Patent ID: 6794827
Filing Date: 2004-09-21
Classification: H02M,H05B

Abstract:
A lighting system powered by an alternating current source, the system comprising:a power factor correction circuit for rectifying and smoothing a voltage signal from the alternating current source creating a direct current bus signal; a first ballast; a first alternating current switch in operational connection to the first ballast that prevents damage to the first ballast when a light source is at least one of a) removed from the first ballast, and b) failing to arc, the first alternating current switch comprising; first and second field effect transistors that when conductive, draw current away from the first ballast; a first inductive tap that supplies power to the first alternating current switch and reverse-biases gates of the first and second field effect transistors; first and second charge pumps which store charge from the first inductive tap; a second ballast in a parallel circuit relationship with the first ballast; a second alternating current switch in operational connection to the second ballast that prevents damage to the second ballast when a light source is at least one of a) removed from the second ballast, and b) failing to arc, the second alternating current switch comprising: third and fourth field effect transistors that when conductive, draw current away from the second ballast; a second inductive tap that supplies power to the second alternating current switch and reverse-biases gates of the third and fourth field effect transistors; third and fourth charge pumps which store charge from the second inductive tap; and, wherein the first and second ballasts are operable independently of one another.