Sophisticated electronic displays represent a growing trend in U.S. car instrumentation. One location, single function displays, such as digital clock, radio, or instrument cluster, are giving way to multiple function displays located across the instrument panel. The large dynamic range of light levels in vehicles establishes the need for some type of real time light controlling system. TRW Optron has developed a monolithic IC approach to this problem. This paper describes that development and illustrates various techniques available to the design engineer developing a system for dynamic brightness control.