A traditional fuel vehicle requires about 500 to 600 chips, a mild hybrid vehicle requires about 1000 chips, and plug-in hybrid and pure electric vehicles require at least 2000 chips. This means that with the rapid development of smart electric vehicles, the demand for advanced process chips is increasing significantly, and the demand for traditional chips will continue to rise. The MCU is one such component; not only is the number mounted in each vehicle constantly increasing, but domain controllers have also created a new demand for high safety, high reliability, and high-performance MCUs.
MCU, or Microcontroller Unit, integrates the CPU, memory, and peripheral functions onto a single chip, forming a chip-level computer with control functions, mainly used for signal processing and control, which is the core of intelligent control systems.
MCUs are closely related to our daily lives and work, such as automotive electronics, industry, computers and networks, consumer electronics, home appliances, and the Internet of Things, among which automotive electronics is the largest market, accounting for 33% globally.
MCU Structure
MCUs are mainly composed of a central processing unit (CPU), memory (ROM and RAM), input/output (I/O) interfaces, serial ports, counters, etc.
CPU: The Central Processing Unit is the core component inside the MCU. The arithmetic logic unit can perform arithmetic and logical operations, bit variable processing, and data transfer operations, while the control unit coordinates work according to a certain timing, analyzing and executing instructions.
ROM: Read-Only Memory is the program memory used to store programs written by manufacturers. Information is read in a non-destructive manner, and the stored data does not disappear after power loss. The MCU executes according to pre-written programs.
RAM: Random Access Memory is the data memory that exchanges data directly with the CPU. This data cannot be retained after power loss. During program execution, data can be written and read at any time, usually serving as a temporary data storage medium for operating systems or other running programs.
Relationship Between CPU and MCU:
The CPU is the core of computational control. Besides the CPU, the MCU also includes ROM or RAM, making it a chip-level chip. Commonly, there’s also SoC (System on Chip), which is a system-level chip that can store and run system-level code, operating systems like QNX and Linux, and includes multiple processing units (CPU + GPU + DSP + NPU + storage + interface units).
Bit width refers to the width of data processed by the MCU at one time; a higher bit width means stronger data processing capability. Currently, the main types are 8-bit, 16-bit, and 32-bit MCUs, with 32-bit being the most prevalent and growing rapidly.
NXP’s S32 automotive processor platform. (Source: NXP)
In automotive electronics applications, 8-bit MCUs are cost-effective and easy to develop, mainly used in relatively simple control areas such as lighting, wipers, windows, seats, and door control. For more complex areas such as instrument display, in-car entertainment information systems, power control systems, chassis, and driving assistance systems, 32-bit MCUs are primarily used, and with the evolution of electric, intelligent, and connected vehicles, the computational requirements for MCUs are also increasing.
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Automotive Related Sections
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Low-end control functions: various subsystems of the vehicle body, such as fan control, air conditioning control, wipers, sunroofs, window lifts, low-end dashboards, junction boxes, seat control, door control modules, etc.
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Mid-range control functions: ① Power transmission systems, such as engine control, gear and clutch control, and electronic turbo systems; ② Chassis mechanisms, such as suspension systems, electronic power steering, torque distribution control, electronic assistance, and electronic brakes.
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High-end control functions: play an important role in L1/L2 intelligent driving functions, such as dashboard control, body control, multimedia information systems, engine control, and emerging safety and power systems with intelligence and real-time capabilities (pre-collision, ACC, driving assistance systems, electronic stability programs, X-by-wire, etc.).
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MCU Automotive Certification
MCU suppliers generally need to complete three major certifications before entering the OEM supply chain: during the design phase, they must comply with functional safety standard ISO 26262; during the wafer and packaging phase, they must adhere to AEC-Q001~004 and IATF16949; and during the certification testing phase, they must follow AEC-Q100/Q104.
Among them, ISO 26262 defines four safety levels of ASIL, ranging from low to high: A, B, C, and D; AEC-Q100 is divided into four reliability levels, from low to high: 3, 2, 1, and 0. AEC-Q100 series certification generally takes 1-2 years, while ISO 26262 certification is more challenging and takes longer.
Application of MCU in the Smart Electric Vehicle Industry
MCUs are widely used in the automotive industry, from body accessories, power systems, chassis, in-car infotainment to intelligent driving. As the era of smart electric vehicles develops, the demand for MCU products will continue to grow.
1. Battery Management System (BMS): BMS needs to control charging and discharging, temperature, and balance between batteries. The main control board requires one MCU, and each slave control board also requires one MCU;
2. Vehicle Control Unit (VCU): The energy management of electric vehicles requires an additional vehicle controller, which needs to be equipped with a 32-bit high-level MCU, with the number varying based on each manufacturer’s design;
3. Engine Controller/Transmission Controller: Stock replacement, where the MCU for controlling the inverter in electric vehicles replaces the engine controller of fuel vehicles. Due to the high rotation speed of the motor, it needs to be reduced by a gearbox, and the MCU control chip equipped replaces the transmission controller of fuel vehicles.
1. Currently, the domestic automotive market is still in the L2 high penetration stage. Based on comprehensive cost and performance considerations, OEMs still use distributed architectures for new ADAS functions. As the loading rate increases, the number of MCUs processing sensor information also increases.
2. As cabin functions increase, the importance of higher-performance chips is growing, while the status of corresponding MCUs is declining.
MCUs prioritize computational power requirements and do not have high requirements for advanced processes. Additionally, the embedded memory within limits the process enhancement of MCUs. Therefore, current automotive-grade MCU process nodes are mainly in the mature process of 40nm and above, with some advanced automotive MCU products adopting 28nm processes. The specifications for automotive-grade chips are mainly 8-inch wafers, and some manufacturers, especially IDM, are beginning to migrate to 12-inch platforms.
Currently, 28nm and 40nm processes are the market mainstream.
Typical Domestic and International Enterprises
Compared to consumer and industrial-grade MCUs, automotive-grade MCUs have higher requirements for operating environments, reliability, and supply cycles. Additionally, the certification threshold for automotive-grade MCUs is relatively high, with long certification times and difficult entry. Therefore, the overall MCU market structure is relatively concentrated, with the top five MCU companies in the world accounting for 82% of the market share in 2021.
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Serial No.
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Company
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Country
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2021 Sales (Billion USD)
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2021 Market Share
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1
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NXP
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Netherlands
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37.95
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18.8%
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2
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Microchip
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USA
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35.84
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17.8%
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3
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Renesas
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Japan
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34.2
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17%
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4
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STMicroelectronics
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Italy
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33.74
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16.7%
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5
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Infineon
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Germany
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23.78
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11.8%
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Currently, China’s automotive-grade MCUs are still in the introduction phase, with significant potential for localization and domestic replacement in the supply chain.
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Mass Production First Passed Time
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Automotive-grade touch MCU, automotive-grade general MCU, and battery management MCU
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Jiefa Technology (subsidiary of NavInfo)
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Core functions such as ABS, BMS, and body control
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Body electronics, smart cockpit
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Automotive lighting, window control, air conditioning panel
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In-vehicle T-BOX safety unit, in-vehicle diagnostic system safety unit, C-V2X communication safety application
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Automotive display applications
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Tail light flowing lights, in-vehicle wireless charging, window control
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