A driver circuit provides a drive current from a power source to an arc lamp to produce a light. The circuit includes a transformer having primary and secondary windings, with the ends of the secondary winding providing the lamp drive current to the arc lamp. A current steering module provides a drive output from the power source to the transformer in response to a current steering input, and a current control loop adjusts the current steering input in response to the current in one of the windings of the transformer. A luminance control loop adjusts the current steering input in response to the brightness of the light and a luminance command. A power control module may be further provided to generate a boost command in response to a difference between the brightness of the arc lamp and a luminance command.