LED-based vehicle headlights are the hot exterior feature in luxury models. LED headlights are cutting-edge technology that gives car designers unprecedented freedom in headlight design. Their distinctive look and environmentally green technologies give luxury carmakers bragging rights in the marketplace and differentiation in a competitive environment.

For instance, witness the Audi R8 LED daytime running lights introduced in a 2008 Superbowl commercial. The headlight was the star. Despite their “star power,” LEDs are not power hungry, expensive or fragile. They run cool and efficiently, saving valuable battery and generator bandwidth for the countless other electronic features in today's high-end vehicles and they are far more durable than other lighting technologies.

Currently, there are three types of bulb-based headlights on the market that can be easily recognized by the color of the light output: incandescent (yellowish light), halogen (yellow-white light) and HID (high-intensity discharge — blue light). Incandescent and halogen bulbs are filament-based and destined to eventually burn themselves out. Their dim yellow color appearance is equated in the current market with old and, for lack of a better word, cheap.

HID bulbs are filament free and last longer, using a high-voltage electric charge to light up the gas to produce a very bright light, but the high-voltage electronics and bulbs are expensive and fragile, and the high temperature color results in a blue tint. Even with the wow factor of bright blue (or purple) HID lamps, their expense is a significant deterrent to widespread use. Plus, they cannot be dimmed.

White high-brightness (HB) LED strings allow headlight designers to give their new models complete lighting makeovers. The strings can be spread out or reshaped into interesting and distinctive, never-before-seen shapes. The Audi R8 LED daytime running lights are a good example, featuring an approximately 10-W LED string. Imagine a complete headlight using 50 W of LEDs. The Cadillac Escalade Platinum released the first 50-W LED headlight this summer and Mercedes, Lexus, and Audi have pledged to follow suit. The race is on.

LED headlights offer several technical advantages over other headlamp types. Efficiency is a key benefit. The growth of vehicle electronics and the ballooning cost of fuel create a need for high-efficiency electronics to minimize the load on the generator and the drain on the battery. LED drivers, with their high-efficiency (>93%), combine with high lumens-per-watt white LEDs to keep the required battery current low.

The ability to tailor lighting color is another advantage. LED color can be either true white light (as close to daylight as possible) or any warm white color in order to resemble “old-style” headlights for the nuevo-retro look, where the lights look old-school, but bright.

A further advantage is long operating life. The lifetime of the LED strings is expected to exceed that of the vehicle, giving the owner peace of mind that expensive headlamp failures and replacements will be minimized, if not completely eliminated.

And not to be overlooked is the relatively low cost and ease-of-use of the electronics that drive 50-W LED headlamps. The DC-DC converter LED driver attaches directly to the battery and maintains a well-regulated output over the battery's wide voltage range. In contrast, other high-power headlight technologies such as HID require very high voltage (difficult-to-work-with and dangerous) electronics and the expense that comes with them. The LEDs themselves are much cheaper than the alternative, and a broken LED is not expensive to replace.

LEDs also make possible instant turn on and turn off. Becasue they are powered by a controlled constant-current drive, they can also be PWM (pulse width modulation) dimmed and quickly adjusted over a wide range of brightness settings without changing the color.