EP0058683B1 - Installation for starting a discharge lamp with heated electrodes - Google Patents

Installation for starting a discharge lamp with heated electrodes Download PDF

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Publication number
EP0058683B1
EP0058683B1 EP81902288A EP81902288A EP0058683B1 EP 0058683 B1 EP0058683 B1 EP 0058683B1 EP 81902288 A EP81902288 A EP 81902288A EP 81902288 A EP81902288 A EP 81902288A EP 0058683 B1 EP0058683 B1 EP 0058683B1
Authority
EP
European Patent Office
Prior art keywords
diode
discharge lamp
voltage
electrode
electrodes
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
Application number
EP81902288A
Other languages
German (de)
French (fr)
Other versions
EP0058683A1 (en
Inventor
Max Kerscher
Anh-Dung Nguyen
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.)
Siemens AG
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Siemens AG
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
Priority claimed from DE19803029644 external-priority patent/DE3029644A1/en
Application filed by Siemens AG filed Critical Siemens AG
Priority to AT81902288T priority Critical patent/ATE11721T1/en
Publication of EP0058683A1 publication Critical patent/EP0058683A1/en
Application granted granted Critical
Publication of EP0058683B1 publication Critical patent/EP0058683B1/en
Expired legal-status Critical Current

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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
    • H05B41/02—Details
    • H05B41/04—Starting switches
    • H05B41/042—Starting switches using semiconductor devices
    • H05B41/044—Starting switches using semiconductor devices for lamp provided with pre-heating electrodes
    • H05B41/046—Starting switches using semiconductor devices for lamp provided with pre-heating electrodes using controlled semiconductor devices
    • 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
    • H05B41/298—Arrangements for protecting lamps or circuits against abnormal operating conditions
    • H05B41/2988—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the lamp against abnormal operating conditions

Definitions

  • the invention relates to an arrangement for operating a discharge lamp with two heatable electrodes connected to auxiliary voltage sources, between which there is a main AC voltage source.
  • Such circuits are generally dimensioned such that the discharge lamp only ignites after sufficient preheating, which benefits its service life. After the ignition, however, the preheating of the electrodes remains during the entire burning time of the lamp although it is then no longer required.
  • the invention is therefore based on the object of reducing the associated losses.
  • the invention is characterized by the features specified in the characterizing part of the claim.
  • the invention is based on the finding that the voltage profile of the two electrodes of a discharge lamp is quite different: at the respective non-emitting electrode (positive anode), the peak value of the voltage drop is, for example, about 2 volts, while it is at the respective emitting electrode (negative Cathode) considerably higher values, e.g. up to about 6 volts.
  • the invention therefore limits the voltage at the emitting electrode to the threshold voltage of a diode, which is approximately 1 volt; this results in a corresponding reduction in the losses caused by the continuous heating. This reduction can also be explained by the parallel connection of the electrode parts on both sides of the focal spot, which results in a lower total resistance.
  • the diodes are practically harmless for preheating mode if, as is usually the case, a significantly higher voltage is applied to the lamp in this phase and therefore a greater current flows than after the lamp was ignited.
  • Different AC voltages for the time before and after the lamp is ignited can be generated in a known manner:
  • the secondary winding of a stray field transformer can serve as the main AC voltage source, which is connected between the two electrodes of the discharge lamp.
  • the discharge lamp L is arranged parallel to the capacitor C23 of the series resonance circuit, so that its electrodes 11, 12 are connected in series with the series resonance circuit.
  • a diode D46 or D47 lies parallel to each electrode: These are polarized so that in each half-wave of the AC voltage applied to C23 only the diode conducts which is connected in parallel to the electrode emitting in this half-wave. Given the polarity of the voltage at C23 shown in the figure, this is the diode D47, which is parallel to the electrode 14 which acts as cathode in this half-wave and bridges this electrode; the other diode D46, on the other hand, is blocked in this half-wave, so that the circuit runs parallel to L4 via L3, C23 and D47. As a result, the voltage at the cathode is limited to the threshold value of the diode (approximately 1 volt), whereas without such a diode approximately 6 volts would be at the cathode.
  • the circuit is dimensioned such that the voltage C23 is sufficient for ignition only if the electrodes are sufficiently preheated. It is even better to keep the voltage at C23 below the value required to ignite a warm lamp for a time sufficient for good preheating and only then to increase it to the value required for ignition.

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  • Circuit Arrangements For Discharge Lamps (AREA)

Abstract

Sometimes a discharge lamp is operated with two heated electrodes while still running the feeding auxiliary installation after the start of the lamp. The invention reduces these unnecessary losses. To this effect, each electrode (13, 14) is provided with a parallel diode (D46, D47) so that, in each half-cycle of the main a-c voltage source (C23) the only conductive diode is the one connected to the negative electrode which is the emitter electrode in that half-period. The voltage on the emitter electrode is thereby limited to 1 volt whereas it would be higher without a diode.

Description

Die Erfindung betrifft eine Anordnung zum Betrieb einer Entladungslampe mit zwei an Hilfsspannungsquellen angeschlossenenen, heizbaren Elektroden, zwischen denen eine Hauptwechselspannungsquelle liegt.The invention relates to an arrangement for operating a discharge lamp with two heatable electrodes connected to auxiliary voltage sources, between which there is a main AC voltage source.

Solche Schaltungen sind in der Regel so bemessen, dass die Entladungslampe erst nach ausreichender Vorheizung zündet, was ihrer Lebensdauer zugute kommt. Nach der Zündung bleibt jedoch die Vorheizung der Elektroden während der gesamten Brenndauer der Lampe bestehen obwohl sie dann nicht mehr benötigt wird. Der Erfindung liegt daher die Aufgabe zugrunde, die damit verbundenen Verluste zu reduzieren.Such circuits are generally dimensioned such that the discharge lamp only ignites after sufficient preheating, which benefits its service life. After the ignition, however, the preheating of the electrodes remains during the entire burning time of the lamp although it is then no longer required. The invention is therefore based on the object of reducing the associated losses.

Die Erfindung ist durch die im Kennzeichen des Anspruches angegebenen Merkmale charakterisiert.The invention is characterized by the features specified in the characterizing part of the claim.

Der Erfindung liegt die Erkenntnis zugrunde, dass der Spannungsverlauf von den beiden Elektroden einer Entladungslampe recht unterschiedlich ist: An der jeweils nicht emittierenden Elektrode (positive Anode) liegt der Spitzenwert des Spannungsabfalles beispielsweise bei etwa 2 Volt, während er an der jeweils emittierenden Elektrode (negative Kathode) erheblich höhere Werte, z.B. bis zu etwa 6 Volt, hat. Durch die Erfindung wird daher die Spannung an der jeweils emittierenden Elektrode auf die Schwellspannung einer Diode begrenzt, die bei etwa 1 Volt liegt; dadurch ergibt sich eine entsprechende Reduzierung der durch die Dauerheizung entstehenden Verluste. Diese Reduzierung lässt sich auch mit der durch die Diode bewirkten Parallelschaltung der zu beiden Seiten des Brennfleckes liegenden Elektrodenteile erklären, wodurch sich ein niedrigerer Gesamtwiderstand ergibt.The invention is based on the finding that the voltage profile of the two electrodes of a discharge lamp is quite different: at the respective non-emitting electrode (positive anode), the peak value of the voltage drop is, for example, about 2 volts, while it is at the respective emitting electrode (negative Cathode) considerably higher values, e.g. up to about 6 volts. The invention therefore limits the voltage at the emitting electrode to the threshold voltage of a diode, which is approximately 1 volt; this results in a corresponding reduction in the losses caused by the continuous heating. This reduction can also be explained by the parallel connection of the electrode parts on both sides of the focal spot, which results in a lower total resistance.

Für den Vorheizbetrieb sind die Dioden praktisch unschädlich, wenn in dieser Phase - wie meist üblich - eine wesentlich höhere Spannung an der Lampe liegt und somit ein grösserer Strom fliesst als nach Zündung der Lampe. Unterschiedliche Wechselspannungen für die Zeit vor und nach Zündung der Lampe können in bekannter Weise erzeugt werden: Hierzu kann beispielsweise die Sekundärwicklung eines Streufeldtransformators als Hauptwechselspannungsquelle dienen, die zwischen den beiden Elektroden der Entladungslampe angeschlossen ist.The diodes are practically harmless for preheating mode if, as is usually the case, a significantly higher voltage is applied to the lamp in this phase and therefore a greater current flows than after the lamp was ignited. Different AC voltages for the time before and after the lamp is ignited can be generated in a known manner: For this purpose, for example, the secondary winding of a stray field transformer can serve as the main AC voltage source, which is connected between the two electrodes of the discharge lamp.

Eine andere Möglichkeit besteht darin, an einen Wechselrichter bekanntner Bauart einen Serienresonanzkreis anzuschliessen, dessen Resonanzfrequenz etwas unter der z.B. durch einen Sättigungstransformator bestimmten Betriebsfrequenz des Wechselrichters liegt; die beiden Elektroden der Lampe sind in diesem Fall zu beiden Seiten des Kondensators des Serienresonanzkreises in diesen Resonanzkreis eingeschaltet. Ein Ausführungsbeispiel dieser Art wird anhand der Figur näher erläutert:

  • Der in der Figur schematisch dargestellte Wechselrichter enthält zwischen seinen Gleichspannungsklemmen w1, w2 zwei Transistoren V7, V8 in Reihenschaltung. Parallel zur Schaltstrecke des Transistors V7 liegt ein Serienresonanzkreis mit der Drossel L7 und dem Kondensator C23 in Reihe mit einem Umschwingkondensator C22 und der Primärwicklung L81 eines Sättigungstransformators T8, dessen Bemessung die Betriebsfrequenz des Wechselrichters bestimmt. Dieser Sättigungstransformator hat zwei Sekundärwicklungen L82, L83, die derart in den Steuerkreisen der Transistoren V7 und V8 liegen, dass diese Transistoren abwechselnd durchgesteuert und gesperrt werden. Die Betriebsfrequenz des Wechselrichters liegt dabei etwas über der Resonanzfrequenz des Serienresonanzkreises. Dadurch wird erreicht, dass beim Einschalten eines Transistors der vorher leitende bereits voll gesperrt ist und der Strom zu diesem Zeitpunkt über die jeweils gegensinnig parallel geschaltete Diode fliesst. Die Betriebsfrequenz liegt bei etwa 40 kHz.
Another possibility is to connect a series resonance circuit to an inverter of known design, the resonance frequency of which is somewhat lower than the operating frequency of the inverter determined, for example, by a saturation transformer; in this case, the two electrodes of the lamp are switched into this resonance circuit on both sides of the capacitor of the series resonance circuit. An embodiment of this type is explained in more detail with reference to the figure:
  • The inverter shown schematically in the figure contains two transistors V7, V8 connected in series between its DC voltage terminals w1, w2. Parallel to the switching path of the transistor V7 is a series resonance circuit with the inductor L7 and the capacitor C23 in series with a switching capacitor C22 and the primary winding L81 of a saturation transformer T8, the dimensioning of which determines the operating frequency of the inverter. This saturation transformer has two secondary windings L82, L83, which are located in the control circuits of transistors V7 and V8 in such a way that these transistors are alternately turned on and off. The operating frequency of the inverter is slightly above the resonance frequency of the series resonance circuit. It is thereby achieved that when a transistor is switched on, the previously conductive one is already fully blocked and the current flows at this point in time via the diode connected in parallel in opposite directions. The operating frequency is around 40 kHz.

Parallel zu dem Kondensator C23 des Serienresonanzkreises ist die Entladungslampe L angeordnet, so dass deren Elektroden 11, 12 in Reihenschaltung mit dem Serienresonanzkreis liegen. Parallel zu jeder Elektrode liegt eine Diode D46 bzw. D47: Diese sind so gepolt, dass in jeder Halbwelle der an C23 liegenden Wechselspannung immer nur die Diode leitet, die der in dieser Halbwelle emittierenden Elektrode parallel geschaltet ist. Bei der in der Figur angegebenen Polarität der Spannung an C23 ist dies die Diode D47, die der in dieser Halbwelle als Kathode wirkenden Elektrode 14 parallel liegt und diese Elektrode überbrückt; die andere Diode D46 ist dagegen in dieser Halbwelle gesperrt, so dass der Stromkreis über L3, C23 und D47 parallel zu L4 verläuft. Dadurch ist die Spannung an der Kathode auf den Schwellwert der Diode (etwa 1 Volt) begrenzt, während ohne eine solche Diode etwa 6 Volt an der Kathode liegen würden.The discharge lamp L is arranged parallel to the capacitor C23 of the series resonance circuit, so that its electrodes 11, 12 are connected in series with the series resonance circuit. A diode D46 or D47 lies parallel to each electrode: These are polarized so that in each half-wave of the AC voltage applied to C23 only the diode conducts which is connected in parallel to the electrode emitting in this half-wave. Given the polarity of the voltage at C23 shown in the figure, this is the diode D47, which is parallel to the electrode 14 which acts as cathode in this half-wave and bridges this electrode; the other diode D46, on the other hand, is blocked in this half-wave, so that the circuit runs parallel to L4 via L3, C23 and D47. As a result, the voltage at the cathode is limited to the threshold value of the diode (approximately 1 volt), whereas without such a diode approximately 6 volts would be at the cathode.

Im übrigen ist die Schaltung so bemessen, dass die Spannung C23 nur bei ausreichend vorgeheizten Elektroden für eine Zündung ausreicht. Noch besser ist es, die Spannung an C23 während einer für eine gute Vorheizung ausreichenden Zeit unter dem für die Zündung einer warmen Lampe erforderlichen Wert zu halten und erst dann auf den zur Zündung erforderlichen Wert zu erhöhen.Otherwise, the circuit is dimensioned such that the voltage C23 is sufficient for ignition only if the electrodes are sufficiently preheated. It is even better to keep the voltage at C23 below the value required to ignite a warm lamp for a time sufficient for good preheating and only then to increase it to the value required for ignition.

Claims (1)

  1. An arrangement for starting a discharge lamp having two heatable electrodes connected to auxiliary voltage sources and having an a.c. mains voltage source arranged between them, characterised in that each of the two electrodes (11, 12) is bridged by a diode (D46, D47) poled in such manner that in each half-wave of the a.c. voltage supplied by the a.c. mains voltage source only that diode connected parallel to the electrode which is emissive in this half-wave is conductive.
EP81902288A 1980-08-05 1981-07-29 Installation for starting a discharge lamp with heated electrodes Expired EP0058683B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81902288T ATE11721T1 (en) 1980-08-05 1981-07-29 ARRANGEMENT FOR OPERATION OF A DISCHARGE LAMP WITH HEATABLE ELECTRODES.

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE19803029644 DE3029644A1 (en) 1980-08-05 1980-08-05 Operating circuit for discharge lamp - has pre-heated electrodes and uses shunt diode across each electrode
DE3029644 1980-08-05
DE3115598 1981-04-16
DE3115598 1981-04-16

Publications (2)

Publication Number Publication Date
EP0058683A1 EP0058683A1 (en) 1982-09-01
EP0058683B1 true EP0058683B1 (en) 1985-02-06

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ID=25787078

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Application Number Title Priority Date Filing Date
EP81902288A Expired EP0058683B1 (en) 1980-08-05 1981-07-29 Installation for starting a discharge lamp with heated electrodes

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EP (1) EP0058683B1 (en)
DE (1) DE3168772D1 (en)
FI (1) FI812304L (en)
IT (1) IT1137760B (en)
WO (1) WO1982000561A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0750447A1 (en) * 1995-06-22 1996-12-27 ECKERLE INDUSTRIE-ELEKTRONIK GmbH Circuit arrangement for the ignition of a fluorescent lamp

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3246454A1 (en) * 1982-12-15 1984-06-20 Siemens AG, 1000 Berlin und 8000 München INVERTER WITH A LOAD CIRCUIT CONTAINING A SERIES RESONANCE CIRCUIT AND A DISCHARGE LAMP
DE3805510A1 (en) * 1988-02-22 1989-08-31 Patent Treuhand Ges Fuer Elektrische Gluehlampen Mbh CIRCUIT ARRANGEMENT FOR OPERATING A LOW-PRESSURE DISCHARGE LAMP

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE823160C (en) * 1949-06-24 1951-12-03 Siemens Schuckertwerke A G Device for switching off and operating gas or vapor-filled discharge tubes, in particular fluorescent lamps
US4122375A (en) * 1976-02-06 1978-10-24 Rudolf Studli Circuit arrangement for increasing the luminous flux in fluorescent tube hand lamps

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0750447A1 (en) * 1995-06-22 1996-12-27 ECKERLE INDUSTRIE-ELEKTRONIK GmbH Circuit arrangement for the ignition of a fluorescent lamp
DE19522675A1 (en) * 1995-06-22 1997-01-02 Eckerle Ind Elektronik Gmbh Circuit arrangement for igniting a fluorescent lamp

Also Published As

Publication number Publication date
IT1137760B (en) 1986-09-10
EP0058683A1 (en) 1982-09-01
IT8123279A0 (en) 1981-07-31
DE3168772D1 (en) 1985-03-21
WO1982000561A1 (en) 1982-02-18
FI812304L (en) 1982-02-06

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