In these complex electronic systems, inductors, as a key fundamental component, play an indispensable role. Their performance, especially their reliability, has a profound impact on the safe operation of automobiles.
Among the many electronic systems in a car, ADAS and ADS are arguably the most critical and complex, playing a decisive role in vehicle safety. These systems, comprised of multiple advanced sensors, high-performance processors, and sophisticated algorithms, work together to perceive the vehicle's surroundings in real time and make precise decisions. In ADAS/ADS, processors bear the heavy responsibility of data processing and decision-making, requiring a stable and reliable power supply. These processors typically operate in low-voltage environments, with a power rail voltage of approximately 1 volt, but their current requirements can reach tens of amps. Such high current demands pose stringent challenges to power management integrated circuits (PMICs). Power inductors work in conjunction with PMICs, serving as a key component of buck converters and playing a central role in the power conversion process.
When a buck converter operates, it converts a higher input voltage to a lower output voltage through a switch connected in series with the input voltage source and a low-pass filter consisting of a power inductor and an output capacitor. During the TON period (when the switch is on), the input voltage drives the output and charges the power inductor, causing the inductor current to rise linearly to its peak value, Ipeak. During the TOFF period (when the switch is off), the energy stored in the inductor continues to supply power to the load through the commutation diode, and the inductor current gradually decreases, forming a triangular ripple current. The magnitude of the ripple current is closely related to the inductance of the power inductor. A suitable inductance value ensures that the ripple current is maintained at a reasonable level, typically set to generate a ripple current of 20-30% of the rated output current. When the load suddenly increases, the output voltage drops instantaneously. At this time, the power inductor needs to cope with the abnormally large peak current and quickly charge the output capacitor to maintain voltage stability. During this process, the inductance value of the power inductor has a significant impact on the transient response of the converter; a smaller inductance value speeds up the recovery time, while a larger inductance value prolongs the recovery time. Therefore, in automotive applications, the performance of power inductors directly affects whether the ADAS/ADS system can operate stably and reliably, thus impacting vehicle driving safety.
As a crucial component ensuring driving safety at night and in adverse weather conditions, automotive headlights also rely heavily on high-quality inductors for performance. With the widespread application of LED lighting technology and the increasing demands of car users for headlight safety, modern automotive headlights not only possess basic lighting functions but also boast intelligent features such as automatic on/off, automatic height and brightness adjustment, adaptive headlights, and automatic high/low beam switching. The realization of these functions depends on complex electronic circuits, with inductors being key components. Automotive headlight electronic circuits are high-power designs operating in extremely complex environments. Inductors face numerous challenges in this environment. First, they must withstand high currents, maintaining sufficient inductance under high transient peak current conditions to ensure normal circuit operation. Simultaneously, they must withstand continuous high current output for extended periods while ensuring the inductor surface temperature rise does not exceed specified limits, preventing overheating that could shorten inductor lifespan or even cause headlight malfunction. Second, due to the relatively high operating frequency of automotive headlight designs, inductors must utilize low-loss magnetic core materials to effectively reduce high-frequency core losses, decrease headlight heat generation, achieve energy conservation and environmental protection, and improve output efficiency. Furthermore, the automotive operating environment is complex and variable, including harsh weather, extreme temperature differences, and high vibration. This requires inductors to have high reliability and maintain good electrical performance under various extreme environments. At the same time, the magnetic shielding structure design can effectively reduce electromagnetic interference and ensure the stable operation of the vehicle lighting system.
To meet the stringent requirements of the automotive industry for high-reliability inductors, numerous electronic component manufacturers are continuously innovating and developing a series of high-performance inductor products specifically designed for automotive applications. Taking TDK's CLT32 series power inductors as an example, this series is tailored for ADAS/ADS applications and boasts numerous superior characteristics. It utilizes magnetically molded materials to ensure soft-saturation characteristics, effectively reducing inductance changes caused by magnetic saturation, i.e., saturation drift. The entire inductor is formed around a single, thick copper coil, employing an integrated terminal structure to avoid unreliable operation that might result from internal connections. The thick copper coil also results in a series resistance as low as 0.39 milliohms, significantly reducing power loss and heat generation under load. The coil is encapsulated in a newly developed ferromagnetic plastic compound, forming both the core and shell. This core material exhibits excellent electrical characteristics in high-temperature and high-frequency applications, with extremely low core losses. Furthermore, this series of inductors is compact, using a flat 3.2×2.5×2.5 mm package, offering high volumetric efficiency and allowing multiple inductors to be used without increasing the circuit board size. Its rated operating temperature range is -40℃ to +165℃, far exceeding the AEC-Q200 maximum test temperature requirement of 125℃, enabling it to adapt to various extreme automotive operating environments. In terms of ripple current power loss, the CLT32 inductor has a significant advantage over thin-film or metal composite inductor technologies. Lower AC ripple loss means it can tolerate higher ripple current, allowing for lower capacitance values in DC/DC converters, thereby improving overall efficiency.
KEDAJI has independently developed and designed several series of automotive-grade molded inductors, such as the VSHB, VSHB-T, VSAB, and VSEB-H series, to meet the needs of automotive lighting applications. These inductors are manufactured using low-loss alloy powder die-casting, resulting in the lowest power consumption and DC impedance for their size. The high Bm value of the alloy powder core provides superior DC bias capability. The products feature a fully magnetically shielded structure, offering strong resistance to electromagnetic interference. The tight integration of the coil and core effectively prevents noise generation and allows them to withstand high-intensity mechanical shocks and vibrations. The VSHB-T series, in particular, utilizes a dual hot-press molding process and a T-Core core structure design, further reducing core loss and short-circuit risk. The innovative T-core structure ensures the reliability and consistency of the inductor's electrical performance. This series operates within a temperature range of -55℃ to +165℃, achieving the highest temperature resistance rating of AEC-Q200 Grade 0, making it ideal for demanding automotive applications such as engine compartments and lighting systems.
In automotive electronic systems, highly reliable inductors play an irreplaceable role in ensuring vehicle safety. From the stable power supply of ADAS/ADS systems to the reliable operation of automotive lights, the performance of inductors directly affects the realization of critical automotive functions and the guarantee of safety performance. As the automotive industry continues to develop towards intelligence and electrification, the requirements for the performance and reliability of electronic components such as inductors will become increasingly stringent. Electronic component manufacturers need to continuously invest in research and development, innovate constantly, and launch more high-performance, high-reliability inductor products to meet the growing needs of the automotive industry and provide solid technical support for safe driving.
