Patent ID: 6600274
Filing Date: 2003-07-29
Classification: H05B,Y02B

Abstract:
An illumination circuit powered by a DC voltage input in an aircraft lighting system for providing a fixed current through one or more light sources, compensating for varying DC input voltages, said system comprising:one or more light sources for radiating light signals, each said light source having a corresponding light source current; a current regulation circuit electrically coupled to said one or more light sources, wherein each said light source current is maintained at a predetermined level based upon a voltage drop across said current regulation circuit; said current regulation circuit including a transistor, a collector of which is electrically coupled to said one or more said light sources; diode means electrically coupled across a base-emitter junction of said transistor; and resistance means having a first terminal electrically coupled to an emitter of said transistor and a second terminal electrically coupled to ground, said resistance means connected in parallel with said diode means, wherein each said light source current is maintained at a predetermined level based upon a summation of voltage drops across said diode means, said transistor and said resistance means.