Electric lamp and discharge devices: systems – Periodic switch in the supply circuit – Impedance or current regulator in the supply circuit
Reexamination Certificate
1999-08-19
2001-01-30
Wong, Don (Department: 2821)
Electric lamp and discharge devices: systems
Periodic switch in the supply circuit
Impedance or current regulator in the supply circuit
C315S291000, C315S219000
Reexamination Certificate
active
06181076
ABSTRACT:
TECHNICAL FIELD
The invention relates to an apparatus for and a method of providing high-frequency, constant power through an electronic ballast circuit for a high intensity discharge (HID) lamp. Specifically, an inverter circuit used to provide an AC signal to the HID lamp is operated at a frequency higher than a resonant frequency of a tank circuit.
BACKGROUND ART
Known HID lamp circuits operate in various frequency ranges. Low frequency switching ballast circuits (square wave), such as those which operate in the range of 100-200 Hz, require ignition circuits and complex constant power control. Additionally, the physical size of the components required in a low frequency implementation is restrictively large.
Middle frequency switching ballasts, such as those operating in the frequency range of 10-100 kHz with a resonant ignition, require complex control circuits for arc instability detection and frequency modulation. An example of such a circuit is described in U.S. Pat. No. 5,623,187 issued on Apr. 22, 1997 to Caldeira et al. The system described in this patent includes a complex circuit required to detect and adjust the operating frequency of the inverter circuit to avoid acoustic resonance of the discharge arc.
Other references, such as U.S. Pat. No. 5,719,474 issued on Feb. 17, 1998 to Vitello and U.S. Pat. No. 5,850,127 issued on Dec. 15, 1998 to Zhu et al. disclose lamp circuits which operate at up to 100 kHz. The circuit of Vitello requires a microprocessor to control the inverter circuit, and neither patent utilizes the leakage inductance inherent in a transformer output as a current regulating device.
U.S. Pat. No. 5,877,592 issued Mar. 2, 1999 to Hesterman et al. describes a ballast circuit which operates in the 40-50 kHz range and includes inductive elements in the lamp connections. The system relies upon a timer circuit to switch from the preheat phase, however, and does not operate in a manner in which the inverter can operate uncontrolled by its control circuit until the lamp heats up.
All of the foregoing patents describe electronic ballast circuits for lamps which operate in a frequency range of up to 100 kHz. None of the circuits operate in the range of 300 kHz, and none are designed in conjunction with a transformer output circuit with high leakage inductance and an operating frequency of the inverter which exceeds the resonant frequency of the tank circuit.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide an improved method of and system for operating an HID lamp.
Another object of the present invention is to overcome the disadvantages of the prior art by providing an improved apparatus for and a method of providing high-frequency, constant power through an electronic ballast circuit to an HID lamp.
Yet another object of the present invention is to provide an improved system for and a method of energizing an HID lamp with high frequency electric power so as to have a fundamental electric power frequency above the highest lamp resonant acoustic frequency so as to avoid problems associated with operating at or near the lamp's acoustic resonant frequencies.
Still yet another object of the present invention is to provide an improved apparatus for and method of operating above the highest lamp acoustic resonant frequency, greatly simplifying the ballast's construction and reducing ballast cost.
A further object of the present invention is to provide an electronic lamp circuit with a transformer output with a high leakage inductance value, to provide: a) resonant boosting of output voltage during ignition phase of operation, b) inductive current limiting during warm-up and c) lossless switching of inverter during normal lamp operation.
An additional object of the present invention is to provide an improved apparatus for and method of supplying high frequency power to a lamp circuit to increase the speed of ignition and warm-up.
It is still another object of the present invention to provide all of the foregoing using a simplified circuit using smaller, reduced cost components.
This invention achieves these and other objects by providing an improved system and method useful in the operation of a HID lamp. Specifically, a HID lamp circuit includes a transformer output with high leakage inductance. An inverter circuit provides AC power through the transformer at a frequency higher than the resonant frequency of the tank circuit formed by an output capacitor and the leakage inductance of the transformer, thereby providing rapid ignition and warm-up with a simplified circuit.
REFERENCES:
patent: 4415839 (1983-11-01), Lesea
patent: 4904904 (1990-02-01), Zarate
patent: 5192897 (1993-03-01), Vossough et al.
patent: 5426239 (1995-06-01), Nilssen
patent: 5623187 (1997-04-01), Caldeira et al.
patent: 5719474 (1998-02-01), Vitello
patent: 5796216 (1998-08-01), Beasley
patent: 5850127 (1998-12-01), Zhu et al.
patent: 5877592 (1999-03-01), Hesterman et al.
patent: 5933340 (1999-08-01), Adamson
patent: 6088249 (2000-07-01), Adamson
patent: 6094017 (2000-07-01), Adamson
“Development of the Versatile Electronic Ballast for Metal Halide Lamps with Phase-Shift Soft-Switching Control”, Tsay et al, pp. 2112-2119, 1996.
“Phase Shift Resonant Controller”, Unitrode Product Data Handbook, p. 3-363, Apr. 1997.
“Phase Shifted, Zero Voltage Transition Design Consideration and the UC3875 PWM Controller”, Unitrode Applications Handbook, pp. 3-300 to 3-313, Apr. 1997.
Bay David L.
Trestman Grigoriy A.
Alemu Ephrem
Bessone Carlo S.
Osram Sylvania Inc.
Wong Don
LandOfFree
Apparatus and method for operating a high intensity gas... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for operating a high intensity gas..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for operating a high intensity gas... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2437879