Claims
- 1. 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) means for generating a signal at a fundamental second frequency including higher odd harmonic components connected across said series LC circuit to drive said LC circuit with a voltage at said second frequency and higher odd harmonic components,
- c) said resonant first frequency being equal to at least .sqroot.5 times the fundamental second frequency but other than equal to the frequency of any one of said higher odd harmonic components,
- d) said ballast circuit operating with a voltage at a single frequency equal to said second frequency including the higher odd harmonic components during both starting and steady-state operating of said lamp.
- 2. A solid-state ballast for starting and steady-state operating a gaseous discharge lamp to be connected to ballast terminals of the solid-state ballast, 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 terminals of said discharge lamp,
- 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 including higher odd harmonic components,
- c) said resonant first frequency being equal to at least .sqroot.5 times the fundamental second frequency but other than equal to the frequency of a higher odd harmonic component,
- d) said solid-state ballast producing at its ballast terminals during steady-state operating a substantially sinusoidal lamp current at said second frequency.
- 3. 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 including higher odd harmonic components thereof,
- c) said resonant first frequency being equal to at least .sqroot.5 times the fundamental second frequency but not being equal to the frequency of a higher odd harmonic component,
- C) said lamp terminals during steady-state operating receiving a substantially sinusoidal lamp current at said second frequency.
- 4. A ballast circuit for generating a driving signal sufficient to ignite a lamp load, comprising:
- a) inductor means adapted to exhibit the properties of inductance,
- b) a capacitor for providing the driving signal and serially connected to said inductor means so as to form a serially-connected inductor-capacitor circuit,
- c) generating means for applying a generated signal to the circuit, said generating signal having at least a fundamental frequency and including higher odd harmonic components,
- d) wherein the inductor means and capacitor are characterized by a resonant frequency which is at least .sqroot.5 times greater than the fundamental frequency but other than equal to the frequency of a higher odd harmonic component.
- 5. A method of generating a driving signal sufficient to ignite a lamp load, comprising the steps of:
- a) supplying a generated signal having at least a fundamental frequency and including higher odd harmonic components,
- b) applying said generated signal to a series-connected inductor and capacitor,
- c) producing the driving signal across said capacitor,
- d) wherein the inductor and capacitor are characterized by a single resonant frequency which is at least .sqroot.5 times greater than the fundamental frequency but other than equal to the frequency of a higher odd harmonic component.
- 6. The ballast circuit of claim 1, wherein the generated signal is a train of square waves.
- 7. The ballast circuit of claim 1, wherein the generating means includes a half-bridge inverter.
- 8. The ballast circuit of claim 1, wherein the resonant first frequency is less than a third harmonic of said fundamental frequency.
- 9. The ballast circuit of claim 1, wherein the resonant first frequency is less than a third or a fifth harmonic of said fundamental frequency.
- 10. The method of claim 5, wherein the generated signal is a train of square waves.
- 11. The method of claim 5, further including selecting a capacitor wherein the resonant frequency is less than a third or a fifth harmonic of said fundamental frequency.
- 12. The method of claim 5, 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.
- 13. The solid-state ballast of claim 2 wherein said resonant first frequency is not equal to any higher odd harmonic component of the fundamental second frequency.
- 14. The ballast circuit as claimed in claim 2 wherein said resonant first frequency is greater than three times the fundamental second frequency.
- 15. The ballast circuit as claimed in claim 4 wherein said resonant frequency is greater than three times the fundamental frequency.
- 16. The ballast circuit as claimed in claim 3 wherein said resonant first frequency is greater than the third harmonic of the fundamental second frequency.
Parent Case Info
This is a continuation of application Ser. No. 08/329,700, filed Oct. 26, 1994, and now U.S. Pat. No. 5,463,284, which is a continuation of application Ser. No. 07/932,840, filed Aug. 20, 1992, now abandoned.
US Referenced Citations (5)
Continuations (2)
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Number |
Date |
Country |
Parent |
329700 |
Oct 1994 |
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Parent |
932840 |
Aug 1992 |
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