EP0520735A1 - Elektronische Zündschaltung für Leuchtstofflampen - Google Patents

Elektronische Zündschaltung für Leuchtstofflampen Download PDF

Info

Publication number
EP0520735A1
EP0520735A1 EP92305744A EP92305744A EP0520735A1 EP 0520735 A1 EP0520735 A1 EP 0520735A1 EP 92305744 A EP92305744 A EP 92305744A EP 92305744 A EP92305744 A EP 92305744A EP 0520735 A1 EP0520735 A1 EP 0520735A1
Authority
EP
European Patent Office
Prior art keywords
circuit
capacitor
starter
starter circuit
charge
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Withdrawn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
EP92305744A
Other languages
English (en)
French (fr)
Inventor
David John Martin
Allan Richardson
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.)
LIGHTING ELECTRONICS Ltd
Original Assignee
LIGHTING ELECTRONICS Ltd
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 LIGHTING ELECTRONICS Ltd filed Critical LIGHTING ELECTRONICS Ltd
Publication of EP0520735A1 publication Critical patent/EP0520735A1/de
Withdrawn legal-status Critical Current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
    • H05B41/02—Details
    • H05B41/04—Starting switches
    • H05B41/042—Starting switches using semiconductor devices
    • H05B41/044—Starting switches using semiconductor devices for lamp provided with pre-heating electrodes
    • H05B41/046—Starting switches using semiconductor devices for lamp provided with pre-heating electrodes using controlled semiconductor devices

Definitions

  • This invention relates to a circuit for starting a discharge lamp, such as a fluorescent lamp, and particularly to the types of fluorescent lamp starter circuit which utilise half-wave rectified current to pre-heat the lamp cathodes.
  • a particular application of the invention is to starter circuits which employ a fluorescent lamp electronic starter switch device of the kind described in Specification GB-A 2201307 (Martin). More particularly the starter switch device is a device such as that known as a Fluoractor available from Texas Instruments. The Fluoractor device and its use in starter circuits for fluorescent lamps is described in Specifications EP-A 0118309 and EP-A 0269485 (Texas Instruments).
  • the starter circuits disclosed in the three specifications referred to in the preceding paragraph are concerned with the use of Fluoractor devices in full-wave operation, that is the circuits are energised on each half-cycle of the applied mains power supply, as by feeding the circuits through a bridge rectifier.
  • the present invention is concerned with starter circuits in which the Fluoractor device is triggered in half-cycles of one polarity of the applied mains supply.
  • An example of this type of circuit is described in Specification GB-A 2234868 (Martin).
  • Fig. 1 of the accompanying drawings is reproduced from this specification to which reference can be made for a fuller description of that circuit. It is noted that the device F shown in Fig. 1 is a Fluoractor having anode, gate and cathode terminals A, G and K respectively. The device F provides the main current path of the starter circuit.
  • the timing means of fluorescent lamp starter circuits is commonly provided by deriving a low voltage as a result of the main current flow and using that voltage to charge a timing capacitor through a resistor.
  • This is exemplified in Fig. 1 by the forward voltage of diodes D2, D3 and D4 charging capacitor C1 through R12 and R13.
  • An alternative to the three diodes of Fig. 1 is to place a low voltage Zener diode (Z1) in the current path to achieve the same effect (Fig. 2).
  • the Zener diode voltage is typically 4.7 volts. Because the RC timing is fed from a low voltage and because the timing relies on the capacitor C1 charging from zero to typically 1.5v, the value of the capacitance needed in practice is high. Values of 22 ⁇ to 100 ⁇ F are common. The only reasonable course is to use an electrolytic capacitor in positions such as C1.
  • Electrolytic capacitors are small and inexpensive but they have a number of disadvantages. In particular the temperature range over which they will operate is restricted and their working and shelf lives are limited. The variation of the initial capacitance value of an electrolytic capacitor and changes of value during use are both high so that variations in timing values for starters relying on these capacitors is considerable (typically +/- 40% or more).
  • Embodiments of the present invention will be described hereinafter in which it is possible to replace the low voltage, high capacitance of the timing means by much lower values of capacitance working over much larger voltage excursions.
  • Such capacitors are readily available with close tolerance values and good stability when working over wide temperature ranges. They also maintain their characteristics over a long working life.
  • a fluorescent lamp starter circuit in which one polarity of the AC voltage is used for heating the lamp cathodes and the other polarity is used to charge a capacitor in a series of steps resulting from the charge and discharge of a second capacitor, in order to define and control the time of heating and high voltage pulsing provided by the starter.
  • Circuits of the type shown in Figs. 1 and 2 are characterised by the fact that they operate on only one polarity of mains voltage. They are known as rectifying or half-wave types. In the circuits of Figs. 1 and 2, as drawn, only the positive half cycle of the supply is conducted by the starter for heating and high voltage generation. When conduction ceases in the positive direction the voltage at the starter terminals goes fully negative to the value of the supply voltage.
  • This negative voltage excursion is used in embodiments of the present invention to derive the main timing function.
  • Fig. 3 shows a half-wave type of starter circuit as connected to a lamp.
  • a fluorescent lamp or tube T of the type having heated cathodes is connected to the mains supply V S through the conventional ballast inductor L.
  • the starter circuit is connected between the circuit points X and Y so as to be in series with the cathodes of tube T for the flow of heating current and in parallel with the tube for the generation of the high voltage ignition pulses.
  • the heating current path extends through the controllable Fluoractor device F.
  • the half-wave operation of device F and its gate control circuitry (on positive half-waves as shown) is ensured by diode D1.
  • the flow of triggering current to gate G of device F is controlled by the fully controllable transistor switch TR2 which is constituted by a Darlington pair transistor.
  • the switch transistor is operable when turned on by control of its base to divert current from the gate G. This control includes diverting triggering current from entering the gate to turn the device F on, and also, when the device F is conducting, diverting latching current from the gate in order to turn the device off.
  • the large value capacitor C1 of Fig. 1 or Fig. 2 is replaced in the circuit of Fig. 3 by C4 a small value capacitor (typically 10 to 30nF) and C4 is charged negatively via a main timing capacitor C3 (value typically 30 to 150nF).
  • the capacitor C3 is connected to the mains supply side of diode D1 through the oppositely-poled diode D5, capacitors C3 and C4 being in series with this diode between starter terminals X, Y.
  • the circuit operates as follows (referring to Fig. 3).
  • the capacitors are at zero voltage.
  • the first negative going half cycle which occurs causes C4 and C3 to charge negatively through the diode D5.
  • the capacitance value of C4 is smaller than that of C3 (typically C3 ⁇ 5xC4) so C4 charges to a higher negative voltage than C3.
  • the negative voltage on C4 gives a negative voltage on the base of the clamping transistor TR2 and maintains TR2 in a non-conducting state.
  • the Fluoractor, or similar device, F acts in its thyristor mode and triggers and conducts without any modification of the operation by the clamp device TR2.
  • C4 is charged towards the Zener diode Z1 voltage via resistors R12 and R13. Values are chosen such that, at first, the voltage on the base of TR2 stays below zero.
  • the negative voltage maximum occurring at the base of TR2 can be quite high and it would be necessary with the basic circuit as given in Fig. 3 to place a diode, connected in the same sense as the base-emitter junction of TR2, in series with the base connection from R12 and R13 in order to prevent damage from too high a reverse Vbe.
  • Fig. 3 The functioning of the circuit of Fig. 3 operates in four distinct phases. Whilst the voltage on the base of TR2 is cycling below zero (the left-hand portion of Fig. 4), the Fluoractor F is triggered into conduction on each positive half cycle and provides heating current to the cathodes. This first phase of operation is illustrated by the waveforms of Fig. 5 in which dash line V S is the mains supply, full line V X is the voltage between terminals X and Y, and I A is the heating current flowing through the Fluoractor F.
  • the third phase occurs as C3 charges still further so that TR2 comes on increasingly early in the conduction period of device F. If it does so when the main current is below 200mA, device F is caused to unlatch immediately so high voltage pulsing occurs early in the positive half cycle as seen in Fig.7. In this phase there is no significant heating current.
  • the advantage of two phases of high voltage pulsing - one with heating current still applied and one without, is that under normal conditions the lamp will start as soon as the high voltage pulses start, but a lamp which is not sufficiently warm at this stage will continue to heat and start later in the second phase or if necessary in the third.
  • the starter is thus adaptive i.e. the start time adapts in length of operation to the requirements of the particular lamp.
  • Fig. 8 shows C4 connected to the opposite terminal of C3.
  • C4 is connected directly between the points X and Y through the diode D5 to be charged in negative half-cycles.
  • C4 is subject to large excursions of negative voltage, whilst C3 charges in smaller increments which accumulate over a number of cycles. The charge from C4 empties into C3 between successive negative charging half-cycles through the cathode circuit of the Fluoractor F.
  • Figs. 9 and 10 show alternative connections of the electrode of capacitor C4 remote from C3 which leads to the Y terminal. These alternatives have advantages in providing greater stability in the timed out or quiescent condition.
  • the capacitor C4 is connected to the Y side of the starter circuit via the Zener diode Z1; in Fig. 10 it is connected to the Fluoractor gate G and hence to the Y side of the circuit through internal resistance (not shown) in the gate-cathode path of the Fluoractor F and the diode 21.
  • These alternative connections of C4 can apply to circuits based on Fig. 3 or Fig. 8.
  • Fig. 11 shows the Darlington Transistor TR2 to be replaced with a Field Effect Transistor (FET) TR1 in the circuit of Fig. 3.
  • FET Field Effect Transistor
  • the FET TR1 can be substituted for the bipolar transistor TR2 generally in the various circuits that have been described.
  • capacitors C3 and C4 need a voltage rating equal to the peak mains voltage.
  • Fig. 12 shows a circuit in which this requirement is eased.
  • a resistor R16 of relatively high value is placed in series with D5 to provide a voltage drop because of the current in R15 and the charging current in C3 and C4. This resistor also has the effect of reducing the negative maximum voltage at the base of transistor TR2.
  • diode D5 must have a very high PIV rating (2000V), but if it, as well as the Fluoractor gate circuit, is fed through R1, with an extra diode D6 connecting R1 to the gate of device F, the PIV rating of D5 can be reduced to 400V.
  • diode D1 is now placed separately in the anode circuit of the Fluoractor.
  • the table of Fig. 13 shows suitable values for the starter circuit of Fig. 12. These values provide an initial start time (until the first high voltage pulse) of approximately 0.3 seconds and a total start time until time-out of approximately 0.75 seconds.

Landscapes

  • Circuit Arrangements For Discharge Lamps (AREA)
EP92305744A 1991-06-27 1992-06-23 Elektronische Zündschaltung für Leuchtstofflampen Withdrawn EP0520735A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB919113813A GB9113813D0 (en) 1991-06-27 1991-06-27 Improvements to electronic starters for fluorescent lamps
GB9113813 1991-06-27

Publications (1)

Publication Number Publication Date
EP0520735A1 true EP0520735A1 (de) 1992-12-30

Family

ID=10697372

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92305744A Withdrawn EP0520735A1 (de) 1991-06-27 1992-06-23 Elektronische Zündschaltung für Leuchtstofflampen

Country Status (2)

Country Link
EP (1) EP0520735A1 (de)
GB (1) GB9113813D0 (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2042397A2 (es) * 1991-10-15 1993-12-01 Jerez Sanchez Jose Maria Cebador electronico perfeccionado para alumbrado.
DE4329228A1 (de) * 1993-08-25 1995-03-02 Elpro Ag Verfahren und Schaltungsanordnung zum elektronischen Zünden von Leuchtstofflampen
EP0710052A1 (de) * 1994-10-28 1996-05-01 STMicroelectronics S.A. Elektronische Startschaltung für eine Leuchtstofflampe
WO2003037044A1 (en) * 2001-10-25 2003-05-01 Koninklijke Philips Electronics N.V. Safety starter for fluorescent lamps

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0170528A2 (de) * 1984-07-31 1986-02-05 David John Martin Elektronische Startschaltung für Entladungslampen
EP0333359A1 (de) * 1988-03-17 1989-09-20 THORN EMI plc Anlaufschaltungen für Entladungslampen
EP0407170A2 (de) * 1989-07-05 1991-01-09 Motorola, Inc. Ladungspumpe

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0170528A2 (de) * 1984-07-31 1986-02-05 David John Martin Elektronische Startschaltung für Entladungslampen
EP0333359A1 (de) * 1988-03-17 1989-09-20 THORN EMI plc Anlaufschaltungen für Entladungslampen
EP0407170A2 (de) * 1989-07-05 1991-01-09 Motorola, Inc. Ladungspumpe

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2042397A2 (es) * 1991-10-15 1993-12-01 Jerez Sanchez Jose Maria Cebador electronico perfeccionado para alumbrado.
DE4329228A1 (de) * 1993-08-25 1995-03-02 Elpro Ag Verfahren und Schaltungsanordnung zum elektronischen Zünden von Leuchtstofflampen
EP0710052A1 (de) * 1994-10-28 1996-05-01 STMicroelectronics S.A. Elektronische Startschaltung für eine Leuchtstofflampe
FR2726426A1 (fr) * 1994-10-28 1996-05-03 Sgs Thomson Microelectronics Starter electronique pour lampe fluorescente
US5616992A (en) * 1994-10-28 1997-04-01 Sgs-Thomson Microelectronics S.A. Electronic starter circuit for fluorescent lamp
WO2003037044A1 (en) * 2001-10-25 2003-05-01 Koninklijke Philips Electronics N.V. Safety starter for fluorescent lamps
US6731073B2 (en) 2001-10-25 2004-05-04 Koninklijke Philips Electronics N.V. Safety starter for fluorescent lamps

Also Published As

Publication number Publication date
GB9113813D0 (en) 1991-08-14

Similar Documents

Publication Publication Date Title
US4414492A (en) Electronic ballast system
US4572988A (en) High frequency ballast circuit
CA1120995A (en) Discharge lamp starter circuit
CA2184321C (en) Lamp starting circuit
US4629944A (en) Starter circuit for a fluorescent tube lamp
GB2216350A (en) Operating discharge lamps
US4673844A (en) Starter circuit for a fluorescent tube lamp
US4464585A (en) Gate circuit of gate turn-off thyristor
US4970439A (en) Power supply circuit for a gaseous discharge tube device
EP0048137B1 (de) Zündschaltung für eine Entladungsröhre
US4587463A (en) Absorbance monitor
GB2201307A (en) Electronic starter for discharge lamps
US4429359A (en) Inverter circuit with symmetry control
US4227118A (en) Circuits for operating electric discharge lamps
US4092564A (en) Discharge lamp operating circuit
EP0034401B1 (de) Schaltung für Entladungslampen
EP0033002A2 (de) Energiesparschaltung für Gasentladungslampen
US4039895A (en) Device for starting and feeding a discharge lamp
GB2234868A (en) Simplified electronic starter for fluorescent lamps
EP0011410B1 (de) Elektronische Starterschaltungen für Entladungslampen
JPS61151999A (ja) 放電ランプの小型点弧装置
US6603275B2 (en) Electronic starter for fluorescent lamps
US4426603A (en) HPS Starting aid
EP0170528A2 (de) Elektronische Startschaltung für Entladungslampen
GB2194400A (en) Starter & discharge lamp including it

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): DE ES FR GB IT SE

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

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19930701