automotive design

The automotive industry is changing. Our vehicles are getting electrified, connected and automated. As this trend is accelerating, it’s having an impact on how semiconductor devices, including MEMS sensors, are designed and qualified for automotive. As automotive semiconductor designers carefully consider product definition, product validation, and long-term reliability, MEMS sensor suppliers are responding to new opportunities created by electrified and automated vehicles by developing inertial measurement units (IMUs) for automated driving as well as battery pressure monitoring sensors for Li-ion EV batteries. The most complex MEMS device of all The automotive MEMS IMU is probably the most complex MEMS device that will be used inside a vehicle. This type of IMU is a System-in-Package (SiP) comprised of multiple gyroscope and accelerometer sensing elements plus a signal processing ASIC, integrated into one package that creates an inertial sensor able to measure up to six degrees of freedom (6DoF): yaw, roll and pitch for rotational movements, and lateral, longitudinal and vertical acceleration for linear movements. Degrees of freedom in a vehicle For vehicles with Level 3 autonomy and above (per SAE definition), the IMU is mandatory for taking over the trajectory control of the vehicle in case other sensors, such as the camera, radar or LiDAR, become impaired. Should such a failure occur, the IMU will function as a guidance sensor to bring the car to a safe stop within a short period of time and distance. The IMU is also used to control the regular movement of the car while driving in automated mode. While IMU technology already exists for aerospace applications, there are significant challenges to adapting it for automotive. The automotive IMU requires high performance at costs that are compatible with the automotive industry. Because automotive life cycles are long, MEMS sensor suppliers must produce the device in high volume for an extended period of time. They must also guarantee the sensor’s performance and reliability over a 10- to 15-year lifetime with no maintenance or recalibration of the sensor required. Only a few MEMS suppliers have the capability and willingness to embark on this kind of journey. Electrification is creating new applications for MEMS sensors The conversion from internal combustion engines to electrified propulsion is going to affect the powertrain MEMS market. For example, pressure sensors used in engine management for air pressure and fuel pressure will simply go away with electrification. However, the use of large Li-ion batteries in electrified vehicles has created a new application for MEMS sensors. One of the known risks of Li-ion batteries is the small probability for a battery cell to go into a thermal runaway situation that will lead to a fire. The press has reported multiple cases of EV batteries catching fire. Thermal runway effects When it comes to thermal runaway events, every second counts. Detecting the event as early as possible enables the vehicle safety system to take all necessary measures to warn occupants of an imminent fire and activate timely countermeasures (e.g., trigger fire extinguisher and call fire brigade) to mitigate the impact of the fire. Published studies have shown that measuring the pressure inside the battery pack is a good indication that a thermal runaway is starting. The outgassing of a battery cell, plus a sudden rise in temperature, will increase pressure inside the battery pack, which will generate a pressure pulse. To detect such a pressure pulse, a MEMS pressure sensor must permanently measure the pressure inside the pack. It must also report to the battery management system any suspicious change in pressure, independent of atmospheric pressure changes. It’s important to keep this kind of sensor on all the time to detect any pressure anomaly in the system, even when the vehicle is completely off. NXP has developed a pressure sensor to specifically address this new safety application in EVs, and several automotive manufacturers are already using this solution. NXP battery pressure management sensor The quest for zero defects While the automotive industry is targeting zero fatalities as its ultimate goal, the semiconductor industry and module suppliers are targeting zero defects for each and every semiconductor device. For safety-critical automotive MEMS sensors complying with the Automotive Electronics Council (AEC) Q100 qualification for semiconductors, it’s necessary but clearly not sufficient to guarantee a zero defects production launch and long-term reliability of the device. To boost the reliability and robustness of automotive sensors, NXP has developed Above and Beyond (AaB), a new methodology that studies advanced reliability and robustness well ahead of the device’s qualification and production release. Based on risk-mitigation analysis, AaB consist of extensive testing, such as test-to-fail, corner lot testing, and new use-case testing combined with advanced statistics, all of which help NXP understand how these different parameters interact with each other. As sensor suppliers must integrate AaB into their project planning, it does add time and cost to the project. The upside is that this early investment pays off as long as weaknesses in the device can be detected and corrected before a production launch. Field failures, on the other hand, can lead to unplanned redesign and requalification of a device. Worst-case, they can lead to a recall campaign that costs a huge amount of money. We’re systematically using the AaB methodology at NXP for safety-critical MEMS sensors because its potential benefits far outweigh its costs. For more information about NXP MEMS sensors, register for the upcoming webinar series, MEMS to Market: Ingredients for Success, where NXP will discuss The Growing Importance of MEMS Reliability (May 5, 2021). Register by March 10 to watch all the webinars LIVE. Each webinar will also be available to watch on-demand at your convenience. Contact the author via LinkedIn or learn more about NXP sensors. About the Author With nearly 30 years of experience in the field of automotive and MEMS sensors, Marc Osajda is responsible for European automotive MEMS sensors business development activities at NXP Semiconductors. Osajda holds an engineering degree in mechanics and electronics from the French Ecole Nationale Superieure d’Arts et Métiers (ENSAM). NXP Semiconductors is an active member of MEMS Sensors Industry Group®(MSIG), a SEMI technology community that connects the MEMS and sensors supply network in established and emerging markets to enable members to grow and prosper. Visit us today.

In 2000, the average car sported 30 to 50 semiconductors. By 2025, the number of chips and sensors in an automobile will soar to an eye-popping 70,000 as it comes uber-connected and immeasurably smarter, powered by machine learning, artificial intelligence (AI), Internet of Things (IoT), visual sensing, high-precision mapping and other advanced capabilities.Today, the proliferation of semiconductors in cars is remaking the automotive industry as four major forces – electrification, connectivity, autonomous driving and diverse mobility – take hold, according to the consultancy firm McKinsey in its report Automotive Revolution – Perspective towards 2030 report. The chip industry saw auto-related sales jump from US$7 billion in 1995 to US$30 billion in 2015, a trajectory that has steepened over the past two years as major chip suppliers have rolled out products for precision mapping, navigation, in-car entertainment, and communications. With semiconductors fast becoming a major aspect of automotive design, traditional automakers are quickly moving to build strong partnerships with the semiconductor sector.Audi, a leading German car brand, took a big step to just that when it became the first automotive OEM to join SEMI as a member in June 2019 and strengthen the automaker’s ties to the semiconductor industry. With a massive market potential to tap, are Taiwan's auto electronics firms well-positioned to work even more closely with first-tier car brands like Audi?At the Smart Transportation Forum on September 18 at SEMICON Taiwan, Andre Blum, project manager at AUDI AG, will join Ian Chan, CTO of Cyntec, to offer insights into how automakers can team up with Taiwanese auto electronics companies. TechOrange, a Taiwanese tech news online media, spoke Blum ahead of the event about Audi's smart car efforts and the carmaker’s work to integrate new technologies into its automotive designs as it forms new partnerships with the semiconductor industry.Blum joined Audi in 2004 and since 2016 has led manifold projects within the group driving Audi’s work with semiconductor companies (Progressive Semiconductor Program). He has seen the automotive industry rapidly accelerate the integration of high technology in vehicles, an area where Audi excels. “The industry is changing how it works and new partners are joining the ecosystems," Blum said.Audi Wants to be the Next Apple in the Car SectorAudi's business developments in recent years echo Apple's early push to integrate the Internet and a panoply of applications into mobile phones. The difference now is Audi is working to integrate a wide range of smart applications into its automobiles for – ala Apple – the best user experience.For example, Audi has recently launched cars designed with Traffic Jam Pilot, Parking Pilot, and Garage Pilot three smart driver-assisting systems. With Traffic Jam Pilot, drivers no longer need to be on standby when stuck in the traffic. Instead, they can kill time with an infotainment system. While out shopping or making other stops, Parking Pilot helps drivers find a parking spot and park automatically. Garage Pilot provides a more comfortable parking-at-home experience – the driver waits maneuvers the car into the garage using handheld remote control. Audi stepped up its efforts in 2019 and revealed its latest concept car at the Shanghai Auto Show. Dubbed Audi AI:ME, the vehicle is equipped with a dizzying array of high tech: level-four self-driving technology, technology that allows the driver to control features with eye movements, LED units in headlights and taillights that change brightness accordingly at night and in bad weather, and VR goggles for onboard infotainment. Innovation and Tech Both Key to the New Driving ExperienceAutomotive technology is rapidly advancing in areas such as electric vehicles, autonomous driving and smart auto electronics. Cars of the future must have more computing power and connectivity to deliver a great user experience that includes high battery efficiency to extend the duration between recharges, in-car entertainment, and intelligent voice assistants – all capabilities made possible by semiconductors.Unburdened by the tasks of driving, passengers will enjoy a more intimate relationship with their vehicles. "The in-car entertainment system will allow passengers to have a teleconference or enjoy a movie in a theater-like setting,” Blum said. Switch on the self-driving system and you can drive through the night from Munich to Hamburg, covering a distance of 800 kilometers in the comfort of a home-like environment. The trip is even possible on one charge, meeting high energy-saving standards.These capabilities are technologically feasible now, but government regulations and policies still need to catch up. In the meantime, Blum says that Audi is focusing on creating a top-notch experience for car users today."The minute you step into a car, all the features, including the seat, radio channels, and the entertainment system will have already been adjusted to your liking and seamlessly connected to your mobile or other hand-held devices," he said.What does the Future Hold for Taiwan in the Next Blue Ocean Market?Semiconductors are the heart of these features, and Blum believes Taiwan is uniquely positioned to drive advances in automotive chips. Taiwan is home to semiconductor powerhouses TSMC and ASE as well as auto electronics companies, and its sophisticated mobile phone supply chain has endowed it with deep experience in integrating semiconductors with electronic modules – advantages that give Taiwan a head start in the automotive semiconductor market.Audi, too, is in a strong position to thrive in the new age of automotive electronics as it looks to its membership with SEMI to collaborate with companies across the microelectronics supply chain.“With rapid advances in automotive electronics technology, semiconductors now play a critical role in innovation and product differentiation,” said Dr. Klaus Buettner, executive vice president of Development Electrics/Electronics, CarIT, Audi.“To fulfill the promise of sustainable, connected-to-everything, highly automated mobility up to autonomous driving, we need to also align automotive requirements across the entire semiconductor value chain,” he said. “With its global platform, SEMI is the right association to bring together supply chain stakeholders for the close collaboration critical to driving technology innovation.”Emmy Yi is a marketing specialist at SEMI Taiwan.