Patent ID: 7696701
Filing Date: 2010-04-13
Classification: H05B,Y02B

Abstract:
1. A circuit for powering at least one halogen lamp, the circuit comprising: an inverter; and an output circuit coupled between the inverter and the at least one halogen lamp; wherein the inverter and output circuit are operable to provide a magnitude-limited current to the at least one halogen lamp, such that the lamp power during an initial period is substantially less than the lamp power during a steady-state operating period; wherein the inverter comprises: first and second inverter input terminals for receiving a substantially direct current (DC) voltage source; an inverter output terminal, at which the inverter provides a substantially alternating current (AC) output voltage; first and second inverter switches coupled to the inverter input terminals and to the inverter output terminal; and an inverter control circuit coupled to the first and second inverter switches, and operable: and wherein the inverter control circuit comprises: an inverter driver circuit coupled to the first and second inverter switches, the inverter driver circuit including a DC supply input, a first frequency control input, and a second frequency control input; a startup circuit coupled between the first and second inverter input terminals and the DC supply input of the inverter driver circuit; a bootstrapping circuit coupled between the output terminal of the inverter and the DC supply input of the inverter driver circuit; and a frequency control circuit coupled to the bootstrapping circuit and to the first and second frequency control inputs of the inverter driver circuit, wherein the frequency control circuit is operable;