High voltage, low power transformer for efficiently firing a gas discharge luminous display

• US 4,472,661 A
• Filed: 09/30/1982
• Issued: 09/18/1984
• Est. Priority Date: 09/30/1982
• Status: Expired due to Fees

• Current Assignee: Clifford T. Culver
• Original Assignee: Clifford T. Culver
• Inventors: Culver, Clifford T.
• Primary Examiner(s): LAROCHE, EUGENE
• Application Number:
  US06/431,471
• Time in Patent Office: 719 Days
• Field of Search: 315/206, 315/219, 315/224, 315/276, 315/279, 315/307, 315/DIG. 7, 331/117 R
• US Class Current: 315/276
• CPC Class Codes: H05B 41/2881 Load circuits; Control thereof
• CPC Class Codes: H05B 41/392 using semiconductor devices, e.g. thyristor
• CPC Class Codes: Y10S 315/07 Starting and control circuits for gas discharge lamp using transistors

Abstract

A power system comprising a high voltage, low power transformer that utilizes self-resonance parameters and pulse control techniques for efficiently firing a gas discharge lamp of the type commonly used to form a luminous advertising display. The transformer is fabricated from a material, such that the transformer will have a characteristic self-resonating frequency. The transformer is driven by Direct Current pulses from a source of supply thereof. The widths of the current pulses are controlled so as not to exceed one fourth the wavelength of the self-resonating frequency of the transformer. Performance is optimized when the repetition rate of the current pulses is directly controlled according to the self-resonating frequency of the transformer. By virtue of the present invention, an efficient transformer of relatively low weight, size, and cost is provided by which to fire the lamp of the display and thereby produce an apparent optical intensity that is approximately equal to that available from a conventional gas discharge power transformer. However, the energy consumed by the present transformer is substantially less than that expended by presently available transformers.

Claims

1. An electrical system for providing power to a load, said system including a source of current pulses and an energy efficient transformer interconnected between said source of current pulses and said load for receiving current pulses from said source and for driving said load, said transformer having primary and secondary windings and a core, said transformer being fabricated from a material which causes said transformer to have a self-resonating frequency, the widths of the current pulses that are supplied to said transformer being less than or equal to one-fourth the wavelength of the self-resonating frequency of the transformer.

2. The electrical system recited in claim 1, wherein said transformer is fabricated from a ferrite material.

3. The electrical system recited in claim 2, wherein the primary winding of said transformer comprises 20 wire turns capable of supporting a voltage thereacross of approximately 8 volts per turn.

4. The electrical system recited in claim 1, wherein said source of current pulses comprises a Direct Current source connected in electrical series with the primary winding of said transformer, so that Direct Current pulses are supplied to said primary winding.

5. The electrical system recited in claim 4, wherein said system further includes an electronic switch means interconnected with said transformer primary winding to control the flow of said current pulses therethrough, and

pulse source means providing a signal to control the operation of said switch means and thereby selectively establish the width of said current pulses that are supplied to said primary winding.

6. The electrical system recited in either of claims 1 or 5, further including means by which to control the repetition rate of said current pulses so as to be substantially equal to the self-resonating frequency of the transformer.

7. The electrical system recited in claim 1, wherein said system further includes an electronic switch means interconnected with said transformer primary winding to control the flow of said current pulses therethrough,

pulse source means providing a signal to control the operation of said switch means and thereby selectively establish the width of said current pulses that are supplied to said primary winding, and

a zero crossing detector by which to control the repetition rate of said current pulses so as to be substantially equal to the self-resonating frequency of the transformer, said zero crossing detector connected between said electronic switch means and said pulse source means and responsive to the polarity of the output voltage developed at the transformer primary winding, said zero crossing detector controlling both the width and rate of the control pulses being supplied by said pulse source means to said electronic switch means depending upon the polarity of the transformer output voltage.

8. The electrical system recited in claim 1, wherein said load comprises at least one gas discharge lamp.

9. The electrical system recited in claim 1, wherein said transformer is on a duty cycle of less than or equal to 25%.

10. For interconnection in an electrical circuit including a source of Direct Current pulses, an efficient transformer for driving a load, said transformer having a primary winding to receive Direct Current pulses from said source thereof, said transformer also having a secondary winding interconnected with said load so as to provide a driving voltage to said load, and said transformer further being fabricated from a ferrite material, whereby to cause said transformer to have a characteristic self-resonating frequency, the widths of said Direct Current pulses being less than or equal to one fourth the wavelength of the self-resonating frequency of the transformer.

11. The transformer recited in claim 10, said electrical circuit further including means by which to adjust the widths of the current pulses being supplied to said transformer primary winding, said adjusting means comprising:

electronic switch means connected in electrical series with said transformer primary winding to control the flow of said current pulses therethrough, and

pulse source means providing pulses to control the operation of said switch means, so as to selectively vary the widths of said current pulses.

12. The transformer recited in claim 11, wherein the width of the control pulses from said pulse source means is selected to be less than or equal to one-fourth of the wavelength of the self-resonating frequency of the transformer.

13. The transformer recited in claim 10, wherein the primary winding thereof comprises 20 wire turns that are capable of supporting a voltage thereacross of approximately 8 volts per turn.

14. A method for efficiently powering an electrical load by means of a transformer having primary and secondary windings and a core, said method comprising the steps of:

forming said transformer from a material to cause said transformer to have a self-resonating frequency,

driving the primary winding of said transformer by Direct Current pulses, and

controlling the widths of said current pulses so as to be less than or equal to one-fourth the wavelength of the self-resonating frequency of the transformer.

15. The method for powering a load recited in claim 14, including the additional step of forming said transformer from a ferrite material.

16. The method for powering a load recited in claim 14, including the additional step of controlling the repetition rate of said current pulses so as to be substantially equivalent to the self-resonating frequency of the transformer for causing said transformer to have a variable duty cycle of relatively short duration.