Claims
- 1. A ballast circuit for generating a driving signal sufficient to ignite a lamp load, comprising:
- inductor means adapted to exhibit the properties of inductance;
- a capacitor for providing the driving signal and serially connected to said inductor means so as to form a serially connected inductor-capacitor circuit; and
- generating means for applying a generated signal to the circuit, said generated signal having at least a fundamental frequency;
- wherein the inductor means and capacitor are characterized by a single resonant frequency which is at least .sqroot.5 times but less than three times greater than the fundamental frequency.
- 2. The ballast circuit of claim 1, wherein the generated signal is a train of square waves.
- 3. The ballast circuit of claim 1, wherein the generating means includes a half-bridge inverter.
- 4. The ballast circuit of claim 2, wherein the generating means includes a half-bridge inverter.
- 5. The ballast circuit of claim 1, wherein the lamp load following ignition enters into a steady-state mode of operation in which current therethrough is maintained at a substantially constant level, said generating means during said steady-state mode further operable for continuing to apply said generated signal at the same fundamental frequency to the serially connected inductor means and capacitor.
- 6. The ballast circuit of claim 1, wherein said lamp load is connected across the capacitor.
- 7. The ballast circuit of claim 2, wherein the lamp load following ignition enters into a steady-state mode of operation in which current therethrough is maintained at a substantially constant level, said generating means during said steady-state mode further operable for continuing to apply said generated signal at the same fundamental frequency to the serially connected inductor means and capacitor.
- 8. The ballast circuit of claim 3, wherein the lamp load following ignition enters into a steady-state mode of operation in which current therethrough is maintained at a substantially constant level, said generating means during said steady-state mode further operable for continuing to apply said generated signal at the same fundamental frequency to the serially connected inductor means and capacitor.
- 9. The ballast circuit of claim 5, wherein said lamp load is connected across the capacitor.
- 10. The ballast circuit of claim 6, wherein the lamp load includes at least one fluorescent lamp.
- 11. A method for generating a driving signal sufficient to ignite a lamp load, comprising the steps of:
- supplying a generated signal having at least a fundamental frequency;
- applying said generated signal to a series connected inductor and capacitor; and
- producing the driving signal across the capacitor;
- wherein said inductor and capacitor are characterized by a single resonant frequency which is at least .sqroot.5 greater than but less than a third harmonic of the fundamental frequency.
- 12. The method of claim 11, wherein the generated signal is a train of square waves.
- 13. The method of claim 11, wherein the generated signal is produced from a half-bridge inverter.
- 14. The method of claim 11, wherein the lamp load following ignition enters into a steady-state mode of operation in which current therethrough is maintained at a substantially constant level and further including continuing to produce substantially the same generated signal during the steady-state mode.
- 15. The method of claim 11, wherein the lamp load following ignition enters into a steady-state mode of operation in which current therethrough is maintained at a substantially constant level and further including continuing to produce substantially the same generated signal during the steady-state mode.
- 16. The method of claim 12, wherein the lamp load following ignition enters into a steady-state mode of operation in which current therethrough is maintained at a substantially constant level and further including continuing to produce substantially the same generated signal during the steady-state mode.
- 17. The method of claim 12, wherein the generated signal is produced from a half-bridge inverter.
- 18. The method of claim 12, wherein the lamp load following ignition enters into a steady-state mode of operation in which current therethrough is maintained at a substantially constant level and further including continuing to produce substantially the same generated signal during the steady-state mode.
- 19. The method of claim 13, wherein the lamp load following ignition enters into a steady-state mode of operation in which current therethrough is maintained at a substantially constant level and further including continuing to produce substantially the same generated signal during the steady-state mode.
- 20. The method of claim 13, wherein the lamp load following ignition enters into a steady-state mode of operation in which current therethrough is maintained at a substantially constant level and further including continuing to produce substantially the same generated signal during the steady-state mode.
- 21. The method of claim 17, wherein the lamp load following ignition enters into a steady-state mode of operation in which current therethrough is maintained at a substantially constant level and further including continuing to produce substantially the same generated signal during the steady-state mode.
- 22. The method of claim 17, wherein the lamp load following ignition enters into a steady-state mode of operation in which current therethrough is maintained at a substantially constant level and further including continuing to produce substantially the same generated signal during the steady-state mode.
- 23. A ballast circuit for generating a driving signal sufficient to ignite a lamp load, comprising:
- an inductor and a capacitor connected in series, the lamp load being connected in parallel with the capacitor; and
- a half-bridge inverter for applying a train of square waves to the series connected inductor and capacitor, each square wave including at least a fundamental frequency and a third harmonic of the fundamental frequency;
- wherein the inductor and capacitor are characterized by a single resonant frequency which is at least .sqroot.5 times greater than the fundamental frequency and less than the third harmonic.
- 24. A solid-state ballast circuit for starting and steady-state operating a gaseous discharge lamp, comprising:
- a) a series LC circuit comprising an inductance and a capacitance forming a first series resonant circuit at a single resonant first frequency, said lamp being coupled across said capacitance,
- b) a source of AC voltage at a fundamental second frequency connected across said series LC circuit to drive said LC circuit with a voltage at said second frequency,
- c) said resonant first frequency being equal to at least .sqroot.5 times but less than a third has more of the fundamental second frequency,
- d) said ballast circuit operating with a voltage at a single frequency equal to said second frequency during both starting and steady-state operating of said lamp.
- 25. A solid-state ballast circuit for starting and steady-state operating a gaseous discharge lamp, comprising:
- a) a series LC circuit comprising an inductance and a capacitance forming a first series resonant circuit at a single resonant first frequency, said lamp being coupled across said capacitance,
- b) a source of AC voltage at a fundamental second frequency connected across said series LC circuit to drive said LC circuit with a voltage at said second frequency,
- c) said resonant first frequency being equal to at least .sqroot.5 but less than 3 times the fundamental second frequency,
- d) said ballast circuit operating with a voltage at a single frequency equal to said second frequency during both starting and steady-state operating of said lamp.
- 26. A solid-state ballast having ballast terminals for starting and steady-state operating a gaseous discharge lamp connected to said ballast terminals for receiving an operating voltage, said solid-state ballast comprising:
- a) a series LC circuit comprising an inductance and a capacitance forming a series resonant first circuit at a single resonant first frequency, said ballast terminals being coupled across said capacitance for connection to said lamp terminals,
- b) a source of AC voltage at a fundamental second frequency connected across said series LC circuit to drive said LC circuit with a current at said second frequency,
- c) said resonant first frequency being equal to at least .sqroot.5 times but less than a third harmonic of the fundamental second frequency,
- d) said solid-state ballast producing at its ballast terminals during steady-state operating a substantially sinusoidal lamp current at said second frequency.
- 27. A circuit comprising:
- A) a gaseous discharge lamp having terminals for receiving an operating voltage,
- B) a solid-state ballast for starting and operating said lamp, said solid-state ballast comprising:
- a) a series LC circuit comprising an inductance and a capacitance forming a series resonant first circuit at a single resonant first frequency, said lamp terminals being coupled across said capacitance,
- b) a source of AC voltage at a fundamental second frequency connected across said series LC circuit to drive said LC circuit with a current at said second frequency,
- c) said resonant first frequency being equal to at least .sqroot.5 times but less than a third harmonic of the fundamental second frequency,
- C) said lamp terminals during steady-state operating receiving a substantially sinusoidal lamp current at said second frequency.
Parent Case Info
This is a continuation of application Ser. No. 07/932,840, filed Aug. 20, 1992, now abandoned.
US Referenced Citations (6)
Continuations (1)
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Number |
Date |
Country |
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932840 |
Aug 1992 |
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