Top 10 automotive LEDs and LED drivers

Lighting plays a dual role in vehicle design. The first is for safety with improved illumination and an extended range to protect people and objects on the road, and the second is for more aesthetically pleasing lighting for both the interior and exterior of the vehicles. LEDs are making inroads thanks to their better illumination over traditional lighting technologies, higher levels of integration for sleeker designs, and the need to cut CO₂ emissions.

The global automotive lighting market is expected to reach $32.7 billion in 2022, according to TrendForce Corp.’s 2022 Global Automotive LED Product Trend and Regional Market Analysis. Advanced technologies like intelligent headlights, logo lamps, and intelligent ambient lights are expected to drive growth in the LED headlight segment. Market penetration for LED headlights is about 90% for electric vehicles, according to TrendForce.

Another growth driver is global regulations calling for reduced carbon emissions in vehicles. Thanks to LED lighting’s high power efficiency and reduced CO₂ emissions, these lights are being implemented in headlights, turn lights, daytime running lights (DRLs), parking lights, and brake lights, according to Allied Market Research.

Researchers also find that new technologies like adaptive driving-beam headlights and adaptive front-lighting systems, which provide better visibility to drivers, will contribute to greater demand for LED lighting.

The mainstream intelligent design uses matrix LEDs with 12 to 100 LEDs, which use individually controlled high-performance LEDs to expand the driver’s field of vision at night, said TrendForce. In addition, glare-free high beams are being designed in to reduce discomfort caused by the lights of vehicles ahead of the driver, oncoming vehicles, and pedestrians.

Similarly, the LED driver market is expected to grow significantly, reaching $62.1 billion by 2030, up from $8.7 billion in 2021, according to P&S Intelligence. The second-highest growth segment for LED drivers is automotive, growing at a compound annual growth rate of 24.5% over the forecast period.

LEDs

Over the past year, LED manufacturers have developed new devices in smaller packaging with higher brightness and reliability, along with technologies that deliver greater illumination choices in automotive applications. One of those trends is the use of RGB LEDs for ambient lighting.

Aimed at increasing demand for multi-color lighting in the automotive industry, particularly electric and autonomous vehicles, Dominant Opto Technologies has claimed the industry’s first high-power RGB LED for the automotive market. The automotive-grade SpicePlus 3030 Multi Color (S6RTB-THG) RGB LED complies to the AEC-Q102 standard.

Suited for interior or exterior ambient lighting, the SpicePlus 3030 offers high brightness in a small package size of 3 × 3 × 0.7 mm. Rated at 200 mA, the emitting luminous flux is 30 lumens (lm) typical for red (23.5–39.8 lm), 55 lm typical for true green (39.8–67.2 lm), and 11 lm typical for blue (8.2–13.9 lm). The LEDs also offer a wide RGB color gamut, with red at 621 nm typical (619–629 nm), true green at 527 nm typical (520–535 nm), and blue at 460 nm typical (458–466 nm), which provides designers with more color combination choices.

The SpicePlus 3030 also provides a high operating temperature of up to 125˚C and a junction temperature of 150˚C. All three LED chips are positioned on a large heat-dissipation center pad for more effective heat dissipation. It also features a gold leadframe that is said to provide “outstanding” corrosion resistance and is qualified to the H2S Test Class A.

In addition to the small package, the Spice 3030 LED features a small light-emitting surface of 2.4 × 2.4 mm, enabling it to fit narrow light guides with diameters as small as 3 mm.

Also looking at the RGB LED market is ams Osram. The company recently partnered with TactoTek, a specialist in in-mold electronics, on a new design for interior illumination, by integrating side-looking automotive RGB LEDs in thin smart structures using an in-mold process. The new product leverages ams Osram’s OSIRE E5515 LED, which is designed for in-mold processes, and TactoTek’s in-mold structural electronics (IMSE) technology. The result is “thin, seamlessly integrated three-dimensional illuminated structures,” said ams Osram.

The companies have developed a demonstrator with the LED OSIRE E5515 molded into a thin plastic trim part with TactoTek’s IMSE technology. It delivers greater flexibility through the combination of surface decoration, illumination, and functionality in a single smart surface.

The OSIRE E5515 is a three-color, RGB side emitter that enables light coupling into thin materials, such as light guides, and it provides a low height for in-mold applications. It also offers high brightness performance of 1,100 mcd for red, 2,600 mcd for green, and 500 mcd for blue at 20 mA. Deep-blue colors are available.

The RGB LED also provides flexibility in terms of the driver and interconnection by providing six pins, so each color chip can be contacted to both its individual anode and cathode, said the company. This gives designers more flexibility in the choice of electronics architecture for the driver and between high-side and low-side drivers for the board design.

The new KRTB AELPS2.32 in the OSIRE E5515 family has been validated by TactoTek for its IMSE technology and qualified for use in automotive applications (AEC-Q102) by ams OSRAM, which is expected to open new illumination opportunities.

Introduced in 2021, ams OSRAM also claimed the brightest LED on the market for automotive front lighting with the introduction of the Oslon Black Flat X family. Designed for standard low- and high-beam headlights, the Oslon Black Flat X family offers brightness of 460 lumens at 1 A and is available in one- and two-chip versions. The one-chip variant is housed in a small, 3.75 × 3.75-mm package.

The leadframe-based LEDs feature a “special” QFN platform that enables simple thermal management, said ams Osram. Depending on the system, heat sinks can be either significantly reduced in size or eliminated. The leadframe package is also said to achieve a lower thermal resistance than the leading ceramic packages.

Together with a special TiO₂ encapsulation, the black package of the LEDs offers high contrasts of 1:200. They are also characterized by a very homogenic color over angle radiation due to the dielectric coating, said the company. The operating temperature range is –40˚C to 135˚C and the maximum junction temperature is 150˚C.

Also introduced last year, LG Innotek’s new Nexlide-E automotive lighting module produces a bright and uniform light. The module consists of an LED package mounted on a thin substrate with optical resin, which covers the package and substrate for protection. An optical film is attached to the top of the package to spread the light uniformly. It is designed for taillights, stoplights, and headlights.

The Nexlide-E is said to be 63% brighter than the previous product and produces more uniform light, increased from 80 cd to 130 cd. Thanks to its high brightness, this lighting module can replace multiple automotive lamps with different brightness standards into one module, said the company.

With fewer lighting modules required, automakers can design slimmer and smaller lamps. The module is also power-efficient, which is an important factor for electric and hydrogen vehicles in increasing their mileage range, said the company.

The company attributes the module’s bright and uniform light to the new optical film, which is only 0.2 mm thick. It is produced using the company’s unique micropatterning technique. The optical films in combination with the micropatterns enable LG Innotek to manufacture custom lighting modules without complex design changes or using additional components, said the company.

With the high demand for LED lighting in EVs, heat dissipation is becoming more important to improve efficiency and to extend lifetime. Last year, Seoul Semiconductor Co. Ltd. launched its WICOP TE (Top Electrode) LED, which is designed to improve the thermal efficiency of headlamps. The company changed its method of attaching the LED package, which is now directly on the heat sink to quickly discharge the heat generated in the headlight. The WICOP TE design also delivers a weight reduction for headlamps in EVs.

LED drivers and controllers

Targeting next-generation LEDs, LED driver manufacturers are focused on boosting performance and new levels of integration to help automakers develop sleeker lighting designs.

STMicroelectronics recently introduced a 32-channel LED driver for next-generation OLED automotive lighting. This multi-pixel driver controls automotive lighting using the CAN FL Light protocol and can drive individual pixels in external and interior lighting applications.

The integrated L99LDLH32 linear current regulator delivers 32 regulated current sources, which are independently programmable from 1 mA to 15 mA. Global dimming is provided with 8-bit resolution. The driver produces outputs of up to 35 V to cover a wide-emitter forward-voltage spread while powered at the vehicle battery voltage.

The integrated CAN-FD Light protocol handler and transceiver simplify connection to the vehicle’s communication infrastructure and controlling-domain electronic control unit, said STMicroelectronics. Thanks to the CAN-FD Light’s synchronized commander/responder communication, which is designed for controlling simple devices like lights and sensors, it saves on external components like timing crystals. In addition, the data bandwidth of 1 Mbit/s enables complex animated light patterns and delivers smoothly modulated transitions and dimming, said the company.

Key features include on-chip memory cells that enable programming of parameters like current level and PWM dimming for standalone operation, providing a failsafe mode to cover malfunctioning of the communication bus or controller, and frequency dithering to minimize electromagnetic emissions.

The LED driver also provides functional safety features that target safety-critical lighting like taillights, stoplights, and turn indicators. These include a fault-status pin, voltage and temperature monitors, a programmable timeout watchdog, and short-circuit and open-load detection.

The L99LDLH32 is AEC-Q100–qualified. It is housed in a 7 × 7-mm QFN48 package with wettable flanks and an exposed thermal pad.

Taiwan Semiconductor has launched its TS19503 single-channel, continuous-conduction, hysteretic-mode converter for driving single or multiple LEDs. This 2-A stepdown LED driver integrates the N-channel FET high-side current sense, PWM, and analog dimming capability.

Featuring a 4.5- to 75-V input range and 2-A output, the TS19503 LED driver offers up to 97% efficiency and 2% accuracy over a range of external conditions and applications.

With the hysteretic (bang-bang) control technique, the AEC-Q100–qualified TS19503 provides high accuracy and reduced external part count, said the company.

Target automotive applications include high- and low-beam headlights, DRLs, turn indicators, position indicator lights, fog lights, and ATV and four-wheel–drive high-brightness lamps. The LED driver is also well-suited for DC input industrial and medical applications in which SELV and line isolation considerations are a concern.

Key specifications include 25 W of output power, a low-R_DS(on) internal MOSFET that enables up to 97% efficiency, a 1,000:1 dimming range, and an adjustable frequency up to 1 MHz. The operating temperature range is –40˚C to 125˚C.

Melexis has expanded its MeLiBu (Melexis Light Bus) high-speed communication portfolio with the introduction of the MLX81143 automotive LED driver. The MeLiBu interface for animated light applications makes it possible to drive up to 3,000 LEDs in a car at the same time, said the company, and it improves power management thanks to advanced smart options integrated into the chip.

The fully integrated smart automotive RGB-LED controller, housed in a QFN32 5 × 5-mm package, includes 21 LED drivers and offers a wide dimming range for optimal brightness adjustments during the night or day.

Car manufacturers use animated lighting in the cabin to provide important information like driver-assistance prompts and vehicle status updates; however, changing colors and different blinking sequences, which enhance messages for driver attention, present engineering challenges, such as maintaining consistent color across all of the LEDs and implementing simultaneous light changes, said the company.

The MLX81143 addresses these challenges by integrating the Melexis CAN over UART MeLiBu (patented license-free) solution, which controls individual LEDs to implement the lighting effects. The intelligent RGB-LED controller features color-mixing accuracy of less than 1% to eliminate any distinguishable differences between LEDs and real-time compensation of any color drift caused by environmental changes, thanks to the combination of the UART and MeLiBu protocol, said Melexis.

The MeLiBu communication interface uses a CAN-FD physical layer for performance at up to 2-Mbit speeds, similar to the previous two product offerings with MeLiBu integration. Applications include highly animated light modules, animated rear light and DRL, and interior driver communication by light, such as voice command signal confirmation, safety warnings, advanced navigation, and blind-spot warning.

The MLX81143 is AEC-Q100–qualified and ASIL-compliant. It meets ISO 26262 functional safety requirements and supports ASIL B integration. In addition, the device’s architecture helps designers to meet EMC requirements and offers low electromagnetic interference (EMI) emissions and high levels of EMI immunity, said the company.

Allegro MicroSystems Inc. has added two LED drivers to its automotive lighting portfolio with the introduction of the A80803 and A80804 controllers. These drivers are designed for high-end lighting in mainstream vehicles.

Both products help designers reduce the number of ICs required to create safety-enhanced automotive lighting systems, said Allegro. The ICs can be used standalone or integrated into advanced driver-assistance system (ADAS) applications.

The A80803 LED driver leverages multi-topology conversion and IP to enable smooth high-/low-/high-beam transitions in a single IC, eliminating the need for a second LED driver. The A80804 linear LED driver provides high power for automotive lighting applications through multiple, independently configurable channels, each with an independent enable/PWM input.

Addressing common pain points when adding advanced functionality to automotive headlights, the A80803 is a switch-mode, constant-current controller designed for high-power LED automotive lighting applications. The multi-topology, single-ended controller design, combined with wide input-/output-voltage capability, provides a universal solution for a variety of use cases and/or number of LEDs. Configuration options include SPI-based control or E²PROM-based end-of-line programming for standalone operation.

Other features include a “unique” slew-control feature that minimizes LED current overshoot and undershoot while transitioning between high and low beams, as well as diagnostics for ASIL capability, with two programmable fault pins and reporting via SPI.

The A80804 is Allegro’s first four-channel linear driver for high-power LEDs. In addition to targeted applications like DRL/position and stop-/taillights, it enables features like sequential turn signals, animation effects, and theater-style transitions. No switching elements or inductors are required, said Allegro, and the A80804’s low EMI output helps it achieve CISPR25 Class 5 compliance. It also offers multiple analog and PWM dimming methods, as well as dual-brightness–mode operation, and it is configurable without the need for a microcontroller.

Other key features include the ability to switch between low and full intensity for applications including stop-/taillights or DRL/position lighting, without the need of a local microcontroller, and selectable LED current slew-rate control for tuning PWM edge times for better EMI performance. A unique “MINOUT” function is said to significantly reduce power losses by dynamically adjusting for the inherent changes in LED V_F versus temperature.

The A80804 can also parallel multiple devices to extend the number of LED strings. It also provides a variety of protection capabilities to protect the device and the LEDs and an integrated/optional derating for high V_IN and/or temperature.

Both LED drivers offer multiple methods for analog LED setting/control, LED binning, NTC foldback, or hybrid dimming. They also provide multiple methods for PWM LED control via an internal PWM signal (standalone mode) or an external PWM signal for direct PWM control on the EN/PWM pin (MCU mode).

The A80803 is available in a thermally enhanced 32-pin, 5 × 5-mm QFN package with a wettable flank, and the A80804 is available in a 32-pin 5 × 5-mm QFN package with a wettable flank.

Lumissil Microsystems, a division of Integrated Silicon Solution Inc. (ISSI), has expanded its automotive lighting portfolio with the addition of the IS32LT3146 and IS32LT3147 LED drivers. The six-channel LED drivers are AEC-Q100–qualified and offer a wide input voltage range of 5 V to 40 V to handle the automotive battery voltage supply range and spikes as well as low headroom voltage. Applications include sequential turn lights, welcome lights, rear lights, and stoplights or taillights.

The LED drivers provide six channels of adjustable constant-current sources that are each adjustable from 10 mA to 75 mA. The channels can be connected in parallel for increased current-drive capacity up to a maximum of 450 mA per device. The devices also feature a low headroom voltage and low quiescent current for low power consumption. The max headroom is 500 mV at 25 mA per channel and 900 mV at 75 mA per channel. Both devices operate over a temperature range of –40˚C to 150˚C.

The devices integrate advanced thermal management and fault protection. The thermal shunt circuitry minimizes driver thermal stress, while the fault detection and reporting offer additional system reliability, said the company. In addition, the current slew-rate control optimizes EMI and the thermal rolloff helps ensure device reliability over its lifetime.

The IS32LT3146 provides additional logic to turn on output channels in groups of one, two, three, or six in one-group-after-another-group sequential mode or all-channels blinking on/off mode, said Lumissil. The LED driver is designed for standalone operation whereby a vehicle’s body-control–module signal powers the device and all functions can be configured via external resistors without a microcontroller host.

The IS32LT3147 device’s output channels provide individual PWM dimming via dedicated PWM input control pins. An off-the-shelf microcontroller host’s GPIOs can be used to control PWM inputs, or Lumissil’s IS32LT3134 animation controller could be used with up to two IS32LT3147 devices to modulate up to 12 output-current sources for complex pattern playback, said Lumissil. Both drivers are housed in a thermally enhanced 6.5 × 4.4-mm eTSSOP-20 package.