EP0496040B1 - AC Ballast for discharge lamps - Google Patents

AC Ballast for discharge lamps Download PDF

Info

Publication number
EP0496040B1
EP0496040B1 EP91117443A EP91117443A EP0496040B1 EP 0496040 B1 EP0496040 B1 EP 0496040B1 EP 91117443 A EP91117443 A EP 91117443A EP 91117443 A EP91117443 A EP 91117443A EP 0496040 B1 EP0496040 B1 EP 0496040B1
Authority
EP
European Patent Office
Prior art keywords
switch
lamp
control unit
supply voltage
voltage
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
Application number
EP91117443A
Other languages
German (de)
French (fr)
Other versions
EP0496040A1 (en
Inventor
Ferdinand Mertens
Fred Dr. Hasemann
Norbert Wittig
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.)
Trilux GmbH and Co KG
Original Assignee
Trilux Lenze GmbH and Co KG
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
Application filed by Trilux Lenze GmbH and Co KG filed Critical Trilux Lenze GmbH and Co KG
Publication of EP0496040A1 publication Critical patent/EP0496040A1/en
Application granted granted Critical
Publication of EP0496040B1 publication Critical patent/EP0496040B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • 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 AC ballast for electrical discharge lamps, and in particular for fluorescent lamps which have heated electrodes.
  • An electronic ballast according to the preamble of claim 1 is known from AT-B-358 134.
  • the control unit controls the first switch in the blocking state and the second switch in the conductive state, so that the lamp current, which previously flowed through the first switch, now flows through the now closed circuit only under the effect of the energy stored in the inductance of the coil and thereby decreases.
  • the two switches are switched back to the mains-fed operating position, the first switch being switched on and the second switch being blocked.
  • the peak areas of the sinusoidal supply voltage are cut off and the energy stored in the coil is discharged during the times of the peak areas of the supply voltage.
  • a coil of high inductance which is heavy is required.
  • the efficiency of such a circuit is low because only the lower areas of the supply voltage are used for energy transmission to the lamp and the lamp is supplied with a relatively low voltage.
  • ballast for a discharge lamp in which a first switch with a series connection on an inductance and discharge lamp is connected in series, while a second switch is connected in parallel with this series connection and a third switch is connected in parallel with the discharge lamp is.
  • This ballast is intended for connection to a DC voltage source, the first two switches forming a half-bridge inverter and the switch lying in parallel with the discharge lamp being used in conjunction with the inductor to generate ignition pulses for the discharge lamp.
  • the switches are only controlled in a time-dependent manner according to a predetermined cycle.
  • the invention has for its object to provide a ballast that has a very good efficiency and manages with a low inductance.
  • the lamp is only operated continuously with the third switch locked, that is to say without a short circuit, when the amplitude of the supply voltage is greater than the limit value.
  • the limit value is preferably set to the value at which the lamp would not just go out. If the supply voltage is below the limit, the further switch is switched on and off alternately. When the further switch is in the conductive state, the inductance is charged via the first switch and in the off state of the further switch it is discharged via the lamp, a lamp voltage being produced on the lamp which is greater than the supply voltage. By switching the further switch at high frequency on and off it is thus achieved that the lamp voltage assumes a value, even with small amplitudes of the supply voltage, which is sufficient for maintaining the lamp operation.
  • the level of the lamp voltage that arises can be changed to the desired extent by changing the pulse duty factor and / or the frequency of actuation of the further switch.
  • the first switch is repeatedly switched on and off within a half-wave of the supply voltage when another switch is blocked. In this way, the amount of that energy can also be changed by changing the duty cycle and / or the frequency of this switching on and off be changed, which is transmitted to the lamp with a relatively large amplitude of the supply voltage.
  • the AC ballast according to the invention divides each half-wave of the supply voltage into three sections, namely a first section in which the amplitude is small, a second section in which the amplitude is large, and a third section in which the amplitude is again small .
  • the inductance is constantly charged and discharged by high-frequency switching, so that a high-frequency alternating voltage of the desired amplitude is produced on the lamp.
  • the supply voltage can be continuously switched through in the second section.
  • This type of conversion of the AC supply voltage into a high-frequency AC voltage has the result that the lamp does not go out even in the transition region between two half-waves of the supply voltage.
  • the energy that can be transmitted to the lamp within a half-wave of the supply voltage is considerably greater than with a direct AC voltage supply to the lamp, because the outer limit regions of the half-wave are better utilized.
  • the AC ballast according to the invention can be operated or set so that practically no harmonics are generated that would have to be kept away from the network by filtering. If the setting is made so that harmonics occur, then these harmonics are so high-frequency that they are without large effort can be filtered out, so that the filter effort is significantly reduced compared to a DC ballast.
  • the ballast shown in Fig. 1 contains a low-pass filter TP, which is connected to the lines L and N of the AC supply network, to which the line voltage U N of, for example, 50 Hz and 230 V is present.
  • the line N is pulled through the low-pass filter TP.
  • the series circuit comprising an electronic switch S1 and a discharge branch 10 containing a second electronic switch S2 is connected to the output of the low-pass filter TP.
  • the switches S1 and S2 are operated inversely to one another, ie if the switch S1 is blocked, the switch S2 is conductive, and if the switch S1 is conductive, the switch S2 is blocked.
  • the inductance L which is connected in series with the discharge lamp EL, is connected to the connection point of the two switches S1 and S2.
  • the series connection of inductance L and discharge lamp EL is connected in parallel to the second switch S2.
  • the lamp EL is a fluorescent lamp which has two heatable electrodes E1 and E2, each with two electrode connections.
  • the one electrode connections of the electrodes E1 and E2 are connected to one another by a third electronic switch S3, which can short-circuit the lamp EL.
  • All electronic switches S1, S2 and S3 are controlled by the control unit SE, which is, for example, a microprocessor.
  • the control unit SE is connected to the lines N and L and therefore receives the respective amplitude of the supply voltage U N.
  • the control unit is connected to a line leading to the electrode E1 so that it receives the lamp voltage U LA .
  • the control unit can be connected to a current detector D, which measures the lamp current and supplies the control unit with a corresponding signal.
  • the switches S1, S2 and S3 must be bidirectional switches, for example FETs, BIP transistors or IGBT transistors (isolated gate bipolar transistor) contained in the direct current branch of a full bridge rectifier.
  • the switches are shown as mechanical switches only for ease of understanding.
  • FIG. 2 shows the type of control of the various electronic switches by the control unit SE during a half-wave of the supply voltage U N.
  • U G At a limit value U G is set in the control unit on a manually operated adjusting device A.
  • the switch S1 is conductive (FIG. 2b) and the switch S2 is blocked (FIG. 2c).
  • FIG. 2d shows, the switch S3 is alternately switched on and off at a high frequency in this state. This frequency is on the order of 30 to 40 kHz. While switch S3 is conductive, a current flows through switch S3 via conductive switch S1 and inductance L. The inductance L is charged by this current.
  • the inductance L tries to maintain the current, the coil current then flowing through the lamp EL.
  • the lamp is therefore flowed through by high-frequency current pulses, the time interval between which is so small that the lamp cannot go out between two pulses.
  • the lamp voltage U LA receives the amplitude required for lamp operation with each current pulse.
  • the third switch S3 is blocked and the first switch S1 and the second switch S2 are switched on and off alternately with high-frequency control. While switch S1 is conductive and switch S2 is blocked, a current flows through switch S1, inductance L and lamp EL. Then switch S1 blocked and the switch S2 conductive, the inductance L discharges through the lamp EL and the switch S2.
  • the frequency of the pulses with which the switches S1 and S2 are controlled in the middle section of the half-wave of the supply voltage is also 30 to 40 kHz.
  • the limit value U G By changing the limit value U G by adjusting the adjusting device A, the division of the individual sections of the half-wave of the supply voltage can be changed.
  • the limit is set to an amplitude of the lamp supply voltage at which the lamp would not go out.
  • the control unit can be designed such that it sets the duty cycle of the operation of the switches S1, S2 and the duty cycle of the operation of the switch S3 such that a desired lamp voltage U LA (as High-frequency voltage).
  • the current detector D it is also possible to use the current detector D to detect the lamp current and to carry out the regulation of the duty cycles in such a way that the lamp current remains constant. Basically, the lamp current is proportional to the lamp voltage.
  • the lamp power P L is dependent on the time in each case with two half-waves the supply voltage.
  • Figure 3a shows the case that would result if the lamp were an ohmic resistor.
  • the lamp power would be wherein R would represent the lamp resistance U LA 2 / R. It can be seen that the lamp power is exposed to strong fluctuations within a period of the supply voltage.
  • 3b shows the lamp power that can be transmitted in the three regions of a half-wave of the supply voltage if the goal is to make the power transmission as even as possible over time. It can be seen that the power transferred to the lamp can be made virtually constant over time, with a brief dip B only occurring between two successive half-waves, in which the lamp does not go out, however.
  • 3c shows a form of the power curve of the lamp which, when set on the control unit SE, causes limited permissible harmonics at the input of the ballast.
  • the high-frequency operation of the switches ensures that the inductance can be relatively small, so that a small and lightweight coil is sufficient for this.
  • the time during which the inductance L is traversed by current and is being charged that is to say the time of the charging pulses of the high frequency, is a measure of the level of the voltage which is generated on the lamp when the inductance L is discharged.
  • the charging time can be changed by changing the duty cycle of the high-frequency pulses. If the amplitude of the supply voltage is small, the charging pulses must be longer than with a large amplitude in order to provide the same energy to the lamp.
  • the inductance is completely discharged after each charge. However, it is also possible to change the frequency of the high-frequency control in order to influence the energy which is transmitted to the lamp in each period of the high-frequency control.
  • the function of the control unit SE with stationary lamp operation has been described above.
  • the control unit also controls the preheating and starting phases.
  • the preheating phase the switch S3 is turned on, the switches S1 and S2 are operated at high frequency, so that a heating current flows through the lamp electrodes E1 and E2.
  • the ignition phase then takes place after a predetermined period of time.
  • the switch S3 is switched alternately into the conductive and the blocked state when the first switch S1 is conductive. This generates burst pulses that ignite the lamp.
  • the embodiment of FIG. 4 corresponds to that of FIG. 1, with the difference that the discharge branch 10 contains a capacitor C1 instead of the second electronic switch S2.
  • the control device SE controls the first electronic switch S1 in the same way as in the first exemplary embodiment.
  • the inductance L is charged via it in the manner described above.
  • the capacitor C1 is also charged.
  • the switch S1 is switched to the blocking state, the inductance L discharges through the capacitor C1, so that a current flows through this capacitor and the capacitor the same It functions like a switch that is in the conducting state.
  • the embodiment of FIG. 4 offers the advantage that the electronic switch S2, including the associated full bridge rectifier, is saved.

Abstract

The ballast has two switches (S1, S2) which are connected to the AC supply in series and can be operated inversely with respect to one another. A series circuit consisting of an inductor (L) and a discharge lamp (EL) is connected to this switch arrangement. The discharge lamp (EL) is shorted out by a third switch (S3). As long as the amplitude of the supply voltage (UN) is less than a limiting value, the third switch (S3) is switched on and off a plurality of times within one half cycle of the supply voltage, with the first switch (S1) turned on. In this way, it is achieved that, in those regions of the half cycle in which the lamp would normally be extinguished because the supply voltage is not adequate, a sufficiently high voltage for lamp operation is made available by the inductor (L). The power transferred during one half cycle of the lamp can be varied corresponding to a desired power curve by varying the duty cycle of the pulses. <IMAGE>

Description

Die Erfindung betrifft ein Wechselspannungs-Vorschaltgerät für elektrische Entladungslampen, und insbesondere für Leuchtstofflampen, welche beheizbare Elektroden aufweisen.The invention relates to an AC ballast for electrical discharge lamps, and in particular for fluorescent lamps which have heated electrodes.

Ein elektronisches Vorschaltgerät nach dem Oberbegriff des Patentanspruchs 1 ist bekannt aus AT-B-358 134. Bei diesem Vorschaltgerät steuert die Steuereinheit, sobald der Lampenstrom einen Grenzwert übersteigt, den ersten Schalter in den Sperrzustand und den Zweiten Schalter in den leitenden Zustand, so daß der Lampenstrom, der zuvor über den ersten Schalter geflossen ist, nunmehr nur noch unter der Wirkung der in der Induktivität der Spule gespeicherten Energie durch den jetzt geschlossenen Stromkreislauf fließt und dabei abnimmt.An electronic ballast according to the preamble of claim 1 is known from AT-B-358 134. In this ballast, the control unit, as soon as the lamp current exceeds a limit value, controls the first switch in the blocking state and the second switch in the conductive state, so that the lamp current, which previously flowed through the first switch, now flows through the now closed circuit only under the effect of the energy stored in the inductance of the coil and thereby decreases.

Sobald der abnehmende Strom einen vorgegebenen Sollwert unterschreitet, werden die beiden Schalter in die netzgespeiste Betriebslage zurückgeschaltet, wobei der erste Schalter leitend geschaltet und der zweite Schalter gesperrt wird. Dadurch werden die Spitzenbereiche der sinusförmigen Versorgungsspannung gewissermaßen abgeschnitten und die in der Spule gespeicherte Energie wird während der Zeiten der Spitzenbereiche der Versorgungsspannung entladen. Hierdurch wird zwar die Lichtwelligkeit verringert, jedoch wird eine Spule von großer Induktivität benötigt, die schwergewichtig ist. Der Wirkungsgrad einer derartigen Schaltung ist gering, weil nur die unteren Bereiche der Versorgungsspannung für eine Energieübertragung an die Lampe ausgenutzt werden und die Lampe mit einer relativ niedrigen Spannung versorgt wird.As soon as the decreasing current falls below a predetermined setpoint, the two switches are switched back to the mains-fed operating position, the first switch being switched on and the second switch being blocked. As a result, the peak areas of the sinusoidal supply voltage are cut off and the energy stored in the coil is discharged during the times of the peak areas of the supply voltage. Although this reduces the light ripple, a coil of high inductance which is heavy is required. The efficiency of such a circuit is low because only the lower areas of the supply voltage are used for energy transmission to the lamp and the lamp is supplied with a relatively low voltage.

Aus US 4 912 375 ist ein Vorschaltgerät für eine Entladungslampe bekannt, bei dem ein erster Schalter mit einer Reihenschaltung auf einer Induktivitäts- und Entladungslampe in Reihe geschaltet ist, während ein zweiter Schalter zu dieser Reihenschaltung parallel geschaltet und ein dritter Schalter zu der Entladungslampe parallel geschaltet ist. Dieses Vorschaltgerät ist Zum Anschluß an eine Gleichspannungsquelle bestimmt, wobei die beiden ersten Schalter einen Halbbrücken-Wechselrichter bilden und der zur Entladungslampe parallel liegende Schalter in Verbindung mit der Induktivität zur Erzeugung von Zündimpulsen für die Entladungslampe benutzt wird. Die Schalter werden ausschließlich zeitabhängig nach einem vorbestimmten Takt gesteuert.From US 4 912 375 a ballast for a discharge lamp is known, in which a first switch with a series connection on an inductance and discharge lamp is connected in series, while a second switch is connected in parallel with this series connection and a third switch is connected in parallel with the discharge lamp is. This ballast is intended for connection to a DC voltage source, the first two switches forming a half-bridge inverter and the switch lying in parallel with the discharge lamp being used in conjunction with the inductor to generate ignition pulses for the discharge lamp. The switches are only controlled in a time-dependent manner according to a predetermined cycle.

Der Erfindung liegt die Aufgabe zugrunde, ein Vorschaltgerät zu schaffen, das einen sehr guten Wirkungsgrad hat und mit einer geringen Induktivität auskommt.The invention has for its object to provide a ballast that has a very good efficiency and manages with a low inductance.

Die Lösung dieser Aufgabe erfolgt erfindungsgemäß mit den im Patentanspruch 1 angegebenen Merkmalen.This object is achieved according to the invention with the features specified in claim 1.

Bei dem erfindungsgemäßen Wechselspannungs-Vorschaltgerät wird die Lampe nur dann ständig mit gesperrtem dritten Schalter, also ohne Kurzschluß, betrieben, wenn die Amplitude der Versorgungsspannung größer ist als der Grenzwert. Der Grenzwert ist vorzugsweise auf denjenigen Wert eingestellt, bei dem die Lampe gerade nicht erlöschen würde. Bei unterhalb des Grenzwerts liegender Versorgungsspannung wird der weitere Schalter abwechselnd ein- und ausgeschaltet. Im leitenden Zustand des weiteren Schalters lädt sich die Induktivität über den ersten Schalter auf und im Sperrzustand des weiteren Schalters entlädt sie sich über die Lampe, wobei an der Lampe eine Lampenspannung entsteht, die größer als die Versorgungsspannung ist. Durch das Ein- und Ausschalten des weiteren Schalters mit Hochfrequenz wird somit erreicht, daß die Lampenspannung auch bei kleinen Amplituden der Versorgungsspannung einen Wert annimmt, der für die Aufrechterhaltung des Lampenbetriebs ausreicht. Die Höhe der dabei entstehenden Lampenspannung kann durch eine Veränderung des Tastverhältnisses und/oder der Frequenz der Betätigung des weiteren Schalters in dem jeweils gewünschten Maße geändert werden.In the AC ballast according to the invention, the lamp is only operated continuously with the third switch locked, that is to say without a short circuit, when the amplitude of the supply voltage is greater than the limit value. The limit value is preferably set to the value at which the lamp would not just go out. If the supply voltage is below the limit, the further switch is switched on and off alternately. When the further switch is in the conductive state, the inductance is charged via the first switch and in the off state of the further switch it is discharged via the lamp, a lamp voltage being produced on the lamp which is greater than the supply voltage. By switching the further switch at high frequency on and off it is thus achieved that the lamp voltage assumes a value, even with small amplitudes of the supply voltage, which is sufficient for maintaining the lamp operation. The level of the lamp voltage that arises can be changed to the desired extent by changing the pulse duty factor and / or the frequency of actuation of the further switch.

Gemäß einer bevorzugten Ausbildung der Erfindung werden, solange die Amplitude der Versorgungsspannung den Grenzwert überschreitet, der erste Schalter bei gesperrtem weiterem Schalter innerhalb einer Halbwelle der Versorgungsspannung mehrfach ein- und ausgeschaltet. Auf diese Weise kann durch Veränderung des Tastverhältnisses und/oder der Frequenz dieser Ein- und Ausschaltung auch das Maß derjenigen Energie verändert verändert werden, die bei relativ großer Amplitude der Versorgungsspannung zur Lampe übertragen wird.According to a preferred embodiment of the invention, as long as the amplitude of the supply voltage exceeds the limit value, the first switch is repeatedly switched on and off within a half-wave of the supply voltage when another switch is blocked. In this way, the amount of that energy can also be changed by changing the duty cycle and / or the frequency of this switching on and off be changed, which is transmitted to the lamp with a relatively large amplitude of the supply voltage.

Das erfindungsgemäße Wechselspannungs-Vorschaltgerät teilt jede Halbwelle der Versorgungsspannung in drei Abschnitte auf, nämlich einen ersten Abschnitt, in dem die Amplitude klein ist, einen zweiten Abschnitt, in dem die Amplitude groß ist, und einen dritten Abschnitt, in dem die Amplitude wieder klein ist. In dem ersten und dem dritten Abschnitt erfolgt durch Hochfrequenzumschaltung ein ständiges Aufladen und Entladen der Induktivität, so daß an der Lampe eine Hochfrequenz-Wechselspannung von gewünschter Amplitude entsteht. In dem zweiten Abschnitt kann die Versorgungsspannung ständig durchgeschaltet sein. Jedoch ist es auch möglich, in diesem zweiten Abschnitt eine Taktung durchzuführen, bei der ebenfalls abwechselnd Aufladungen und Entladungen der Induktivität vorgenommen werden. Diese Art der Umsetzung der Versorgungswechselspannung in eine Hochfrequenz-Wechselspannung hat zur Folge, daß die Lampe selbst in dem Übergangsbereich zwischen zwei Halbwellen der Versorgungsspannung nicht erlischt. Die Energie, die innerhalb einer Halbwelle der Versorgungsspannung auf die Lampe übertragen werden kann, ist erheblich größer als bei direkter Wechselspannungsversorgung der Lampe, weil die äußeren Grenzbereiche der Halbwelle besser ausgenutzt werden.The AC ballast according to the invention divides each half-wave of the supply voltage into three sections, namely a first section in which the amplitude is small, a second section in which the amplitude is large, and a third section in which the amplitude is again small . In the first and third sections, the inductance is constantly charged and discharged by high-frequency switching, so that a high-frequency alternating voltage of the desired amplitude is produced on the lamp. The supply voltage can be continuously switched through in the second section. However, it is also possible to carry out a clocking in this second section, in which charging and discharging of the inductance are also carried out alternately. This type of conversion of the AC supply voltage into a high-frequency AC voltage has the result that the lamp does not go out even in the transition region between two half-waves of the supply voltage. The energy that can be transmitted to the lamp within a half-wave of the supply voltage is considerably greater than with a direct AC voltage supply to the lamp, because the outer limit regions of the half-wave are better utilized.

Das erfindungsgemäße Wechselspannungs-Vorschaltgerät kann so betrieben bzw. eingestellt werden, daß praktisch keine Oberwellen erzeugt werden, die durch Filterung vom Netz ferngehalten werden müßten. Wenn die Einstellung so vorgenommen ist, daß Oberwellen entstehen, so sind diese Oberwellen so hochfrequent, daß sie ohne großen Aufwand herausgefiltert werden können, so daß der Filteraufwand gegenüber einem Gleichspannungs-Vorschaltgerät erheblich reduziert ist.The AC ballast according to the invention can be operated or set so that practically no harmonics are generated that would have to be kept away from the network by filtering. If the setting is made so that harmonics occur, then these harmonics are so high-frequency that they are without large effort can be filtered out, so that the filter effort is significantly reduced compared to a DC ballast.

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

Es zeigen:

Fig. 1
ein schematisches Schaltbild des Wechselspannungs-Vorschaltgerätes,
Fig. 2
ein Diagramm der Schalterbetätigungen in Abhängigkeit vom Verlauf der Versorgungsspannung,
Fig. 3
verschiedene Diagramme der der Lampe zugeführten Leistung in Abhängigkeit von der Zeit und
Fig. 4
ein schematisches Schaltbild eines zweiten Ausführungsbeispiels.
Show it:
Fig. 1
1 shows a schematic circuit diagram of the AC ballast,
Fig. 2
a diagram of the switch operations depending on the course of the supply voltage,
Fig. 3
different diagrams of the power supplied to the lamp as a function of time and
Fig. 4
a schematic diagram of a second embodiment.

Das in Fig. 1 dargestellte Vorschaltgerät enthält ein Tiefpaßfilter TP, das an die Leitungen L und N des Wechselspannungs-Versorgungsnetzes angeschlossen wird, an denen die Netzspannung UN von z.B. 50 Hz und 230 V ansteht. Die Leitung N ist durch das Tiefpaßfilter TP hindurchgezogen.The ballast shown in Fig. 1 contains a low-pass filter TP, which is connected to the lines L and N of the AC supply network, to which the line voltage U N of, for example, 50 Hz and 230 V is present. The line N is pulled through the low-pass filter TP.

An den Ausgang des Tiefpaßfilters TP ist die Reihenschaltung aus einem elektronischen Schalter S1 und einem einen zweiten elektronischen Schalter S2 enthaltenden Entladungszweig 10 angeschlossen. Die Schalter S1 und S2 sind invers zueinander betrieben, d.h. wenn der Schalter S1 gesperrt ist, ist der Schalter S2 leitend, und wenn der Schalter S1 leitend ist, ist der Schalter S2 gesperrt.The series circuit comprising an electronic switch S1 and a discharge branch 10 containing a second electronic switch S2 is connected to the output of the low-pass filter TP. The switches S1 and S2 are operated inversely to one another, ie if the switch S1 is blocked, the switch S2 is conductive, and if the switch S1 is conductive, the switch S2 is blocked.

An den Verbindungspunkt der beiden Schalter S1 und S2 ist die Induktivität L angeschlossen, die mit der Entladungslampe EL in Reihe geschaltet ist. Die Reihenschaltung aus Induktivität L und Entladungslampe EL ist dem zweiten Schalter S2 parallelgeschaltet.The inductance L, which is connected in series with the discharge lamp EL, is connected to the connection point of the two switches S1 and S2. The series connection of inductance L and discharge lamp EL is connected in parallel to the second switch S2.

Die Lampe EL ist eine Leuchtstofflampe, die zwei beheizbare Elektroden E1 und E2 mit jeweils zwei Elektrodenanschlüssen aufweist. Die einen Elektrodenanschlüsse der Elektroden E1 und E2 sind durch einen dritten elektronischen Schalter S3 miteinander verbunden, welcher die Lampe EL kurzschließen kann.The lamp EL is a fluorescent lamp which has two heatable electrodes E1 and E2, each with two electrode connections. The one electrode connections of the electrodes E1 and E2 are connected to one another by a third electronic switch S3, which can short-circuit the lamp EL.

Sämtliche elektronischen Schalter S1,S2 und S3 werden von der Steuereinheit SE gesteuert, bei der es sich z.B. um einen Mikroprozessor handelt. Die Steuereinheit SE ist mit den Leitungen N und L verbunden und empfängt daher die jeweilige Amplitude der Versorgungsspannung UN. Außerdem ist die Steuereinheit mit einer zu der Elektrode E1 führenden Leitung verbunden, so daß sie die Lampenspannung ULA empfängt. Ferner kann die Steuereinheit mit einem Stromdetektor D verbunden sein, der den Lampenstrom mißt und der Steuereinheit ein entsprechendes Signal zuführt.All electronic switches S1, S2 and S3 are controlled by the control unit SE, which is, for example, a microprocessor. The control unit SE is connected to the lines N and L and therefore receives the respective amplitude of the supply voltage U N. In addition, the control unit is connected to a line leading to the electrode E1 so that it receives the lamp voltage U LA . Furthermore, the control unit can be connected to a current detector D, which measures the lamp current and supplies the control unit with a corresponding signal.

Da das Vorschaltgerät sowohl positive als auch negative Halbwellen verarbeitet, müssen die Schalter S1,S2 und S3 bidirektionale Schalter sein, beispielsweise im Gleichstromzweig einer Gleichrichter-Vollbrücke enthaltene FETs, BIP-Transistoren oder IGBT-Transistoren (Isolated Gate Bipolar Transistor). In der Zeichnung sind die Schalter lediglich zur Vereinfachung des Verständnisses als mechanische Schalter dargestellt.Since the ballast processes both positive and negative half-waves, the switches S1, S2 and S3 must be bidirectional switches, for example FETs, BIP transistors or IGBT transistors (isolated gate bipolar transistor) contained in the direct current branch of a full bridge rectifier. In the drawing, the switches are shown as mechanical switches only for ease of understanding.

Fig. 2 zeigt die Art der Steuerung der verschiedenen elektronischen Schalter durch die Steuereinheit SE während einer Halbwelle der Versorgungsspannung UN. An der Steuereinheit ist ein Grenzwert UG an einer manuell zu betätigenden Verstelleinrichtung A eingestellt. Solange die Versorgungsspannung UN kleiner ist als der Grenzwert UG, ist der Schalter S1 leitend (Fig. 2b) und der Schalter S2 gesperrt (Fig. 2c). Wie Fig. 2d zeigt, wird in diesem Zustand der Schalter S3 mit hoher Frequenz abwechselnd ein- und ausgeschaltet. Diese Frequenz liegt in der Größenordnung von 30 bis 40 kHz. Während der Schalter S3 leitend ist, fließt über den leitenden Schalter S1 und die Induktivität L ein Strom durch den Schalter S3. Durch diesen Strom wird die Induktivität L aufgeladen. Wird der Schalter S3 anschließend gesperrt, so versucht die Induktivität L den Strom aufrechtzuerhalten, wobei der Spulenstrom dann über die Lampe EL fließt. Die Lampe wird also von hochfrequenten Stromimpulsen durchflossen, deren zeitlicher Abstand so klein ist, daß die Lampe zwischen zwei Impulsen nicht erlöschen kann. Die Lampenspannung ULA erhält bei jedem Stromimpuls die für den Lampenbetrieb erforderliche Amplitude. Durch Änderung des Tastverhältnisses derjenigen Impulse, mit denen der Schalter S3 gesteuert wird, kann die Zeit der Aufladung der Induktivität L, und damit auch die Höhe der Aufladung und die Größe der für die Entladung zur Verfügung stehenden Energie, verändert werden.2 shows the type of control of the various electronic switches by the control unit SE during a half-wave of the supply voltage U N. At a limit value U G is set in the control unit on a manually operated adjusting device A. As long as the supply voltage U N is less than the limit value U G , the switch S1 is conductive (FIG. 2b) and the switch S2 is blocked (FIG. 2c). As FIG. 2d shows, the switch S3 is alternately switched on and off at a high frequency in this state. This frequency is on the order of 30 to 40 kHz. While switch S3 is conductive, a current flows through switch S3 via conductive switch S1 and inductance L. The inductance L is charged by this current. If the switch S3 is then blocked, the inductance L tries to maintain the current, the coil current then flowing through the lamp EL. The lamp is therefore flowed through by high-frequency current pulses, the time interval between which is so small that the lamp cannot go out between two pulses. The lamp voltage U LA receives the amplitude required for lamp operation with each current pulse. By changing the pulse duty factor of those pulses with which the switch S3 is controlled, the time of charging the inductance L, and thus also the amount of charging and the size of the energy available for the discharge, can be changed.

In demjenigen Abschnitt, in dem die Netzspannung UN größer ist als der Grenzwert UG, wird der dritte Schalter S3 gesperrt und der erste Schalter S1 und der zweite Schalter S2 werden mit Hochfrequenzsteuerung wechselseitig ein- und ausgeschaltet. Während der Schalter S1 leitend und der Schalter S2 gesperrt ist, fließt ein Strom über den Schalter S1, die Induktivität L und die Lampe EL. Wird anschließend der Schalter S1 gesperrt und der Schalter S2 leitend, so entlädt sich die Induktivität L über die Lampe EL und den Schalter S2. Die Frequenz der Impulse, mit denen die Schalter S1 und S2 in dem mittleren Abschnitt der Halbwelle der Versorgungsspannung gesteuert werden, beträgt ebenfalls 30 bis 40 kHz. Durch Änderung des Tastverhältnisses der Steuerimpulse kann auch in diesem Abschnitt die Energie beeinflußt werden, die bei jedem Impuls von der Netzspannung auf die Lampe übertragen wird.In the section in which the mains voltage U N is greater than the limit value U G , the third switch S3 is blocked and the first switch S1 and the second switch S2 are switched on and off alternately with high-frequency control. While switch S1 is conductive and switch S2 is blocked, a current flows through switch S1, inductance L and lamp EL. Then switch S1 blocked and the switch S2 conductive, the inductance L discharges through the lamp EL and the switch S2. The frequency of the pulses with which the switches S1 and S2 are controlled in the middle section of the half-wave of the supply voltage is also 30 to 40 kHz. By changing the duty cycle of the control pulses, the energy which is transmitted from the mains voltage to the lamp with each pulse can also be influenced in this section.

Durch Änderung des Grenzwertes UG durch Verstellung der Stellvorrichtung A kann die Aufteilung der einzelnen Abschnitte der Halbwelle der Versorgungsspannung verändert werden. Der Grenzwert ist auf eine Amplitude der Lampen-Versorgungsspannung eingestellt, bei der die Lampe nicht erlöschen würde.By changing the limit value U G by adjusting the adjusting device A, the division of the individual sections of the half-wave of the supply voltage can be changed. The limit is set to an amplitude of the lamp supply voltage at which the lamp would not go out.

Es ist auch möglich, einen Dimmbetrieb durchzuführen und die Lampenspannung ULA auf einen bestimmten gewünschten Wert einzuregeln. Da der Wert der Lampenspannung ULA der Steuereinheit zugeführt wird, kann die Steuereinheit so ausgebildet sein, daß sie das Tastverhältnis des Betriebs der Schalter S1,S2 und das Tastverhältnis des Betriebs des Schalters S3 so einstellt, daß sich eine gewünschte Lampenspannung ULA (als Hochfrequenzspannung) konstant einstellt.It is also possible to carry out a dimming operation and to regulate the lamp voltage U LA to a certain desired value. Since the value of the lamp voltage U LA is supplied to the control unit, the control unit can be designed such that it sets the duty cycle of the operation of the switches S1, S2 and the duty cycle of the operation of the switch S3 such that a desired lamp voltage U LA (as High-frequency voltage).

Es ist auch möglich, mit dem Stromdetektor D den Lampenstrom zu erfassen und die Regelung der Tastverhältnisse in der Weise durchzuführen, daß der Lampenstrom konstant bleibt. Grundsätzlich ist der Lampenstrom proportional zur Lampenspannung.It is also possible to use the current detector D to detect the lamp current and to carry out the regulation of the duty cycles in such a way that the lamp current remains constant. Basically, the lamp current is proportional to the lamp voltage.

In den Diagrammen von Fig. 3 ist die Lampenleistung PL in Abhängigkeit von der Zeit jeweils bei zwei Halbwellen der Versorgungsspannung dargestellt. Fig. 3a zeigt den Fall, der sich ergeben würde, wenn die Lampe ein ohmscher Widerstand wäre. Die Lampenleistung wäre dann ULA²/R, wobei R den Lampenwiderstand darstellen würde. Man erkennt, daß die Lampenleistung innerhalb einer Periode der Versorgungsspannung starken Schwankungen ausgesetzt ist.In the diagrams of FIG. 3, the lamp power P L is dependent on the time in each case with two half-waves the supply voltage. Figure 3a shows the case that would result if the lamp were an ohmic resistor. The lamp power would be wherein R would represent the lamp resistance U LA ² / R. It can be seen that the lamp power is exposed to strong fluctuations within a period of the supply voltage.

Fig. 3b zeigt diejenige Lampenleistung, die in den drei Bereichen einer Halbwelle der Versorgungsspannung übertragen werden kann, wenn das Ziel besteht, die Leistungsübertragung zeitlich möglichst gleichmäßig zu machen. Man erkennt, daß die auf die Lampe übertragene Leistung praktisch zeitlich konstant gemacht werden kann, wobei nur zwischen zwei aufeinanderfolgenden Halbwellen ein kurzzeitiger Einbruch B vorhanden ist, in dem die Lampe jedoch nicht erlischt.3b shows the lamp power that can be transmitted in the three regions of a half-wave of the supply voltage if the goal is to make the power transmission as even as possible over time. It can be seen that the power transferred to the lamp can be made virtually constant over time, with a brief dip B only occurring between two successive half-waves, in which the lamp does not go out, however.

Fig. 3c zeigt eine Form der Leistungskurve der Lampe, die, wenn sie an der Steuereinheit SE eingestellt ist, begrenzte, zulässige Oberwellen am Eingang des Vorschaltgerätes hervorruft.3c shows a form of the power curve of the lamp which, when set on the control unit SE, causes limited permissible harmonics at the input of the ballast.

Durch den Hochfrequenzbetrieb der Schalter wird erreicht, daß die Induktivität relativ klein sein kann, so daß hierfür eine kleine und leichtgewichtige Spule ausreicht. Die Zeit, in der die Induktivität L von Strom durchflossen ist und aufgeladen wird, also die Zeit der Ladeimpulse der Hochfrequenz, ist ein Maß für die Höhe derjenigen Spannung, die an der Lampe erzeugt wird, wenn die Induktivität L sich entlädt. Die Aufladezeit kann durch Änderung des Tastverhältnisses der Hochfrequenzimpulse verändert werden. Wenn die Amplitude der Versorgungsspannung klein ist, müssen die Aufladeimpulse länger sein als bei großer Amplitude, um die gleiche Energie an der Lampe zur Verfügung zu stellen. Nach jeder Aufladung wird die Induktivität vollständig entladen. Es besteht allerdings auch die Möglichkeit, die Frequenz der Hochfrequenzsteuerung zu verändern, um dadurch diejenige Energie zu beeinflussen, die in jeder Periode der Hochfrequenzsteuerung auf die Lampe übertragen wird.The high-frequency operation of the switches ensures that the inductance can be relatively small, so that a small and lightweight coil is sufficient for this. The time during which the inductance L is traversed by current and is being charged, that is to say the time of the charging pulses of the high frequency, is a measure of the level of the voltage which is generated on the lamp when the inductance L is discharged. The charging time can be changed by changing the duty cycle of the high-frequency pulses. If the amplitude of the supply voltage is small, the charging pulses must be longer than with a large amplitude in order to provide the same energy to the lamp. The inductance is completely discharged after each charge. However, it is also possible to change the frequency of the high-frequency control in order to influence the energy which is transmitted to the lamp in each period of the high-frequency control.

Vorstehend wurde die Funktion der Steuereinheit SE bei stationärem Lampenbetrieb beschrieben. Die Steuereinheit steuert auch die Vorheiz- und Startphase. In der Vorheizphase ist der Schalter S3 leitend geschaltet, die Schalter S1 und S2 werden hochfrequent betrieben, so daß über die Lampenelektroden E1 und E2 ein Heizstrom fließt. Nach einer vorgegebenen Zeitspanne erfolgt darauf die Zündphase. Hierbei wird der Schalter S3 bei leitendem ersten Schalter S1 abwechselnd in den leitenden und den gesperrten Zustand geschaltet. Dadurch werden Burst-Impulse erzeugt, die die Lampe zünden.The function of the control unit SE with stationary lamp operation has been described above. The control unit also controls the preheating and starting phases. In the preheating phase, the switch S3 is turned on, the switches S1 and S2 are operated at high frequency, so that a heating current flows through the lamp electrodes E1 and E2. The ignition phase then takes place after a predetermined period of time. In this case, the switch S3 is switched alternately into the conductive and the blocked state when the first switch S1 is conductive. This generates burst pulses that ignite the lamp.

Das Ausführungsbeispiel von Fig. 4 entspricht demjenigen von Fig. 1, mit dem Unterschied, daß der Enladungszweig 10 anstelle des zweiten elektronischen Schalters S2 einen Kondensator C1 enthält. Das Steuergerät SE steuert den ersten elektronischen Schalter S1 in derselben Weise wie bei dem ersten Ausführungsbeispiel. Wenn dieser Schalter S1 im leitenden Zustand ist, wird über ihn in der oben beschriebenen Weise die Induktivität L aufgeladen. Gleichzeitig wird auch der Kondensator C1 aufgeladen. Wenn der Schalter S1 in den Sperrzustand geschaltet wird, entlädt sich die Induktivität L über den Kondensator C1, so daß über diesen Kondensator ein Strom fließt und der Kondensator dieselbe Funktion hat, wie ein im leitenden Zustand befindlicher Schalter. Das Ausführungsbeispiel von Fig. 4 bietet den Vorteil, daß der elektronische Schalter S2, einschließlich der dazugehörigen Gleichrichter-Vollbrücke, eingespart wird.The embodiment of FIG. 4 corresponds to that of FIG. 1, with the difference that the discharge branch 10 contains a capacitor C1 instead of the second electronic switch S2. The control device SE controls the first electronic switch S1 in the same way as in the first exemplary embodiment. When this switch S1 is in the conductive state, the inductance L is charged via it in the manner described above. At the same time, the capacitor C1 is also charged. When the switch S1 is switched to the blocking state, the inductance L discharges through the capacitor C1, so that a current flows through this capacitor and the capacitor the same It functions like a switch that is in the conducting state. The embodiment of FIG. 4 offers the advantage that the electronic switch S2, including the associated full bridge rectifier, is saved.

Claims (11)

  1. An A.C. ballast for electric discharge lamps, comprising
       a series connection connectable to a supply A.C. voltage and consisting of a first electronic switch (S1), an inductance (L), and a discharge lamp (EL),
       a discharge branch (10) connected in series with the first electronic switch (S1) and shunting the series connection of the inductance (L) and the discharge lamp (EL), the discharge branch (10) discharging the inductance (L) via the discharge lamp (EL) when the first switch (S1) is blocked,
       a control unit (SE) controlling the first electronic switch (S1),
    characterized in
    that a further electronic switch (S3) shunting the electrodes of the discharge lamp (EL) is provided, which is controlled by the control unit (SE) in such a manner that, when the first switch (S1) is in the conducting state, it is repeatedly switched on and off within one half-wave of the supply voltage as long as the instantaneous value of the supply voltage falls below a limit value (UG), this limit value being set to a value of the supply voltage at which the discharge lamp would not be extinguished.
  2. The ballast according to claim 1, characterized in that, when the further switch (S3) is blocked, the first switch (S1) is repeatedly switched on and off within one half-wave of the supply voltage as long as the amplitude of the supply voltage exceeds the limit value (UG).
  3. The ballast according to claim 1 or 2, characterized in that the control unit (SE) controls the first switch (S1) by impulses of a predetermined frequency, the pulse-duty factor of the impulses being variable.
  4. The ballast according to claim 1 or 2, characterized in that the control means controls the further switch (S3) by impulses of a predetermined frequency, the pulse-duty factor of the impulses being variable.
  5. The ballast according to claim 3 or 4, characterized in that the control unit (SE) receives information on the lamp voltage or the lamp current and varies the pulse-duty factor such that the lamp voltage or the lamp current adopts a predetermined constant value.
  6. The ballast according to one of claims 1 to 3, characterized in that the control unit (SE) controls the first switch (S1) by impulses of variable frequency.
  7. The ballast according to one of claims 1 to 3, characterized in that the control unit (SE) controls the further switch (S3) by impulses of variable frequency.
  8. The ballast according to claim 6 or 7, characterized in that the control unit (SE) receives information on the lamp voltage or the lamp current and varies the impulse frequency such that the lamp voltage or the lamp current adopts a predetermined constant value.
  9. The ballast according to one of claims 1 to 8, characterized in that the control unit (SE), in a preheating phase, switches the first and the further switches (S1,S3) into the conducting state and, in an ignition phase, when the first switch (S1) is in the conducting state, switches the further switch (S3) alternately into the conducting state and the blocked state.
  10. The ballast according to one of claims 1 to 9, characterized in that the discharge branch (10) includes a second electronic switch (S2) being controlled inversely to the first electronic switch (S1).
  11. The ballast according to one of claims 1 to 9, characterized in that the discharge branch (10) includes a capacitor (C1).
EP91117443A 1991-01-24 1991-10-12 AC Ballast for discharge lamps Expired - Lifetime EP0496040B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4101980 1991-01-24
DE4101980A DE4101980A1 (en) 1991-01-24 1991-01-24 AC voltage ballast for electric discharge lamps

Publications (2)

Publication Number Publication Date
EP0496040A1 EP0496040A1 (en) 1992-07-29
EP0496040B1 true EP0496040B1 (en) 1994-12-28

Family

ID=6423585

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91117443A Expired - Lifetime EP0496040B1 (en) 1991-01-24 1991-10-12 AC Ballast for discharge lamps

Country Status (3)

Country Link
EP (1) EP0496040B1 (en)
AT (1) ATE116509T1 (en)
DE (2) DE4101980A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4128314A1 (en) * 1991-08-27 1993-03-04 Diehl Gmbh & Co POWER SUPPLY CIRCUIT
DE59209374D1 (en) * 1992-11-06 1998-07-16 Trilux Lenze Gmbh & Co Kg AC ballast for electric discharge lamps
US5652481A (en) * 1994-06-10 1997-07-29 Beacon Light Products, Inc. Automatic state tranition controller for a fluorescent lamp
US5708330A (en) * 1995-09-19 1998-01-13 Beacon Light Products, Inc. Resonant voltage-multiplication, current-regulating and ignition circuit for a fluorescent lamp
WO1997011586A1 (en) * 1995-09-19 1997-03-27 Beacon Light Products, Inc. Method of regulating lamp current through a fluorescent lamp by pulse energizing a driving supply

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3505562A (en) * 1968-04-29 1970-04-07 Westinghouse Electric Corp Single transistor inverter with a gas tube connected directly to the transistor
DE2332682C2 (en) * 1973-06-25 1985-06-27 Deutsche Itt Industries Gmbh, 7800 Freiburg Circuit for brightness control of gas discharge lamps
HU173720B (en) * 1976-04-08 1979-07-28 Egyesuelt Izzolampa Circuit array for operating gas-discharge lamps
US4604552A (en) * 1984-08-30 1986-08-05 General Electric Company Retrofit fluorescent lamp energy management/dimming system
US4873471A (en) * 1986-03-28 1989-10-10 Thomas Industries Inc. High frequency ballast for gaseous discharge lamps
FR2617363A1 (en) * 1987-06-26 1988-12-30 Omega Electronics Sa DEVICE FOR SUPPLYING A DISCHARGE LAMP
DE4010435A1 (en) * 1990-03-31 1991-10-02 Trilux Lenze Gmbh & Co Kg Mains connection device for fluorescent lamp - has inverse regulator for prodn. of constant operating voltage, and electronic switch in series branch to load in series with diode

Also Published As

Publication number Publication date
ATE116509T1 (en) 1995-01-15
DE59104073D1 (en) 1995-02-09
DE4101980A1 (en) 1992-08-06
EP0496040A1 (en) 1992-07-29

Similar Documents

Publication Publication Date Title
DE3319739C2 (en) Ballast for gas discharge lamps
AT392384B (en) Ballast for the operation of gas discharge lamps with direct current
EP0382110B1 (en) Output control circuit for reversers, and high-frequency power supply for the DC supply of a welding station
DE2936088A1 (en) RECTANGLE DIMMER SWITCH WITH FIXED FREQUENCY AND VARIABLE IMPULSE FACTOR FOR HIGH-PERFORMANCE GAS DISCHARGE LAMPS
DE2505453A1 (en) BRIGHTNESS CONTROL CIRCUIT
DE2223371A1 (en) X-RAY DIAGNOSTIC APPARATUS WITH A REGULATING DEVICE FOR THE X-RAY PIPE VOLTAGE
DE2824326C2 (en)
DE3829388A1 (en) CIRCUIT ARRANGEMENT FOR OPERATING A LOAD
EP0637118B1 (en) Circuit for limiting inrush current and overvoltage of an electronic ballast
DE19945467A1 (en) Flashing circuit and control for fluorescent lamps
EP0062276A1 (en) Ballast circuit for the operation of low-pressure discharge lamps
DE19729768B4 (en) Circuit arrangement for igniting and operating a fluorescent lamp
DE69835328T2 (en) Control circuit for a fluorescent lamp
WO2002034015A1 (en) Electronic ballast comprising a full bridge circuit
EP0496040B1 (en) AC Ballast for discharge lamps
DE4015397A1 (en) CIRCUIT ARRANGEMENT FOR IGNITING AND OPERATING A HIGH PRESSURE DISCHARGE LAMP IN MOTOR VEHICLES
DE4219958C1 (en) Ballast circuit for discharge lamp - uses phase gate control to short out electrodes for interval in each half cycle, depending on brightness
DE3338464A1 (en) High-frequency brightness control for fluorescent lamps
EP0634087B2 (en) Electronic ballast for a gas discharge lamp
DE10245368A1 (en) Operation of welding power supply, includes switching components controlled to produce required inverter output voltage and current profile
DE3608362A1 (en) Ballast for discharge lamps
DE4220291C1 (en) Ballast circuit for fluorescent lamp with dimmer - includes source supplying brightness signal for control stage for transistor switch bridging lamp electrodes
DE3517297C1 (en) Ballast for discharge lamps
DE3925654C2 (en)
DE3343930A1 (en) CIRCUIT ARRANGEMENT FOR OPERATING FLUORESCENT OR ULTRAVIOLET LOW-VOLTAGE DISCHARGE LAMPS

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT CH DE FR GB IT LI NL

17P Request for examination filed

Effective date: 19920711

17Q First examination report despatched

Effective date: 19940131

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT CH DE FR GB IT LI NL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRE;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.SCRIBED TIME-LIMIT

Effective date: 19941228

Ref country code: FR

Effective date: 19941228

Ref country code: GB

Effective date: 19941228

Ref country code: NL

Effective date: 19941228

REF Corresponds to:

Ref document number: 116509

Country of ref document: AT

Date of ref document: 19950115

Kind code of ref document: T

REF Corresponds to:

Ref document number: 59104073

Country of ref document: DE

Date of ref document: 19950209

EN Fr: translation not filed
NLV1 Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act
GBV Gb: ep patent (uk) treated as always having been void in accordance with gb section 77(7)/1977 [no translation filed]

Effective date: 19941228

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Effective date: 19951012

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19951031

Ref country code: CH

Effective date: 19951031

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20011214

Year of fee payment: 11

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030501