APPLICATION NOTE 4393 Selecting HB LED Drivers for Automotive Lighting Applications
Mar 04, 2009
By: Brian Hedayati
Abstract: This application note provides an overview of HB LED driver selection criteria for automotive lighting applications. It reviews HB LED driver topologies and recommends configurations for various automotive lighting applications, including interior lighting, exterior lighting, and display backlighting. Introduction With the traction of environmental concerns among consumers, solid-state lighting (SSL) is quickly becoming the lighting technology of choice in applications ranging from general illumination to automotive lighting applications. Indeed, market research firm Strategies Unlimited predicts that growth in the high-brightness LED (HB LED) market in the next few years will be driven by general lighting, display backlighting, and automotive applications. The total market for HB LED driver ICs is expected to reach $1.9 billion by 2011.¹ HB LEDs present several advantages over traditional lighting technologies: they do not contain hazardous materials such as the mercury in CCFLs, they consume less power, and they have much longer lifespans. Moreover, HB LEDs are now highly cost competitive with traditional technologies, especially when the total cost of ownership (i.e., operating and maintenance costs) is accounted for. Yet, HB LEDs also pose unique challenges, particularly when used in the harsh operating environment of automotive applications. This application note provides an overview of HB LED driver selection criteria, reviews driver topologies, and recommends configurations for different automotive lighting applications, including dome lighting, daytime running lights (DRL), rear combination lights (RCL), fog lamps, and low-/high-beam lights.