Not long ago, the General Office of the State Council issued the "New Energy Automobile Industry Development Plan (2021-2035)", which clarified the encouragement and support for multiple fields of the new energy automobile industry chain, showing a very positive signal: the development of domestic new energy vehicles The direction will cover the entire industry chain, all scenarios, and the diversified development of energy. It can be said that new energy vehicles are not only the main direction of transformation and upgrading and green development of the global automobile industry, but also the strategic choice for the high-quality development of my country's automobile industry.
Since state subsidies began to decline sharply last year, the new energy vehicle market has experienced a decline and consolidation in the second half of last year and the first half of this year, and has also begun to enter a healthier and benign product and market-driven stage. "Improving the core technology of new energy vehicles is a necessary condition for us to compete with the brands of developed countries." Feng Yixin, director of the product management department of Fujitsu Electronic Components (Shanghai) Co., Ltd., said in a recent event. How to strengthen the core technology of new energy vehicles? As a global leader in high-performance non-volatile memory, Fujitsu Semiconductor’s ferroelectric random access memory products (hereinafter referred to as FRAM) focus on the safety of automotive applications. Since 2017, it has launched a number of models suitable for automotive applications. FRAM products have successfully entered the supply chain of many Tier-1 and Tier-2 OEMs by expanding the operating temperature range (-40°C to 125°C) and further improving product reliability.
Facing the pain points of new energy vehicle storage
In recent years, my country's new energy automobile industry has developed rapidly and has become an important growth point for the automobile industry. According to the sales statistics of new energy vehicles in 2018, 11 brands in the TOP20 are from China. The rapid growth in sales of new energy vehicles has naturally led to the development of the relevant automotive electronics industry chain. Due to the use of electric drives, the structure of new energy vehicles is different from traditional fuel vehicles. Power batteries, battery management systems (BMS), and vehicle control units (VCU) The three major systems have become the core functional components of the car, and the proportion of car electronics costs compared to the value of the whole car has further increased.
"We believe that high-performance memory FRAM will be a key element to improve these core technologies. Whether it is BMS or VCU, these systems need to monitor, record, and analyze the current status information in real time and continuously." Feng Yixin said, "Therefore , It is necessary to improve the memory performance and durability design. Only non-volatile, high-speed, high-endurance car-level memory FRAM can meet the required reliability and no delay.
BMS is an important link connecting vehicle power batteries and electric vehicles. Its main functions include: real-time monitoring of battery physical parameters; battery state estimation; online diagnosis and early warning; charge, discharge and precharge control; balance management and thermal management; and so on. "For a simple example, the battery cell power is generally maintained between 30% and 75% to indicate normal operation. If there is an imbalance, it needs to be supplemented from another unit. At this time, the system needs to detect and record the power and temperature of the battery cell. Data such as, voltage, current, etc., and the time interval of a single monitoring record cannot be too long. This means that the data recording and writing of BMS are also very frequent, and the writing times of non-volatile memory are relatively high. "Feng Yixin said.
At the same time, in actual work, the BMS system will not only record the current data such as the voltage, temperature and current of the battery cell at a frequency of every second or every 0.1 second, but also monitor the short-term (last few charging cycles) and long-term (the entire Life) status, which is essential to maximize battery life. "In response to these unique requirements, it is also necessary to improve the memory performance and durability design. Therefore, non-volatile, high durability, high-speed automotive-grade FRAM is an ideal choice for BMS. At present, some Chinese customers have begun to adopt Fujitsu 3V SPI 128Kbit, 256Kbit, 2Mbit and 5V SPI 64Kbit FRAM." Feng Yixin revealed.
Similarly, the VCU system needs to record the current state of the car and the transmission gear, acceleration, braking and output torque when a failure occurs at a speed of once per second, and FRAM can be carried out through simpler software. Storage and reading, while ensuring high speed and high reliability. "As of now, China's new energy vehicles and low-speed scooters VCU systems have begun to use Fujitsu 64Kbit SPI FRAM." Feng Yixin introduced, "At the same time, Fujitsu launched the latest car-grade product MB85RS2MLY in May this year, which can operate at -40°C to Up to 10 trillion read/write times in the +125°C temperature range, which is very suitable for applications that require real-time data recording (for example, if data is recorded every 0.1 second every day for 10 years, the number of writes will exceed 3 billion). High data write durability and reliability.
Build a strong backing for autonomous driving
With the development of automobile intelligence, more and more vehicles are equipped with autonomous driving technology. According to data from the Foresight Institute of Technology, the domestic autonomous driving market in 2019 is 112.5 billion yuan, and it is expected to reach 238.1 billion yuan by 2023, with a compound annual growth rate of 20%. For major car companies, new energy and autonomous driving as new things can be said to have started at the same time. Its simpler electronic control system and vehicle architecture than traditional fuel vehicles show a high degree of compatibility with this combination. At present, many new new energy vehicles that have just been launched have reached the L2 autonomous driving level. "In fact, the essence of autonomous driving, or ADAS (advanced driving assistance system), is the dialogue between the car and the environment. It is realized through processes such as sensor data collection, memory recording data, processor calculation data, and feedback. All of these processes To complete in a very short time, in addition to high speed, the key is the key-reliability must be guaranteed!" Feng Yixin said when talking about autonomous driving technology.
Three core technologies of autonomous driving
ADAS is the prelude to unmanned driving and the core of the market at this stage. When unmanned driving continues to seize the headlines, ADAS, an advanced driving assistance system, quietly set off a wave of change, fundamentally changing the control methods and user experience of traditional cars. The redundancy and fault tolerance characteristics of autonomous driving require that the more advanced autonomous driving requires more sensors. Feng Yixin pointed out: “All the subsystems of ADAS, such as sensors, cameras, CAN communication, vehicle HMI, etc., must store current status information in real time and continuously for real-time monitoring, recording, analysis or processing. Under such strict regulations, there are Volatile, high-speed writing, and high-endurance FRAM memory just meets the requirements of reliability and no delay required by autonomous driving! Therefore, as ADAS technology matures, FRAM has more and more opportunities in this field. Big."
Take the application of smart airbags in the artificial intelligence decision-making platform as an example. Airbags, as a necessary configuration for most cars, play a great role in ensuring the personal safety of drivers and passengers. For smart airbags, after the airbag is activated and driven, the system should continuously record whether the airbag is operating normally and the airbag's history data, and finally use these data as a legal basis to deal with the accident and investigate the cause and responsibility; in addition, the system needs to be real-time Monitor and continuously record empty seat information and passenger weight to ensure accurate and timely activation of airbags. "These requirements make FRAM an ideal choice. At present, Tier1's continental has adopted FRAM in their smart airbags, and some customers in China have also adopted 16Kbit serial FRAM." Feng Yixin revealed.
Application of FRAM in smart airbag
In addition, in the tire pressure monitoring (TPMS) application in the ADAS segment, Fujitsu has taken the first step to seize the automotive application market. According to reports, Fujitsu FRAM memory has been first adopted by Pirelli tires and used in the TPMS system of its motor vehicle tires to achieve reliable low power consumption, high-speed writing and high-endurance data processing functions. Pirelli is one of the most prestigious tire companies in the world. Pirelli tires with more than 100 years of history have become synonymous with "reliable quality" and "excellent performance" in the tire industry! In this regard, Feng Yixin said: “TPMS needs to monitor tire pressure in real time and continuously. If there is insufficient inflation, an alarm will be issued immediately. Tire pressure monitoring is installed in a harsh environment with high temperature and high pressure. The battery is not easy to replace, in order to extend battery life. , The use of low-power memory is a necessary condition. These requirements make FRAM an ideal choice for tire pressure monitoring.
Cost competition, is FRAM really expensive?
Although FRAM has more advantages than traditional Flash and EEPROM in terms of read and write durability, write speed and power consumption, it also has the disadvantages of higher cost and low capacity. “Generally speaking, some manufacturers may not choose FRAM for cost reasons, but use EEPROM instead, but it may not really save costs.” Feng Yixin explained, “They often don’t realize that FRAM and EEPROM work. Huge difference."
FRAM has better durability than EEPROM
As shown in the figure above, the number of writes for FRAM is about 107 times that of EEPROM, which means that the latter requires a much larger overall capacity under the same number of writes. Assuming that FRAM has a capacity of 4KB, although it is small, it allows 1013 data to be written repeatedly in the same area of the entire memory. On the contrary, the capacity of EEPROM can be much larger than 4KB, but it is limited by the number of writes (only 106 times). If the A area in the entire memory reaches the limit of the number of writes, the stable data writing of the A area will not be guaranteed. In addition, change the B area to rewrite; then the replacement process of the new and old areas needs Wear Leveling (wear leveling technology) to control, which invisibly increases the software configuration cost.
In addition, the writing speed of FRAM is about 30,000 times that of EEPROM. In special circumstances such as power failure, the former can write and save data in a very short period of time (about 0.00015ms), while the latter is to ensure that the power remains To record data, it is often necessary to use super capacitors to "charge" the circuit, which is another cost. Moreover, in order to reserve a sufficient number of writes, especially in applications that frequently record data like BMS, the greater the demand for EEPROM capacity, the higher the cost. In other words, the cost of EEPROM is equivalent to its own capacity + capacitance + software, so there is not much cost advantage compared with FRAM.
Car infotainment with EEPROM
In addition, FRAM can not only perform high-speed writing, but also high-speed erasing. In this regard, low-power and high-speed FRAM can use small battery power to instantly erase important data, thereby ensuring user information security. At this time, FRAM only needs 0.1mA of working current to erase 256bit data in 0.3ms, which has significant advantages over EEPROM.
FRAM, EEPROM, FLASH operating current and erasing time comparison
Because the Chinese auto market started late, in relatively mature auto markets such as Europe, America, Japan and South Korea, auto brands are already concentrated, perhaps only three or four, while in the Chinese market, there are still hundreds of auto brands with different demands. different. "If Chinese companies want to beat their opponents or stand in the same position as much as possible, they need to keep up with international car regulations and select better quality and more reliable electronic components to design and manufacture more advanced products." Feng Yixin Said, "By adopting Fujitsu FRAM, car companies will no longer have to worry about key data storage!