EP0050131B1 - Ballast for a discharge lamp - Google Patents

Ballast for a discharge lamp Download PDF

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Publication number
EP0050131B1
EP0050131B1 EP81900979A EP81900979A EP0050131B1 EP 0050131 B1 EP0050131 B1 EP 0050131B1 EP 81900979 A EP81900979 A EP 81900979A EP 81900979 A EP81900979 A EP 81900979A EP 0050131 B1 EP0050131 B1 EP 0050131B1
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EP
European Patent Office
Prior art keywords
ballast
inverter
transistor
switching device
bistable switching
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
EP81900979A
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German (de)
French (fr)
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EP0050131A1 (en
Inventor
Max Kerscher
Armin KRÖNING
Anh-Dung Nguyen
Reinhold Priller
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Siemens AG
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Siemens AG
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Publication date
Priority claimed from DE3014419A external-priority patent/DE3014419C2/en
Priority claimed from DE19803029672 external-priority patent/DE3029672A1/en
Application filed by Siemens AG filed Critical Siemens AG
Priority to AT81900979T priority Critical patent/ATE8316T1/en
Publication of EP0050131A1 publication Critical patent/EP0050131A1/en
Application granted granted Critical
Publication of EP0050131B1 publication Critical patent/EP0050131B1/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
    • H05B41/14—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
    • H05B41/2981—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions
    • H05B41/2985—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions against abnormal lamp operating conditions

Definitions

  • the invention relates to a ballast according to the preamble of claim 1, as described for example in DE-A-26 42 272.
  • the invention has for its object to protect the ballast against overload.
  • the solution to this problem is characterized in claim 1.
  • an additional winding of the saturation transformer supplying the control voltages for the transistors of the inverter is preferably short-circuited. According to a development of the invention, this also simultaneously supplies the current-dependent voltage for the RC element in the input of the bistable switching device.
  • the RC Link in the input circuit of the bistable switching device must still be charged to such an extent that a new response is triggered.
  • the RC element is also connected in parallel with the transistor of the bistable switching device via a decoupling diode via a decoupling diode and is thus discharged when it is triggered.
  • the current-dependent shutdown of the ballast is also effective when the lamp is missing if, according to a development of the invention, the connections for the electrodes of the lamp are each bridged by a capacitor dimensioned such that a sufficiently high current flows in the series resonant circuit.
  • Another embodiment of the invention relates to a ballast in which a single step-up converter feeds two inverters.
  • a selective shutdown of the respective inverter concerned is provided, whereas the intact inverter continues to work and the lamp which it supplies can therefore continue to burn.
  • the step-up converter according to fig. 1 contains a storage capacitor C18 which is connected on the one hand via the charging diode D27 and the charging inductor L4 and on the other hand via a measuring resistor R33 to a main rectifier G1 in a two-way circuit, which is fed by an AC voltage network N and has an essentially unsmoothed voltage at its terminals 1, 4 delivers.
  • a two-position controller X (see FIG. 2), which controls the main transistor V6 as a switch, is used to regulate the voltage at the storage capacitor C18.
  • the signal at the measuring resistor R33 located between the main transistor V6 and the storage capacitor C18 on the one hand and the main rectifier G1 on the other hand is fed to the input 7 of the controller X via a delay element (resistor R27 and capacitor C14).
  • the inverter W contains two transistors V7, V8 connected in series between its terminals 11, 8 on the storage capacitor C18. 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 with secondary windings L82, L83, L84.
  • the discharge lamp L is arranged in parallel with the capacitor C23, so that its electrodes are connected in series with the series resonant circuit.
  • a circuit known per se, of which only the secondary windings L83, L84 of the saturation transformer T8 are shown, is used for alternating control of the transistors V7, V8: this alternately results in a charging of the reversing capacitor C22 via V8 from C18 and then a discharge via V7.
  • the operating frequency of the inverter determined by the saturation transformer is slightly above the resonance frequency of the series resonance circuit: This creates a gap between the reversal of V7 and V8.
  • a delayed start-up of the inverter is ensured by means of a capacitor C19, which is only charged when the controller X is working; If there is sufficient voltage at C19, V8 is activated via a trigger diode D34 and C19 is then discharged again via D33 (sufficient energy for a cold start).
  • the capacitor C19 is in turn connected in parallel via a capacitor C20 and a diode D32 to the switching path of the main transistor V6 and can therefore only be charged to a value sufficient for the inverter to oscillate when the controller is clocked properly.
  • the capacitor C20 is connected in parallel with the protective capacitor C17 via a resistor R40: the energy from C20, like that from C17, therefore serves to charge the partial capacitors C8 and C9, which supply the operating voltages for the electronics.
  • the saturation transformer T8 has an additional secondary winding L82 through which a current flows via a bistable switching device K. dependent shutdown is effected.
  • the switching device K contains a comparator V12 fed back via a diode D16 and a transistor V10 controlled by it.
  • the output - terminal 16 - of the comparator 12 has a negative potential. It only switches over (positive potential at the output) when the voltage at its positive input becomes greater than a reference voltage at its negative input. Then V17 receives a control current via R60 and blocks the transistors V2, V3 and, via these, also V5 and the main transistor V6.
  • the transistor V10 blocked in normal operation - positive potential at terminal 15 - is turned on via R13 - zero potential at terminal 15 - and thereby the winding L82 of transformer T8 is short-circuited via diode D41.
  • the transistors V7, V8 of the inverter therefore no longer receive a control voltage and block.
  • the capacitor C11 is simultaneously discharged to such an extent that no immediate shutdown takes place when the device is started up again.
  • the shutdown described is dependent on the voltage across the capacitors C11 and C10, which are discharged via R14 and charged via the diode D41 and resistor R41 with a voltage that is supplied by the secondary winding L82 of the transformer T8 in the inverter and that flows through the current L7 is proportional (particularly high with the lamp not ignited, the series resonance circuit not damped).
  • Capacitors C10 and R14 are dimensioned in such a way that a quick succession of fewer start pulses - starting a new lamp - does not lead to switch-off any more than a larger number of pulses with a greater distance (start of an old lamp).
  • capacitors C26 and C27 are provided in parallel to the electrodes L1, L2 and are dimensioned such that the current flowing when the lamp is missing is above the response limit value.
  • the reactance of the capacitors C26 and CC27 is approximately ten times the resistance of an electrode at the average operating frequency of approximately 40 kHz.
  • the heart of the two-point controller shown in FIG. 2 is a comparator V13, the output of which is connected via a resistor R25 to a terminal P, to which a positive operating voltage can be switched via a transistor V3.
  • V13 controls a transistor V4, the collector of which is connected to the base of a further transistor V5, via which the control current of the main transistor V6 is then conducted.
  • V5 The basis of V5 is also based on the tap of a voltage divider which is connected between the positive terminal P and the terminal 4 which is at zero potential and which supplies the setpoint for the comparator V13; For this purpose, a signal dependent on the rectified mains voltage is fed to the resistor R2 of the voltage divider via the terminal 1 and the resistor R1.
  • the hysteresis of the two-point regulator is determined by connecting the collector of transistor V4 to a tap of this voltage divider.
  • the setpoint of the controller can be reduced by connecting a transistor V16 to R2 in parallel:
  • V16 is controlled by a comparator V15, which normally has a negative output potential, so that V16 blocks. However, V15 controls V16 when the bistable switching device K of the monitoring part U tilts into the switch-off state:. Then the negative input of V15 via D52, terminal 15 and transistor V10 is at zero potential.
  • the transistor V3 is used to switch off the controller under certain critical operating conditions, via which the positive operating voltage can be switched to the controller (terminal P).
  • This transistor is controlled by a further transistor V2, which is only turned on when the operating voltage has reached a minimum value required for operation.
  • the potential of the base of V2 is sufficiently greater than that at the emitter, which is determined by the Zener diode D13: This makes the transistors V2 and V3 conductive and the supply voltage for the controller is at P.
  • V3 remains on as long as the monitoring part Ü is in the normal state, has a negative potential at the output of the comparator V12 and at terminal 16, and thus transistor V17 is blocked via diode D62.
  • the second inverter is to be connected in parallel with its terminals 11, 13, 14, 8 and 4 to the terminals of the same name in FIG. 1. Only terminals 15 and 16 of the second inverter are to be connected to terminals 15 'and 16' of the common controller X.
  • the inputs 16 and 16 ' belong to an AND circuit (R60, D61, D62) on the control path of transistor V17, which is only turned on and thus switches off the controller when both inverters are switched off: as long as one of the inverters is still working, is at terminal 16 or 16 'of its monitoring part minus potential, through which the associated diode D62 or D61 is turned on and V17 is blocked.
  • R60, D61, D62 AND circuit

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  • Circuit Arrangements For Discharge Lamps (AREA)

Abstract

Discharge lamps are often connected to the AC network through an inverter and a rectifier, the inverter operating at a frequence of at least 10 kHz. It is possible in this way to maintain the necessary inductance for limiting the low current and at the same time to obtain a high lighting efficiency. However, with this system, the shape of the current extracted from the network differs very much from the sinusoidal shape. In order to avoid this disadvantage the extraction of current has already been controlled by means of a two-state rectifier receiving the half-wave of the network as an order value and the lamp current has an effective value. With this ballast the resulting modulation of the lamp voltage with the network voltage is avoided.

Description

Die Erfindung betrifft ein Vorschaltgerät gemäß Oberbegriff von Anspruch 1, wie dies zum Beispiel in DE-A-26 42 272 beschrieben ist.The invention relates to a ballast according to the preamble of claim 1, as described for example in DE-A-26 42 272.

Der Erfindung liegt die Aufgabe zugrunde, das Vorschaltgerät gegen Überlastung zu schützen. Die Lösung dieser Aufgabe ist in Anspruch 1 gekennzeichnet.The invention has for its object to protect the ballast against overload. The solution to this problem is characterized in claim 1.

Zur Abschaltung des Wechselrichters wird vorzugsweise eine zusätzliche Wicklung des die Steuerspannungen für die Transistoren des Wechselrichters liefernden Sättigungstransformators kurzgeschlossen. Diese liefert gemäß einer Weiterbildung der Erfindung zugleich auch die stromabhängige Spannung für das RC-Glied im Eingang der bistabilen Schalteinrichtung.To switch off the inverter, an additional winding of the saturation transformer supplying the control voltages for the transistors of the inverter is preferably short-circuited. According to a development of the invention, this also simultaneously supplies the current-dependent voltage for the RC element in the input of the bistable switching device.

Hierbei kann es allerdings zu einem unbeabsichtigten Ansprechen der bistabilen Schalteinrichtung und damit zu einer Abschaltung des Vorschaltgerätes kommen, wenn das Vorschaltgerät sehr schnell nach einer vorangegangenen Abschaltung und Beseitigung des Fehlers wieder in Betrieb genommen wird : Wenn diese Zeitspanne zu klein ist, kann das RC-Glied im Eingangskreis der bistabilen Schalteinrichtung noch soweit aufgeladen sein, daß dadurch ein erneutes Ansprechen ausgelöst wird. Um dies zu vermeiden, wird das RC-Glied gemäß einer Weiterbildung der Erfindung über eine Entkopplungsdiode ebenfalls parallel zu dem Transistor der bistabilen Schalteinrichtung gelegt und somit bei deren Ansprechen entladen.However, this can lead to an unintentional response of the bistable switching device and thus to a shutdown of the ballast if the ballast is put back into operation very quickly after a previous shutdown and elimination of the error: If this period is too short, the RC Link in the input circuit of the bistable switching device must still be charged to such an extent that a new response is triggered. In order to avoid this, the RC element is also connected in parallel with the transistor of the bistable switching device via a decoupling diode via a decoupling diode and is thus discharged when it is triggered.

Die stromabhängige Abschaltung des Vorschaltgerätes ist auch bei fehlender Lampe wirksam, wenn gemäß einer Weiterbildung der Erfindung die Anschlüsse für die Elektroden der Lampe jeweils durch einen derart bemessenen Kondensator überbrückt sind, daß in dem Reihenresonanzkreis ein genügend hoher Strom fließt.The current-dependent shutdown of the ballast is also effective when the lamp is missing if, according to a development of the invention, the connections for the electrodes of the lamp are each bridged by a capacitor dimensioned such that a sufficiently high current flows in the series resonant circuit.

Eine weitere Ausgestaltung der Erfindung hat ein Vorschaltgerät zum Gegenstand, bei dem ein einziger Hochsetzsteller zwei Wechselrichter speist. Hierbei ist eine selektive Abschaltung des jeweils betroffenen Wechselrichters vorgesehen, wogegen der intakte Wechselrichter weiter arbeiten und damit die von ihm gespeiste Lampe weiter brennen kann.Another embodiment of the invention relates to a ballast in which a single step-up converter feeds two inverters. In this case, a selective shutdown of the respective inverter concerned is provided, whereas the intact inverter continues to work and the lamp which it supplies can therefore continue to burn.

Die Erfindung wird anhand des in den Figuren dargestellten Ausführungsbeispieles näher erläutert ; es zeigen

  • Figur 1 das Schaltbild eines Hochsetzstellers mit einem daran angeschlossenen Wechselrichter und dessen Überwachungsteil und
  • Figur 2 den Aufbau des Zweipunktreglers des mit dem Überwachungsteil eines Wechselrichters.
The invention is explained in more detail with reference to the embodiment shown in the figures; show it
  • 1 shows the circuit diagram of a step-up converter with an inverter connected to it and its monitoring part and
  • Figure 2 shows the structure of the two-point controller with the monitoring part of an inverter.

Der Hochsetzsteller gemäß fig. 1 enthält einen Speicherkondensator C18, der einerseits über die Ladediode D27 und die Ladedrossel L4 und andererseits über einen Meßwiderstand R33 an einen Hauptgleichrichter G1 in Zweiwegschaltung angeschlossen ist, der von einem Wechselspannungsnetz N gespeist wird und an seinen Klemmen 1, 4 eine im wesentlichen ungeglättete Spannung liefert.The step-up converter according to fig. 1 contains a storage capacitor C18 which is connected on the one hand via the charging diode D27 and the charging inductor L4 and on the other hand via a measuring resistor R33 to a main rectifier G1 in a two-way circuit, which is fed by an AC voltage network N and has an essentially unsmoothed voltage at its terminals 1, 4 delivers.

Zur Regelung der Spannung an dem Speicherkondensator C18 dient ein Zweipunktregler X (siehe Fig.2), der den Haupttransistor V6 als Schalter steuert. Das Signal an dem zwischen Haupttransistor V6 und Speicherkondensator C18 einerseits und Hauptgleichrichter G1 andererseits liegenden Meßwiderstand R33 wird über ein Verzögerungsglied (Widerstand R27 und Kondensator C14) dem Eingang 7 des Reglers X zugeführt.A two-position controller X (see FIG. 2), which controls the main transistor V6 as a switch, is used to regulate the voltage at the storage capacitor C18. The signal at the measuring resistor R33 located between the main transistor V6 and the storage capacitor C18 on the one hand and the main rectifier G1 on the other hand is fed to the input 7 of the controller X via a delay element (resistor R27 and capacitor C14).

Der Wechselrichter W enthält zwischen seinen am Speicherkondensator C18 liegenden Klemmen 11, 8 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 mit Sekundärwicklungen L82, L83, L84. Parallel zu dem Kondensator C23 ist die Entladungslampe L angeordnet, so daß deren Elektroden in Reihenschaltung mit dem Serienresonanzkreis liegen.The inverter W contains two transistors V7, V8 connected in series between its terminals 11, 8 on the storage capacitor C18. 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 with secondary windings L82, L83, L84. The discharge lamp L is arranged in parallel with the capacitor C23, so that its electrodes are connected in series with the series resonant circuit.

Zur abwechselnden Durchsteuerung der Transistoren V7, V8 dient eine an sich bekannte Schaltung, von der nur die Sekundärwicklungen L83, L84 des Sättigungstransformators T8 dargestellt sind : Daraus ergibt sich abwechselnd eine Aufladung des Umschwingkondensators C22 über V8 aus C18 und anschließend eine Entladung über V7. Die durch den Sättigungstransformator bestimmte Betriebsfrequenz des Wechselrichters liegt dabei etwas über der Resonanzfrequenz des Serienresonanzkreises : Dadurch entsteht zwischen der Umsteuerung von V7 und V8 jeweils eine Lücke.A circuit known per se, of which only the secondary windings L83, L84 of the saturation transformer T8 are shown, is used for alternating control of the transistors V7, V8: this alternately results in a charging of the reversing capacitor C22 via V8 from C18 and then a discharge via V7. The operating frequency of the inverter determined by the saturation transformer is slightly above the resonance frequency of the series resonance circuit: This creates a gap between the reversal of V7 and V8.

Ein verzögerter Anlauf des Wechselrichters wird mit Hilfe eines Kondensators C19 sichergestellt, der erst aufgeladen wird, wenn der Regler X arbeitet ; Bei ausreichender Spannung an C19 wird V8 über eine Trigger-Diode D34 durchgesteuert und dabei C19 über D33 wieder entladen (ausreichende Energie für Kaltstart).A delayed start-up of the inverter is ensured by means of a capacitor C19, which is only charged when the controller X is working; If there is sufficient voltage at C19, V8 is activated via a trigger diode D34 and C19 is then discharged again via D33 (sufficient energy for a cold start).

C19 ist seinerseits über einen Kondensator C20 und eine Diode D32 der Schaltstrecke des Haupttransistors V6 parallel gelegt und kann sich daher erst auf eine zum Anschwingen des Wechselrichters ausreichenden Wert aufladen, wenn der Regler ordnungsgemäß taktet. Zur periodischen Entladung bei durchgesteuertem Haupttransistor V6 ist der Kondensator C20 über einen Widerstand R40 dem Schutzkondensator C17 parallel geschaltet : Die Energie von C20 dient daher wie die von C17 der Aufladung der Teilkondensatoren C8 und C9, die die Betriebsspannungen für die Elektronik liefern.C19 is in turn connected in parallel via a capacitor C20 and a diode D32 to the switching path of the main transistor V6 and can therefore only be charged to a value sufficient for the inverter to oscillate when the controller is clocked properly. For periodic discharge with the main transistor V6 turned on, the capacitor C20 is connected in parallel with the protective capacitor C17 via a resistor R40: the energy from C20, like that from C17, therefore serves to charge the partial capacitors C8 and C9, which supply the operating voltages for the electronics.

Der Sättigungstransformator T8 hat eine zusätzliche Sekundärwicklung L82, durch die über eine bistabile Schalteinrichtung K eine stromabhängige Abschaltung bewirkt wird. Die Schalteinrichtung K enthält einen über eine Diode D16 rückgekoppelten Komparator V12 und einen von ihm gesteuerten Transistor V10.The saturation transformer T8 has an additional secondary winding L82 through which a current flows via a bistable switching device K. dependent shutdown is effected. The switching device K contains a comparator V12 fed back via a diode D16 and a transistor V10 controlled by it.

Im Normalbetrieb hat der Ausgang - Klemme 16 - des Komparators 12 negatives Potential. Er schaltet erst um (positives Potential am Ausgang), wenn die Spannung an seinem Positiveingang größer wird als eine Referenzspannung an seinem Negativeingang. Dann erhält V17 über R60 einen Durchsteuerstrom und sperrt die Transistoren V2, V3 und über diese auch V5 und den Haupttransistor V6.In normal operation, the output - terminal 16 - of the comparator 12 has a negative potential. It only switches over (positive potential at the output) when the voltage at its positive input becomes greater than a reference voltage at its negative input. Then V17 receives a control current via R60 and blocks the transistors V2, V3 and, via these, also V5 and the main transistor V6.

Gleichzeitig wird auch der im Normalbetrieb gesperrte Transistor V10 - positives Potential an Klemme 15 - über R13 durchgesteuert - Nullpotential an Klemme 15 - und dadurch die Wicklung L82 des Transformators T8 über Diode D41 kurzgeschlossen. Damit erhalten die Transistoren V7, V8 des Wechselrichters keine Steuerspannung mehr und sperren. Über den durchgesteuerten Transistor V10 und Widerstand R41 wird zugleich der Kondensator C11 soweit entladen, daß bei erneuter Inbetriebnahme keine sofortige Abschaltung erfolgt.At the same time, the transistor V10 blocked in normal operation - positive potential at terminal 15 - is turned on via R13 - zero potential at terminal 15 - and thereby the winding L82 of transformer T8 is short-circuited via diode D41. The transistors V7, V8 of the inverter therefore no longer receive a control voltage and block. Via the controlled transistor V10 and resistor R41, the capacitor C11 is simultaneously discharged to such an extent that no immediate shutdown takes place when the device is started up again.

Die beschriebene Abschaltung ist abhängig von der Spannung an den Kondensatoren C11 und C10, die über R14 entladen und über die Diode D41 und Widerstand R41 mit einer Spannung aufgeladen werden, die von der Sekundärwicklung L82 des Transformators T8 im Wechselrichter geliefert wird und die dem Strom durch L7 proportional ist (besonders hoch bei nicht gezündeter Lampe, nicht gedämpften Serienresonanzkreis).The shutdown described is dependent on the voltage across the capacitors C11 and C10, which are discharged via R14 and charged via the diode D41 and resistor R41 with a voltage that is supplied by the secondary winding L82 of the transformer T8 in the inverter and that flows through the current L7 is proportional (particularly high with the lamp not ignited, the series resonance circuit not damped).

Nach einer Abschaltung liegt das Potential am Positiveingang des Komparators V12 (Spannungsteiler R12, D16 und R14) über dem Referenzpotential am Negativeingang : Eine Wiederinbetriebnahme ist daher nur durch Abschalten der Netzspannung und einen Neustart möglich.After switching off, the potential at the positive input of comparator V12 (voltage dividers R12, D16 and R14) is above the reference potential at the negative input: restarting is therefore only possible by switching off the mains voltage and restarting.

Die Abschaltung wirkt nicht nur bei Überlast, sondern auch bei dauernd zündunwilliger Lampe. Kondensator C10 und R14 sind dabei so bemessen, daß eine schnelle Folge weniger Startimpulse - Start einer neuen Lampe - ebenso wenig zur Abschaltung führt wie eine größere Anzahl von Impulsen mit größerem Abstand (Start einer alten Lampe).The switch-off is effective not only in the event of an overload, but also in the case of a lamp that is permanently unable to ignite. Capacitors C10 and R14 are dimensioned in such a way that a quick succession of fewer start pulses - starting a new lamp - does not lead to switch-off any more than a larger number of pulses with a greater distance (start of an old lamp).

Eine Abschaltung ist schließlich auch bei fehlender Lampe erforderlich. Um hierfür dieselbe stromabhängige Abschaltung nutzen zu können, sind Kondensatoren C26 und C27 parallel zu den Elektroden L1, L2 vorgesehen und so bemessen, daß der bei fehlender Lampe flie- ßende Strom über dem Ansprechgrenzwert liegt. Der Blindwiderstand der Kondensatoren C26 und CC27 liegt hierzu bei der mittleren Betriebsfrequenz von etwa 40 kHz bei etwa dem zehnfachen Wert des Widerstandes einer Elektrode.Finally, a switch-off is also necessary if the lamp is missing. In order to be able to use the same current-dependent cut-off for this purpose, capacitors C26 and C27 are provided in parallel to the electrodes L1, L2 and are dimensioned such that the current flowing when the lamp is missing is above the response limit value. For this purpose, the reactance of the capacitors C26 and CC27 is approximately ten times the resistance of an electrode at the average operating frequency of approximately 40 kHz.

Der in Fig. 2 dargestellte Zweipunktregler hat als Herzstück einen Komparator V13, dessen Ausgang über einen Widerstand R25 an einer Klemme P liegt, an die über einen Transistor V3 eine positive Betriebsspannung schaltbar isi. V13 steuert einen Transistor V4, dessen Kollektor mit der Basis eines weiteren Transistors V5 verbunden ist, über den dann der Steuerstrom des Haupttransistors V6 geführt ist.The heart of the two-point controller shown in FIG. 2 is a comparator V13, the output of which is connected via a resistor R25 to a terminal P, to which a positive operating voltage can be switched via a transistor V3. V13 controls a transistor V4, the collector of which is connected to the base of a further transistor V5, via which the control current of the main transistor V6 is then conducted.

Die Basis von V5 liegt ferner an dem Abgriff eines Spannungsteilers, der zwischen der positiven Klemme P und der auf Nullpotential liegenden Klemme 4 angeschlossen ist und der den Sollwert für den Komparator V13 liefert ; hierzu wird dem Widerstand R2 des Spannungsteilers über die Klemme 1 und den Widerstand R1 ein von der gleichgerichteten Netzspannung abhängiges Signal zugeführt. Durch den Anschluß des Kollektors von Transistor V4 an einen Abgriff dieses Spannungsteilers ist die Hysterese des Zweipunktreglers bestimmt. Der Sollwert des Reglers ist durch Parallelschalten eines Transistors V16 zu R2 reduzierbar: Hierzu ist V16 von einem Komparator V15 gesteuert, der normalerweise negatives Ausgangspotential hat, so daß V16 sperrt. V15 steuert jedoch V16 durch, wenn die bistabile Schalteinrichtung K des Überwachungsteiles U in den Abschaltzustand kippt: . Dann liegt nämlich der Negativeingang von V15 über D52, Klemme 15 und Transistor V10 auf Nullpotential.The basis of V5 is also based on the tap of a voltage divider which is connected between the positive terminal P and the terminal 4 which is at zero potential and which supplies the setpoint for the comparator V13; For this purpose, a signal dependent on the rectified mains voltage is fed to the resistor R2 of the voltage divider via the terminal 1 and the resistor R1. The hysteresis of the two-point regulator is determined by connecting the collector of transistor V4 to a tap of this voltage divider. The setpoint of the controller can be reduced by connecting a transistor V16 to R2 in parallel: For this purpose V16 is controlled by a comparator V15, which normally has a negative output potential, so that V16 blocks. However, V15 controls V16 when the bistable switching device K of the monitoring part U tilts into the switch-off state:. Then the negative input of V15 via D52, terminal 15 and transistor V10 is at zero potential.

Zur Abschaltung des Reglers bei bestimmten, kritischen Betriebsbedingungen dient der Transistor V3, über den die positive Betriebsspannung an den Regler (Klemme P) schaltbar ist. Dieser Transistor wird von einem weiteren Transistor V2 gesteuert, der erst durchgesteuert wird, wenn die Betriebsspannung einen für den Betrieb erforderlichen Mindestwert erreicht hat. In diesem Fall ist das Potential der Basis von V2 ausreichend größer als das am Emitter, das durch die Zenerdiode D13 bestimmt ist : Damit werden die Transistoren V2 und V3 leitend und die Versorgungsspannung für den Regler liegt an P.The transistor V3 is used to switch off the controller under certain critical operating conditions, via which the positive operating voltage can be switched to the controller (terminal P). This transistor is controlled by a further transistor V2, which is only turned on when the operating voltage has reached a minimum value required for operation. In this case, the potential of the base of V2 is sufficiently greater than that at the emitter, which is determined by the Zener diode D13: This makes the transistors V2 and V3 conductive and the supply voltage for the controller is at P.

V3 bleibt durchgesteuert, solange sich der Überwachungsteil Ü im Normalzustand befindet, am Ausgang des Komparators V12 und an Klemme 16 negatives Potential liegt und dadurch Transistor V17 über Diode D62 gesperrt ist.V3 remains on as long as the monitoring part Ü is in the normal state, has a negative potential at the output of the comparator V12 and at terminal 16, and thus transistor V17 is blocked via diode D62.

Der nicht dargestellte zweite Wechselrichter ist mit seinen Klemmen 11, 13, 14 , 8 und 4 den gleichbezeichneten Klemmen in Fig. 1 parallel zu schalten. Lediglich die Klemmen 15 und 16 des zweiten Wechselrichters sind an die Klemmen 15' bzw. 16' des gemeinsamen Reglers X anzuschließen.The second inverter, not shown, is to be connected in parallel with its terminals 11, 13, 14, 8 and 4 to the terminals of the same name in FIG. 1. Only terminals 15 and 16 of the second inverter are to be connected to terminals 15 'and 16' of the common controller X.

Die Eingänge 15 und 15' gehören zu einer ODER-Schaltung (R50, D51, D52), so daß V15 umgesteuert und der Sollwert des Reglers reduziert wird, wenn einer der beiden Wechselrichter durch sein Überwachungsteil abgeschaltet wird.The inputs 15 and 15 'belong to an OR circuit (R50, D51, D52), so that V15 is reversed and the setpoint of the controller is reduced if one of the two inverters is switched off by its monitoring part.

Die Eingänge 16 und 16' gehören dagegen zu einer UND-Schaltung (R60, D61, D62) an der Steuerstrecke von Transistor V17, der erst durchgesteuert wird und dadurch den Regler abschaltet, wenn beide Wechselrichter abgeschaltet sind : Solange noch einer der Wechselrichter arbeitet, liegt an Klemme 16 bzw. 16' seines Überwachungsteiles Minuspotential, durch das die zugeordnete Diode D62 bzw. D61 durchgesteuert und damit V17 gesperrt ist.The inputs 16 and 16 ', on the other hand, belong to an AND circuit (R60, D61, D62) on the control path of transistor V17, which is only turned on and thus switches off the controller when both inverters are switched off: as long as one of the inverters is still working, is at terminal 16 or 16 'of its monitoring part minus potential, through which the associated diode D62 or D61 is turned on and V17 is blocked.

Claims (8)

1. A ballast for connecting a discharge lamp (1) to an alternating voltage supply network (N), having an inverter (W) with transistors (V7, V8) whose operating frequency is at least 10 kHz and is determined by a saturation transformer (T8) which controls the transistors, and having a series resonant circuit (C23, L7) whose resonant frequency lies below the operating frequency of the inverter, via which the inverter (W) feeds the discharge lamp (L), the discharge lamp (L) being connected parallel to the capacitor (C23) of the series resonant circuit, and having a high-level setting unit comprising a charging choke (L4), a main transistor (V6), a charging diode (D27) and a storage capacitor (C18) between the alternating voltage supply network and the inverter, and a two-position controller (X) which controls the main transistor (V6) at a switching frequency of at least 20 kHz, characterised by a monitoring device (U) which responds to the current through the choke (L7) of the series resonant circuit to switch off the two-position controller (X) and the inverter (W) if the time integral of the current through the choke (L7) of the series resonant circuit exceeds a specific maximal value.
2. A ballast as claimed in Claim 1, characterised in that the monitoring device (U) comprises a bistable switching device (K) which has a transistor (V10) and is controlled by an RC-element in dependence upon the current through the choke of the series resonant circuit and which slips into a switch-off state in which its transistor (V10) is conductive at a limit value of its input voltage.
3. A ballast as claimed in Claim 2, characterised in that the saturation transformer (T8) has an additional secondary winding (L82) connected parallel to the transistor (V10) of the bistable switching device (K) and to which is connected the RC-element (R41, R14, C10, C11) in the input circuit of the switching device.
4. A ballast as claimed in Claim 3, characterised in that the RC-element (C11, R14, C14) in the input circuit of the bistable switching device (K) is likewise connected parallel to the transistor (V10) of the bistable switching device (K).
5. A ballast as claimed in Claim 2, characterised in that there is provided a single high-level setting unit which serves to feed two inverters each having an assigned monitoring device, and which is switched off by means of an AND-gate (R60, D61, D62) if the bistable switching devices (K) of the two inverters (W) are in the switch-off state.
6. A ballast as claimed in Claim 5, characterised in that the theoretical value of the two-position controller (X) is reduced by means of an OR-gate (R50, D51, D52) if the bistable switching device (K) of one of the inverters is in the switch-off state.
7. A ballast as claimed in one of Claims 1 to 6, characterised in that the discharge lamp (L) has heatable electrodes, that the capacitor (C23) of the series resonant circuit (C23, L7) is arranged between the electrodes, and that each electrode is bridged by a capacitor (C26, C27) of such dimensions that the bistable switching device (K) even responds when no lamp (L) is available.
8. A ballast as claimed in Claim 7, characterised in that at the average operating frequency of the inverter the impedance of the capacitors (C26, C27) connected parallel to the electrodes (11, 12) approximately equals the ten-fold value of the resistance of one electrode.
EP81900979A 1980-04-15 1981-04-14 Ballast for a discharge lamp Expired EP0050131B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81900979T ATE8316T1 (en) 1980-04-15 1981-04-14 BALLAST FOR A DISCHARGE LAMP.

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE3014419 1980-04-15
DE3014419A DE3014419C2 (en) 1980-04-15 1980-04-15 Ballast for a discharge lamp
DE3029672 1980-08-05
DE19803029672 DE3029672A1 (en) 1980-08-05 1980-08-05 Discharge lamp auxiliary power supply - has separate oscillator and independently powered regulation circuit providing high stability lamp voltage

Related Child Applications (2)

Application Number Title Priority Date Filing Date
EP83101515A Division EP0092654A3 (en) 1981-04-14 1981-04-14 Ballast apparatus
EP83101515.1 Division-Into 1983-02-17

Publications (2)

Publication Number Publication Date
EP0050131A1 EP0050131A1 (en) 1982-04-28
EP0050131B1 true EP0050131B1 (en) 1984-07-04

Family

ID=25784967

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81900979A Expired EP0050131B1 (en) 1980-04-15 1981-04-14 Ballast for a discharge lamp

Country Status (4)

Country Link
EP (1) EP0050131B1 (en)
FI (1) FI69540C (en)
IT (1) IT1137447B (en)
WO (1) WO1981003102A1 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0092654A3 (en) * 1981-04-14 1984-04-18 Siemens Aktiengesellschaft Ballast apparatus
JP2520856B2 (en) * 1981-07-31 1996-07-31 シ−メンス、アクチエンゲゼルシヤフト Frequency converter
DE3301632A1 (en) * 1983-01-19 1984-07-26 Siemens AG, 1000 Berlin und 8000 München INVERTER
AU2708684A (en) * 1983-05-05 1984-11-08 Dubank Electronics Pty. Ltd. Electronic ballast and starter
DE3503778C2 (en) * 1985-02-05 1986-11-20 Trilux-Lenze Gmbh + Co Kg, 5760 Arnsberg Fluorescent lamp ballast
AT390156B (en) * 1985-05-14 1990-03-26 Zumtobel Ag PROTECTIVE CIRCUIT FOR A INVERTER CIRCUIT

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL7315253A (en) * 1972-11-13 1974-05-15
US3913002A (en) * 1974-01-02 1975-10-14 Gen Electric Power circuits for obtaining a high power factor electronically
US3969652A (en) * 1974-01-04 1976-07-13 General Electric Company Electronic ballast for gaseous discharge lamps

Also Published As

Publication number Publication date
EP0050131A1 (en) 1982-04-28
IT8121036A0 (en) 1981-04-10
IT1137447B (en) 1986-09-10
FI811179L (en) 1981-10-16
WO1981003102A1 (en) 1981-10-29
FI69540C (en) 1986-02-10
FI69540B (en) 1985-10-31

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