Aggregate ignition method in high frequency metal halide lamps
AssigneeOsram Sylvania Inc.
InventorsAndrew Johnsen, Phillip Whitt, Harold Rothwell
Life of this patent
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Abstract
A high frequency ballast for a metal halide lamp comprises a controller, a switch, and an oscillator. The controller selectively enables and disables the oscillator via the switch to ignite the lamp. The ignition method includes enabling the oscillator such that the oscillator provides the lamp with a pulse train comprising a rapid series of short ignition pulses, cools for a period of time, and provides an addition pulse train to the lamp if necessary to ignite the lamp. When the lamp ignites, the ballast maintains enablement of the oscillator.
Claims20
A method of igniting a metal halide lamp driven by a high frequency ballast, said ballast including an oscillator for selectively providing power to the lamp, said method comprising:
- providing an ignition pulse train to the lamp for a first period, wherein providing the ignition pulse train comprises:
- enabling oscillations of the oscillator to provide power to the lamp for an ignition pulse period;
- thereafter determining whether the lamp has ignited;
- thereafter disabling the oscillator for an inter-pulse cooling period if the determining indicates that the lamp has not ignited;
- repeating said enabling oscillations of the oscillator, said determining whether the lamp has ignited, and said disabling the oscillator a predetermined number of times or until the lamp has ignited;
- thereafter determining whether the lamp has ignited;
- thereafter disabling the oscillator for an additional cooling period if said determining indicates that the lamp has not ignited;
- and
- repeating the above if the lamp has not ignited.
A high frequency metal halide lamp ballast for providing power to a metal halide lamp from an alternating current (AC) power source, said ballast comprising:
- a direct current (DC) converter for receiving AC power from the AC power source and providing DC power;
- an oscillator connected to the converter for receiving the DC power and connected to the lamp for selectively providing high frequency AC power to the lamp;
- a switch connected to the oscillator for selectively enabling oscillations of the oscillator to provide the high frequency AC power to the lamp;
- and
- a controller connected to the switch for controlling the switch to selectively enable oscillations of the oscillator, wherein the controller controls the switch to:
- provide an ignition pulse train to the lamp for a first period, wherein providing the ignition pulse train comprises:
- enabling oscillations of the oscillator to provide power to the lamp for an ignition pulse period;
- thereafter determining whether the lamp has ignited;
- thereafter disabling the oscillator for an inter-pulse cooling period if the determining indicates that the lamp has not ignited;
- repeating said enabling oscillations of the oscillator to provide power, determining whether the lamp has ignited, and disabling the oscillator a predetermined number of times or until the lamp ignites;
- thereafter determine whether the lamp has ignited;
- thereafter disable the oscillator for an additional cooling period if said determining indicates that the lamp has not ignited;
- and
- repeats the above until the controller determines that the lamp has ignited, and
- thereafter enables the oscillator to provide power to the lamp.
A light source comprising:
- a metal halide lamp for providing light in response to receiving power;
- and
- a ballast for igniting the lamp and providing power to the lamp from an alternating current (AC) power source, said ballast comprising:
- a direct current (DC) converter for receiving AC power from the AC power source and providing DC power;
- an oscillator for receiving the DC power from the DC converter and selectively providing high frequency AC power to the lamp;
- a switch for selectively enabling oscillations of the oscillator to provide power to the lamp;
- and
- a controller for controlling the switch to selectively enable the oscillator, wherein the controller controls the switch to:
- provide at least one ignition pulse train to the lamp for a first period, wherein providing the ignition pulse train comprises:
- enabling oscillations of the oscillator to provide power to the lamp for an ignition pulse period;
- thereafter determining whether the lamp has ignited;
- thereafter disabling the oscillator for an inter-pulse cooling period if the determining indicates that the lamp has not ignited;
- repeating said enabling oscillations of the oscillator to provide power, determining whether the lamp has ignited, and disabling the oscillator a predetermined number of times or until the lamp ignites;
- thereafter determine whether the lamp has ignited;
- thereafter disable the oscillator for an additional cooling period if said determining indicates that the lamp has not ignited;
- repeat the above until the controller determines that the lamp has ignited, and
- thereafter enable the oscillator to provide power to the lamp.
Dependencies are inferred from the claim text.