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EP0198632A2 - Ballast électronique pour lampe fluorescente - Google Patents

Ballast électronique pour lampe fluorescente Download PDF

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Publication number
EP0198632A2
EP0198632A2 EP86302471A EP86302471A EP0198632A2 EP 0198632 A2 EP0198632 A2 EP 0198632A2 EP 86302471 A EP86302471 A EP 86302471A EP 86302471 A EP86302471 A EP 86302471A EP 0198632 A2 EP0198632 A2 EP 0198632A2
Authority
EP
European Patent Office
Prior art keywords
transistor
lamp
voltage
electronic ballast
transformer
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.)
Withdrawn
Application number
EP86302471A
Other languages
German (de)
English (en)
Other versions
EP0198632A3 (fr
Inventor
Chwee Tor Lee
Chwee Hock Lee
Chuie Puak Lee
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of EP0198632A2 publication Critical patent/EP0198632A2/fr
Publication of EP0198632A3 publication Critical patent/EP0198632A3/fr
Withdrawn legal-status Critical Current

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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
    • H05B41/2981—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

  • This invention relates to an electronic ballast for fluorescent lamps.
  • Electronic ballasts are currently used with fluorescent lamps to convert the frequency of a voltage supply to the lamp from mains frequency (50/60 Hz) to a very high frequency such as 30 KHz. This has several advantages, for example providing_flickerless operation of the lamp, lower power consumption and an increased efficiency (largely due to an improved power factor).
  • ballast for example that described in EP-A-0075176, use a high frequency oscillator employing two switching transistors, base driven by secondary windings of a transformer whose primary is connected to supply drive current to a fluorescent lamp. Current supply to the lamp is provided during discharge of a capacitor connected in parallel with the lamp.
  • GB 1471150 describes a ballast using a single transistor biasedto Class C operation with an LC oscillating arrangement driving the primary winding of a transformer.
  • the secondary winding of a transformer is used both to provide HT voltage to the lamp and to supply current to heat up both the ignition filament of the lamp. In the event that a lamp is not present, and the ballast is inadvertently not turned off, current and voltage will continue to be supplied constituting a safety hazard.
  • an electronic ballast for a discharge lamp which ballast comprises: a voltage supply terminal for connection to a voltage supply; a transistor-oscillator arrangement having a voltage supply input and operable to provide therefrom high frequency alternating voltage for operation of the lamp; and first and second lamp connector terminals for connection across an ignition filament of such a discharge lamp, wherein the supply terminal is connected to the first lamp connector terminal, and the voltage supply input of the transistor-oscillator arrangement is connected to the second lamp connector terminal so that operation of the ballast is only permitted when an operative filament is connected between the first and second lamp connector terminals.
  • the voltage supply terminal is connected to a supply which comprises an a.c. voltage source and rectifying means for supplying from the a.c. voltage source d.c. voltage to the transistor-oscillator arrangement, the first lamp connector terminal being connected to the a.c. voltage source and the second lamp connector terminal being connected to the transistor oscillator arrangement via the rectifying means.
  • the first and second windings may form the primary of the transformer, the secondary of which is adapted to be connected across the discharge lamp for the supply of said high frequency voltage to the lamp.
  • a further ignition filament of the lamp may be connected across a portion of that secondary winding.
  • Biasing means may be provided for adjustably biasing the transistor of the transistor-oscillator arrangement to vary the magnitude of the high frequency alternating voltage provided for operation of the lamp.
  • high frequency used herein denotes a frequency of greater than 1KHz, and preferably greater than 10KHz.
  • the transistor of the transistor-oscillator arrangement is preferably biased to class A operation.
  • Such an arrangement has the following features; (i) the input and output waveforms are substantially 180° out of phase; (ii) there is a transformer coupling from the transistor output to the lamp; (iii) when there is no input signal due to the feedback signal being cut-off, the transistor employs an idle current as a standby current for the operation of the transistor; (iv) the transistor is operating in an amplifying mode, usually biased so that the quiescent collector, or control path, current is midway between the maximum and miniumum values of the output current swing.
  • Such a construction and features give simplicity, less harmonic distortion/interference, economy (i.e. fewer components and hence less power consumption) and better control of the input against the output, so that the feedback has a more stabilising effect.
  • a fluorescent lamp to be used with the ballast is designated by reference numeral 1 and has first and second ignition filaments 2,3.
  • the lamp may be, for example, a Philips TLD 54, 36 Watts lamp.
  • the line filter shown to the left of broken line X-X in Figure 1, serves to pass mains frequency to operate the ballast, and to prevent the return of high frequency components to mains and comprises two chokes Ll and L2 in the "live" line and in the "neutral” line respectively, and a capacitative arrangement comprising a capacitor Cl connected in parallel with two capacitors C2, C3, connected in series between the live and neutral lines. The junction of the capacitors C2 and C3 is earthed. A 0.5A fuse F is connected in the live line.
  • Each choke has an E - I shaped core arrangement as shown in Figure 3, in which the dimensions of the E section are as follows:
  • the thickness of the core is 1.3 cm, and the winding is 1000 turns of SWG 32 on the central limb of the core. Both chokes are identical.
  • the input waveform is substantially sinusoidal at 50Hz so as to cause as little interference as possible on the mains circuit.
  • the output waveform that is across winding L5 of Figure 1
  • the two waveforms are shown in Figures 7 and 8.
  • a resistor Rl is connected between live input L and one terminal 4 for releasable connection to one end of the filament 2 of the fluorescent lamp 1.
  • a second terminal 5, for releasable connection to the other end of the filament 2 is connected to neutral input N via two poles of a rectifying means in the form of a diode bridge Dl-D4, the other two poles of which have connected across them an electrolytic capacitor C4.
  • the other filament 3 is also provided with releasable terminals 4 1 and 5'.
  • the terminals 4, 5, 4' and 5' are provided by sockets or plugs to which the lamp 1 is releasably connected.
  • the transistor TS has its base B connected to the junction 6 of the first variable resistor R2 and the parallel arrangement, and its emitter E connected to ground. Its collector C is connected, via an LC oscillating arrangement OS, to a pole of the electrolytic capacitor C4 and to the first variable resistor.
  • An inductive portion L3 of the LC oscillator OS is constituted by part of a primary winding of a transformer TR1. The capacitative portion is formed by a capacitor C6.
  • a feedback winding L4 of the transformer TR1 is connected between the base B of the transistor and the said junction 6.
  • the secondary winding of the transformer TR1 is for loading the fluorescent lamp 3 and has two sections L5, L6 for providing respectively a high tension supply for the lamp, and a voltage supply for the second lamp filament 3.
  • a suitable transformer would be a Ferrite switching transformer.
  • the turns of the transformer are chosen to limit the open circuit voltage across L5, so as to prevent cold starting, and to ensure that the starting frequency is sufficient above 5KHz to avoid audible noise.
  • a diode clamp D5 e.g. BY 527 Philips x 2 connected in series, is connected between the collector C and emitter E of the transistor TS to limit the peak-to-peak swing thereacross.
  • capacitor C6 With the transistor TS turned off, capacitor C6 is charged by current flow from the oscillator winding L3 of the primary winding until it has acquired such a stored voltage as to prevent further current flow through winding L3. Then the capacitor C6 discharges, as in a conventional LC oscillating circuit, to cause a reverse current to flow through winding L3 and hence through secondary winding L5. The capacitor C6 discharge also causes a base current to flow again through the base drive part L4 of the transformer to turn on the transistor and repeat the process. Hence there is induced in the secondary winding a voltage and current for driving the lamp 1, at a frequency which is much greater than mains frequency and which depends on the oscillating frequency of the LC oscillating circuit OS. Typically, the operating frequency of the lamp may be 30 KHz or above.
  • the advantages of using a higher frequency include less power consumption by the ballast/lamp arrangement and accordingly a smaller increase in temperature during operation of the lamp.
  • the high frequency ensures that the lamp is substantially "flicker free" in use.
  • the power supply was 39.6W, the current drawn 137mA and the power factor 93.55%.
  • the corresponding Figures were 49.8W, 210mA and 98.8%.
  • the current flows to the diode bridge from the input L by way of resistor Rl and lamp connector terminal 4, filament 2, and lamp connector terminal 5.
  • the ballast will not operate, as there will be no current path via the filament 2.
  • the lamp may be operated with only one operative filament, provided that this is connected as filament 2.
  • the cut off arrangement is designed to detect an excessive voltage across the lamp and includes, connected in series between the diode bridge D1-D4 and ground, a resistor R4, 12V relay winding 6 and a thyristor 7.
  • the thyristor 7 is triggered via an arrangement comprising a zener diode 8 and electrolytic capacitor C7 connected in sequence to the base B of the transistor TS. As soon as the capacitor C7 is charged to the zener voltage of diode 8, the thyristor 7 is triggered.
  • One contact terminal 9 of the relay 6 is connected to ground, while another 10 is connected to the base B of the transistor TS.
  • a resistor R5 is connected between the trigger of thyristor 7 and ground and a diode D6 is connected between the cathode of the zener diode 8 and ground.
  • FIG. 5 Another form of cut off arrangement is shown in Figure 5: the remaining components of the ballast are as described above with reference to Figure 1.
  • This form of arrangement is similar to that described with reference to Figure 4 but with the triggering of the thyristor 7 being effected by a transformer TR2 having one winding L7 connected across winding L6 of the transformer TR1 and the other winding L8 connected in parallel with a variable resistor R7 used to trigger the thyristor.
  • This arrangement is more sensitive than that described above with reference to Figure 1 and operates as follows.
  • a dimming function may be carried out by adjusting the bias of the transistor TS using the biasing arrangement R2, R3 to alter the operation point of the transistor on its characteristic curve and hence to alter the output collector voltage.
  • an external dimmer may be connected in series with the power supply to vary the input current and voltage.
  • Figure 6 illustrates an arrangement with two lamps 20, 21 each with their associated transistor-oscillator arrangement.
  • the arrangements are connect by respective diodes D7, D8 and fuses F2, F3 to the rectifying means Dl-D4 of the ballast.
  • Auto-cut off means may be included, as shown in Figure 4 or 5. This is indicated generally at 23 in Figure 6.
  • Capacitor C8 charges up during the existence of the back EMF and, assuming the value is high enough and remains for a sufficient time, transistor TR2 is turned on, giving a voltage drop across R5 to trigger thyristor 7. The current through R6 is then bypassed through the thyristor 7 ⁇ so that transistor TR1 turns off and thus stops the oscillator.
  • Diode D8 absorbs current on switching off transistor TSl, so protecting that transistor.
  • Suitable components might be:

Landscapes

  • Circuit Arrangements For Discharge Lamps (AREA)
EP86302471A 1985-04-04 1986-04-03 Ballast électronique pour lampe fluorescente Withdrawn EP0198632A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8508913 1985-04-04
GB858508913A GB8508913D0 (en) 1985-04-04 1985-04-04 Electronic ballast

Publications (2)

Publication Number Publication Date
EP0198632A2 true EP0198632A2 (fr) 1986-10-22
EP0198632A3 EP0198632A3 (fr) 1987-03-25

Family

ID=10577241

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86302471A Withdrawn EP0198632A3 (fr) 1985-04-04 1986-04-03 Ballast électronique pour lampe fluorescente

Country Status (2)

Country Link
EP (1) EP0198632A3 (fr)
GB (1) GB8508913D0 (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0253732A1 (fr) * 1986-07-15 1988-01-20 Sefli-Societe D'equipement Et De Fabrication Pour La Luminescence Et L'incandescence Dispositif d'alimentation de lampes à décharge
EP0330118A3 (fr) * 1988-02-22 1991-02-27 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Circuit pour alimenter une lampe à décharge à basse pression
EP0418612A1 (fr) * 1989-08-31 1991-03-27 Toshiba Lighting & Technology Corporation Appareil pour alimenter une fluorescente
EP0620700A1 (fr) * 1993-04-15 1994-10-19 Heinrich Korte Ballast électronique
EP0681415A1 (fr) * 1994-05-06 1995-11-08 Valeo Vision Dispositif d'alimentation de lampe à décharge, notamment pour l'éclairage intérieur ou la signalisation de véhicule
WO1999041954A1 (fr) * 1998-02-10 1999-08-19 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Circuiterie pour actionner au moins une lampe a decharge sans electrodes
RU2147680C1 (ru) * 1998-09-28 2000-04-20 Самарский государственный технический университет Способ выявления расположения древних водонефтяных контактов в продуктивных карбонатных пластах
EP0974081A4 (fr) * 1996-12-20 2000-09-20 Motorola Inc Alimentation et ballast electronique presentant une source d'alimentation bon marche a auto-elevation par onduleur
WO2002060227A3 (fr) * 2000-11-21 2003-05-01 Gen Electric Geometrie de cablage pour lampes integrales multiples

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4005335A (en) * 1975-07-15 1977-01-25 Iota Engineering Inc. High frequency power source for fluorescent lamps and the like
GB1570277A (en) * 1975-10-01 1980-06-25 Sonca Ind Ltd Fluorescent lamp arrangement

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0253732A1 (fr) * 1986-07-15 1988-01-20 Sefli-Societe D'equipement Et De Fabrication Pour La Luminescence Et L'incandescence Dispositif d'alimentation de lampes à décharge
EP0330118A3 (fr) * 1988-02-22 1991-02-27 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Circuit pour alimenter une lampe à décharge à basse pression
EP0418612A1 (fr) * 1989-08-31 1991-03-27 Toshiba Lighting & Technology Corporation Appareil pour alimenter une fluorescente
US5084652A (en) * 1989-08-31 1992-01-28 Toshiba Lighting & Technology Corporation Fluorescent lamp lighting apparatus
EP0620700A1 (fr) * 1993-04-15 1994-10-19 Heinrich Korte Ballast électronique
EP0681415A1 (fr) * 1994-05-06 1995-11-08 Valeo Vision Dispositif d'alimentation de lampe à décharge, notamment pour l'éclairage intérieur ou la signalisation de véhicule
FR2719734A1 (fr) * 1994-05-06 1995-11-10 Valeo Vision Dispositif d'alimentation de lampe à décharge, notamment pour l'éclairage intérieur ou la signalisation de véhicule.
EP0974081A4 (fr) * 1996-12-20 2000-09-20 Motorola Inc Alimentation et ballast electronique presentant une source d'alimentation bon marche a auto-elevation par onduleur
WO1999041954A1 (fr) * 1998-02-10 1999-08-19 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Circuiterie pour actionner au moins une lampe a decharge sans electrodes
US6181080B1 (en) 1998-02-10 2001-01-30 Patent-Treuhand-Gesellschaft Fuer Elektrische Gluehlampen Mbh Circuit for actuating at lease one electrode-less discharge lamp
RU2147680C1 (ru) * 1998-09-28 2000-04-20 Самарский государственный технический университет Способ выявления расположения древних водонефтяных контактов в продуктивных карбонатных пластах
WO2002060227A3 (fr) * 2000-11-21 2003-05-01 Gen Electric Geometrie de cablage pour lampes integrales multiples

Also Published As

Publication number Publication date
EP0198632A3 (fr) 1987-03-25
GB8508913D0 (en) 1985-05-09

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