How have automotive sensors, cables, storage, connectors, and testing solutions evolved?

However, "more intelligent driving cannot be achieved by relying solely on sensors, because the distance that sensors can perceive is limited after all. 5G can solve problems at longer distances, which are places that sensors cannot detect." But what 5G cannot do is to use networks like WiFi to make accurate distance judgments, so "V2X often solves problems that are longer than sensors and shorter than wide area networks. Only when 5G and sensors are combined can we have a higher level of intelligent driving." The "longer distance problems" mentioned here include long-distance detection of front-side anomalies, real-time updates of dynamic maps, and fast and reliable sharing of sensor data.

After C-V2X introduced the 5.9GHz ITS frequency band for communication, it uses direct connection between devices to complete communication without relying on cellular operating networks, reducing latency. It can complement millimeter wave radar better. It is mainly reflected in: 5.9GHz V2X transmits data information, and millimeter wave radar provides accurate relative distance, relative speed, and position angle between vehicles. The entire data layer completes the calculation and provision of 3 pieces of information within 100ms.

"Although based on our experience, integration is not easy, the future will definitely be vision + millimeter wave radar + 5G V2X," said Li Jianlin.

In the process of moving towards autonomous driving, in addition to the fusion of on-board sensors, we also learned about the fusion solution of wired connections from Deng Tao, senior business development manager of Valens Automotive Electronics Division. "There are many things to transmit in the car: audio, video, Ethernet, control, serial port, power supply, etc. We aggregate all these signals into one cable for uploading." This is actually Valens' HDBaseT on-board chip, which realizes intelligent connection through one cable. In addition to high speed and low latency, "the minimum bandwidth is 2Gbps, 4G/8G are available, and we will release 16Gbps next year." It is not easy to transmit so many signals through one cable. We are multi-point to multi-point communication, which requires addressing and protocol stack. We will do this solution well. The video signal has a video packet header, and the audio signal has an audio packet header. The data can be directly restored within 10ms."

Therefore, this solution supports star topology and daisy chain. "The daisy chain in the car is very popular among car manufacturers and can simplify the cable topology." The signal modulation method to implement this solution is PAM16, and the DSP in the chip can perform channel monitoring, real-time bit error rate analysis, and automatic frequency modulation, and can switch between PAM16, PAM8, PAM4, and PAM2.

In more specific applications, for example, "USB used to require a hub for multiple connections, but our chip can directly connect all the devices; entertainment systems can also be connected in a ring like this, making it easy to create redundancy solutions." This is a very practical example of simplifying wiring and topology. As shown in the figure above, these are the traditional solution and the connection solution using Valens.

This is another manifestation of the increasing integration and fusion of vehicle components in the era of intelligent connected vehicle development.

New requirements for automotive components: memory, connectors, sampling resistors

I heard that Mercedes-Benz will soon widely adopt Valens' HDBasedT-supported specifications and PCIe (PCIe over HDBasedT) chips in its high-end models, including in-vehicle Ethernet that can be integrated into HDBasedT. All these indicate that the internal connection speed of smart connected cars has a much higher demand than before.

The "high-speed" connection demand can also be seen in GigaDevice's in-vehicle storage at the conference. Shi Youqiang, GigaDevice's automotive marketing director, said, "Autonomous driving requires adding a large number of sensors to the car. The car is transformed from steel to intelligent software. We want to provide eyes for the car, the robot."

"The Domain Controller is surrounded by various sensors, including visual, millimeter-wave radar, LIDAR, etc., including DMS (driver status monitoring system)." Shi Youqiang said, "But everyone knows how high the speed requirements are for cars nowadays. Some newer cars have adopted full-screen. The display requires very low latency, so the subsequent technical support must be powerful."

This is a typical application scenario of GigaDevice's GD25LX series SPI NOR flash memory, as shown in the figure above - "We have just released a product that complies well with the ISO26262 standard." This is the first domestically produced high-speed 8-port SPI NOR Flash, and its high speed mainly includes 400MB/s data throughput, "efficient XiP (on-chip execution), 8-port command input, and 8-port DRT transmission of address and data."

IHS Market's forecast data shows that SPI NOR has always had the largest share in the ADAS storage market. According to the data provided by GigaDevice, GigaDevice is currently the third largest supplier of SPI NOR flash memory in the world, which is also the foreseeable opportunity and future of GigaDevice in the automotive market.

There are many aspects that can reflect the higher requirements of intelligent connected vehicles on vehicle components. In addition to the high speed mentioned in the previous two examples, it also includes reliability, adaptability to environments more stringent than industrial environments, durability, etc. These requirements are more significantly reflected in some more specific components, such as connectors.

The connectors displayed by Hirose at the booth

Connectors are probably the nodes that best reflect the technological transformation in the era of 5G, smart connected cars, and even IoT. Mr. Li Gang, a senior technical director from Hirose, said that the connectors for ADAS front cameras, surround/rear view cameras, millimeter wave radars, LIDARs, etc. all have their own characteristics. "For front cameras, most of the current connections are vertical connections between the sensor circuit board and the control board, using flexible flat cables; the surround view camera is very small, so a board-to-board connector must be used; LIDAR and millimeter wave radars use board-to-board connectors or FPC flexible flat cable connectors."

"As the level of autonomous driving increases, the number of on-board cameras, millimeter-wave radars, LIDAR and other sensors increases." Li Gang said that according to Fuji Chimera Research data, by 2030, a car will need to have 10-15 cameras and 4-10 millimeter-wave radars. "The chip processing power is also getting higher and higher. As a result, the heat generated is also very high. Therefore, connectors must at least be resistant to high temperatures and small in size." "Miniaturization is the trend of ADAS internal components in the future."

"Products need to undergo rigorous automotive-grade tests, including thermal aging and thermal shock tests. For example, our DF40 series of small board-to-board connectors can withstand thermal shock tests such as 125°C and -55~125°C for 2,000 cycles, while still maintaining stable contact resistance." The picture above is a comparison between the ZE05 series and competing products in thermal shock tests.

"There are also cars driving on steep roads, so the board-to-board connector needs to have a very reliable structure. We designed a board-to-board connector with a small lock and a snap-on structure on the male and female ends, so it is not easy to fall off due to car vibration. For large board-to-board connectors with high-speed transmission functions and dedicated power terminals, it can save multiple pin signal terminals."

The FX26 series products using vibration-free floating technology have floating design at the contact point, and after the composite vibration test, the contact resistance change is compared with that of competing products.

"At the same time, with this floating design, two or three connectors can be installed on one board." It is suitable for connecting motherboards and sub-boards with complex computing functions and high pin count requirements. "And during assembly, it can absorb the assembly tolerance between the upper shell and the lower shell, reducing the load on the circuit board pins."

In addition to connectors, electric vehicles have also put forward new requirements for sampling resistors. Qian Chendong, a field application engineer at Isabel Huite, said: "Sampling resistors are widely used in automobiles, and fuel vehicles also need them. From the perspective of current collection and current detection, a car has hundreds or even hundreds of parts that need to use sampling resistors. The main applications include BMS (power management system) and motor control."

In automobiles, sampling resistors are used for current signal detection and sampling for batteries on the one hand; on the other hand, they are used for motor drives, electric power steering, as well as automobile air conditioners, fans, water pumps, and oil pumps to drive various motors - ultimately achieving stepless control and stepless drive through voltage signal acquisition.

Isabelle Huite sampling resistor display

"There are two ways to sample current: one is current detection based on shunts; the other is Hall sensors. Hall sensors have been widely used in the industrial field because of their relatively simple materials and manufacturing processes, and they are easy to manufacture. But with the advancement of technology, manufacturing a high-performance, high-precision resistor is no longer an obstacle."

"Now, the advantages of shunts and resistors over Hall sensors are becoming more and more obvious, and the market adoption rate is also increasing. The main advantages of Hall sensors are no power loss and insulation withstand voltage; the signal of the shunt is a small signal, the resistance value is small, and the final voltage sampling signal is relatively small. The signal needs to be amplified by the circuit - some people will regard this as a disadvantage of the shunt, because compensation and processing are required later. But in addition to this, shunts have advantages in all aspects, especially small size, low cost, and simple principle: Ohm's law, current = voltage/resistance."