Executives from Philips Semiconductor Division here said recently that demand for its automotive chipsets has grown, thus feeding speculation that many automakers are still planning to add more specialized databuses to handle the dizzying new array of chips needed for airbags, safety sensors, interior motors, and drive-by-wire systems.
Philips executives say that the percentage of the company's semiconductors sold into automotive applications has jumped from 9% to 14% in the past two years, despite an economic downturn that has crippled much of the electronics industry. "Our automotive business has been going up while the rest of the electronics industry has been struggling," says Jack Morgan, director of the Automotive Segment, North America, for Philips Semiconductor Division.
Morgan says that three databuses are quickly garnering support among automotive engineers. The Local Interconnect Network (LIN) bus, FlexRay bus, and Safe-By-Wire are all gaining momentum as automakers respond to growing demand for safer, more luxurious vehicles, he says.
Automakers plan to employ the LIN bus for simple on-off devices such as motors for door locks, car seats, sunroofs, HVAC flaps, windshield wipers, and mirrors, as well as features such as cruise control and rain sensing. Proponents of the technology, which include Philips, Motorola, Audi, Volkswagen, DaimlerChrysler, and Volvo, believe that it will cut costs for automakers and simplify engineering for suppliers. The technology is said to be less costly than the popular CAN (Controller Area Network) bus because it uses one signal wire instead of two, eliminates on-board voltage regulators and control modules, employs simpler electrical interfaces and receivers, and requires less costly microcontrollers.
LIN's low cost is said to make the idea of a databus more attractive to automakers, because it enables them to eliminate hundreds of feet of discrete point-to-point wiring without imposing a large price penalty. "We've identified automotive platforms that are using as many as five LIN buses," Morgan says.
Many automakers are also said to be looking harder at the idea of using the so-called FlexRay bus, a safety-critical electrical architecture aimed at steer-by-wire, brake-by-wire, suspension-by-wire, and throttle-by-wire systems. Although such systems aren't expected to play a big role in the automotive industry during the next two years, many automakers are already making plans to use FlexRay because it uses time-triggered techniques to ensure that there is always a slot for crucial messages from the brakes or steering system. Time-triggered techniques are considered superior to the event-driven methods used by the more traditional CAN-based buses (see DN 09.09.02, p. 36). Proponents of the technology include General Motors, DaimlerChrysler, BMW, Philips Semiconductors, Motorola, and Bosch Automotive Group, as well as Texas Instruments and Ford, which recently announced they are putting their weight behind the technology.
Support is also growing for a relatively new architecture known as Safe-By-Wire, which is seen as an enabler for the automotive industry's futuristic "safety cocoon" concept. Safe-By-Wire is said to offer a solution to the wiring problems posed by the multitude of new automotive restraint systems, which includes side-, headrest-, and rear-seat airbags, as well as inflatable knee bolsters and side curtains, pyrotechnically actuated seat belt pre-tensioners, and dual-stage airbags. Because safety devices are wired discretely today, engineers are said to be wondering how they will connect the proliferation of new safety devices to future electronic control units.
Safe-By-Wire reportedly could solve the problem by allowing engineers to connect the devices to a two-wire, twisted-pair copper bus that operates between 20 and 200 kbits/sec. The bus would carry data to and from sensors, and would also transport electrical power to devices that depend on pyrotechnic reactions. Proponents of the technology include Philips, Motorola, Delphi Automotive, and TRW, among others.
Philips' Morgan notes that automakers continue to look at such solutions, despite the recent downturn in the economy. "The economy may be down, but consumers continue to demand new features."
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