Throughout history, car lights have evolved with the development of automobiles, especially under the trend of intelligentization. Car companies attach greater importance to consumer demand and are committed to providing intelligent, personalized, and more intimate services. As an eye-catching component in the entire vehicle, car lights have been given more expectations. The innovative design of automotive LED headlights, as an indispensable and important component of vehicles, not only directly affects nighttime driving safety, but also reflects the level and quality of vehicle design. The trend of software defined cars and the popularity of automotive Ethernet provide new ideas for the E/E architecture design in the automotive lighting domain.

Benchmark solution for automotive LED matrix headlight module

At the recently concluded PCIM Asia, the onsemi booth showcased the high-performance automotive matrix headlight solution launched by the Dalian University Shiping Group. It uses the latest generation of Boost Buck headlight LED driver IC NCV78964 from onsemi, which can provide two Buck outputs up to 60V/1.6A, drive LED light strings, and support PWM dimming function. Among them, Boost, as a stable voltage source, can ensure the voltage drop requirement accumulated by multiple LED light strings, while Buck, as a stable current source, directly drives the LED to emit light. Since the current source is not affected by load voltage transients, it can achieve fast switching and has excellent performance in adaptive high beam matrix/pixel light groups.

According to the relevant person in charge, this solution has extremely high flexibility due to its SPI programmability, allowing for the use of more LED strings in extended designs. The modular design of replaceable LED drivers provides flexible product choices for application deployment. For example, if a single lighting module requires more than 2 LED channels, multiple NCV78964 or NCV78763 devices can be combined to complete it, greatly accelerating the design cycle and reducing indirect engineering costs.

The LED bead control adopts the Anson pixel driver controller NCV78343 chip, designed specifically for automotive dynamic lighting applications, especially high current LEDs, with functions such as open circuit, short circuit, and overvoltage diagnostic protection. Each NCV78343 can independently turn on/off 1-12 light beads and perform PWM dimming control. Multiple NCV78343 chips can be combined to achieve independent control of more light beads.

The motor drive of the matrix headlights is controlled by the Anson Mei NCV70517. As a driver for micro stepper motors, the NCV70517 is connected to an external microcontroller through I/O pins and SPI interface. It uses proprietary PWM algorithm for reliable current control, meets the voltage requirements of automobiles, and has safety monitoring function. If electrical errors, undervoltage or junction temperature rise are detected, the chip will issue a warning.

As an advanced automotive matrix headlight LED module, this solution can meet the highest functional safety standard ASIL-D in the automotive industry, which means its performance in complex driving environments is more reliable. The LED driver chip NCV78964 adopts dual phase boost technology, which not only improves energy utilization efficiency, but also effectively reduces electromagnetic interference (EMI) and battery current ripple, making the vehicle more energy-efficient and quiet during operation. The flexible E/E reference design scheme allows manufacturers to customize according to their own needs, ensuring that the product can be better integrated into the design of various vehicle models, greatly enhancing the competitiveness of joint venture and foreign automotive brands, and is an ideal choice for improving the quality of automotive lighting systems.

In addition, this solution has a complete design consideration for the functional safety and low power consumption requirements of the headlight ECU. The NCV68261 used is an ideal diode controller with high edge drive from Anson Mei. In addition to providing comprehensive headlight ECU protection functions such as battery overvoltage, reverse voltage, and reverse current, it can also turn off the power supply of the LED driver IC and the light bead control IC to meet the needs of low power consumption functions.

From ECU to "headlight domain", infinite imagination of automotive Ethernet

In fact, the intelligent transformation of automobiles is not only reflected in the cool light and shadow of the headlights, but also in the increasingly significant trend of software defined vehicle SDV. To achieve various functions and services of vehicles through software, it is required that the vehicle must have high-speed and stable data transmission capabilities inside. Although traditional in vehicle networks such as CAN have played an important role in the past, they can no longer meet the needs of future intelligent vehicles in terms of data transmission speed and bandwidth. Automotive Ethernet is not only a bridge connecting various parts of the vehicle's nervous system, but also an indispensable communication technology support to promote the transformation of the automotive industry towards intelligence and networking.

At PCIM Asia, in addition to the built-in LED driver NCV78964 and pixel controller NCV78343, another automotive LED solution from Anson Mei achieved precise control of car headlights using 10BASE-T1S. These components together form a highly integrated headlight control system that can achieve area control through the ECU Light architecture. Each lighting function can be controlled through a graphical user interface (GUI), providing highly flexible headlight configurations. This means that car manufacturers can design more personalized and diverse headlight systems to meet the needs of different vehicle models and driving conditions. At the same time, the diagnostic information of the LED driver can be read regularly to ensure that the system always maintains optimal performance.

Automotive Ethernet 10BASE-T1S can provide more efficient data throughput and more deterministic latency, with every node having a fair opportunity to participate in communication, providing a solid foundation for achieving multiple high-resolution displays, advanced driving assistance systems, real-time remote diagnosis, and other functions in the car. At the same time, it can promote seamless integration of various subsystems within the vehicle and support future OTA updates, enabling the vehicle to be continuously upgraded and optimized throughout its entire lifecycle.

An expert from Ansenmei emphasized that the biggest highlight of this solution is that the entire car headlight system architecture responds to and conforms to the trend of SDV, realizing the Ethernet of each node in the car, such as the "last mile" in the regional architecture of the headlight system. This means that both control commands and data transmission can be achieved through unshielded twisted pair automotive Ethernet, ensuring efficient and reliable data exchange at every link from the central processing unit to the end actuators. This not only simplifies the wiring structure inside the vehicle, but also greatly improves the overall system's response speed and collaborative ability.

Undoubtedly, with the continuous advancement of technology, automotive LED lighting has not only become more intelligent, but also plays an increasingly important role in energy conservation, environmental protection, improving driving safety and comfort. Whether it is the hardware level LED system driver design or the application of 10BASE-T1S technology and advanced automotive E/E architecture, they are driving the development of automotive lighting technology towards a more efficient and intelligent direction, making cars smarter and more environmentally friendly.

This is reported by Top Components, a leading supplier of electronic components in the semiconductor industry

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Name: John Chen

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