US3508112A - Circuit for applying ionizing pulses and boosted alternating current to an arc discharge lamp - Google Patents

Circuit for applying ionizing pulses and boosted alternating current to an arc discharge lamp Download PDF

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US3508112A
US3508112A US649917A US3508112DA US3508112A US 3508112 A US3508112 A US 3508112A US 649917 A US649917 A US 649917A US 3508112D A US3508112D A US 3508112DA US 3508112 A US3508112 A US 3508112A
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circuit
lamp
alternating current
voltage
arc discharge
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US649917A
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Sandford C Peek
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GTE Sylvania Inc
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Sylvania Electric Products Inc
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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
    • H05B41/14—Circuit arrangements
    • H05B41/16—Circuit arrangements in which the lamp is fed by dc or by low-frequency ac, e.g. by 50 cycles/sec ac, or with network frequencies
    • H05B41/20—Circuit arrangements in which the lamp is fed by dc or by low-frequency ac, e.g. by 50 cycles/sec ac, or with network frequencies having no starting switch
    • H05B41/23—Circuit arrangements in which the lamp is fed by dc or by low-frequency ac, e.g. by 50 cycles/sec ac, or with network frequencies having no starting switch for lamps not having an auxiliary starting electrode
    • H05B41/232—Circuit arrangements in which the lamp is fed by dc or by low-frequency ac, e.g. by 50 cycles/sec ac, or with network frequencies having no starting switch for lamps not having an auxiliary starting electrode for low-pressure lamps
    • 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
    • Y10S315/07—Starting and control circuits for gas discharge lamp using transistors

Definitions

  • Conventional fluorescent lamp starting and operating circuits have comprised a ballast for applying a high starting voltage to the lamp to ionize it and start discharge and for inductively limiting current through the ionized lamp. Because of the Weight and bulk of the ballast and its high expense, heating and noise, control circuits have been proposed which start and control the lamp discharge by various electronic switching circuits. Some of the advanced electronically valved circuits comprise pulse generating or gating means for periodically applying a voltage pulse to the lamp thereby ionizing the lamp sufficiently to support an arc discharge for a limited period, usually a half-cycle or less of the alternating current supply.
  • ionizing pulse generation circuits limit the amount of ionization and the amplitude of the ionizing pulses and are adversely afiected by line voltage drops.
  • an arc discharge lamp operating circuit comprises discharge terminals for connection to the lamp, power terminals for connection to a supply of alternating current, a power circuit connecting said power terminals to said discharge terminals including means for applying periodic voltage pulses to said discharge terminals thereby to support an arc discharge by ionization in the lamp and to draw current from said alternating current supply, and a transformer having a primary connected between said power terminals and a secondary connected between one power terminal and one lamp terminal, said primary and secondary being connected such that current in said primary induces current in said secondary substantially in phase with the supply current in said secondary.
  • FIG. 1 is a schematic diagram of a fluorescent lamp operating circuit according to the invention.
  • the operating circuit of FIG. 1 comprises discharge terminals 1 between which are connected two four foot HO lamps L which may be considered as a single lamp.
  • Power for the lamps is supplied from 115 volt, 60 cycle alternating current terminals A and C.
  • Power terminal A is connected to a lamp terminal I through an autotransformer primary T1 and secondary T2 having a turns ratio 3,508,112 Patented Apr. 21, 1970 ICC of 1 to 10 and negligible reactance.
  • Power terminal C is connected to a lamp terminal I through the secondary T4 of a core transformer having a primary T3.
  • the core transformer has a turns ratio of 12 in the primary to l in the secondary and is hence a stepdown transformer.
  • the primary T3 being connected across the 120 volt power terminals A and C, induces about 10 volts in the secondary in phase with line current in the secondary, thereby boosting the RMS value of voltage applied to the lamp.
  • the core transformer reactance is of negligible reactance, e.g. less than ohms, compared to a conventional ballast.
  • a voltage pulse discharging circuit includes a triac V1 (G.E. type SC45B), a diac D1 (G.E. type 5T2), a primary voltage pulse storage capacitor C1 (6 mircrofarad) a secondary storage capacitor C2 (0.33 microfarad) and a coupling capacitor C3 (0.07 microfarad).
  • the primary storage capacitor C1 and triac T1 are connected in series between the power terminals A and C through the autotransformer primary T1, so that during each half-cycle of alternating current the primary storage capacitor C1 charges, through the triac T1. In the succeeding halfcycle the voltage across the secondary capacitor C2 rises toward the breakdown voltage of the diac D1.
  • the diac D1 When this breakdown voltage is exceeded the diac D1 conducts allowing the secondary capacitor C2 to discharge to the gate electrode g of the triac and trigger the triac into avalanche conduction.
  • the primary capacitor then discharges through the triac and autotransformer primary and reverses its charge.
  • the discharge voltage is stepped up by the 1 to 3 ratio of primary to secondary, and the stepped up voltage (eg 300 volts peak) is applied to the lamp terminals 1.
  • the stepped up voltage eg 300 volts peak
  • the amplitude of the ionizing pulse will drop and the lamps may be insufficiently ionized to start discharge or to maintain discharge until the next pulse is applied.
  • the lamps might therefore fail to ignite, extinguish intermittently or flicker objectionably.
  • the core transformer T3, T4 adds a small increment of voltage to the ionizing pulse and to the open circuit voltage applied to the lamps. With one to twelve turns ratio the transformer adds an increment of one-twelfth the line voltage, about ten volts, which is adequate to maintain the voltage for which the lamps and pulsing circuit are designed with expected drops of line voltage, and yet does not increase the ionizing pulse peak voltage so much as to excessively ionize the lamp at or expectably above normal line voltage.
  • the transformer T3, T4 thus substantially increases the reliability of the operating circuit.
  • An arc discharge lamp operating circuit comprising:
  • a power circuit connecting said power terminals to said discharge terminals, and means outside said power circuit for storing and applying periodic voltage pulses to said discharge terminals superimposed on said supply current thereby to support an arc discharge by ionization in the lamp and to draw current from said alternating current supply, and
  • 3 4 a transformer of negligible reactance having a primary References Cit d connected across said power terminals and a secondary connected between one power terminal and one UNITED STATES PATENTS lamp terminal, the windings of said primary and 3,414,768 12 1968 Peek 315--240 secondary being connected in additive voltage phase, 2,944,163 7/ 1960 Walsh 30788 whereby alternating supply current in said primary 5 3,129,380 4/1964 LiChOWSkY 32345 induces current in said secondary substantially in 3,346,874 10/1967 WE 3078 8.5 phase with and in increase of the supply current in 3,310,687 1967 Howell 307-88.5

Description

Aprll 21, 1970 s, C PEEK 3,508,112
CIRCUIT FOR APPLYING IONIZLNG PULSES AND BOOSTED ALTERNATING CURRENT TO AN ARC DISCHARGE LAMP Flled June 29, 1967 United States Patent U.S. Cl. 315240 3 Claims ABSTRACT OF THE DISCLOSURE An electronic circuit having a pulse generating circuit for applying ionizing pulses to a fluorescent lamp which draws discharge current from an alternating current supply, and a transformer connected to the supply for boosting the alternating current applied to the lamp.
Conventional fluorescent lamp starting and operating circuits have comprised a ballast for applying a high starting voltage to the lamp to ionize it and start discharge and for inductively limiting current through the ionized lamp. Because of the Weight and bulk of the ballast and its high expense, heating and noise, control circuits have been proposed which start and control the lamp discharge by various electronic switching circuits. Some of the advanced electronically valved circuits comprise pulse generating or gating means for periodically applying a voltage pulse to the lamp thereby ionizing the lamp sufficiently to support an arc discharge for a limited period, usually a half-cycle or less of the alternating current supply. Because standard lamps and operating circuits are designed for about 110 volt operation at least, they may fail to operate properly if the alternating current supply voltages drop much below 110 volts. Unlike ballast circuits which apply an ionizing voltage well above that required for continuous operation, ionizing pulse generation circuits limit the amount of ionization and the amplitude of the ionizing pulses and are adversely afiected by line voltage drops.
It is the object of the present invention to provide an electronic pulsing circuit of the type described above with means for insuring that the ionizing discharge voltage is adequate for continuous operation of the lamp.
According to the invention an arc discharge lamp operating circuit comprises discharge terminals for connection to the lamp, power terminals for connection to a supply of alternating current, a power circuit connecting said power terminals to said discharge terminals including means for applying periodic voltage pulses to said discharge terminals thereby to support an arc discharge by ionization in the lamp and to draw current from said alternating current supply, and a transformer having a primary connected between said power terminals and a secondary connected between one power terminal and one lamp terminal, said primary and secondary being connected such that current in said primary induces current in said secondary substantially in phase with the supply current in said secondary.
For the purpose of illustration typical embodiments of the invention are shown in the accompanying drawing, in which FIG. 1 is a schematic diagram of a fluorescent lamp operating circuit according to the invention.
The operating circuit of FIG. 1 comprises discharge terminals 1 between which are connected two four foot HO lamps L which may be considered as a single lamp. Power for the lamps is supplied from 115 volt, 60 cycle alternating current terminals A and C. Power terminal A is connected to a lamp terminal I through an autotransformer primary T1 and secondary T2 having a turns ratio 3,508,112 Patented Apr. 21, 1970 ICC of 1 to 10 and negligible reactance. Power terminal C is connected to a lamp terminal I through the secondary T4 of a core transformer having a primary T3. The core transformer has a turns ratio of 12 in the primary to l in the secondary and is hence a stepdown transformer. The primary T3, being connected across the 120 volt power terminals A and C, induces about 10 volts in the secondary in phase with line current in the secondary, thereby boosting the RMS value of voltage applied to the lamp. The core transformer reactance is of negligible reactance, e.g. less than ohms, compared to a conventional ballast.
A voltage pulse discharging circuit includes a triac V1 (G.E. type SC45B), a diac D1 (G.E. type 5T2), a primary voltage pulse storage capacitor C1 (6 mircrofarad) a secondary storage capacitor C2 (0.33 microfarad) and a coupling capacitor C3 (0.07 microfarad). The primary storage capacitor C1 and triac T1 are connected in series between the power terminals A and C through the autotransformer primary T1, so that during each half-cycle of alternating current the primary storage capacitor C1 charges, through the triac T1. In the succeeding halfcycle the voltage across the secondary capacitor C2 rises toward the breakdown voltage of the diac D1. When this breakdown voltage is exceeded the diac D1 conducts allowing the secondary capacitor C2 to discharge to the gate electrode g of the triac and trigger the triac into avalanche conduction. The primary capacitor then discharges through the triac and autotransformer primary and reverses its charge. The discharge voltage is stepped up by the 1 to 3 ratio of primary to secondary, and the stepped up voltage (eg 300 volts peak) is applied to the lamp terminals 1. At this instant a limited number of ions are established in the lamps L, and the lamps fully ignite and conduct line current for part or all of the half-cycle. About when the line voltage passes through zero the arc tends to extinguish depending on the amplitude and duration of the ionizing pulse. If the line voltage drops, the amplitude of the ionizing pulse will drop and the lamps may be insufficiently ionized to start discharge or to maintain discharge until the next pulse is applied. The lamps might therefore fail to ignite, extinguish intermittently or flicker objectionably.
According to the present invention the core transformer T3, T4 adds a small increment of voltage to the ionizing pulse and to the open circuit voltage applied to the lamps. With one to twelve turns ratio the transformer adds an increment of one-twelfth the line voltage, about ten volts, which is adequate to maintain the voltage for which the lamps and pulsing circuit are designed with expected drops of line voltage, and yet does not increase the ionizing pulse peak voltage so much as to excessively ionize the lamp at or expectably above normal line voltage. The transformer T3, T4 thus substantially increases the reliability of the operating circuit.
While one desirable embodiment of the invention has herein been disclosed by way of example, it is to be understood that the invention is broadly inclusive of any and all modifications falling within the terms of the appended claims.
Iclaim:
1. An arc discharge lamp operating circuit comprising:
discharge terminals for connection to the lamp,
power terminals for connection to a supply of alternating current,
a power circuit connecting said power terminals to said discharge terminals, and means outside said power circuit for storing and applying periodic voltage pulses to said discharge terminals superimposed on said supply current thereby to support an arc discharge by ionization in the lamp and to draw current from said alternating current supply, and
3 4 a transformer of negligible reactance having a primary References Cit d connected across said power terminals and a secondary connected between one power terminal and one UNITED STATES PATENTS lamp terminal, the windings of said primary and 3,414,768 12 1968 Peek 315--240 secondary being connected in additive voltage phase, 2,944,163 7/ 1960 Walsh 30788 whereby alternating supply current in said primary 5 3,129,380 4/1964 LiChOWSkY 32345 induces current in said secondary substantially in 3,346,874 10/1967 WE 3078 8.5 phase with and in increase of the supply current in 3,310,687 1967 Howell 307-88.5
said secondary from said supply terminals. 2. A circuit according to claim 1 wherein said trans JOHN HUOKERT Pnmary Exammer former has a step-down turns ratio. B. ESTRIN, Assistant Examiner 3. A circuit according to claim 1 wherein the secondary to primary turns ratio of said transformer is a minor US Cl. X.R.
fraction. 315100, 289; 32324, 45
US649917A 1967-06-29 1967-06-29 Circuit for applying ionizing pulses and boosted alternating current to an arc discharge lamp Expired - Lifetime US3508112A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3643127A (en) * 1968-11-20 1972-02-15 Auco Nv Electronic gas discharge tube starter having a semiconductor switch element controlled by a capacitive voltage divider
US3728610A (en) * 1970-09-21 1973-04-17 H Switsen Constant power regulator from ac source
US3732460A (en) * 1972-01-28 1973-05-08 Gen Electric Circuit for instant restart of high pressure discharge lamp
US4527098A (en) * 1983-01-28 1985-07-02 General Electric Company Discrete starter for HID lamp
US5945784A (en) * 1997-12-09 1999-08-31 Philips Electronics North America Corporation High intensity discharge ballast

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4965672A (en) * 1972-10-31 1974-06-25
FR2507052B1 (en) * 1981-06-02 1985-08-09 Astier Jean DEVICE FOR PRIMING LAMPS OF THE DISCHARGE LIGHTING LAMP TYPE AND FLUORESCENT LAMPS

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2944163A (en) * 1958-03-24 1960-07-05 Philip J Walsh Automatic control apparatus
US3129380A (en) * 1961-06-23 1964-04-14 Ampex Buck boost transformer controlled by silicon controlled rectifier
US3310687A (en) * 1964-02-07 1967-03-21 Gen Electric Power control circuits utilizing a bi-directional semiconductor
US3346874A (en) * 1964-02-07 1967-10-10 Gen Electric Power control circuits
US3414768A (en) * 1966-01-03 1968-12-03 Sylvania Electric Prod Semiconductor ballast for discharge lamp

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2944163A (en) * 1958-03-24 1960-07-05 Philip J Walsh Automatic control apparatus
US3129380A (en) * 1961-06-23 1964-04-14 Ampex Buck boost transformer controlled by silicon controlled rectifier
US3310687A (en) * 1964-02-07 1967-03-21 Gen Electric Power control circuits utilizing a bi-directional semiconductor
US3346874A (en) * 1964-02-07 1967-10-10 Gen Electric Power control circuits
US3414768A (en) * 1966-01-03 1968-12-03 Sylvania Electric Prod Semiconductor ballast for discharge lamp

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3643127A (en) * 1968-11-20 1972-02-15 Auco Nv Electronic gas discharge tube starter having a semiconductor switch element controlled by a capacitive voltage divider
US3728610A (en) * 1970-09-21 1973-04-17 H Switsen Constant power regulator from ac source
US3732460A (en) * 1972-01-28 1973-05-08 Gen Electric Circuit for instant restart of high pressure discharge lamp
US4527098A (en) * 1983-01-28 1985-07-02 General Electric Company Discrete starter for HID lamp
US5945784A (en) * 1997-12-09 1999-08-31 Philips Electronics North America Corporation High intensity discharge ballast

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