Redefining in-vehicle connectivity: from analog to digital, making complexity simple

Valens, from Israel, is a leading provider of audio-visual and automotive high-speed connection solutions. It enables long-distance, high-speed video and data transmission for the audio-visual and automotive industries, constantly pushing the limits and has delivered tens of millions of chips so far . In addition, Valens is also an innovator in the automotive industry. Its pioneering A-PHY standard-compliant chipset helps address many challenges in the current development of electric vehicles: such as control complexity, rising body weight and increasing total connection costs.

Recently, Gideon Kedem, senior vice president and head of automotive business at Valens, said in an interview in Beijing: “In terms of automotive connectivity standards, our primary goal is to do our best to meet customer needs and provide customers with the best service, rather than changing industry standards. "One of the ways Valens impacts the industry is by helping OEMs optimize vehicle wiring architecture and data architecture to meet market demands for new generation vehicles. "In his view, Valens' goal is to meet customer needs down to earth. Not leading industry standards. Indeed, if you can't make a good product, what's the standard?

Example diagram of wiring architecture in vehicle

From proprietary protocols to open standards

Traditional SerDes is a standard customized by some semiconductor manufacturers and is not open. It can be understood as a proprietary technology. Ser and Des in SerDes represent serializer (Serializer) and deserializer (Deserializer) respectively. The main function of SerDes is to convert low-speed parallel signals into high-speed low-voltage differential signals (LVDS) and send and receive them over the serial link.

Early SerDes technology was used in long-distance wide area network . With the continuous improvement of data transmission rate, this technology has been continuously expanded to other application fields and is widely used in various data communication systems and has become a high-speed interface . The mainstream of technology .

As mentioned above, the current SerDes solutions used in automotive applications are proprietary in nature, which means that if not all components come from the same chip supplier, components between manufacturers cannot be used together.

Because SerDes has high-speed transmission characteristics, the automotive field has also used it as an option to achieve high-speed connections in recent years. In September 2020, the MI PI Alliance released the high-speed vehicle video connection A-PHY standard, which has developed rapidly since its release. In 2021, the IEEE Standards Association will list A-PHY as one of its standards, and major well-known OEMs are planning to add it to next-generation solutions.

MIPI Alliance member

So, what are the main differences between the MIPI A-PHY standard and traditional SerDes? Will they coexist in automotive applications in the future? In this regard, Gideon Kedem explained: "The difference between the two is that MIPI A-PHY is a globally accepted open standard. Chip suppliers can design, develop and produce corresponding MIPI A-PHY chips according to this standard."

Since there are no patent restrictions, any chip manufacturer can develop and manufacture it as long as it has the technical capabilities. For some manufacturers, it is not difficult to produce chips based on the MIPI A-PHY standard, but it requires some technical accumulation. Currently, in addition to Valens, the first company to launch a chipset that meets the A-PHY protocol, there are also LGInno te k A few manufacturers have also joined the team to develop and produce MIPIA-PHY chip modules.

"For example, A-PHY is like the Ethernet standard. There are many chip players in the industry, and everyone will develop and produce chips that meet the A-PHY protocol." Gideon Kedem said. "In the future, more and more A-PHY chip manufacturers will appear at home and abroad, but different chip manufacturers have different R&D capabilities, and the products they produce will have some differences in performance or cost-effectiveness. In general, A-PHY is more Help build a better and more standardized ecosystem within the industry.”

Regarding the signal transmission distance, he explained that previous protocols such as C-PHY and D-PHY were mainly used for short-distance ECU video transmission in vehicles, while A-PHY is suitable for longer-distance signal transmission, such as from the camera to the ECU. Long-distance data transmission can achieve a transmission distance of up to 15 meters. In early 2022, Valens cooperated with the American heavy truck company Stoneridge. The chip was equipped with Stoneridge trailers to realize the connection between the rear camera and the cabin display. In harsh noise environments, the 40-meter-long high-speed data link solves key safety hazards, improves road safety, and reduces the operating costs of the OEM.

Supports high-speed data links up to 40 meters in harsh noisy environments

In addition, GMSL or FPD-Link are also private protocols for analog signals, and more and more OEMs hope to use open standards to replace private protocols. As for how OEMs choose, Gideon Kedem said: "We respect our customers' choice of the connection solution that best suits their situation. Our core purpose is to provide customers with appropriate solutions."

What can MIPI A-PHY bring to cars?

MIPI A-PHY has the advantages of excellent electromagnetic compatibility ( EMC ), ultra-high bandwidth, simplifying the automotive architecture and ensuring end-to-end security. What benefits can it provide to the automotive industry?

First, connectivity solutions need to support high bandwidth, zero latency and excellent EMC performance to ensure high-speed connectivity for automotive safety and time-sensitive applications. However, due to various limitations in density and length of automobile structures, the space, weight and complexity of automobiles have reached their limits.

The next-generation vehicle safety connection solution VA7000 chipset demonstrated by Valens at CES 2023 adopts the MIPI A-PHY standard and uses unshielded twisted pairs and simple connectors for plug-and-play, which can greatly reduce the total system cost and provide automobile manufacturers with Provide efficient solutions.

According to Gideon Kedem, compared with other existing solutions, the essential advantage of VA7000 is that it is based on the open standard A-PHY. Based on this advantage, there are three other points to pay attention to:

First, VA7000 provides high bandwidth for the automotive industry, and there is room for further improvement of bandwidth, which has great potential. VA7000 can achieve a transmission rate of 8Gbps, and the chip expected to be launched in 2025 can reach 16Gbps. This is because our chip is based on a digital design and therefore can increase the transmission rate proportionally. Also for this reason, Valens chips have enhanced electromagnetic compatibility (EMC).

The second point is the ability to resist electromagnetic interference. The traditional connection solution uses a forward error correction mechanism (FEC), which cannot deal with vehicle EMI problems alone and can only deal with Gaussian noise. Therefore, additional measures such as shielded wires are required in practical applications. As cars develop toward intelligence antennas and road transmission cables, make data transmission in an environment with extremely strong electromagnetic noise, posing severe challenges to the normal operation of the AD AS system, which is crucial to driving safety. The Valens chip uses its unique mechanism to deal with EMI issues, and compared to other connection solutions on the market, it can ensure the stability of the transmission link in noisy automotive environments.

Third, it helps OEMs reduce costs. Valens chips can use lower-cost cable harnesses and connection interface architectures, significantly reducing overall system costs. The "MIPI A-PHY Technology based on UTP" report by the independent agency A2MAC1 shows that compared with traditional GMSL-based solutions, the Porsche pure electric sports car Tay can using the MIPI A-PHY surround view system can save approximately US$17-27 in cost; using VA7000 You can save about $10-20 on an average passenger car.

Surround imaging system based on MIPI A-PHY significantly reduces Taycan cost

"The development of automobiles towards electrification is a general trend, and the number and weight of cables deployed in electric vehicles have reached the upper limit. In order to achieve sustainable development, cable simplification is the only way to go." Gideon Kedem added. "Using Valens connection solutions can simplify vehicle cable layout and reduce the number of cables and weight. Compared with traditional diesel locomotives, the average weight reduction can reach 30-40%."

According to him, the Valens chip used in each car is different according to the different configurations of the car. Taking Mercedes-Benz as an example, it includes several major modules such as automatic transmission control unit ( DC U), engine control, and central control electric door lock control. , each module uses one or two Valens chips respectively.

"We believe that OEMs, Tier1 and Tier2 will have great interest in Valens' industry-leading solutions and promote the application of VA7000 on more vehicles." Gideon Kedem said confidently.

Valens for autonomous driving

Currently, the automotive industry is accelerating towards autonomous driving. Driven by ADAS and autonomous driving, the automotive industry is undergoing a major transformation toward sensor fusion. Only by combining different types of sensors, such as cameras, lidar and radar, can the data and functionality required for safety applications such as ADAS be met. However, the infrastructure connecting cars to sensors and processors still needs to be improved.

At present, vehicle manufacturers have installed 8-megapixel cameras and 15-megapixel cameras on their vehicles. With the upgrade of on-board cameras, cars have higher requirements for transmission bandwidth and speed. In this regard, Gideon Kedem said that a major advantage of Valens technology is that it can increase the transmission data rate proportionally, from the current 8Gbps per second to 16Gbps for next-generation chips, and 32Gbps chips are also under development. "In terms of the number of cameras, I predict that future vehicles will be equipped with an average of 10-20 cameras, including interior and exterior cameras," Gideon said.