ELECTRIC CIRCUIT FOR RAPIDLY IGNITING A DISCHARGE TUBE

• US 3,676,734 A
• Filed: 11/14/1969
• Issued: 07/11/1972
• Est. Priority Date: 11/15/1968
• Status: Expired due to Term

• Current Assignee: Makoto Iwakura, Tetsuji Shimizu
• Original Assignee: Makoto Iwakura, Tetsuji Shimizu
• Inventors: Shimizu, Tetsuji, Iwakura, Makoto
• Primary Examiner(s): Lake, Roy
• Assistant Examiner(s): Dahl, Lawrence J.
• Application Number:
  US04/876,898
• Time in Patent Office: 970 Days
• Field of Search: 315/100,1U,200,219,227,258
• US Class Current: 315/200.00R
• CPC Class Codes: H05B 41/046 using controlled semiconductor devices

Abstract

This invention discloses a circuit for rapidly and certainly igniting a discharge tube such as a fluorescent lamp, mercury-arc lamp, neon tube lamp or the like, which comprises a capacitor adapted to effect charge or discharge thereof at substantially the peak value of AC wave of power source by the action of a switching means, a transformer or ballast choke coil which is adapted to produce high voltage pulse in response to said charge or discharge of the capacitor, said high voltage pulse being applied to a discharge tube at its electrodes which are preliminarily heated thereby to ignite the discharge tube. According to this invention, simultaneously when a power source is closed, a high voltage is generated at substantially the peak value of positive and/or negative half cycle of the AC power source by the operation of a specific circuit, thereby enabling the discharge tube to be rapidly or instantaneously ignited. The present circuit is very useful for various commercial purposes.

Claims

1. A circuit for rapidly and certainly igniting a discharge lamp, comprising in combination:

a power source having a fluctuating output voltage amplitude, means energizable from said source for preliminarily heating the electrodes of said discharge lamp, a capacitor, switching means actuable for rapidly changing the charge condition of said capacitor and including a switch, means for connecting said capacitor to said switching means, actuating means connected to said power source and switching means responsive to the phase of said power source for actuating said switching means at substantially the peak value of said output voltage of said power source, inductor means for producing a high voltage pulse in response to said change of said charge condition of said capacitor, means for connecting said inductor means to said capacitor and said switching means, and means applying said high voltage pulse to said discharge lamp at said electrodes.

2. An ignition starting circuit for a discharge lamp, comprising in combination:

an A.C. power source, a transistor having a control electrode, an initial stage SCR having a gate, means connecting the gate of said initial SCR with said power source for turning on said initial SCR during a positive half cycle of said source, means interconnecting the gate of said initial SCR and the control electrode of said transistor for rendering said transistor conductive upon conduction of said initial SCR, a subsequent stage SCR having a gate, means connected to the gate of said subsequent SCR for turning on said subsequent SCR prior to conduction of said initial SCR, and means connecting said transistor to the gate of said subsequent SCR for interrupting gate current thereof on conduction of said transistor to prevent further conduction of said subsequent SCR, said initial stage SCR and said subsequent stage SCR having further electrodes and at said further electrodes being connected in parallel and with the same polarity across each of the discharge lamp and A.C. power source, a ballast choke coil and means connecting same in series with said source and lamp and to said subsequent SCR for applying a high-voltage counter electromotive force to said lamp in response to the turn-off of said subsequent stage SCR so as to effect a discharge through said lamp, said subsequent SCR flowing current through said coil from said source when turned on.

3. An electric circuit for producing a pulse for igniting a fluorescent lamp, comprising in combination:

an A.C. power source, a ballast choke coil in circuit with said lamp and source, a thyristor and a neon tube lamp and means connecting said neon tube lamp to the gate of said thyristor and to said A.C. source for enabling said thyristor for conduction substantially at a voltage peak of said A.C. supply, a further coil, a capacitor and means connecting said further coil and capacitor in series with said thyristor across said source for producing a pulse in said further coil substantially at said peak in response to discharge of said capacitor through said thyristor and source and further coil, and means inductively coupling said further coil to said lamp for substantially simultaneously applying a high voltage to said lamp to initiate discharge of said lamp, said fluorescent lamp being kept ignited by current flow thereto from said source through said ballast choke coil.

4. An electric circuit for igniting a plurality of discharge lamps, comprising in combination:

a plurality of ballast choke coils, a power source, means connecting said plurality of discharge lamps in parallel to said power source through respective ones of said ballast choke coils, a diode and a capacitor and means connecting said diode and capacitor in series with said source for charging said capacitor during a negative half cycle of power source voltage through said diode, a semiconductor controlled rectifier element, an oscillation producing coil and means connecting said controlled rectifier element and oscillation coil to said capacitor for causing said capacitor to discharge as well as be inversely charged by said controlled rectifier element when said controlled rectifier element is turned on, thereby producing a high-voltage pulse in said oscillation producing coil usable for igniting said plurality of discharge lamps, and a plurality of neon tube lamps and means connecting each said neon tube lamp between a gate of said controlled rectifier element and a respective one of said ballast choke coils for causing said controlled rectifier element to turn on at substantially the peak of the positive half cycle of said power source.

5. An electric circuit for igniting a discharge lamp, comprising in combination:

a power source;

means for preheating the filaments of said discharge lamp including a controlled rectifier element adapted to turn on at substantially the peak of positive half cycle of the power source voltage and connected between filaments of said discharge lamp; and

a high-voltage pulse generating circuit comprising a capacitor and means connecting said capacitor to said source for charging said capacitor at the negative half cycle of power source voltage, a transformer, means connecting the secondary side of said transformer to said lamp, and means connecting said capacitor and the primary side of said transformer to said controlled rectifier element for rapidly inversely charging said capacitor at substantially the peak of the positive half cycle of said power source in a manner that said charging current produces an oscillating pulse at the primary side of said transformer, said pulse is raised to excite a high-voltage oscillating pulse at the secondary side thereof, and said high-voltage oscillating pulse is impressed on said filaments to ignite said discharge lamp.

6. An electric circuit for igniting a plurality of discharge lamps, comprising in combination:

an A.C. power source;

a controlled rectifier circuit including a controlled rectifier element;

a filament preheating circuit including means connecting said controlled rectifier element in circuit with the filaments of said discharge lamps and said source for preheating the respective filaments by conduction through said controlled rectifier element;

a high-voltage pulse generating circuit including a capacitor, means connecting said capacitor to said source for charging said capacitor during the negative half cycle of said source voltage, a transformer, meAns connecting the secondary side of said transformer to said lamps, and means connecting the primary side of said transformer and said capacitor in common to said controlled rectifier circuit and responsive to conduction of said controlled rectifier element for rapidly inversely charging said capacitor at substantially the peak of the positive half cycle of said source voltage in a manner that the capacitor inverse charging current produces an oscillating pulse at the primary side of said transformer, said pulse is raised in voltage to provide a high-voltage oscillating pulse at the secondary side of said transformer and the high-voltage oscillating pulse is impressed on said filaments to ignite said plurality of discharge lamps and a gate current controlling circuit including neon lamps and means connecting said neon lamps to the filaments of respective ones of said discharge lamps, said gate current controlling circuit feeding current to a gate of said controlled rectifier element to turn on said controlled rectifier element at substantially the peak of the positive half cycle of said source.

7. A discharge lamp igniting circuit, comprising in combination:

an A.C. power source, a discharge lamp, a transformer having a secondary coil and a primary coil, means connecting said secondary coil across said lamp, a ballast choking coil, means connecting said secondary coil across said A.C. power source through said ballast choking coil, a capacitor, a resistor, means connecting said primary coil of said transformer and said capacitor and said resistor in a series circuit across said A.C. power source, a switch operable at substantially the peak of both positive and negative half cycles of the power source voltage and means connecting said switch across a portion of said series circuit for causing said secondary coil to produce a high voltage pulse utilizing transient phenomena caused by charge and discharge of said capacitor upon operation of said switch, whereupon the thus produced high voltage pulse produces a counter electromotive force on the ballast choke coil and then said high-voltage pulse, counter electromotive force and power source voltage are applied to the discharge lamp.

8. A discharge lamp igniting circuit, comprising in combination:

an A.C. power source, a discharge lamp, a transformer having a secondary coil and a primary coil, means connecting said secondary coil across said lamp, a ballast choke coil, means connecting said secondary coil in parallel to said A.C. power source through said ballast choke coil, a series circuit connected across said A.C. power source and including said primary coil of said transformer as well as a capacitor and a diode for making approximately twice charging or discharging current of said capacitor and applying it every cycle of A.C. voltage, a switch which operates at substantially the peak of the positive or negative half cycles of the power source voltage and means connecting said switch across a portion of said series circuit for causing said secondary coil to produce a high voltage pulse utilizing transient phenomena caused every cycle by charging and discharging of said capacitor whereupon the thus produced high voltage pulse produces a counter electromotive force on the ballast choke coil and then said high voltage pulse, counter electromotive force and power source voltage are applied to the discharge lamp.

9. A discharge lamp igniting electric circuit, comprising in combination:

an A.C. power source, a ballast choke coil, a discharge lamp and a transformer having a secondary coil connected in parallel to said A.C. power source through said ballast choke coil, a series circuit connected across said A.C. source and comprising a primary coil of said transformer as well as a capacitor and a current flow control device of a type capable of continuously passing D.C. current in at least one direction, a switch connected across a portion of said series circuit and adapted to synchronize with substantiAlly the peak voltage of said A.C. source, tertiary and biquadratic coils and means inductively energizing same from said A.C. source for preheating filaments of said discharge lamp, said tertiary and biquadratic coils being combined into a unitary coil, the secondary coil being inductively coupled at least to said primary coil for producing a high-voltage pulse utilizing a transient phenomena caused by charging and discharging of said capacitor, whereupon the thus produced high-voltage pulse produces a counter-electromotive force at the ballast choke coil, said tertiary and biquadratic coil producing a pulse voltage proportional to that of the primary coil.

10. A circuit for sequentially igniting a plurality of fluorescent lamps, comprising in combination:

a power source;

lamp circuits each including a ballast choke coil connected between said source and a corresponding lamp, said ballast choke coil having a secondary coil, a capacitor chargeable from said source, a thyristor, a neon tube, means connecting said neon tube to said source and thyristor for turning said thyristor on at substantially the peak of the power source voltage, and means connecting said capacitor to said secondary coil and thyristor for causing discharge of said capacitor therethrough to produce a high voltage pulse in the ballast choke coil for igniting the corresponding one of said lamps, said lamp circuits being interconnected;

a plurality of transistors and means connecting each said transistor to a corresponding one of said lamp circuits for rendering each said lamp circuit inoperative when the corresponding one of said transistors is rendered conductive; and

control circuit means for controlling the conductive state of said transistors and connected to said transistors, said control circuit means including a transistor circuit for each said transistor, each said transistor circuit having two further transistors connected to a time constant circuit, and further including means interconnecting said transistor circuits for igniting said fluorescent lamps sequentially and for extinguishing said fluorescent lamps all at once after being ignited.

11. An electric circuit for flashing an A.C. load, comprising in combination:

an A.C. power source;

a rectifier circuit having an A.C. side and a D.C. side, said A.C. side being connected to said A.C. power source through said A.C. load;

a time constant circuit connected across the D.C. side of said rectifier circuit and including a resistor and capacitor;

an SCR connected across said D.C. side of said rectifier circuit;

means including a Zener diode connecting said capacitor to a gate of said SCR for turning on said SCR with current flowing to said gate thereof when the charging voltage of said capacitor of said time constant circuit is raised to exceed the Zener voltage of said Zener diode thereby to cause said capacitor of said time constant circuit to discharge;

a diode and means connecting said diode from a point between said capacitor and Zener to a point between said SCR and said rectifier circuit for maintaining conduction of said SCR for a predetermined period of time thereby to energize the load.

12. The circuit of claim 3 in which said further coil is inductively coupled to said ballast coil so that said pulse in said further coil induces a high voltage pulse in said ballast coil, said ballast coil applying said further high voltage pulse to said fluorescent lamp for discharging same substantially at said peak of said source.

13. The circuit of claim 3 including a still further coil and means connecting same in series with said fluorescent lamp, said still further coil being inductively coupled to said further coil for discharging said fluorescent lamp upon appearance of said pulse.

14. The circuit of claim 3 including a diode in series with said thyristor and means connecting said source, said ballast choke coil, said diode and thyristor in seriEs loop with the electrodes of said fluorescent lamp for preheating said electrodes when said thyristor conducts.

15. The circuit of claim 4 in which said oscillation coil is inductively coupled to each of said ballast coils so that said high voltage pulse in said oscillation coil produces higher voltage pulses in each of said ballast coils, said ballast coils applying said higher voltage pulses to respective ones of said discharge lamps for igniting same.

16. The circuit of claim 4 including a further coil inductively coupled with said oscillation coil, and means connecting said further coil in series with each of said discharge lamps for igniting said discharge lamps upon appearance of said high voltage pulse.

17. The circuit of claim 4 including means for connecting each of said neon tube lamps in parallel with the corresponding one of said discharge lamps for causing ignition of said discharge lamps to prevent further actuation of said controlled rectifier element by the corresponding ones of said neon tube lamps and upon failure of one of said discharge lamps to ignite allowing the corresponding one of said neon tube lamps to subsequently turn on said controlled rectifier element.