US3857063A - Ballast circuits for discharge lamps - Google Patents

Ballast circuits for discharge lamps Download PDF

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Publication number
US3857063A
US3857063A US00332717A US33271773A US3857063A US 3857063 A US3857063 A US 3857063A US 00332717 A US00332717 A US 00332717A US 33271773 A US33271773 A US 33271773A US 3857063 A US3857063 A US 3857063A
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United States
Prior art keywords
circuit
lamp
ballast
voltage
capacitor
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Expired - Lifetime
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US00332717A
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English (en)
Inventor
P Major
K Ogden
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Thorn Electrical Industries Ltd
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Thorn Electrical Industries Ltd
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/02—Details
    • H05B41/04—Starting switches
    • H05B41/042—Starting switches using semiconductor devices
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S315/00—Electric lamp and discharge devices: systems
    • Y10S315/05—Starting and operating circuit for fluorescent lamp

Definitions

  • This invention relates to improvements in ballast circuits for discharge lamps, particularly, though not exclusively for use with mercury halide discharge lamps.
  • ballast for discharge lamps of varying degrees of effectiveness and complexity.
  • Mercury halide lamps have however proved to be particularly difficult to ballast because of the very high pre-strike voltages required to start them. This is all the more difficult when it is desired to run the lamp on direct current.
  • US. patent application Ser. No. 279,445 filed Aug. 10, 1972, now Patent. No. 3,787,751 discloses one type of ballast providing a dc output from an ac. source which produces a peak open-circuit pre-strike voltage of /2 times the r.m.s. supply voltage. This is sufficient to strike a high pressure mercury vapour discharge lamp, but insufficient to strike a mercury halide discharge lamp.
  • a similar problem will arise in a simpler ballast circuit comprising a series inductor followed by a bridge rectifier.
  • a ballast circuit for a discharge lamp comprising input terminals for connection to an a.c. source of supply, output terminals for supplying direct current to a discharge lamp, a bridge rectifier providing a first path between the input terminals and the output terminals, and an electronic voltage increasing circuit providing a second path between the input and output terminals, the voltage increasing circuit containing a sufficiently high capacitance to be effective during starting of a discharge-lamp and a sufficiently high impedance to be substantially ineffective during normal running of the lamp.
  • FIG. 1 shows a basic ballast circuit embodying the invention
  • FIG. 2 is a diagram showing lamp waveforms associated with the ballast of FIG. 1'
  • FIGS. 3, 4 and 6 show modifications of the basic circuit of FIG. 1;
  • FIG. is a diagram showing lamp waveforms associated with the ballast of FIG.-4;
  • FIGS. 7 and 8 show preferred ballasts embodying the invention.
  • FIGS. 9 and 10 show further modifications of the circuit of FIG. 1.
  • FIG. 1 shows a ballast circuit adapted to provide sufficient pre-strike voltage to enable it to be used with mercury halide discharge lamps.
  • the ballast includes two input terminals 60 to one of which is connected an inductor 62.
  • a bridge rectifier 64 comprising diodes 66, 68, 70 and 72 is connected to the inductor 62 and the other input terminal and provides an output to a lamp 74.
  • the ballast also includes a voltage doubler circuit 80 which is of itself of conventional type and when supplied with a voltage Vsinwt produces a dc output of 2V.
  • the voltage doubler circuit consists of a capacitor 82 and diode 84 connected in series across its inputs, and a diode 86 and capacitor 88 connected across the diode 84. The output is taken across the capacitor 88 and is connected to the appropriate end of the lamp 74, in this case that end which is connected to the diodes 68 and 72.
  • capacitors 82 and 88 are such that their reactances are large compared with the reactance of inductor 62.
  • suitable values for the capacitors 82 and 88 would be of the order of 0.5 microfarads.
  • the capacitors 82 and 88 must be sufficiently large to be able to supply the required current at starting but sufficiently small to have no real effect on the operation of the circuit when the lamp is running normally. That is to say, they must present a high impedance to the lamp current in normal operation.
  • the choke 62 is of conventional type.
  • the voltage doubler circuit 80 is effective to add to the voltage provided by the bridge rectifier 64.
  • the voltage doubler 80 plays no effective part in the operation of the ballast. It will be seen therefore that lamp current does not in normal operation pass through the voltage doubler circuit.
  • the voltage doubler circuit has two functions, first to provide sufficient voltage across the lamp to ionise the starting gas, and second to pass sufficient energy through the gas and lamp electrodes to establish a state of conduction in the discharge which can be maintained by the lower supply voltage. This second phase of starting is the result of capacitor discharge.
  • the bridge comprises two bridge circuits with certain circuit elements in common.
  • the first bridge consists of inductor 50, and diodes 54, 58, 46 and 48, and the second bridge consists of capacitor 49, and diodes 52, 56, 46 and 48.
  • the outputs of the bridges are effectively added, and in this way a high power factor can be obtained.
  • the voltage doubler circuit 80 itself is identical to that of FIG.
  • the polarity of the diodes84 and 86 may be reversed. In this case, the output of the voltage doubler circuit 80 in FIG. 1 is connected to the other terminal of the lamp 74. All these modifications produce an open-circuit pre-strike voltage of the form shown in FIG. 2.
  • diodes 84 and 86 are effectively in parallel with diode 72.
  • diode 72 can be removed without affecting the operation of the circuit, as shown in FIG. 4.
  • the capacitor 88 has been removed.
  • the opencircuit voltage V8436 across the two diodes 84 and 86 is now sinusoidal with a mean of +V volts and peak of +2V volts, as shown in FIG. 5.
  • the voltage V across diode 70 is as before, and the open-circuit pre-strike voltage V across the lamp is thus as shown in FIG. 5, having a peak of 2V and minimum of V volts. This peak voltage is still sufficient to strike-a mercury iodide discharge lamp at a supply voltage of 200 250 volts r.m.s.
  • the diode 86 no longer serves any useful circuit function, as it is effectively in series with diode 70, and can be replaced by a direction connection. This gives rise to the circuit shown in FIG. 6, here again the peak open-circuit pre-strike voltage across the lamp is twice the r.m.s. supply voltage.
  • FIG. 6 can benefit from the addition of a resistor in series with the capacitor 82 to prevent extinction of the lamp during run-up.
  • a resistor is included in FIG. 7, which shows a preferred embodiment of the invention in which the capacitor 82 is connected through resistor 90 to the other one of the input terminals.
  • capacitor 82 is 2 microfarads
  • resistor 90 is l kilohm. The resistor 90 reduces the current through the capacitor 82 when the voltage reverses across diode 70, thus preventing the capacitor 82 drawing so much current that the lamp would extinguish.
  • the circuit of FIG. 8 is based on FIG. 7 and uses the same component values but is adapted to provide an open-circuit voltage across the lamp of Vsinwt 2V resulting in a peak pre-strike lamp voltage of 3V.
  • the circuit includes two capacitors 82 and 82" connected in series with respective resistors 90' and 92" to the two ends of the lamp 74.
  • FIG. 8 is in fact based on the circuit of FIG. 1 with a further voltage doubler of opposite polarity connected between the other supply input terminal 60 and the other end of the lamp 74.
  • a circuit which included two voltage doubler's of the type 80 shown in FIG. 1 would produce a voltage across the lamp 74 of 4V Vsinwt, giving a peak of 5V.
  • capacitors 82 and 88 are charged to V and 2V respectively, and the pre-strike voltage has the form shown in FIG. 2. This can be increased to a steady 3V by the addition of a further capacitor 94 in parallel with diode 70, which is charged to the peak supply voltage V through diode 66, as shown in FIG. 10. Also shown in this figure are resistors 96 and 98 in series with capacitors 88 and 94 respectively to prevent extinction of the lamp during run-up.
  • circuits illustrated enable mercury halide discharge lamps to be operated on d.c. circuits with a high starting voltage.
  • a transformerless ballast circuit for a metal halide discharge lamp comprising:
  • a ballast circuit including a second capacitor and a second resistor connected in second series circuit coupling the other of said input terminals and the other of said output terminals, said second series circuit also presenting a sufficiently high capacitance to be effective during starting of said discharge lamp and a sufficiently high impedance to be substantially ineffective during run-up and normal running of said lamp.
  • a ballast circuit according to claim 1 including a choke between one of said input terminals and said bridge rectifier.

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  • Circuit Arrangements For Discharge Lamps (AREA)
US00332717A 1972-02-16 1973-02-15 Ballast circuits for discharge lamps Expired - Lifetime US3857063A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB725772A GB1387842A (en) 1972-02-16 1972-02-16 Ballast circuits for discharge lamps

Publications (1)

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US3857063A true US3857063A (en) 1974-12-24

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Application Number Title Priority Date Filing Date
US00332717A Expired - Lifetime US3857063A (en) 1972-02-16 1973-02-15 Ballast circuits for discharge lamps

Country Status (7)

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US (1) US3857063A (xx)
AU (1) AU5227673A (xx)
DE (1) DE2307416A1 (xx)
GB (1) GB1387842A (xx)
IN (1) IN137730B (xx)
NL (1) NL7302136A (xx)
ZA (1) ZA731022B (xx)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4260932A (en) * 1978-10-12 1981-04-07 Vance Johnson Method and circuit for facilitating the starting and steady state flickerless operation of a discharge lamp
WO1983001555A1 (en) * 1981-10-13 1983-04-28 Lights Of America Inc Circuit for starting and operating discharge lamps
US4394603A (en) * 1978-09-26 1983-07-19 Controlled Environment Systems Inc. Energy conserving automatic light output system
US4463285A (en) * 1982-03-08 1984-07-31 Nilssen Ole K DC Ballasting means for fluorescent lamps
US4611148A (en) * 1983-02-21 1986-09-09 Hitachi, Ltd. Low-pressure mercury vapor discharge lamp
US4929871A (en) * 1986-06-16 1990-05-29 Gerfast Sten R Transformerless current-limiting circuit
US5447583A (en) * 1992-04-29 1995-09-05 Aluminum Company Of America Extrusion quenching apparatus and related method
US20080205108A1 (en) * 2007-02-28 2008-08-28 Sanden Corporation Power Converter Apparatus

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2454246A1 (fr) * 1979-04-12 1980-11-07 Gen Electric Circuit d'amorcage pour lampe a arc du type haute intensite, haute pression remplie avec un gaz
JPS5782100U (xx) * 1980-11-07 1982-05-20
HU191319B (en) * 1985-03-11 1987-02-27 Sebestyen,Laszlo,Hu Method and circuit arrangement for firing light sources of high firing voltage
DE3614708A1 (de) * 1986-04-30 1987-11-19 Schmidt Michael Steuerschaltung fuer eine lichtbogenlampe

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2892126A (en) * 1956-12-26 1959-06-23 Gen Electric Starting and operating circuit for arc discharge device
US3170084A (en) * 1961-11-03 1965-02-16 Westinghouse Electric Corp Lamp starting and operating circuit
US3354379A (en) * 1966-01-26 1967-11-21 Gen Electric Rectifier circuit with voltage multiplication
US3676735A (en) * 1969-09-25 1972-07-11 Sylvania Electric Prod Resonator ballast for arc discharge lamps
US3679934A (en) * 1970-02-05 1972-07-25 Hewlett Packard Co Automatic restarting laser power supply
US3758815A (en) * 1972-01-04 1973-09-11 Gte Sylvania Inc Supplemental energy storage circuit for arc discharge lamps

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2892126A (en) * 1956-12-26 1959-06-23 Gen Electric Starting and operating circuit for arc discharge device
US3170084A (en) * 1961-11-03 1965-02-16 Westinghouse Electric Corp Lamp starting and operating circuit
US3354379A (en) * 1966-01-26 1967-11-21 Gen Electric Rectifier circuit with voltage multiplication
US3676735A (en) * 1969-09-25 1972-07-11 Sylvania Electric Prod Resonator ballast for arc discharge lamps
US3679934A (en) * 1970-02-05 1972-07-25 Hewlett Packard Co Automatic restarting laser power supply
US3758815A (en) * 1972-01-04 1973-09-11 Gte Sylvania Inc Supplemental energy storage circuit for arc discharge lamps

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4394603A (en) * 1978-09-26 1983-07-19 Controlled Environment Systems Inc. Energy conserving automatic light output system
US4260932A (en) * 1978-10-12 1981-04-07 Vance Johnson Method and circuit for facilitating the starting and steady state flickerless operation of a discharge lamp
WO1983001555A1 (en) * 1981-10-13 1983-04-28 Lights Of America Inc Circuit for starting and operating discharge lamps
US4463285A (en) * 1982-03-08 1984-07-31 Nilssen Ole K DC Ballasting means for fluorescent lamps
US4611148A (en) * 1983-02-21 1986-09-09 Hitachi, Ltd. Low-pressure mercury vapor discharge lamp
US4697121A (en) * 1983-02-21 1987-09-29 Hitachi, Ltd. Low-pressure mercury vapor discharge lamp
US4929871A (en) * 1986-06-16 1990-05-29 Gerfast Sten R Transformerless current-limiting circuit
US5447583A (en) * 1992-04-29 1995-09-05 Aluminum Company Of America Extrusion quenching apparatus and related method
US20080205108A1 (en) * 2007-02-28 2008-08-28 Sanden Corporation Power Converter Apparatus

Also Published As

Publication number Publication date
AU5227673A (en) 1974-08-22
GB1387842A (en) 1975-03-19
ZA731022B (en) 1973-11-28
IN137730B (xx) 1975-09-13
DE2307416A1 (de) 1973-08-23
NL7302136A (xx) 1973-08-20

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