Universal ignition circuit for high pressure discharge lamps
AssigneeU.S. Philips Corporation
InventorAnton C. Blom
Life of this patent
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Abstract
A circuit arrangement (II) for igniting a high-pressure discharge lamp provided with a pulse transformer, a switching device and a capacitive element for a periodic charge inversion via the transformer and the switching device. The circuit arrangement is also provided with a peak current limiting impedance to protect the switching device. A voltage limiting device is added to the transformer. By the provision of the voltage limiting device, the lamp ignition is to a high degree made to be independent of lamp connection line impedances.
Claims15
A circuit arrangement for igniting a high-pressure discharge lamp, comprising:
- pulse transformer means, switching means and capacitive means coupled to the pulse transformer means so as to provide for periodic charge change of the capacitive means via the transformer means and switching means, and peak current limiting means connected in the circuit so as to protect the switching means, characterized in that voltage limiting means are coupled to the transformer means.
A circuit for igniting a high pressure discharge lamp comprising:
- a pair of input terminals for connection to a source of AC voltage,
- a pair of output terminals for connection to a high pressure discharge lamp,
- means for coupling said input terminals to said output terminals via at least a first winding of a transformer,
- an ignition capacitor,
- means for coupling said ignition capacitor to said input terminals,
- switching means for coupling the ignition capacitor to a second winding of said transformer so as to generate a high voltage ignition pulse in said first winding for igniting a high pressure discharge lamp when connected to said pair of output terminals,
- means coupled to the switching means for limiting the current therein so as to protect the switching means, and
- means coupled to one of said transformer windings for limiting the voltage developed therein upon discharge of the ignition capacitor into said second winding of the transformer and via said switching means.
Dependencies are inferred from the claim text.