The electronic architecture of autonomous driving is a core component of modern automotive technology, designed to process vast amounts of data and achieve highly automated driving functions. The future development of autonomous driving technology will involve more technological integration and innovation, aiming to achieve higher levels of automated driving, providing safer, more comfortable, and efficient travel experiences. This article will introduce the development directions of autonomous driving technology and the characteristics of higher-safety components provided by KEMET and YAGEO for automotive-related electronic systems, such as Polymer Capacitors, Multilayer Ceramic Capacitors (MLCC), and Circuit Protection Components (CPC).
Autonomous driving systems with sensing and cognitive abilities
In recent years, the development of autonomous electric vehicles has garnered significant attention from researchers and engineers. Numerous changes are revolutionizing the electronic and electrical (EE) architecture of automobiles, bringing about autonomous driving and related challenges. Autonomous vehicles must be able to perceive their surroundings and navigate safely without human intervention. The National Highway Traffic Safety Administration (NHTSA) in the United States has defined different levels of autonomous driving, ranging from Level 0 (no automation) to Level 5 (full automation).
At higher levels of autonomy, vehicles must use multiple sensors to perceive their environment, such as LiDAR, cameras, GPS, and more. Based on sensor input, vehicles must locate themselves in real-time, make decisions, and take actions for driving. The Advanced Driver Assistance Systems (ADAS) utilize these sensors to enhance driving safety, focusing on the "sensing" capability. On the other hand, the various systems in autonomous driving (AD) handle data from sensing, decision-making, and commanding to actuators (braking, steering, etc.), referred to as having "cognitive" abilities, which process sensor data, perception, and decision-making.
Autonomous driving is a highly complex system. To support the highest levels of autonomy, the evolution of EE architecture is moving from numerous Electronic Control Units (ECUs) to functional Domain Control Units (DCUs), such as AD/ADAS, connectivity, smart cockpit, and more, and further to centralized computer’s Central Control Units (CCUs) and zonal gateways’ Zone Control Units (ZCUs).
These control units collaborate within the autonomous driving system to achieve complex vehicle control tasks, providing efficient, safe, and intelligent driving experiences. The traditional multi-ECU architecture is transitioning towards centralization, with more functions being integrated into DCUs or CCUs to reduce complexity and cost.
Polymer capacitors to support the power requirements of autonomous driving
As the level of autonomous driving increases, the number of installed sensors must also increase accordingly to gather environmental data. With the increase in sensors, the amount of data processed by the SoC also rises, leading to higher power consumption of the main semiconductor devices that perform data processing. This evolution increases power consumption to optimize the cognitive "brain" ability.
To ensure the stable operation of autonomous driving systems, using polymer capacitors to support the increased power consumption in AD and ADAS DCUs (Domain Control Units) is crucial. Among these, tantalum polymer capacitors, composed of a tantalum (Ta) anode, tantalum pentoxide (Ta2O5) dielectric, and solid polymer electrolyte, offer multiple advantages. These include high temperature ratings and stability over temperature, voltage, and time, making them capable of meeting and exceeding AEC-Q200 automotive standards.
KEMET manufactures organic capacitors constructed with a conductive polymer cathode, offering optimized performance across a wide range of applications. KEMET's product portfolio combines extremely low Equivalent Series Resistance (ESR) with improved high-frequency capacitance retention and a broad range of product sizes, supporting designers through innovation and technology.
KEMET's Tantalum Polymer Capacitors (KO-CAP™ series) feature low ESR to minimize power loss and unwanted noise, withstand high temperatures, and extend the lifetimes of automotive applications. Specifically, the T598 Tantalum Polymer Capacitors provide ideal high capacitance, low ESR, and excellent ripple performance, supporting the increased power consumption in AD and ADAS DCUs.
KEMET's T598 Tantalum Polymer Capacitors exhibit low series resistance, ranging from 6 mΩ to 150 mΩ (100kHz, RT), and maintain stable capacitance and ESR across a temperature range of -55°C to 125°C, enhancing high-frequency capacitance retention and offering a super long expected lifespan.
The T598 automotive-grade polymer capacitors provide solutions for designers needing to save circuit board space, achieve high volumetric efficiency, miniaturization, and reliability. The T598 series, with a specific case size of EIA 7343-31, has a rated capacitance of 470µF and a rated voltage of 2.5V, successfully applied in ADAS/AD DCUs.
Automotive-grade ceramic capacitors meeting stringent requirements
Multilayer Ceramic Capacitors (MLCCs) are capacitors that utilize multiple layers of ceramic material as the dielectric. These capacitors are widely used in modern electronic devices due to their high capacitance values, small size, and excellent electrical performance.
Like all capacitors, the primary function of MLCCs is to store and release electrical energy. They can charge and discharge quickly, making them ideal for smoothing voltage and stabilizing power supplies in electronic circuits. MLCCs are commonly used in filtering applications to remove high-frequency noise from power supplies and smooth voltage fluctuations. They are prevalent in switching power supplies, DC-DC converters, and audio circuits.
In bypass applications, MLCCs provide a low-impedance path to bypass high-frequency noise, protecting sensitive circuits from interference. In decoupling applications, MLCCs stabilize voltage, preventing fluctuations from affecting the normal operation of sensitive components, especially in digital circuits. MLCCs are also used in coupling applications, allowing AC signals to pass between different circuits while blocking DC signals.
Due to their multilayer structure, MLCCs can provide high capacitance values in a relatively small volume, which is useful for applications requiring high capacitance. The miniaturization advantage of MLCCs makes them suitable for high-density assembly needs in modern electronic devices. MLCCs have low ESR, effectively filtering out high-frequency noise and enhancing circuit performance. They also exhibit high reliability and can operate across a wide temperature range, making them suitable for various demanding working environments. MLCCs show good stability under temperature and voltage changes, ensuring consistent performance under different working conditions.
In automotive electronics applications, MLCCs are used in automotive power systems, engine control units (ECU), in-vehicle entertainment systems, and other electronic control modules to enhance system reliability and performance. KEMET provides automotive-grade MLCC devices designed with safer failure mechanisms, conforming to industry standards such as AEC-Q200 and VW AUDI 80808. KEMET's components have been validated on the road and in laboratories, with a broad record of reliability. KEMET's automotive-grade products are tested to operate in harsh temperatures ranging from -50°C to 125°C and are certified for powertrain, onboard electronics, and charging systems applications.
KEMET offers a wide range of MLCC devices, including surface-mount commercial/automotive SMD, ESD-rated, KPS, MIL-PRF, high-temperature, high-voltage, ArcShield, STD KONNEKT, with Flex Term, floating electrode, open-mode, and Sn, SnPb, Au terminations.
Comprehensive circuit protection components ensure the stable operation of systems
Circuit Protection Components (CPC) play a crucial role in electronic circuits, designed to protect circuits from overcurrent, overvoltage, short circuits, and other electrical anomalies. There are various types of circuit protection components, and here we provide a brief overview of some common products.
Common circuit protection components include TVS (Transient Voltage Suppressor), Zener diodes, rectifier diodes, fuses, PTC resettable fuses, varistors (MOV), ESD protection devices, ceramic gas discharge tubes (GDT), SPGs (Surge Protection Devices), thyristors (TSS), and negative temperature coefficient thermistors (NTC). These components protect circuits from unstable currents and voltages.
Circuit protection components are widely used in the automotive industry. For example, in battery management systems (BMS), fuses and PTC resettable fuses protect the battery pack from overcurrent and short circuits, ensuring safe operation. Thermistors monitor battery temperature to prevent overheating.
In engine control units (ECU), fuses and TVS diodes protect against overcurrent and overvoltage, ensuring the stability of engine control systems. In lighting systems, varistors and fuses protect against voltage fluctuations and overcurrent, extending bulb life.
In entertainment and information systems, surge protectors and TVS diodes protect against lightning and electrostatic discharge. In electric vehicle charging systems, varistors and fuses protect against overvoltage and overcurrent.
In airbag systems, thermistors and fuses ensure proper deployment in emergencies and disconnect in case of overheating or short circuits. In onboard networks, PTC resettable fuses and TVS diodes protect communication buses like CAN and LIN from overcurrent and overvoltage.
YAGEO provides a complete range of circuit protection solutions, including overvoltage protection components like TVS, MOV, GDT, SPG, ESD, and TSS, as well as overcurrent protection components like PPTC and NTC. TVS, MOV, and ESD products offer precise voltage clamping capabilities, limiting voltage to permissible levels by shunting excess current to the ground. GDT, SPG, and TSS act as circuit switches, diverting abnormal currents to the ground. PPTC and NTC components change resistance with temperature variations to protect circuits. YAGEO's protection products are widely used in automotive, industrial, power, communication, and consumer electronics sectors.
In the automotive market, YAGEO's solutions can be applied in ADAS, lighting, DC-AC inverters, on-board chargers (OBC), DC-DC converters, and battery management systems (BMS). The product line includes transient suppression diodes (TVS, general/automotive), Zener diodes, rectifier diodes, chip fuses, varistors (MOV), ESD protection devices, ceramic gas discharge tubes, resettable fuses, surge protection devices, thyristors, and negative temperature coefficient thermistors (NTC).
Conclusion
In the development of autonomous driving technology, protection components play a vital role in ensuring the safety and stability of vehicle systems. These components are responsible for protecting circuits from overcurrent, overvoltage, short circuits, and overheating. In autonomous vehicles, these protection components are widely applied across various electronic and electrical subsystems. They ensure that each subsystem can respond quickly to abnormal situations, preventing the spread of faults and thereby enhancing the overall safety and reliability of the vehicle. The protection components from KEMET and YAGEO introduced in this article offer excellent product quality, ensuring the stable operation of autonomous driving systems.