Bench Talk

New Tech Tuesday

Join journalist Tommy Cummings for a weekly look at all things interesting, new, and noteworthy for design engineers.

In the recent past, when driving at night, you knew a luxury car was approaching. It had crisp, bright lights—LED (light-emitting diode) lights—a notch above the fading, uneven headlights on the front of your car.

Today, LED lighting is becoming more common on vehicles, whether they're luxury or not. Trends tend to start in the luxury space before moving to lower-end brands. A report by Strategy Analytics projects the value demand for LEDs in automotive lighting will nearly triple from US$1.4 billion to US$3.8 billion by 2024.

With the ever-increasing demand for energy-efficient technology, LEDs will gain value as a light source and gain ground on conventional halogen and incandescent bulbs. LEDs provide better light—with more display controls and smaller size. Additional LED lighting advantages include:

• Lifespan: Quality LEDs can have a lifespan of 20,000 hours, which is 20 times longer than a halogen bulb. In a 2021 study, AAA determined that US drivers spent 59.3 minutes per day driving. Divide that into 20,000 hours, and LEDs could last more than 55 years.
• Efficiency: LEDs use 260 percent less drain on a battery. This is important when considering the myriad sensors and transducers put on a vehicle’s power supply.
• Brightness: LEDs are 275 percent brighter than halogens.
• Design: Bulb design limits the artistic design in traditional headlights. LEDs have more flexible design potential.

LEDs also have their drawbacks. Upfront, they cost more than halogen versions, but keep that 55-year lifespan in mind. They produce heat, which requires an additional cooling component to protect the other parts and assemblies and creates design issues, hence the added cost.

Also, design engineers should be aware that US states regulate aftermarket headlights, so it's a good idea to check the regulations before applying LEDs to your design.

In this week's New Tech Tuesdays, we'll look at LED products from Infineon Technologies, ROHM Semiconductor, and Diodes Incorporated.

The Infineon Technologies Automotive Front Light LED Reference Design is a power-management solution. The board—which provides state-of-the-art diagnosis—uses a single DC-DC channel to drive the front light high beams and low beams. This setup is suitable for entry-level LED headlamps. The high beam can be activated with the low beam, or the low beam can be activated alone. A power-width modulation dimming feature also allows more control of the brightness and derating in extreme operating conditions. The device also controls daytime running lights and turn indicators.

The ROHM Semiconductor Automotive LED product family features a full portfolio of AEC-Q101-qualified surface-mounted device LEDs. They're available in various colors, brightness, and packages. The LEDs are suitable for stop lamps, car audio, automotive panels, navigation, air condition, and in-dash cluster panels. These LEDs meet a wide range of interior and exterior automotive application requirements. The challenges of automotive LEDs are outlined in ROHM’s Driving the Future of Automotive Solutions e-book.

The Diodes Incorporated AL5873Q Automotive LED Driver is a 3-channel linear driver with power-width modulation (PWM) dimming control for use in a range of applications. Each channel can drive up to 250mA with a combined driving current up to 750mA. The AL5873Q regulates LED current for each channel, accurate to ±4 percent. The AL5873Q enters standby mode to save power if no PWM signal is detected. They're used in auto LED inner lamps, rear lights, tail and stop lights, rear turn indicators, parking lights, fog lights, and reverse lights.

The genie is out of the bottle on automotive LED illumination. It's no longer an amenity to luxury cars. They're available on many of the affordable new models. Consumers are finding that LEDs have many advantages over traditional headlights. Where else are you going to get a headlight that can last 55 years?