HIGH-FREQUENCY LAMP-OPERATING CIRCUIT

• US 3,628,086 A
• Filed: 09/11/1969
• Issued: 12/14/1971
• Est. Priority Date: 09/11/1969
• Status: Expired due to Term

• Current Assignee: Joe A. Nuckolls
• Original Assignee: Joe A. Nuckolls
• Inventors: Nuckolls, Joe A.
• Primary Examiner(s): Lake, Roy
• Assistant Examiner(s): Dahl, Lawrence J.
• Application Number:
  US04/857,010
• Time in Patent Office: 824 Days
• Field of Search: 315/1000,199,226,227,244,258,283,289
• US Class Current: 315/80
• CPC Class Codes: H05B 41/2885 Static converters especially adapted therefor; Control thereof H05B41/2882 takes precedence
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

High-frequency circuit for operating gaseous discharge lamps includes an inductor-capacitor resonant circuit having the lamp load connected across the inductor, and a pair of siliconcontrolled rectifiers operated alternately by a unijunction oscillator-triggering circuit to provide for controlled series resonance of the resonant circuit for producing high-frequency voltage across the inductor for energizing the lamp load.

Claims

1. A high-frequency starting, operating, and control circuit comprising, in combination, a source of current, an inductor and a capacitor connected in series across said source and forming a series-resonant circuit, first and second controlled rectifiers connected in series across said source, said resonant circuit connected to the junction of said controlled rectifiers, a load connected across said inductor for energization thereby, and triggering means connected to said controlled rectifiers for alternate actuation thereof, whereby the alternate energizing of said controlled rectifiers provides controlled series resonance of said series-resonant circuit producing high-frequency voltage across said inductor for energizing said load.

2. A circuit as defined in claim 1, said triggering means comprising voltage-sensitive switching means connected to at least one of said controlled rectifiers, and an RC circuit connected to said current source and said switching means for actuating said switching means at predetermined time intervals.

3. A circuit as defined in claim 1, said triggering means comprising first voltage-sensitive switching means connected to one of said controlled rectifiers and a first RC circuit connected to said current source and said first switching means, and a seCond voltage-sensitive switching means connected to the other controlled rectifier and a second RC circuit connected to said second switching means.

4. A circuit as defined in claim 3, wherein said first switching means is a unijunction transistor connected to the gate of said one controlled rectifier and said second switching means is a unidirectional diode connected to the gate of said other controlled rectifier.

5. A circuit as defined in claim 4, said second RC circuit being connected across said other controlled rectifier.

6. A circuit as defined in claim 2, said voltage-sensitive switching means comprising a unijunction transistor having an emitter connected to said RC circuit and its bases connected across said current source.

7. A circuit as defined in claim 6, and voltage-clamping means connected to said unijunction transistor for providing a constant base-to-base voltage therefor.

8. A circuit as defined in claim 7, and variable-voltage means connected to said RC circuit for applying a predetermined voltage thereto.

9. A circuit as defined in claim 2, and pulse transformer means having primary winding means connected to aid voltage-sensitive switching means and secondary winding means connected to each controlled rectifier for separate actuation thereof.

10. A circuit as defined in claim 9, said voltage-sensitive switching means comprising a pair of unijunction transistors connected together at their emitters, each having a transformer primary winding connected to the output thereof.

11. A circuit as defined in claim 10, and a coupling capacitor connected to said unijunction transistors for providing alternate operation thereof.

12. A circuit as defined in claim 10, each said unijunction transistor having an RC circuit connected thereto and to said current source for actuating said unijunction transistors at predetermined time intervals, and voltage divider means connected to said RC circuits for applying a predetermined voltage thereto.

13. A circuit as defined in claim 1, said current source providing direct current, and a storage capacitor connected across said direct current source for charging thereby to provide instantaneous current at a minimum voltage.

14. A circuit as defined in claim 1, one of said controlled rectifiers being connected in series conduction relation with said resonant circuit, and the other controlled rectifier being connected across said resonant circuit.

15. A circuit as defined in claim 14, said resonant circuit including a second capacitor connected in parallel conduction relation with said first mentioned capacitor.

16. A circuit as defined in claim 1, and high-voltage generating means connected across said load for applying a high voltage for starting the same.

17. A circuit as defined in claim 16, said high-voltage generating means comprising an induction coil connected in series with said load, and charging capacitance means connected in series with a predetermined number of turns of said induction coil and forming therewith a discharge loop, said induction coil stepping up the voltage produced across said predetermined number of turns by operation of said discharge loop.

18. A circuit as defined in claim 2, impedance means connected in series with said load, and feedback means connected to said impedance means for sensing and compensating for variations of power supplied to said load.

19. A circuit as defined in claim 18, said feedback means comprising light-producing means connected to said impedance means, and photoconductor means arranged in proximity to said light-producing means and connected to said RC circuit for varying the voltage applied thereto in response to variations in light produced by said light-producing means.