WO1998036623A1 - Agencement de circuit - Google Patents

Agencement de circuit Download PDF

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Publication number
WO1998036623A1
WO1998036623A1 PCT/IB1998/000102 IB9800102W WO9836623A1 WO 1998036623 A1 WO1998036623 A1 WO 1998036623A1 IB 9800102 W IB9800102 W IB 9800102W WO 9836623 A1 WO9836623 A1 WO 9836623A1
Authority
WO
WIPO (PCT)
Prior art keywords
frequency
discharge lamp
circuit arrangement
power consumed
lamp
Prior art date
Application number
PCT/IB1998/000102
Other languages
English (en)
Inventor
Paulus Petrus Bernardus Arts
Arnold Willem Buij
Etienne Nicolaas Kathalijntje Paulus Marie Eberson
Original Assignee
Koninklijke Philips Electronics N.V.
Philips Ab
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 Koninklijke Philips Electronics N.V., Philips Ab filed Critical Koninklijke Philips Electronics N.V.
Priority to JP10529215A priority Critical patent/JP2000509890A/ja
Priority to EP98900335A priority patent/EP0913073A1/fr
Priority to PCT/IB1998/000102 priority patent/WO1998036623A1/fr
Publication of WO1998036623A1 publication Critical patent/WO1998036623A1/fr

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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
    • H05B41/36—Controlling
    • H05B41/38—Controlling the intensity of light
    • H05B41/39—Controlling the intensity of light continuously
    • H05B41/392—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor
    • H05B41/3921—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations
    • H05B41/3925—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations by frequency variation

Definitions

  • the invention relates to a circuit arrangement for supplying a discharge lamp, comprising
  • a converter for generating a high-frequency current with frequency f from a supply voltage, - a circuit portion I for adjusting the power consumed by the discharge lamp through adjustment of the frequency.
  • the invention also relates to a compact fluorescent lamp and to a method of supplying a discharge lamp.
  • a circuit arrangement as mentioned in the opening paragraph is known from US 5,003,230.
  • an inductive element is connected in series with the discharge lamp. If the frequency f is made higher, the impedance of the inductive element increases, so that the lamp current decreases. It is thus possible to dim the discharge lamp by means of the known circuit arrangement in that the frequency is adjusted by means of the circuit portion I.
  • a disadvantage of supplying a discharge lamp with a high- frequency current is that, for example in the case of a low-pressure mercury discharge lamp, striations may arise in the discharge lamp, especially if the discharge lamp burns in the dimmed state.
  • a further disadvantage is that there is no unequivocal relation between the power consumed by the discharge lamp and the frequency f, especially for comparatively low luminous flux values and comparatively low ambient temperatures. As a result of this, the luminous flux of the discharge lamp will fluctuate in time, a phenomenon which is usually referred to as "moding".
  • a problem which also arises in this dimming method is that the color point of the light radiated by the discharge lamp lies comparatively far removed from the blackbody line in the color triangle during dimming.
  • a circuit arrangement of the kind mentioned in the opening paragraph is for this purpose characterized in that the circuit portion I is provided with a circuit portion ⁇ for low-frequency square-wave modulation of the frequency f and for adjusting the duty cycle of said square- wave modulation. Owing to the square- wave modulation, a current of a first frequency fl and a current of a second frequency f2 flow alternately through a discharge lamp which is supplied by means of the circuit arrangement according to the invention.
  • the time interval during which the discharge lamp passes a current of the first frequency f 1 in each cycle of the square- wave modulation is ⁇ tl.
  • the time interval during which the discharge lamp passes a current of the second frequency f2 in each cycle of the square- wave modulation is ⁇ t2.
  • the duty cycle of the square-wave modulation is understood to be the ratio ⁇ tl/( ⁇ tl + ⁇ t2).
  • the frequency f2 is preferably chosen such that the discharge lamp consumes approximately a power which is equal to the rated power of the discharge lamp at this frequency.
  • the frequency f 1 is preferably chosen such that the power consumed by the discharge lamp has a very low value at this frequency, but without moding or striations.
  • the luminous flux of the discharge lamp is comparatively low during ⁇ tl and the luminous flux of the lamp is comparatively high during ⁇ t2. If the frequency of the square- wave modulation is chosen to be high enough, the transition from a comparatively high luminous flux to a comparatively low luminous flux and vice versa is not observable to the human eye, and the observed luminous flux is the time-averaged luminous flux over a cycle of the square-wave modulation.
  • the time intervals ⁇ tl and ⁇ t2 are adjusted during the adjustment of the duty cycle.
  • the perceived, time-averaged luminous flux is adjusted thereby at the same time. It was found that striations and moding do not occur in this method of dimming. It was also found that the color point of the light radiated by the discharge lamp shows no undesirable shift during dimming of the discharge lamp, but remains comparatively close to the blackbody line while being shifted.
  • US 5,365, 151 describes a circuit arrangement for supplying a discharge lamp with a high-frequency current, in which the frequency is square- wave modulated.
  • the second frequency f2 is chosen such that the discharge lamp consumes a power higher than the rated power of the discharge lamp during the time interval ⁇ t2.
  • ⁇ tl when the frequency is equal to the value fl, a comparatively low power is consumed by the discharge lamp.
  • the value of the power consumed by the discharge lamp averaged over a cycle of the square-wave modulation is chosen to be approximately equal to the rated lamp power.
  • a suitable choice of ⁇ tl and ⁇ t2 and of the powers consumed by the discharge lamp during these time intervals renders it possible to adjust the color point and the luminous flux of the light radiated by the discharge lamp to desired values (when the rated lamp power is consumed). It is not possible in the circuit arrangement described in US 5,365,151 to adjust the duty cycle of the square-wave modulation, and thus the luminous flux of the discharge lamp, so that the circuit arrangement described in US 5,365,151 differs substantially from a circuit arrangement according to the invention.
  • circuit arrangement comprises a bridge circuit.
  • the average power consumed by the discharge lamp will change, while the values of the frequency f and the duty cycle of the square-wave modulation remain the same, for example in the case of ageing of the discharge lamp.
  • the power is controlled at a substantially constant value in this manner both during the time interval ⁇ tl and during the time interval ⁇ t2, the time average of the power consumed by the discharge lamp is also constant. It was found that the stability of the discharge was further improved by this power control.
  • the circuit arrangement is highly suitable for supplying and dimming such a discharge lamp.
  • the circuit arrangement is provided inside the housing of the compact fluorescent lamp.
  • the low-frequency modulation is realized in that alternately and with low frequency the power consumed by the discharge lamp is adjusted to a first value PI through adjustment of the frequency f during a first time interval and the power consumed by the discharge lamp is adjusted to a second value P2 through adjustment of the frequency f during a second time interval, with PI ⁇ Pnom and P2 ⁇ Pnom, Pnom being the rated power of the discharge lamp.
  • Fig. 1 is a circuit diagram of an embodiment of a circuit arrangement according to the invention.
  • Fig. 2 plots the frequency of the lamp current of a discharge lamp supplied by means of a circuit arrangement as shown in Fig. 1 as a function of time;
  • Fig. 3 shows part of a compact fluorescent lamp provided with a circuit arrangement according to the invention.
  • Kl and K2 are terminals for connection to a supply voltage source.
  • This supply voltage source is a DC voltage source in the embodiment shown in Fig. 1.
  • Terminals Kl and K2 are interconnected by a series arrangement of two switching elements SI and S2.
  • SC is a circuit portion for generating a control signal for rendering the switching elements SI and S2 alternately conducting with a frequency f.
  • a first and a second output of circuit portion SC are for this purpose coupled to a control electrode of switching element SI and a control electrode of switching element S2, respectively.
  • II is a circuit portion for the low-frequency square-wave modulation of the frequency f and for the adjustment of the duty cycle of the square- wave modulation.
  • An output of circuit portion II is for this purpose coupled to an input of circuit portion SC.
  • the circuit portions II and SC in this embodiment together form a circuit portion I for adjusting the frequency f.
  • Switching element S2 is shunted by a series arrangement of an inductive element L, terminals for connecting a discharge lamp K3 and K4, and capacitor C4.
  • a discharge lamp La is connected to the terminals K3 and K4.
  • the discharge lamp La is shunted by a capacitor C3.
  • the operation of the circuit arrangement shown in Fig. 1 is as follows. When the terminals Kl and K2 are connected to a supply voltage source, the circuit portion SC will render the switching elements SI and S2 alternately conducting with frequency f. As a result, a high-frequency current with frequency f will flow through the discharge lamp.
  • the frequency f is subjected to a low-frequency square- wave modulation by the circuit portion ⁇ .
  • the frequency of the lamp current alternately has the comparatively high value fl during a time interval ⁇ tl and the comparatively low value f2 during a time interval ⁇ t2. Since the impedance of the inductive element L in series with the discharge lamp is comparatively high for comparatively high values of the frequency f of the lamp current, the discharge lamp La will consume a comparatively low power PI during the time interval ⁇ tl.
  • the impedance of the inductive element L is comparatively low in the case of comparatively low values of the frequency f, so that the discharge lamp will consume a comparatively high power P2 during the time interval ⁇ t2.
  • the average power Pav consumed by the discharge lamp is theoretically:
  • This average power Pav consumed by the discharge lamp, and thus also the luminous flux of the discharge lamp, can be adjusted in that the ratio between ⁇ tl and ⁇ t2, i.e. the duty cycle of the square- wave modulation, is adjusted.
  • time is plotted on the horizontal axis in arbitrary units and the frequency on the vertical axis in arbitrary units.
  • the square- wave curve represents the frequency of the lamp current of a discharge lamp supplied by a circuit arrangement as shown in Fig. 1 as a function of time. It is apparent that the frequency f alternately has the value fl during a time interval ⁇ tl and the value f2 during a time interval ⁇ t2.
  • reference numeral 8 denotes part of a discharge vessel which is sealed in a gastight manner and which transmits radiation.
  • a wall 6 of a housing is connected to the discharge vessel 8 and is provided with a lamp cap 3, a circuit arrangement B according to the invention being present in a space 7 surrounded by said housing.
  • the circuit arrangement is diagrammatically represented in the form of components P and C1-C4.
  • Connection wires 9 are present between the circuit arrangement and electrodes (not shown) in the discharge vessel.
  • E denotes connection wires between the circuit arrangement and electrical contacts 1 and 2 arranged on the lamp cap. It is possible to adjust the duty cycle of the square-wave modulation of the frequency f of the lamp current by means which are not shown in Fig. 3 and which are arranged outside the housing.
  • fl was chosen to be equal to 45 kHz and f2 to be equal to 25 kHz.
  • a low-pressure mercury discharge lamp (make Philips) of the TLD type having a power rating of 58 watts was - supplied by means of this circuit arrangement.
  • time interval ⁇ tl when the frequency of the lamp current was 45 kHz, the discharge lamp consumed a power of 0.2 watt.
  • time interval ⁇ t2 when the frequency of the lamp current was 25 kHz, the discharge lamp consumed a power of 42 watts.
  • f 1 was chosen to be equal to 90 kHz and f2 to be equal to 45 kHz in a corresponding manner.
  • a compact fluorescent lamp (make Philips) of the PLET type having a power rating of approximately 15 watts was supplied by means of this circuit arrangement. It was found to be possible to adjust the power consumed by the compact fluorescent lamp over a range from approximately 1 watt up to approximately 14 watts by means of this circuit arrangement without striations and/or moding occurring and without undesirable shifts in the color point of the light.

Landscapes

  • Circuit Arrangements For Discharge Lamps (AREA)
  • Discharge-Lamp Control Circuits And Pulse- Feed Circuits (AREA)

Abstract

Agencement de circuit destiné à alimenter une lampe à décharge, qui comprend un convertisseur servant à générer un courant haute fréquence de fréquence f à partir d'une tension d'alimentation, et une partie I de circuit permettant de régler la puissance consommée par la lampe à décharge par réglage de la fréquence. Selon la présente invention, la partie I de circuit est dotée d'une partie II de circuit pour la modulation basse fréquence par des signaux carrés de la fréquence f et pour le réglage du cycle de travail de ladite modulation par signaux carrés. On parvient ainsi à réduire la lumière de la lampe à décharge sur une large plage sans qu'apparaissent des stries ou une fluctuation non désirée du flux lumineux et sans que se produisent des décalages indésirables du point coloré de la lumière.
PCT/IB1998/000102 1997-02-13 1998-01-27 Agencement de circuit WO1998036623A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP10529215A JP2000509890A (ja) 1997-02-13 1998-01-27 回路装置
EP98900335A EP0913073A1 (fr) 1997-02-13 1998-01-27 Agencement de circuit
PCT/IB1998/000102 WO1998036623A1 (fr) 1997-02-13 1998-01-27 Agencement de circuit

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP97200404.8 1997-02-13
PCT/IB1998/000102 WO1998036623A1 (fr) 1997-02-13 1998-01-27 Agencement de circuit

Publications (1)

Publication Number Publication Date
WO1998036623A1 true WO1998036623A1 (fr) 1998-08-20

Family

ID=11004660

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB1998/000102 WO1998036623A1 (fr) 1997-02-13 1998-01-27 Agencement de circuit

Country Status (1)

Country Link
WO (1) WO1998036623A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1326485A2 (fr) * 2002-01-02 2003-07-09 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Ballast pour une lampe, et procédé de commande dudit ballast
WO2005027592A1 (fr) * 2003-09-17 2005-03-24 Philips Intellectual Property & Standards Gmbh Agencement de circuit et procede de commande d'une lampe a decharge dans un gaz

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4373146A (en) * 1980-10-20 1983-02-08 Gte Products Corporation Method and circuit for operating discharge lamp
US5365151A (en) * 1991-07-12 1994-11-15 Tridonic Bauelemente Gmbh Gas discharge lamp ballast circuit with frequency modulated pulse control

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4373146A (en) * 1980-10-20 1983-02-08 Gte Products Corporation Method and circuit for operating discharge lamp
US5365151A (en) * 1991-07-12 1994-11-15 Tridonic Bauelemente Gmbh Gas discharge lamp ballast circuit with frequency modulated pulse control

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1326485A2 (fr) * 2002-01-02 2003-07-09 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Ballast pour une lampe, et procédé de commande dudit ballast
EP1326485A3 (fr) * 2002-01-02 2005-01-12 Patent-Treuhand-Gesellschaft für elektrische Glühlampen mbH Ballast pour une lampe, et procédé de commande dudit ballast
WO2005027592A1 (fr) * 2003-09-17 2005-03-24 Philips Intellectual Property & Standards Gmbh Agencement de circuit et procede de commande d'une lampe a decharge dans un gaz

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