Car safety electronics go for system-level approach

The ability of MCU- and microprocessor-based systems to satisfy automobile customers' needs for comfort, safety, information and entertainment in the car is fueling an explosion of applications and of cooperation between automakers and chip companies.

The International Automotive Electronics Congress held in France earlier this month was a forum for the growing synergies between semiconductor suppliers and car manufacturers. But the message from the event was that despite the short-term boom in demand for automotive-grade MCUs and processor-based SoCs, the longer-term winners are going to be those chip and EDA companies that help automakers use fewer MCUs by way of a system-level, whole-vehicle approach to design and electronics integration.

Great expectations
According to research firm Databeans Inc., the market for automotive semiconductors amounted to $18 billion in 2006 and is expected to reach $29 billion by 2012, garnering an annual growth rate of 8 percent on average. Frost & Sullivan, meanwhile, expects the market for active safety systems to grow from about $13 billion to about $21.3 billion over the same period.

STMicroelectronics NV—the third-largest supplier to the auto market after Freescale Semiconductor Inc. and Infineon Technologies AG—illustrates this upward trend. ST's Automotive Product Group reported sales of $1.36 billion for 2006, compared with total automotive billing of less than $400 million in 1996. The chipmaker's compound annual growth rate (CAGR) in this market is 14 percent, while the CAGR of the market itself is about 6 percent. Looking 10 years ahead, ST's spokesperson said it plans to maintain a CAGR of more than 10 percent.

The automotive segment, therefore, shows good revenue potential for chipmakers, and carmakers see chip companies as the route to improving fuel economy, CO₂ emissions and safety.

Indeed, carmakers are under continuous pressure to make such improvements.

Reinhard Schulte-Braucks, head of the automotive unit of the Enterprise and Industry Directorate-General of the European Commission, said carmakers will have to help reduce CO₂ emissions to reach the community target of 120g/km by 2012 and enhance road safety through crash-avoidance technologies. The requirements are detailed in the Competitive Automotive Regulatory System for the 21st Century (CARS 21) strategy being promoted by the European Commission.

Electronics is the key to solving the tensions between environmental constraints, high-safety cars and low-cost technologies, said Rémi Bastien, director of Renault Electronic Engineering Network.

Parallel trends
"We are in a context where two parallel trends complement themselves," said Bastien. "Customers' demands and environmental requirements expressed by governments are rising exponentially. Standards on polluting gas emissions are twice as severe every five years, and CO₂ emissions decrease by 20 percent every five years. In addition, customers are expecting more and more comfort and security as well as an increasing number of links to telematics. And electronics, making use of Moore's Law, brings a host of opportunities to meet these challenges. "We are in a perfect win-win relationship between these two players."

MCUs first entered the automobile for purposes of engine control as a result of the California Clean Air Act in the 1970s, said Denis Griot, senior VP at Freescale Semiconductor and general manager for Europe, Middle East and Africa. "The motor control conditioned the evolution of the MCU technology. MCU computing performance has multiplied by 20, while that of data processing has increased by seven over the past 10 years," he said.

Electronic waves
While the first penetration wave was the use of electronics for engine control via MCUs, Griot said, the second wave is the use of electronics for safety.

"As the economic impact of car accidents in Europe amounts to about $120 billion per year, we should take safety as something that does not suffer compromises," he said.

This second wave will require changes in vehicle architecture, he added. Functions such as ABS, vehicle stability control and occupant protection, so far independent, will have to communicate with each other for optimal safety. In addition, new driver assistance systems such as autonomous cruise control, lane departure warning, and night-vision and blind-spot monitoring will be introduced, requiring semiconductor-based sensors and high-performance processors and memory.

When safety is applied to the whole system, the key is dependability with regard to sensing, actuation, communication, interconnection, power and computation. This implies a need for safety through redundancy—a classic approach developed in the military and in avionics.

"Safety through chip redundancy is another technological breakthrough that will contribute to the move from passive safety to active, and even predictive, safety," said Griot. "Our collaboration with Continental AG favors a multicore approach with three cores that will work together, control themselves, and bring computing and control performances in a context of reduced energy consumption while meeting safety and fault-tolerance constraints."

Under their "Space" design program, Freescale and Continental plan to develop a three-core 32bit MCU based on Freescale's Power Architecture.

Multicore approach
Infineon also provides heterogeneous multicore MCUs for automotive applications, through its Audo and Audo NG devices, which combine a TriCore MCU with a separate peripheral control processor. This architecture is said to be suitable for the type of deterministic, real-time performance required in engine control and other power-train applications.

"The multicore approach is very promising and is part of our strategy," said Bastien of Renault. "This will, however, not happen in the short term, as we do not master each electronic control unit. Concerning the power train, there have been tests with only one ECU to control both the engine and gear box. With Autosar, it is conceivable to pilot many modules from one of the microcontrollers, but this will not be extended in large volumes before 2012."

Asked how Autosar will embrace multicore processors, Alain Gilberg, Autosar project leader for PSA Peugeot Citro?n, said that after 2009, when the project is finalized, "we will continue to work to maintain Autosar, and, in the future, we hope to be able to bring the multicore approach completely in Autosar."

According to Griot, all the technological building blocks for comprehensive and holistic integration are available, including actuators, sensors and microprocessors. However, the challenge of choosing the right architectures and design approaches remains. "We have to be the first ones to integrate technologies," asserted Griot, pointing out that Freescale signed a collaboration agreement with ST in June 2007 to accelerate the microprocessor integration process.

Bastien said: "Renault is investing significantly in the system approach. For instance, software can, via appropriate algorithms, remove the need for some sensors. The more the system dimension is extended, the more coordination is needed between various players. The best way to accelerate system integration is to define, in practical terms, with our suppliers the possibilities to integrate functions that can increase the value of chipmakers' most advanced technologies. Autosar is a good opportunity to achieve these integrations."

Global system
"We need to have a global system approach and have an overall system," said Gilberg. "If we have so many ECUs, it is because everything is broken into pieces."

According to Patrick Leteinturier, automotive system senior principal at Infineon, the need to reduce the number of ECUs in vehicles, and the interconnections between them, will lead to the emergence of more centralized architectures that are more efficient and reliable, less complex and more cost-effective.

Griot concluded: "We are at a turning point where innovation is coming more from the software than from the hardware. I believe it is putting us in front of a wall and encouraging us to innovate. We need a breakthrough in the software/hardware top-down architecture approach. This approach would make the whole system cheaper and the vehicle safer."

- Anne-Francoise Pele
EE Times Europe