Patent ID: 7928665

Claim:
A driver circuit for providing a drive current from a power source to an arc lamp producing a light having a brightness, the circuit comprising: a transformer having a primary winding and a secondary winding, wherein each of the primary and secondary windings have a first and a second end and are configured to conduct an electrical current having a polarity, and wherein the ends of the secondary winding are coupled to provide the lamp drive current to the arc lamp; a current steering module configured to provide a drive output from the power source to the transformer in response to a current steering input; a current control loop configured to adjust the current steering input in response to the current in one of the windings of the transformer; a luminance control loop configured to adjust the current steering input in response to the brightness of the light; and a power control module coupled to the luminance control loop, wherein the power control module is configured to generate a boost command in response to a difference between the brightness of the light and a luminance command exceeding a threshold value.