescent lamps LL1, LL2, ... LLn can then be ignited. The ignition takes place after the deactivation of the preheating control VH by swinging the self-controlled switch bridge arrangement, the bridge switches S1 and S2 are alternately closed in rhythm with the high-frequency switching frequency.
Die selbstgesteuerte Schalterbrückenanordnung weist für die Selbsterregung einen Sättigungsübertrager SÜ auf, mit dessen Hilfe die positive Rückkopplung des Ausgangskreises des Wechselrichters auf die Steuereingänge der Brückenschalter S11 und S12 verwirklicht wird. Wie der im Block dargestellte Wechselrichter WR erkennen läßt, weist der Sättigungsübertrager SÜ eine Zusatz-Sekundärwicklung Wz mit einem Mittelabgriff P auf, der zwei Dioden D1 und D2 gegensinnig in Reihe geschaltet sind. Mittels der Sperrschaltung SS kann der gemeinsame Verbindungspunkt der beiden Dioden D1 und D2 ebenfalls über ein Zeitschaltglied an Bezugspotential gelegt und damit die Zusatz-Sekundärwicklung Wz kurzgeschlossen werden. Die Sperrschaltung SS spricht ebenfalls wie die Vorheizsteuerung VH bei Einschalten des Vorschaltgerätes an und verhindert damit während der Vorheizphase ein parasitäres Anschwingen der selbstgesteuerten Schalterbrückenanordnung.The self-controlled switch bridge arrangement has a saturation transmitter SÜ for self-excitation, with the aid of which the positive feedback of the output circuit of the inverter to the control inputs of the bridge switches S11 and S12 is realized. As can be seen from the inverter WR shown in the block, the saturation transformer SÜ has an additional secondary winding Wz with a center tap P, which two diodes D1 and D2 are connected in series in opposite directions. By means of the blocking circuit SS, the common connection point of the two diodes D1 and D2 can also be connected to the reference potential via a time switching element and the additional secondary winding Wz can thus be short-circuited. The blocking circuit SS also responds like the preheating control VH when the ballast is switched on and thus prevents parasitic oscillation of the self-controlled switch bridge arrangement during the preheating phase.
Die Aktivierung der Sperrschaltung SS erfolgt wie bei der Vorheizsteuerung VH durch die sich bei einem Einschaltvorgang am Ladekondensator Co aufbauende Betriebsgleichspannung Ub. Die Sperrschaltung SS weist noch einen Steuerausgang auf, über den sie nach Aufheben des Kurzschlusses der Zusatz-Sekundärwicklung Wz des Sättigungsübertragers SÜ die Starterschaltung ST für ein definiertes Anschwingen der selbstgesteuerten Schalterbrückenanordnung aktiviert.The blocking circuit SS is activated, as in the preheating control VH, by the operating DC voltage Ub building up at the charging capacitor Co during a switch-on process. The blocking circuit SS also has a control output via which it activates the starter circuit ST for a defined oscillation of the self-controlled switch bridge arrangement after the short circuit of the additional secondary winding Wz of the saturation transformer SÜ has been removed.
Um mit dem Anschwingen des Wechselrichters den zu zündenden Leuchtstofflampen LL1, LL2, ... LLn des Lastkreises LK jeweils eine ausreichende Zündspannung zur Verfügung stellen zu können, sind die Transformatoren TR1, TR2, ... TRn als Streufeldtransformatoren ausgeführt, deren in Fig. 1 nicht dargestellten Streuinduktivitäten mit den Zündkondensatoren C1, C2, ... Cn Serienresonanzkreise bilden, die annähernd auf die hochfrequente Schaltfrequenz des Wechselrichters abgestimmt sind.In order to be able to provide the fluorescent lamps LL1, LL2,... LLn of the load circuit LK with sufficient ignition voltage when the inverter starts to fire, the transformers TR1, TR2, ... TRn are designed as stray field transformers whose stray inductances (not shown in FIG. 1) form series resonance circuits with the ignition capacitors C1, C2, ... Cn, which are approximately matched to the high-frequency switching frequency of the inverter.
In den Zeitdiagrammen der Fig. 2 ist der Ablauf eines Einschaltvorgangs, soweit er die Vorheizung der Heizelektroden der Leuchtstofflampen LL1, LL2, ... LLn mit dem Vorheizstrom iVH betrifft, über der Zeit dargestellt. Die Zeitdiagramme stellen von oben nach unten den Verlauf der Betriebsgleichspannung Ub, das Schaltverhalten der Vorheizsteuerung VH, das Schaltverhalten der Sperrschaltung SS, den zeitlichen Verlauf des von der Starterschaltung ST abgegebenen Startimpulses I sowie den Verlauf des Vorheizstromes iVH über der Zeit t dar.In the time diagrams of FIG. 2, the sequence of a switch-on process, as far as it concerns the preheating of the heating electrodes of the fluorescent lamps LL1, LL2,... LLn with the preheating current iVH, is shown over time. The time diagrams represent the course of the DC operating voltage Ub, the switching behavior of the preheating control VH, the switching behavior of the blocking circuit SS, the time course of the starting pulse I emitted by the starter circuit ST and the course of the preheating current iVH over time t from top to bottom.
Mit dem Einschalten des Vorschaltgerätes und damit dem Auftreten der Betriebsgleichspannung Ub am Ladekondensator Co im Zeitpunkt t1 werden gleichzeitig die Vorheizsteuerung VH und die Sperrschaltung SS aktiviert. Die Sperrschaltung SS bleibt im Abschaltzeitpunkt der Vorheizsteuerung VH im Zeitpunkt t2 noch aktiviert und zwar bis zum Zeitpunkt t3, in dem unvermeidbare Prellungen der Arbeitskontakte a1 und a2 beim Abfallen des Relais A abgeklungen sind. Dieses Prellverhalten der genannten Arbeitskontakte a1 und a2 ist im Stromdiagramm für den Vorheizstrom iVH dargestellt. Im Zeitpunkt t3, in dem der Vorheizstrom iVH nach dem Abschalten im Zeitpunkt t2 völlig abgeklungen ist, schaltet auch die Sperrschaltung SS ab und gibt damit den Wechselrichter WR frei. Die Sperrschaltung SS erzeugt beim Abschalten einen Steuerimpuls für die Starterschaltung ST, die damit den Startimpuls I an den Wechselrichter WR abgibt.When the ballast is switched on and thus the DC operating voltage Ub occurs at the charging capacitor Co at time t1, the preheating control VH and the blocking circuit SS are activated at the same time. The blocking circuit SS remains activated at the time t2 at the time of switching off the preheating control VH until time t3, at which unavoidable bruises of the working contacts a1 and a2 have subsided when the relay A has dropped out. This bounce behavior of the above-mentioned normally open contacts a1 and a2 is shown in the current diagram for the preheating current iVH. At time t3, in which the preheating current iVH has completely subsided after being switched off at time t2, the blocking circuit SS also switches off and thus releases the inverter WR. The blocking circuit SS generates a control pulse for the starter circuit ST when it is switched off, which thus outputs the start pulse I to the inverter WR.
Claims (6)
- Electronic ballast for at least one fluorescent lamp (LL1, LL2, ..., LLn) equipped with heatable electrodes, having an inverter (WR) to which an operating DC voltage (Ub) is fed on the input side and which on the output side is connected to a load circuit (LK) which has a fluorescent lamp (LL1, LL2, ..., LLn) and which also comprises a transformer (TR1, TR2, ..., TRn) for the purpose of connecting the fluorescent lamp (LL1, LL2, ..., LLn) to the output of the inverter (WR) in a potential-free fashion, characterised in that- on the load-circuit side the secondary winding of the transformer (TR1, TR2, ..., Trn) forms in series with the heating electrodes of the fluorescent lamp (LL1, LL2, ..., LLn) a DC circuit for the preheating current (iVH) which can be connected to the operating DC voltage (Ub) via switches (S11, S12), actuated by a preheating control (VH), during a switching-on operation for a prescribed preheating time (t1-t2), possibly in series with a preheating resistor (RV).
- Electronic ballast according to Claim 1, characterised in that- two or more transformers (Tr1, Tr2, ..., Trn) are connected on the primary side in an AC fashion to the output of the converter (WR),- in that each transformer (Tr1, Tr2, ..., Trn) is connected on the secondary side to a fluorescent lamp (LL1, LL2, ..., LLn), and- in that the secondary windings of all the transformers (Tr1, Tr2, ..., Trn) are connected in series to one another in such a way that- all the heating electrodes of the fluorescent lamps form in series with the secondary windings the DC circuit for the preheating current (iVH).
- Electronic ballast according to Claim 1 or 2, characterised in that- the switches (S11, S12) are make contacts (a1, a2) of a relay (A) which can be connected with its excitation winding via the preheating control (VH) to the operating DC voltage (Ub).
- Electronic ballast, in which the inverter (WR) is an automatically controlled switch bridge arrangement having a saturation transformer (SÜ) implementing the feedback of the output circuit to the control inputs of the bridge switches (S1, S2), according to one of the preceding claims, characterised in that- the saturation transformer (SÜ) has an additional secondary winding (Wz) which in the event of a switching-on operation is short-circuited by an inhibiting circuit (SS) during the closing time of the switches (S11, S12) in the DC circuit for the preheating current (iVH), and in that- after clearance of the short circuit of the additional secondary winding (Wz) the inhibiting circuit (SS) activates a starter circuit (ST) which transmits to the inverter (WR) a start pulse (I) which initiates the defined response of the inverter (WR).
- Electronic ballast according to Claim 4, characterised in that- the inhibiting circuit (SS) which short-circuits the additional secondary winding (Wz) of the saturation transformer (SÜ) in the event of a switching-on operation does not clear the short circuit until the switches (S11, S12) have broken the connection between the operating DC voltage (Ub) and the DC circuit for the preheating current (iVH) properly.
- Electronic ballast according to one of the preceding claims, characterised in that- the transformers (Tr1, Tr2, ..., Trn) are high-reactance transformers whose stray-field inductances in each case form, together with ignition capacitors (C1, C2, ..., Cn) connected in parallel with the fluorescent lamps (LL1, LL2, ..., LLn), a series resonant circuit which supports the ignition operation of the fluorescent lamps (LL1, LL2, ..., LLn) and is tuned approximately to the switching frequency of the inverter (WR).
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE8989122189T DE58904984D1 (en) | 1989-12-01 | 1989-12-01 | ELECTRONIC CONTROL UNIT FOR FLUORESCENT LAMPS. |
| EP89122189A EP0429716B1 (en) | 1989-12-01 | 1989-12-01 | Electronic ballast for fluorescent lamps |
| US07/604,811 US5049783A (en) | 1989-12-01 | 1990-10-29 | Electronic ballast device for fluorescent lamps |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP89122189A EP0429716B1 (en) | 1989-12-01 | 1989-12-01 | Electronic ballast for fluorescent lamps |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0429716A1 EP0429716A1 (en) | 1991-06-05 |
| EP0429716B1 true EP0429716B1 (en) | 1993-07-21 |
Family
ID=8202190
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP89122189A Expired - Lifetime EP0429716B1 (en) | 1989-12-01 | 1989-12-01 | Electronic ballast for fluorescent lamps |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US5049783A (en) |
| EP (1) | EP0429716B1 (en) |
| DE (1) | DE58904984D1 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2245436A (en) * | 1990-05-30 | 1992-01-02 | Solar Wide Ind Ltd | Solar-powered fluorescent lamp-drive circuit |
| US5444333A (en) * | 1993-05-26 | 1995-08-22 | Lights Of America, Inc. | Electronic ballast circuit for a fluorescent light |
| US5627434A (en) * | 1993-10-26 | 1997-05-06 | Canon Kabushiki Kaisha | Apparatus for operating a fluorescent lamp of an image forming apparatus |
| DE19520999A1 (en) * | 1995-06-08 | 1996-12-12 | Siemens Ag | Circuit arrangement for filament preheating of fluorescent lamps |
| KR0169164B1 (en) * | 1995-08-21 | 1999-04-15 | 이청우 | Rapid start type fluorescent lamp starting circuit |
| US5832196A (en) * | 1996-06-28 | 1998-11-03 | Mci Communications Corporation | Dynamic restoration process for a telecommunications network |
| US5998930A (en) * | 1996-10-24 | 1999-12-07 | Motorola Inc. | Electronic ballast with two-step boost converter and method |
| US6534926B1 (en) | 2000-04-12 | 2003-03-18 | Tmc Enterprises, A Division Of Tasco Industries, Inc. | Portable fluorescent drop-light |
| CN1575626A (en) * | 2001-10-25 | 2005-02-02 | 皇家飞利浦电子股份有限公司 | Safety starter for fluorescent lamps |
| US20070262734A1 (en) * | 2003-07-25 | 2007-11-15 | Koninklijke Philps Electronics, N.V. | Filament Cutout Circuit |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1190570B (en) * | 1963-12-23 | 1965-04-08 | Licentia Gmbh | Vibration transformer for inverters used to supply fluorescent lamps |
| GB1326392A (en) * | 1970-11-14 | 1973-08-08 | Dobson Park Ind | Fluorescent lamp and other circuits |
| CA1333408C (en) * | 1984-10-16 | 1994-12-06 | Calvin E. Grubbs | Electronic ballast circuit for fluorescent lamps |
| DE3607109C1 (en) * | 1986-03-05 | 1987-05-07 | Trilux Lenze Gmbh & Co Kg | Ballast for discharge lamps |
| US4730147A (en) * | 1986-08-19 | 1988-03-08 | Siemens Aktiengesellschaft | Method and arrangement for the operation of a gas discharge lamp |
| GB2212995A (en) * | 1987-10-23 | 1989-08-02 | Rockwell International Corp | Fluorescent lamp dimmer |
-
1989
- 1989-12-01 EP EP89122189A patent/EP0429716B1/en not_active Expired - Lifetime
- 1989-12-01 DE DE8989122189T patent/DE58904984D1/en not_active Expired - Fee Related
-
1990
- 1990-10-29 US US07/604,811 patent/US5049783A/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP0429716A1 (en) | 1991-06-05 |
| DE58904984D1 (en) | 1993-08-26 |
| US5049783A (en) | 1991-09-17 |
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