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December 2014 | Volume 4, Issue 12

www.electronicspecifier.com

Challenges for Next-generation

Automotive Power Systems

Fundemental changes in automotive battery systems

Automotive

Optocouplers

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What’s waiting around the corner for autonomous vehicles?

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Research > Design > Production

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Contents 06

News

10 12

Market & Trends

16 20 24 27 32

In the driving seat

34 38 42 45

Automating design

electronica 2014 review

16

Time for reflection

Inside tomorrow’s autonomous cars How sensors and control systems is enabling self-driving cars

Microcontrollers in automotive applications; the evolving market

On the safe side The journey to a safer, cleaner and smarter automotive industry

Challenges for Next-Generation Automotive Power Systems

20

The fundemental changes coming in automotive battery systems

In the virtual loop Moving nearer to a virtual development paradigm

Life in the fast lane Can automotive component designers embrace a new way of working?

Evolving design automation in the automotive industry

32

Digital isolation is undergoing evolution Increasing optocouplers’ performance by standardising advancements

Building Better Storage Multi-level cell technology is making Flash memory even more prolific

Design Flexibility How Flash with built-in error correction is supporting the latest process technologies

Editor: Philip Ling [email protected] Designer: Stuart Pritchard [email protected]

Ad sales: Ben Price [email protected]

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Head Office: ElectronicSpecifier Ltd Comice Place, Woodfalls Farm Gravelly Ways, Laddingford Publishing Director Kent. ME18 6DA Steve Regnier Tel: 01622 871944 [email protected] www.electronicspecifier.com

Copyright 2013 Electronic Specifier. Contents of Electronic Specifier, its publication, websites and newsletters are the property of the publisher. The publisher and the sponsors of this magazine are not responsible for the results of any actions or omissions taken on the basis of information inthis publication. In particular, no liability can be accepted in result ofany claim based on or in relation to material provided for inclusion. Electronic Specifier is a controlled circulation journal.

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Editor’s Comment

design

Bridging the Embedded — Enterprise Divide While most of the talk at this year’s electronica was still focused on the intricacies of the IoT, such as low power microcontrollers, sensors and sensor nodes, there was an undercurrent amongst some larger companies about the need for the embedded domain to evolve in to something resembling the enterprise world, in order to handle the sheer magnitude of data the Internet of Everything will spawn. And just as the IoT is expected to present enormous opportunity for small/medium sized companies with a focus on nodes, companies such as AMD and Freescale are anticipating increased demand for their high-end processing solutions performing enterpriselike functions. However, this brave new application space won’t simply be an extension of the enterprise, or a clone, it will require new solutions that understand the demands of the embedded domain.

For example, graphics is set to become a greater priority for embedded applications and this will require solutions that are frugal with resources; not a restriction typical graphics solutions are known for. It will also create more integrated solutions than are evident today, single-chip solutions that offer all of the performance at half the power budget. Another trend will be the need to virtualise functions; so called Network Function Virtualisation (NFV). This is only now emerging within the enterprise domain and so could conceivably develop in parallel with it, offering IDMs the chance to minimise R&D costs and maximise design reuse. On this AMD and Freescale agree; both intend to develop platforms that offer different processor choices in pin-compatible formats. t

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electronica Review

design

Let’s get together

According to Messe München’s Deputy CEO, this year’s electronica demonstrates even more strongly that the world really is becoming more connected, as Philip Ling reports With over 73,000 visitors from 80 countries, and 2,737 exhibitors from 50 countries, electronica truly is a global platform for the electronics industry and this, its 50th anniversary, showed how global connectivity will bring all of use closer together. It also highlighted how global connectivity will put greater emphasis on issues such as security, as highlighted in the Security Forum organised by Electronic Specifier. Here’s our round-up of some of the most significant announcements made during the event. The Security Forum organised by Electronic Specifier highlighted the need for better solutions in a more connected world

Sensor evolution

With all attention still on the IoT it wasn’t surprising that many companies exhibiting at electronica were focusing on new sensor technologies. Analog Devices introduced a suite of wireless sensor development kits designed to

enable remote sensing and monitoring for industrial equipment, based on its proprietary protocol, ADRadioNet. Identifying the problem of integrating many sensors, often from different suppliers with diverse driver requirements, NXP has partnered with sensor manufacturers and sensor-processing middleware providers. The first benefits of this strategic move were on show with the launch of the LPC54100 series of microcontrollers aimed at sensor hub applications. It also revealed the ’application in a box’ sensor processing/motion solution, developed in partnership with Bosch Sensortec. It comprises an LPC54102, nine sensors along with middleware. Targeting multiple markets instead of just automotive, Melexis introduced a softwaredefined sensor IC that employs the company’s tri-axis technology to measure changes in magnetic flux in three axes. With that ability to wake up when a change in magnetic flux is detected, it promises low power operation in ‘always on’ applications as typified by the IoT, even those powered by harvested power.

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electronica Review

design Tying up lose threads

As a founding member of the industry alliance focused on delivering the Thread protocol to developers of connected home appliances, Freescale used electronica to launch its Thread beta development program. It is supported by a development kit that includes the Thread stack pre-integrated on a Kinetis wireless MCU. Companies enrolled on the beta program will receive Kinetis KW2x Tower boards, USB dongles, samples and the Thread stack which includes pre-compiled Thread libraries and demonstration application code. Visit www.freescale.com/thread for more information. This software-defined sensor IC from Melexis offers three axes of magnetic flus detection

Also looking to deliver multiple features in a single package, ams revealed a family of sensors that integrate six sensing functions including gesture detection. It claims that the TMG399X product family supports a fully qualified gesture library for the Qualcomm ADSP sensor core as found in the Snapdragon 6 and 8xx processor family, offering four-direction gesture detection. The device is targeting Smartphones, where light, proximity and object detection are increasingly required.

Dominating Devkits

With a strategic eye on dominating the supply of development kits, element14 is extending its offering to include design software, following the announcement that it will soon start distributing a PCB design tool currently under development by Altium.

A new low?

In the continued battle to offer ultra-low power MCUs, Atmel announced a device based on the ARM Cortex-M0+ core that it claims consumes as little as 40μA/MHz in active mode, and 200nA in sleep mode. The SAM L21 is being positioned for the IoT by offering years of operation from a single battery. Although announced at electronica, samples, development tools and the datasheet aren’t scheduled to become available until February 2015, benchmark results using EEMBC’s new ULPBench benchmark are also expected soon.

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However, unlike other PCB design tools offered by other distributors, CircuitStudio isn’t expected to be free of charge. As a result, it may include some of the premium features offered by Altium’s flagship product; Altium Designer. According to Richard Curtin, Global Director of Strategic Alliance for Premier Farnell, the distributor is adding ‘design cycle elements’ in a bid to get engineers who purchase development kits to return to the site. This will include software, debuggers and design software (such as CircuitStudio), as well as services in the form of PCB manufacturing and assembly. Curtin also promises free technical support throughout the cycle: “We want to own the development board space entirely,” commented Curtin, by designing and manufacturing development kits for IDMs. Curtin added that element14 now supplies Digikey and Mouser with development kits it has developed for semiconductor companies, something he expects to increase and become a significant revenue stream.

Control without the code

Microchip chose electronica to introduce a family of 8-bit MCUs that integrate significant new features aimed at reducing the amount of software needed to develop applications. With a focus on motor control, the first product in

design

electronica Review

the PIC16(L)F161X family can implement a full PID control loop without using the core. This significantly reduced the amount of code needed which in turn, according to Greg Robinson, Microchip’s 8-bit MCU Marketing Director, makes it easier to get an application through safety certification. New to this family, but not the PIC range, is the addition of a Configurable Logic Cell (CLC), which Robinson describes as a ‘puddle of gates’ that can be used to implement Boolean logic. Brand new is the math accelerator block, which is one of the device’s Core Independent Peripherals and as such allows more functionality to be offloaded from the core. Although the CLC feature isn’t new, it was only previously present in four families and could be difficult to configure, however Robinson added that it is now supported by a software frontend that makes it more accessible and is expected to be implemented in ‘the majority’ of new devices moving forward.

BLE for broad market

Despite being late to the game, Cypress Semiconductor has positioned its entry in to the Bluetooth Low Energy market with two PSoC devices that it claims will have broad market appeal. The single-chip solutions offer a complete Bluetooth LE

radio embedded within its patented configurable platform.

targeting the board market with its first

It gives Cypress a differentiating feature over the incumbent solutions from competitors such as TI and Nordic Semiconductor, which it believes is crucial in a market that is evolving so quickly.

Bluetooth LE product offerings

Initially there are two variants, one with a Cortex-M0+ core and one without; the former integrates 128kbyte of on-chip memory, 50kbyte of which is available for application code. Although Cypress has offered 2.4GHz RF devices before, they implemented proprietary protocols, which makes this its first foray in to the Bluetooth market.

Microchip believes its new core-independent features will reduce the amount of software needed in many control applications

Cypress is

Taking a more modular approach, Laird was demonstrating its BT900 series of dual-mode Bluetooth modules, which offer both Bluetooth ‘Classic’ and Bluetooth LE operation. Configured through its proprietary SmartBASIC eventdriven language, the module is able to operate in a ‘hostless’ systems. Laird says it will be targeting medical devices as well as other applications. t electronicspecifier.com

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Markets & Trends

Time for reflection Quintin Komaromy, Global Head of Strategic Marketing at Farnell element14, explains why this has been another exciting year for electronics distribution and one that has seen our industry continue to evolve and adapt At Farnell element14 we have seen some consistent themes driving innovation and progress across the board. Earlier this year, we carried out research of 1,500 electronics designers and found that, on average, development kits are used in 45% of all designs. By using readymade, low cost boards engineers can efficiently test their design ideas using a variety of components. These development tools and single board computers are putting powerful design tools into the hands of private innovators. Consequently, the democratisation of the manufacturing industry is quickly becoming a reality and development kits are helping get products to market quicker than we have ever seen before. The launch of the Design Center earlier this year supports engineers through the entire design process. Developed based on customer feedback, the Design Center provides all the support engineers need when starting a new design with videos, data sheets and links to our 270,000 strong Community of experts. Supporting engineers in this way has enabled designs to reach the market more quickly and efficiently. Helping customers move designs through to production has been behind many of the other

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changes we’ve made this year, including the introduction of new packaging as well as extended price breaks. A board with the ability to work as a truly stand-alone computer and platform, we have also been amazed by the continued popularity and growth of the Raspberry Pi and the maker movement. As such, the B+ had a lot to live up to and the reaction from consumers and engineers was incredible. The global success of the Raspberry Pi can be attributed to its ability to serve so many markets and applications, from teaching the next generation of engineers through to powering space-weather balloons. We continue to see interest in single board computers including industrial use with the Raspberry Pi Compute Module as solutions for the Internet of Things become more widespread.

A new era of electronics distribution

It’s not just the vast multitude of development kits being shipped that is revolutionising the electronics industry, but also the role of the companies that distribute them. The distributor is no longer a company that simply ships parts quickly, but rather one that understands how products are used, the problems

facing engineers and someone who can feed this information back into the product development cycle. This requires close links with suppliers and, as in our case, strategic acquisitions like Embest, CadSoft and AVID, which strengthen our ability to support development projects through the entire design process. We’ve already brought a range of new development kits to market, such as the Freescale RIoT board, which would never have existed without our input – and their on-going success continues to prove the existing market need. All of these aspects are seriously disrupting the dynamics of design, distribution and supply in the global electronics market. Engineers are no longer approaching designs in the same way and they expect to be supported right from the start of the design process all the way through to mass production. For those in the distribution space, the challenge is taking the feedback from customers and suppliers and feeding it back into the design cycle to improve the products we offer. We are looking forward to the exciting opportunities 2015 will bring for our new strategy in this area. t

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design

Automotive

Inside Tomorrow’s Autonomous Cars With autonomous cars promised by the end of this decade, the advanced sensing and control systems needed to make that a reality are starting to come together, giving us a better idea of what to expect, as Sally Ward-Foxton discovered recently

Figure 1: The Audi piloted RS7 is put through its paces

The automotive industry has been working on the idea of autonomous vehicles for many years. While today’s cars feature increasing amounts of driver assistance, tomorrow’s vehicles and associated traffic infrastructure will improve road safety, reduce or eliminate traffic jams and minimise CO2 emissions. Here is a closer look at two new concept cars which are demonstrating how driver assistance and automation systems might look in the future.

on the Grand Prix track at Hockenheim

Audi’s piloted concept car (Figures 1 & 2), based on an RS7, is a technology platform developed by Audi to explore piloted driving. Audi recently

tested the car to the limits of its performance around the Grand Prix racetrack at Hockenheim as part of the season finale of the German Touring Car Masters (DTM). It’s also been tested around the Ascari Race Resort track, a much more challenging circuit with ascents and descents, tight chicanes and banked bends. The car uses GPS for orientation around the racetrack, which it gets via WLAN and also via high-frequency radio for redundancy purposes. Audi says its differential GPS system is accurate to within a centimetre. For the demo, the car also had images of buildings around the racetrack pre-loaded, which it compared to the data from a 3D camera to work out where it was. The car drove a clean ideal line around the racetrack, with full throttle on the straights, precise deceleration at the ideal point on each corner, precise turn-in and then equally precise acceleration out of the corners. Maximum speed during the tests at Hockenheim was 240km/h (149.1mph), but the car’s top speed is 305km/h (189.5mph). Although this particular car is just for development purposes, Audi says the technology will be in production cars before the end of the decade, enabling piloted driving in situations such as traffic jams. With the system activated, the car will take over steering, acceleration and braking when it detects traffic jam conditions. The car will also park itself into tight spaces, perhaps against a wall where the driver wouldn’t normally be able to get out of the car. In this situation, the driver gets out of the car before parking and remotely controls it using a

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Automotive

remote key fob or smartphone. The parking pilot only works when the key is in the vicinity of the car, though – so no leaving it to park up while you get started on the shopping. Sensor systems on board include a radar system, which covers a 35-degree field up to 250m from the front of the car to detect objects and other vehicles. It also uses a video camera to look for traffic signals, pedestrians and vehicles. Up to twelve ultrasonic sensors also monitor the area immediately surrounding the car. The newest addition to the car’s sensor systems is a laser scanner, which emits almost 100,000 infrared pulses every second from a laser diode. The scanner covers a 145-degree field of vision at a range of up to 80m; the wide aperture angle helps detect cars entering the same lane as early as possible. The data from all the sensor systems is fed into control unit called zFAS (Figure 3) which uses high-end multi-core processors to calculate a precise model of the car’s surroundings which is used by all the other systems. Audi says its central control unit is novel in the industry, since others are using separate control units for the different systems. The zFAS board is currently about the size of a tablet PC, though this will shrink in the future.

Figure 2: The

Its range is such that drivers can be warned about hazards that are a long way ahead or even out of their line of sight, such as around a corner. The 5.9GHz radio electronics and antenna is in a roof mounted module which will be integrated in production models. When the concept car receives an alert from a piece of infrastructure up ahead, a warning notification is displayed on a tablet installed on the dashboard. Future versions may project the warning onto the windshield or give the driver some other type of feedback, such as vibration through the steering wheel. Future versions may also be able to reduce the number of

electronics systems inside the Audi concept car

Figure 3: Audi’s zFAS central control system for its piloted car

V2X Communications

At Electronica 2014 in Munich, NXP showed off its own concept car that demonstrates vehicleto-vehicle and infrastructure-to-vehicle (V2X) communication driver assistance systems (Figures 4 &5). The car, supplied by Honda, was fitted with NXP’s secure communication technology, while Siemens supplied intelligent road infrastructure for the demo. Cohda Wireless supplied the application software. V2X communication uses IEEE 802.11p, a standard related to WiFi which has been specified especially for the automotive industry. electronicspecifier.com

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Figure 4: The inside of NXP’s concept car. A tablet on the dashboard gives the driver notifications as it receives them from surrounding infrastructure

notifications to avoid unnecessary distractions. The system may only warn the driver if it is relevant – for example, if the driver had already slowed down, the car could assume that the driver had already seen the hazard. Figure 5: The NXP/Honda test vehicles at Electronica 2014, before leaving for Vienna

Security is also of paramount importance. It’s easy to imagine how the system could be abused; if it were possible for an ordinary car to pose as, say, an emergency vehicle, the unscrupulous user would be able to drive around with everyone else pulling over in order to let

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them past as quickly as possible. Of course, this will not be possible. Every signal received will have a dynamic digital signature which the car will authenticate to determine whether it’s trustworthy. The signature’s dynamic nature helps protect drivers’ privacy since it eliminates the possibility of being tracked. Following the show, a convoy of five Hondas with the systems fitted were test-driven along the route of the recently agreed ITS (intelligent transport system) test corridor, which stretches from Vienna to Rotterdam via Frankfurt. The ITS corridor is a co-operation between various ministries, motorway operators and the automotive industry on an unprecedented scale. Roads across Austria, Germany and the Netherlands will be fitted with smart traffic lights, smart road works warnings and sensors which detect conditions like traffic jams. The aim is to improve road safety and traffic flow while ensuring Europe-wide compatibility between ITS systems.NXP and Cohda’s V2X communication technology will be introduced into some new production models of Cadillac in 2017. t

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Automotive

In the driving seat The use of microcontrollers in automotive applications is growing, but Steve Rogerson found there were differences in how the chip makers see the market evolving The pressure for more connectivity in automotive is leading to tasks that were once the domain of 8 and 16bit microcontrollers now requiring 32bit units, a trend helped by the falling prices of the more powerful chips. On the flip side, the increase in sensors and basic motor functions – such as window raisers and seat position adjusters – has meant that 8bit microcontrollers still have a place.

Challenges for modern microcontrollers

Such 8bit MCUs do not need deep technical requirements; they just have a simple job to do. The problem comes when the simple job becomes more complicated because of networking needs, even for the traditional CAN and LIN bus but also with the spread of Autosar. On cost, the 8 and 16bit units can be got for below a dollar compared with nearer $2 for a 32bit unit, though that price is coming down.

“As the cars get more complex, you need more networking functions and diagnostic capability,” said Juergen Jagst, Technical Specialist for Automotive at ARM. “For example, it is not enough to know the window lifter is not working; they have to work out why and network that information, and this is why there is a shift to 32bit.” Ross Bannatyne, General Manager at NXP, said that the growing use of software in vehicles was the key driver behind the move to 32bit: “The amount of software is increasing and that means more Flash and other memory,” he said. “Companies are spending a lot more time, effort and money developing software, which is more costly than the hardware.” Willie Fitzgerald, Director of Microchip’s Automotive Products Group, added: “We have focussed on the 8 and 16bit area but we are starting to enter the 32bit space in this market as well.” The 8bit MCUs can also be found in seatbelt tensioners, HVAC controls, pumps, switches, touchscreens, including capacitive touch sensing, and lighting. “We still see 8bits in low performance ECUs, doing say a smart actuator or a light sensor,” said Axel Hahn, Senior Director of Powertrain MCUs at Infineon. “They are used for window lifting and things like that. They will continue to be used.” The 16bit MCUs still appear in fuel pumps, cooling fans, distance trackers, lowend braking and low-end power steering. The 32bit chips have traditionally been for the main engine and transmission controllers, but now are being used wherever there is a need for network intelligence. “We have seen the trend for five or six years of a shrinking market for 8 and 16bit,” said Fitzgerald. “But these chips have

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applications not in the core but in the peripherals around the core. Look at airbags, they were once 8bit, and then 16bit and now 32bit. But then around the 32bit, you’ll have smaller processors doing the crash sensing. Steering used to have one microprocessor with one core, but that is not enough, so now they have two cores for safety reasons and small microcontrollers around them that measure things such as the steering angle.” There is also still a booming market for the smaller microcontrollers in the budget sector in the west and less sophisticated cars in some areas of the world. “We are still selling 16bit controllers into low-end cars in South America and China,” said Mathias Braeuer, Director of Automotive MCU Marketing at Spansion. “But in Europe, there is the trend towards Autosar and thus you need the more powerful controllers.” On top of that, there is an increasing deployment of 64bit MCUs for high-reliability and more complicated applications such as those found in advanced driver assistance systems (ADAS), for example using radar for distance controls and cameras for object detection. Also, the bird’s eye view systems now being found in high-end

Automotive

models where the images from several cameras are combined to give what appears to be a view from above the car. “Some use DSPs for this, some use high-performance classical CPUs,” said Jagst. “It depends on which Tier 1 designed it. There is no clear direction of which is best.”

Microcontrollers are flying high in automotive

Multicore

Multicore processors are being used more in cars but at present most of the software is not making the best use of them, treating them the same as single-core processors. However, there is a lot evaluation work that looks like changing that with virtualisation used to create separate partitions to allow, say, an RTOS to run on one core for safety critical systems and a more general-purpose operating system, such as Linux or QNX, on a different core. “This is not yet being heavily used in cars,” said Jagst, “but it will be in the future, up to about 2020. One of the problems is that Autosar, for example, is not written in a way that accesses multicore. There is no splitting of tasks.” But up and coming ADAS functions are more likely to use the benefits of multicore, and these will start to be more widely available in the next two to three years. “The challenge for many electronicspecifier.com

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Automotive

functions,” said Fitzgerald.

Architectures

Still the most popular chip architectures in automotive are the proprietary systems such as found in the RH850 series from Renesas, the PowerPC from Freescale and Tricore from Infineon. But ARM’s Cortex cores are starting to find more automotive applications as the company sees this as a key target market.

MCUs enable innovative HMIs for today’s vehicles

users is to benefit from the performance that multicore can offer,” said Hahn. “To do that they have to redesign software that has been developed over a decade or more. That is a challenge for the development teams, but they are doing it.”

“ARM has a very strong offering and will be successful,” said Braeuer. “If you look at what others are offering, Freescale is starting to offer ARM in automotive and a lot of ASIC devices are based on ARM. Renesas and Freescale are using their own architectures but they are also starting to use ARM controllers. I suspect ARM will grow in automotive.”

There is also a possibility of using multicore for safety critical functions where each core will perform the same task and the results compared before making a crucial decision such as automatically applying the brakes. Some will even use three cores for this. Meeting the requirements in ISO26262 will lead to more of this type use of multicore for safety reasons. “As they want to be more safety oriented, there is a need for the microcontrollers to do more

Bannatyne added: “Engineers are trying to standardise software over the different cores and that is why there is success with ARM. A lot of companies are standardising on that. But there are some very good MCU architectures such as from Freescale and Renesas. They have been in the business a long time and a lot of engineers are very familiar with the architectures. But one of the benefits of ARM is that it is CPU agnostic. Engineers want to use the same tools across as

MCU in automotive capacitive touch application

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Automotive

many CPUs as possible so they can reuse software. That is one of the benefits of ARM, the compatibility between these cores and the number of suppliers that support it.” But Hahn said: “We are not seeing widespread use of ARM – people are sticking with their incumbent architectures. One of the challengers for the designer is to meet ISO26262 safety standards. If they have the core totally under their control, they can tweak that to meet the safety targets. You don’t have that flexibility with the ARM architecture. You would have to have discussions with ARM to change that so it will not be under your control.” Intel architectures tend to be used more in the multimedia and infotainment domains, an area also where ARM is scoring. MIPS is being used, though mostly in the smaller MCUs. “We use MIPS,” said Fitzgerald. “But we are not competing with the ARM and PowerPC. We have our own areas doing the likes of watchdog functions and other facilities around the larger processors.” But Bannatyne said: “Body electronics was one area where it was more typical for 8 and 16bit micros for things like mirrors and windows, but now it is more efficient to use 32bit and standardise on a single architecture.” And Hahn said: “Companies want a whole portfolio with software compatibility from low to high end so you can reuse software. We don’t see MIPS in the mid to high end.” The dramatic increase in the use of electronics in motor vehicles has led to a shift in the whole way the car is perceived. What were once simple tasks that could be handled by small microcontrollers now involve networking and diagnostic functions that can only be supplied by more powerful processors. But with these processors comes a need for more peripheral functions that still provide a market for the smaller devices. On that, most players agree, but there is strong disagreement on how that will be implemented in terms of architectures with many strongly rooted in their own path. While some are sticking with proprietary architectures, others are strongly aware of ARM’s move into this market and some are hedging their bets. This is a battle that looks set to be played out over the next few years as more sophisticated safety and control systems find their way in the automotive segment. t

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design

Automotive

On the safe side The journey to a safer, cleaner and smarter automotive industry. By Luc van Dijk, IC Architect for the product line In Vehicle Networking at NXP Semiconductors

Figure 1: Connecting the car

The automotive industry is driving towards a zero accident and zero emission world, an exciting paradigm shift that could be a reality in just 20-30 years. Today, more than 90% of all car accidents are caused by human error. Removing human error through introducing (semi) autonomous driving stands to significantly reduce the number of traffic accidents and road deaths. A number of technologies already exist to enable the shift to (semi) autonomous driving. These technologies can be summarised under the umbrella terms: Car-to-X: Car-to-car, car-to-infrastructure, and car-to-‘other’ communications (Figure 1); X-by-

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Wire: Throttle-by-Wire, Brake-by-Wire, Steer-byWire, and other advancements; Advanced Driver Assistance Systems (ADAS): Systems Adaptive Cruise Control (ACC), Lane Departure Warning and Blind Spot Detection Systems, and more. All three technology systems already exist, will grow rapidly in the mid-to-long term, and will ultimately become commoditised. There is no doubt that the combination of the three systems stand to make (semi) autonomous driving a reality in years to come. The zero emission ambitions of the automotive industry, shared by governments and driven by the dwindling amount of recoverable oil worldwide, will be realised in the longer term. Electrical vehicles with batteries recharged by renewable energy, such as wind energy, will be a reality in the longer term. In the mid-to-

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long term hybrid vehicles in all their different varieties will pave the way. Safety is critical as we strive for zero accident and zero emission vehicles. In a world where cars are (semi) autonomous, the electronic systems controlling vehicles must have failsafe reliability and security. Any failure could be life threatening, and standards such as ISO26262 have an important role to play. Minimising the risk to security caused by possible vulnerability to hacking in X-by-Wire, ADAS and especially Car-to-X Systems is also critical. Currently vulnerability to hacking is not covered by ISO26262; efforts to address the inclusion of security vulnerability related to hacking, and the current role of ISO26262, will be discussed later in this article. Electrical and hybrid vehicles face a different safety challenge, which is also being addressed. The high voltage board net that is

introduced in these vehicles, in conjunction with the 12V board net and high voltage batteries need special safety measures to remove the risk of explosions or fire.

A standard approach

Initially the automotive industry was implementing safety-related applications according to the IEC61508 standard. However, this umbrella standard was designed to be used as a platform for individual industries to build their own standards, as has been demonstrated by mechanical engineering and the nuclear power industry. For the automotive industry it was quickly realised that the ‘catastrophic events’ covered by IEC61508 don’t apply. It is also not possible for the automotive industry to distinguish between one and more fatal injuries, as defined in the IEC61508 standard. Finally, the Safety Integrity Levels (SILs) as defined in the IEC61508 needed adjustment. As it turned out, the automotive systems often needed a safety classification between SIL2 and SIL3.

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nature, while hardware failures can be random or systematic.

Figure 2: Key phases in the development of

The main phases in developing an ISO26262 compliant system are depicted in Figure 2.

an ISO26262compliant system

Generic Safety Architecture

Figure 3 shows a generic solution that can be applied in systems that need to comply with ISO26262. The solution is neither linked to a particular ASIL classification of the system nor to a particular application. Rather, the overall ASIL level that needs to be fulfilled determines the system architecture as well as the definition of the individual components. For example, the safety switch in Figure 3 is required to achieve a failsafe state in systems with an ASIL B level or higher.

The ISO26262, released in November 2011, was designed specifically for the automotive industry, applying to passenger cars and light utility vehicles. The standard defines Automotive Safety Integrity Levels (ASILs) from ASIL A to ASIL D with ASIL D being the highest safety level. The levels represent an acceptable residual risk level and apply to a full system only and cannot be assigned to an individual component. However, this is starting to become common practice. Therefore, the level associated with an individual component can be understood as ‘the component is suited/prepared to be applied in an ASIL x system’. The targeted/required ASIL level is achieved by the reduction of systematic and random failures. Systematic failures are caused by human errors and can be prevented by a proper design process. Random failures, for example those caused by ageing or thermal wear-out, can be detected in the system by introducing appropriate safety measures, like the addition of redundancy, monitoring, and self-tests. Software failures will always be of systematic

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The microcontroller (MCU) is available in many different types, for example on different implementation levels of safety (monitoring) functionality. These MCUs contain, in most cases, two cores that execute the same code in lockstep mode. A compare unit compares the calculation results of the two cores and in case of a difference, the MCU_error_n signal is activated and the system is put in failsafe state, while the safety switch is now opened and actuators cannot be (erroneously) activated anymore. However, this approach still has a weak spot because common cause failures that affect both cores will not be detected by the compare unit. Therefore additional measures, like an external watchdog, temperature sensors and special layout rules are also necessary to achieve the highest Safety Integrity Levels. The memory is in most cases secured by the addition of error detection and correction codes. The peripherals, when part of the system safety functionality, can also include safety monitoring, e.g. monitors that read back the signals that are sent via the ports. System-Basis-Chips (SBCs), such as the

design families UJA107x and UJA116x from NXP Semiconductors, form the basis of many electronic control units. The safety elements implemented in the SBC are the Watchdog (WD), the Voltage Monitor (VM) and a temperature monitor. The purpose of the WD is to supervise the correct operation of the MCU and in case of an incorrect behaviour of the MCU detected by the WD the MCU is put in reset and the system in failsafe state. The VM can detect under- as well as overvoltage on the supply voltage to the MCU, it can also include self-checking functionality. The VM and the Voltage Supply may each have a dedicated supply reference. The temperature monitor measures the temperature inside the SBC and compares that with a predefined threshold, when this threshold is exceeded an over-temperature is detected. It is also possible that the temperature monitor generates a warning at a lower temperature first. When either the WD, VM or over-temperature monitor detects an error, the SBC_error_n signal is activated and the system is put in a failsafe state. The Safety Switch is activated by the SBC, and not via intervention of the MCU as the MCU might not be able to activate the Safety Switch. In addition, in most cases a warning light to inform the driver is turned on when the safety switch is activated (not shown in Figure 3). The power devices as well as the drivers that go with it also contain diagnostics for safety purposes, covering undercurrent and overcurrent detection in driver-on state, as well as open- load detection in driver-off state and overtemperature detection. It follows that the safety monitoring functionality be implemented in all three main

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components in the system, the SBC, the MCU and the Power devices (especially the drivers). Finally, we consider higher levels of integration — the SBC as well as power devices and drivers integrated in one piece of silicon. This solution can result in lower system costs, but care needs to be taken, because the safety functionality (especially the part that activates the safety switch) needs to be functional and available under all conditions. The automotive industry is on the brink of a zero accident and zero emission revolution. Exciting developments in technologies driving the design of (semi) autonomous vehicles will help reduce the 90% of car accidents caused by human error. While hybrid vehicles and the evolution towards electrical vehicles that use renewable energy will help address dwindling oil supplies. Safety is critical to the realisation of a zero accident and zero emission vision. The introduction of ISO26262 is an important step towards addressing safety, while further efforts will help to answer the increased need for security in ‘Car-to-X’ implementations. The journey towards safety is ongoing, and will need to continue in the mid-to-long term. t

Figure 3: A generic ISO26262-compliant architecture

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Challenges for Next-generation

Automotive Power Systems Tougher emissions and fuel economy standards, 48V lithium-ion battery technology, energy harvesting and highpower applications such as Electric Power Steering (EPS), Brake-by-wire (BBW) and Heating, Ventilation & Air-conditioning (HVAC) systems are creating the perfect environment for a fundamental change in automotive battery systems, one that will create a tremendous tailwind for semiconductor suppliers over the next decade, as Philip Chesley, VP of Precision Products at Intersil, explains There’s nothing new about the story of the electrification of cars. In fact, in the 90s, innovative thinkers were working on a 42V standard to dramatically increase the voltage of existing 12 volt systems and enable the introduction of electric motors for a variety of subsystems; from steering to lighting. But other innovations enabled these applications to run off of 12 volt supplies and the idea of larger battery packs to support the higher voltage never took hold. A number of catalysts have moved hybridisation of vehicles beyond a concept and into reality and are creating a whole new area of innovation for semiconductor suppliers. The new standard, adopted by most car makers for models coming as early as 2015, is referred to as 48V BoardNet. This time, the change is for real and the evolution of battery technology has been a key factor. While a

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conventional lead-acid battery is still used in the system to support a 12V network for ‘light’ loads, a 48V lithium-ion battery operates a separate 48V network that supports key functional systems, including power steering, high-end audio systems and HVAC systems. Lithium-ion batteries have significantly higher energy density and simply weigh less, in addition to having more charge. The ability to support high voltage within the vehicle opens up a number of very interesting opportunities to improve the efficiency of the car. Driving at low speeds and in stop and go traffic no longer eats up gasoline, but instead can be a source of harvested energy that can be stored in the electrical system and reused to ultimately reduce fuel consumption. The need to have the automobile ‘always-on’ so it can communicate with a smartphone to remotely start the cooling or heating system and engage or disengage alarm and infotainment systems, for example, can more readily be supported with accurate battery management that increases efficiency and adds battery life.

design The convergence of the right technology, the regulatory environment mandating lower fuel emissions and the opportunity for meaningful energy savings is expected to translate to a strong increase in demand for vehicles supporting higher voltage standards. According to a forecast by Lux Research, the 48V micro-hybrid market will become a $788 million opportunity by 2024, with the first adoption year beginning in 2015. Early adoption is focused on premium vehicles, with global demand led by Europe, the US and China.

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Opportunities

For semiconductor suppliers, the move to 48V is significant as it requires a much different level of capability to provide reliable solutions that are also cost effective. There are very few suppliers today with the ability to provide auto-grade solutions up to 72V, offering the headroom required to support the 48V standard. Standard high voltage processes don’t readily support mixed-signal devices like precision converters and amplifiers. Suppliers are instead developing proprietary process technologies that can deliver the precision required, in a high voltage process, cost effectively. The stringent technical requirements create an opportunity for suppliers with the know-how and the familiarity with the rigours of the automotive market to deliver. For example, a few key focus areas where this innovation directly impacts the driving experience are management for start-stop applications, safety and efficiency. In hybrid vehicle start-stop applications, there are many systems including the alarm, infotainment, rear view cameras and others that can be switched off unintentionally if there is a glitch with the stop-start. It is critical that buck-boost devices can maintain the output power, even when the input drops to as low as 1.8V, allowing these systems to continue to function. Safety is the other key concern. A hybrid/electric vehicle may have from 96 to 190 cells. To accurately monitor the voltage, current and temperature across the cells and communicate that information reliably is critical to maintaining the safe operation of the vehicle. This communication has to be cost effective, reducing wire count and increasing robustness. Intersil developed an innovative daisy chain communications protocol that can

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Figure 1: Many systems will migrate to the 48V subsystem

operate over long cable lengths. This replaces the traditional method of attaching a battery module, a balancing IC, an MCU and a CAN interface to a central control unit, which is costly and introduces many points of potential failure. Accuracy of course is required for any IC technology applied to this market. Intersil, for example, has applied innovative power solutions to deliver up to a 10 percent improvement in efficiency by monitoring each battery cell to 3mV accuracy. In a practical application, this means the driver increases a vehicle’s range from 100 to 110 miles. Or, you can think of the longevity of the battery pack, which is typically warrantied up to 10 years. That 10 percent efficiency gain adds an additional one year to the battery life. And finally flexibility is very important. The evolving power requirements and new standards create complexity for automotive OEMs and their partners designing the power systems. The ability to create one design and reuse it across power system loads and support 12V, 24V and 48V

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requirements results in significant time and cost savings. Intersil developed a highly integrated and versatile buck converter specifically designed to enable easy conversion from high primary rails (Vin – typically 12V, 24V or 48V) to lower secondary rails (Vout – typically 3.3V, 5V or 12V). An integrated peak current mode synchronous PWM controller and integrated high-side and low-side FET drivers further improve efficiency. With more innovations to come, the automotive market will be the proving ground for many of the most important power breakthroughs in semiconductors over the coming decade. t

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In the virtual loop Abstract: With tens of millions lines of code in a single vehicle, the automotive industry is experiencing rapid growth in software content. This explosive growth comes with its own challenges: transition from single core to multicore platforms, developing AUTOSAR (AUTomotive Open System Architecture) applications, integration and test of embedded software and functional safety, and these are just some of the concerns directly linked with growing software content. For many years, developers of automotive embedded control systems have relied upon well-established functional level design approaches such as model-in-the-loop or software-in-the-loop. However, these approaches do not take into account the underlying hardware platform. The increased complexity of these platforms means that developers cannot wait for the ECU hardware to be physically available in order to start developing, integrating and testing their embedded software. New and better techniques need to be introduced that enable early development, integration and test, while also improving the developer’s productivity and containing associated costs.

Moving to a virtual development environment for automotive control embedded software. By Marc Serughetti, Synopsys Simulation technologies are being used to establish a virtual Hardware-in-the-Loop (vHIL) environment well before physical hardware is available. Such an environment combines the simulation of digital hardware using virtual development kits for microcontrollers with other simulators including analog hardware and mechanical system simulation. A vHIL environment is the foundation for a broad range of development activities including early software development, system integration, performance validation, fault and coverage testing in support of ISO 26262 and regression testing. The result is an enhanced development process that shifts design task earlier, improves testing coverage and identifies possible defects early in the design, leading to better overall product quality and reliability, reduced costs and faster time to market. Figure 1: Shifting the development of ECUs to earlier in the design cycle

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Growing content

In recent years, software content in automotive applications has grown drastically. This has led to an increased number of challenges related to recalls and redesigns due to software. The implication of these recalls has had a negative impact on costs as well as brand image. A simple search through the recent automotive recalls and industry discussions currently ongoing, illustrate this trend. As an example, an article from IEEE spectrum highlighted the ‘Recalls of 936,000 More Vehicles for Electrical and Software Fixes’. The article emphasised how software related issues could effect mechanical systems, such as the software upgrade that would ease the transition between gears to reduce the possibility of damage.

Figure 2: Limitations of ‘in-

With between 10 and 100 million lines of code, integrated across 50 to 100 controllers and 150 distributed functions, every car manufacturer is affected by the growing concern of increased software in automotive development. The result is that software development has become the biggest challenge for automotive companies. When it comes to safety critical applications, it then becomes essential to identify new methodologies and tools that will help improve software quality and reliability, scale to the complexity of automotive systems and enable companies to contain software testing costs.

the-loop’ technologies

Over the past 20 years the development of the

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Electronic Control Unit (ECU) has seen some significant evolution. Three areas are of interest are: modeling and simulation; code generation, and AUTOSAR. The fundamental elements of ECUs are the hardware platform (digital and analog), the embedded software infrastructure (OS, connectivity, etc.) and the control algorithm, combined to achieve the targeted function. From a development perspective, the validation and verification of the ECU cannot happen independently and must take place in the context of the environment with which the ECU interacts. In the mid 90s, modeling and simulation emerged as a key approach to model the algorithm and the environment. These models could then be simulated together. Tools such as Matlab/Simulink have played an essential role when it relates to functional simulation of the algorithm. The need for such simulation was driven by the increased complexity of the systems under development. Such simulation environment is also known as ‘Model-in-theLoop’ (MIL). Following the deployment of modeling and simulation, the concept of code generation made in-roads. Given that the developer had models, the idea was to start ‘compiling’ the models from the graphical representation used in algorithm designs to a high-level language like C. The generated code could be executed on a PC,

design specialised hardware or on an embedded target. Code could be generated for the control algorithms or the environment models. The use of code generation led to multiple development platforms including Software-inthe-Loop (SIL); in this approach the control algorithm generated code is compiled on a host PC and executed in conjunction with the environment model. This approach focuses on software correctness and execution speed. Processor-in-the-Loop (PIL) is an approach where the control algorithm is executed on an evaluation board. This approach enables the software to be run on the target hardware architecture. With Hardware-in-the-Loop (HIL), the actual hardware platform executing the embedded software is used in conjunction with code generated for the environment model and executed on a dedicated hardware platform. A few years ago AUTOSAR emerged as a standardised automotive software architecture driven by leading automotive OEM and tier one companies. An AUTOSAR simulator has been used in the development of embedded software, they however are compiled for execution on a host PC and do not incorporate any microcontroller hardware consideration. The evolution of this development process has been focused on early validation of the design and its generated code to avoid design iterations late in the development process. The approaches described above have provided a great set of benefits to automotive ECU developers, but still leave developers with development gaps. MIL and PIL do not take into account the underlying hardware platform, which are increasing in complexity and capabilities (e.g. newer MCU for automotive applications leverage multicore implementations). HIL requires the ECU hardware to be available and a significant gap in time and effort exist between the PIL and HIL availability.

Virtual hardware benefits

Looking at the overall development process, it is clear that modeling and simulation has brought significant value. However these concepts have only been applied to the control algorithm and the environment models; they have not been applied to the hardware platform. This has mostly been due to the fact that hardware oriented simulation to date has not been able to meet the execution speed expectation of developers. In addition

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Figure 3: Example of Virtual Hardware-in-theLoop on a PC using Simulink

these simulation environments are often contained within semiconductor companies and not easily accessible to developers at OEM and tier one companies. Virtual prototyping has emerged over the past few years as a key methodology to enable early software development. Virtual prototyping models digital hardware at a higher level of abstraction using the IEEE 1666 SystemC Language including support for TransactionLevel Modeling. Virtual prototypes are a fast software model emulating a hardware platform (microcontroller, electronic control units or a network of ECUs) and execute on a desktop PC (Windows or Linux). Virtual prototypes execute unmodified software binaries that execute on the hardware platform. Virtual prototypes deliver key capabilities including: observability; controllability; non-intrusiveness; determinism, and; scriptability. These capabilities are enabled through virtual prototype software development tools that work in parallel with existing software tool chains. For example, developers can use virtual prototypes to stop the full system execution at any point in time (even in a heterogeneous multicore hardware platform). They can then read and modify any internal values, correlate hardware and software execution or apply scripts. A Virtual Development Kit (VDK) is a software development kit integrating a virtual prototype as the embedded hardware target. A VDK can be

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easily maintained, deployed and archived to distributed teams worldwide. Virtual prototypes provide the technology required to complement the current limitations of the existing development approach. A virtual Hardware-in-the-Loop environment, combining a VDK executing the embedded software and executing in conjunction with the environment simulation, can be available earlier, deployed more easily and provide a more efficient development platform. Overall it enables developers to integrate, in a simulation environment, the last key element of the ECU: the physical hardware. Overall the deployment of such technology will lead to reduced development costs, improved software quality and system reliability. These benefits are delivered through the major areas of availability, productivity and deployability. Early availability will enable developers to start software development early, to front-load test development and execution. The visibility and controllability provided by a virtual Hardware-inthe-Loop environment enables developers to identify and fix problems more efficiently. With the capability to deploy and maintain, the set-up and maintenance of such environments can be centrally located, making them simpler to archive, or be deployed through FTP or a server farm and easily reconfigured. Once the VDK is integrated in a virtual Hardware-

design in-the-Loop environment, a broad range of use cases can be addressed. First, the system integration and test can be done virtually, developers can front-load the development of the test and their execution. It is a well understood concept that finding errors earlier in the design process significantly reduces the cost of fixing issues later on. The second use case is for coverage and fault testing. In this case a virtual Hardware-in-the-Loop environment provides significant advantages as fault can be injected anywhere, the state of the system can be modified and permanent fault can also be created. Corner cases can be tested and validated. Here again, to understand what errors should be corrected or modification included earlier represents a great benefit. A last example is regression testing. A virtual environment can easily be deployed in a server farm, thus allowing the overnight and early validation of multiple software stacks representing different vehicles or vehicle configurations.

Management perspective

The complexity of microcontroller hardware, functional safety certification and system complexity are driving automotive OEM and tier one companies to continue evolving the development process. Virtual prototypes and VDKs bring modeling and simulation concepts to the hardware, thus enabling the creation of a virtual environment that includes the embedded software, the ECU hardware and the environment being controlled. The integration of a

Automotive

virtual Hardware-in-the-Loop solution in the development process for ECUs enables automotive OEM and tier one companies to contain/reduce development costs, improve software quality and increases the overall system reliability. As management considers the deployment of a virtual approach for automotive electronics, several considerations come to mind. The decision to broadly deploy VDKs in the development process will most likely be based on a strategic direction to improve the development process. Analysis done by leading OEM and tier one suppliers, show that a qualitative analysis decision factor is often based on mitigating development risks, while a quantitative analysis factor will be most influenced by engineers’ productivity. For companies new to this approach, a pilot project should be considered to establish internal experience. A pilot project will be most efficient if clearly defined and targeted to be executed in parallel to a production project. It should also leverage the wide variety of shared knowledge on the topic from industry events and conferences. Finally when it comes to the deployment of virtual technologies, it must be supported by a vendor with a broad range of capabilities including: experience with simulation and tool technologies for hardware, long term established engagements with the automotive IP and semiconductor supply chain, a global presence for local support and deployment services and a financially stable vendor with an investment approach to support long term automotive projects and industry growth. t Figure 4: Earlier fault testing using VDKs

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Life in the fast lane The need for automotive component designers to embrace a new way of working and thinking. By Mark Warren, Perforce Software The pace of change for vehicle and component manufacturers is on an increasingly upwards trajectory. The need to remain competitive in a challenging industry means that innovation is the name of the game, balanced against a requirement for faster time to market, an eye on costs and compliance with standards such as ISO 26262. This is why Agile development – already a focus for many electronics designers – is taking more of a centrestage role in the automotive electronics sector, along with Continuous Delivery. In turn, that means many organisations are having to review and change the processes and tools that support this increasingly complex and demanding environment. Vehicles are very much dependent on software these days; as Marc Andreessen said, everything is really a software business today. Reportedly, the radio and navigation system in the current S-class MercedesBenz requires over 20 million lines of code alone, and that car contains nearly as many ECUs as the new Airbus A380. Then there is the fact that in the age of the smartphone, customers expect high performance, a great user experience and frequent updates in all parts of their lives, including the cars that they drive. Plus, customers are becoming used to features that until recently were only available in premium vehicles. A highly competitive marketplace also means that vehicle manufacturers struggle to find new ways in which to differentiate: after all, most cars are proficient and reliable, so something else is needed to set them apart. Rolling out new features is one way to achieve that. On the other side of the coin to innovation is risk management: like many other industries, there is

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greater regulation and compliance to be observed, such as the the previously mentioned ISO 26262 standard. On the plus side, being able to remotely upgrade vehicle software, diagnose problems, or get information from the drivers’ cabs of commercial vehicles back to base, are all recent developments that are good news for car manufacturers, workshops and fleet owners. Also, the capability of reasonably priced components with impressive processing capabilities, such as the CUDA architecture chips from NVIDIA, now enable powerful functionality even in reasonably priced vehicles. More automotive manufacturers and component suppliers are looking at the potential of Agile and Continuous Delivery to address these market challenges. Agile has been around for over a decade and has more recently been joined by Continuous Delivery, which is a natural complement: Agile includes time-boxed, short development cycles and Continuous Delivery shortens the cycle from development to customer with rapid feedback and iteration. With Continuous Delivery processes, it is assumed that products are always releasable: in other words, at any one time, a product is ready for deployment, even though its development will continue to evolve. Of course, the real release would be at a time determined by the business depending on product

design refresh cycles or marketing priorities but, at least in theory, every change could be released. All this sounds ideal in practice, but there are some hurdles that manufacturers and their electronics component designers need to overcome to access the benefits of Agile and Continuous Delivery as a means to deliver new innovations faster and more efficiently. For a start, many of the tools, processes and systems in use have not evolved since the early days of automation and growing electronic component capabilities that started to appear towards the end of the 20th century. This is understandable, given that many of the tools used are very big, were expensive to purchase, deploy and manage, so changing them is intimidating and inertia is tempting. However, if these tools just aren’t good enough for the changes going on now and in the future, then now is the time to re-evaluate whether they are a support or a hindrance. Consider the fact that there is a varied stack of hardware and software in a final product: memory, processors, drivers, graphics, documentation, test plans and simulators, for example. The ‘old world’ way of working was more siloed, which with the more collaborative Agile and Continuous Delivery, can make co-ordination of rapid releases difficult and costly. The answer is to have a single repository for all the assets associated with a project, one that can protect all the valuable intellectual property (IP) and support the different workflows. As well as helping to maintain better collaboration and delivery, a repository also creates a ‘single source of truth’ that can be referred to at a later date, for instance to check compliance with ISO 26262. Many traditional SCM (software configuration

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management) — AKA version control or version management — tools have done a good job of managing relatively small source code files, but less so for the kind of large binary data files associated with most modern design projects, especially in a continuous integration environment, or with the diversity of types of file, not just code. So, for some automotive component manufacturers, it may be time to re-think how to manage these repositories of assets. Having shared, easily accessible repositories is also going to help the more ‘open approach’ now taking hold in the automotive world, to address the fact that third players need to have an element of standardisation and integration. For example, the Open Automotive Alliance is attempting to create an open architecture where a well documented set of standards provide a common framework for all component builders. We’re also seeing open source tools being used more in design and development processes in all kinds of industries, including automotive. A popular tool for version control is Git, which has its pros and cons: a great, lightweight software development process but poor support for large binary files or IP protection. Fortunately, we are now seeing tools appear that enable organisations to bridge the gap, enabling developers to carry on using Git, but in an environment that puts the control back in the hands of the company. Both test and automation are key tenets of good Continuous Delivery practice and for good reason: manual tasks, especially ‘boring’ repetitive ones, invite human error. The latest generation of tools to support design processes take this into account, for instance compliance testing and simulating, which create high fidelity emulation and obviate the need for physical prototypes or production testing. The automotive industry is going through one of the biggest phases of change in its history and that presents both challenges and exciting new opportunities for electronics designers, whether involved in hardware, software or the growing range of support systems, such as machine-to-machine communications. Turning that change to advantage does, however, require a re-think of the development environment across tools, processes and culture. t electronicspecifier.com

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Automating design The use of design automation is evolving to provide greater productivity in the automotive industry. By Sjon Moore, Mentor Graphics Corp

Figure 1: Weight is a

Engineers have typically optimised Electrical Distribution Systems using unsophisticated and manual spreadsheet tools. Any detailed feedback on critical metrics such as cost or weight typically relies on another organisation and requires week or months. The resulting EDS is inevitably sub-optimised, not due to a lack of engineering ability, but rather the tools available. To ensure that the EDS design is optimised from the outset, the design environment itself must be enhanced. There are four key attributes to this design environment.

common metric to include for systems optimisation

Firstly, automation is required to ensure that designs are synthesised rather than manually created. Secondly, the ability to measure and

assess the design must be available in the design, while the engineer is designing. Thirdly, there must be multiple alternatives to view the resulting data to aid the engineer’s understanding. Measuring a single design is important, but the ability to compare alternatives, or even the same design through time is required. Finally, the measurements provided must become enriched and more accurate as the design matures. Estimations in the architecture space will become exact figures in the harness manufacturing space.

Design automation

Automating the design tasks allows time to run multiple iterations, providing more opportunity for optimisation. It also ensures repeatable results so that variation between alternatives is isolated to only the intended differences, and does not include manually induced variation. The thought and design processes need to move to the platform level to fully automate the wiring design process. At the platform level, it becomes simple to automate the synthesis of wiring designs. In the non-automated design process, the designer has to interact with the design as it progresses and make many decisions at the design moves on, usually using rules to guide the decision process. By abstracting the design process, the designer is now able think in terms of the rules and guidelines rather than their specific application. Capturing these rules allows automation to perform the mundane tasks of applying them. Ensuring that the rules exist in a re-usable format not only improves the design process, but also removes over-reliance on a small subset of highly skilled engineers. The designer can also think in terms of the entire platform, rather than a single design at a time. The captured rules can then be applied to the

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Automotive

Figure 2. Automatically generated FMEA highlighting the failure effect associated with the disconnected ground

platform context and the wiring is created for the user. The decisions about which harness through which to route, what wire size and material to use, and whether to use a splice or a multiterm are made for the user rather than by the user. And these decisions are made with respect to all of the orderable configurations. What results is the synthesis of the entire wiring design. Synthesis of the wiring design through automation significantly increases the number of scenarios the designer can create and test. If the designer wishes to understand the impact of moving an inline to the opposite side of the vehicle, it is trivial to make the change in the platform design environment, then resynthesise the wiring. Even changes to the rules and guidelines themselves that would normally be a difficult task to implement, is now a minor undertaking.

Measuring and assessing

A design can only be assessed if there are methods of measuring the design; it’s impossible to optimise a design if it can’t be assessed and evaluated. And the more precise and accurate the measurement, the better the decisions the designer can make. Generally, metrics are chosen based on the industry, the enterprise, or even the design type itself. Many metrics are engineering related — weight, cost, temperature — however business metrics can be defined as well, such as maximising profit. Metrics can also be created that will point out sub-optimal aspects of the design. For example, a metric could be created that simply reports the number of pass through wires in the platform. These are wires in a harness that

simply go from one inline to another. A metric of this type could help the designer analyse the platform design and guide them to alternative solutions. The point is, metrics can also be used to help guide the designer to areas they should give closer consideration. Measuring and assessing a single design or a single decision is valuable, but being able to compare results from multiple alternatives is equally so. Overlaying two or more sets of results, then seeing how they compare allows the designer to understand which is better, and under what conditions. As mentioned earlier, design automation gives designers time to make comparisons for multiple design alternatives. Perhaps a review of the metrics has suggested that a slightly different harness partitioning might result in lower cost and weight. An alternate design can be created then updated to match this new design. Design automation will then very quickly update all of the wiring data based on this new platform design. The ability to then compare these two designs will enable the designer to know definitively if they were correct. Assuming they were and the new design is superior, it is already designed for them. There is no need to then implement it across many wiring designs. The work is already done. It simply becomes the design of record.

Design evolution

Understanding how a design has evolved over time can be valuable, which means that the tool must enable the designer to save snapshots of the design. Comparing these snapshots will inform the designer of how it has evolved. Perhaps the design was initially fully optimised, electronicspecifier.com

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Automotive

the visual and tabular Count metric is dynamically updated as wiring is deleted and added. What the designer has done up to this point is used automation to very rapidly create a design alternative. This will free up time to fully optimise the design and increases design knowledge at an earlier point. Now the design can be evaluated. One of the questions that will inevitably be asked is are there any failure modes that were not considered; analysis can answer this.

Figure 3: Mentor Graphics Capital has found the error and highlighted it so the designer can take corrective action

but late requirement changes have negatively impacted the metrics. Understanding how these changes have caused the design to drift provides design knowledge of a historical nature that could be useful in attempts to re-optimise the design, or in future platform optimisation efforts. A quick design example using Mentor Graphics’ Capital suite will illustrate the value of automation and its ability to free time to evaluate options. In this example, the designer wants to investigate replacing certain 12V systems with 48V systems in an effort to save cost and weight. The designer swaps out the systems, as an example of working at the platform level by deciding which system designs to integrate into the platform. Placement of the new devices around the vehicle is done by rules that drive placement preferences. Or, if the devices are new the user can very easily manually place them or create new placement rules. Likewise, automatically placing grounds will connect them to available ground points. The new system designs will invalidate some wiring and create the need for some new wiring. Design automation can simply update the existing wiring and synthesise new wiring based on the previously defined rules. This is communicated to the designer continuously as

36 electronicspecifier.com

With a complete wiring design that represents the newly implemented design, automation will be used to create a complete Failure Mode & Effect Analysis (FMEA) report. Reports of this type typically take weeks of manual effort to create and can easily miss failure modes and their effects. Capital offers automation that can test all of the possible switch and failure combinations across the various configurations to uncover all failure modes. In this example (Figure 2), the FMEA is reporting a very high RPN (risk priority number) value related to a failing Body Control Module. This occurs when a seemingly unrelated ground in the front of the vehicle is lifted (meaning it is not connected to sheet metal and is therefore floating). The designer can replay this specific record on the FMEA and observe via colour overlays on the platform where these failures are occurring. Investigating the ground point itself, the designer realises that some of the new 48V grounds have been combined into a single ground location with several 12V lighting grounds. At this point, it becomes easier to visualise the problem by observing the design in a logical form rather than a platform context. The designer opens the appropriate

design logical design and continues the analysis of the issue in the same environment and without interrupting the thought processes. In Figure 3, the entire platform is schematically represented, and colour overlays highlight the FMEA results. From the diagram, it becomes clear that a sneak path exists through the bulbs. When a 48V load is active and the bulbs are not, current will sneak through the bulb and place approximately 20V on the lighting output driver of the Body Control Module. It was not designed with this failure in mind and the module is damaged.

Automotive

number of wires eliminated (or added) can be found and the cost estimated. Design automation abstracts the design process and synthesises wiring solutions. It does this to ensure consistent results that are an absolute requirement for effective optimisation efforts. It also allows for a large number of alternatives to be considered very quickly. The better the method of measuring the design, the more design knowledge can be acquired. Any tool that enables optimisation must have significant capabilities with regards the measuring, assessing and comparing design alternatives and changes through time.

To test this, the designer can simply separate the grounds on the platform design and reMentor Graphics Capital has been used as an synthesise the wiring. While doing so, the example of a tool that supplies the automation designer observes the Cost metric increasing and intelligence to move designs into the next due to additional wires and ground point generation. The automation is available for each attachments being required. Re-running the step of the design process, allowing designers to FMEA will show that the destructive failure optimise any of a number of design criteria, such effect has been eliminated. Note that the as cost, weight, or other factors. Employing such designer learned something valuable not only a solution will result in savings of time and cost, about this specific design, but about and allowing the designer to explore options that implementation of 48V technologies in weren’t possible in the past. The result is a general. Care must be exercised with significantly more optimal design than was ever combined 12V and 48V grounds, especially possible using manual methods. t when a sneak path is available. This is intellectual property that now belongs to the organisation. The designer can then create a rule Figure 4: The Count metric is displayed for the revised driving the placement and design of mixed 12V and 48V systems combination of grounds such that this does not occur in the future. Once the quality of the design is assured, the Count metric can be examined to ascertain if any savings has been realised. Figure 4 shows the Count metric, displayed by wire size. Comparing that to the original design, the electronicspecifier.com

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Optocouplers

Digital isolation is

undergoing evolution Standardising the advancements in the integration of isolation could enable even greater increases in the performance of optocouplers. By Werner Berns, International Standardisation Affairs Representative, and Kannan Soundarapandian, Product Line Manager, Isolation, Interface Group, Texas Instruments

standard, finalised in 1987, and the international standard IEC 60747-5 which followed soon after. Over the years, the standard has seen several revisions and improvements, resulting in the current revision, IEC 60747-5-5 (VDE 0884-5), published in 2013. This standard is seen as one of the most successful component standards worldwide and has provided system engineers the desired degree of confidence in the insulation capability for the circuit to be designed.

For more than two decades, a standard for optocouplers has proven isolation in almost all applications and equipment that demand secure separation of electrical circuits from high-voltage events. The baseline was the German VDE 0884

As technology has evolved, newer methods to create reliable galvanic isolation were developed about 10 years ago, striving for higher data rates and isolated power transfer. Capacitive, and later magnetic, coupled circuits now could be

Figure 1: Determining the working voltage from TDDB lifetime analysis

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Optocouplers

integrated into a chip package. This significantly extended the electrical speed and timing performance of these digital isolators beyond optocouplers in the market. Besides the technical difficulties and challenges of the newer technology in the early days, there remains a key unresolved need that has persisted, even as magnetic and capacitive couplers have become a large and growing share of the market: There is no worldwide standard for magnetic and capacitive couplers.

Smarter S marter Embedded Embedded Design, Faster Deployment

New standard for magnetic and capacitive couplers

In 2003, the work on a dedicated standard for magnetic and capacitive couplers was initiated in the DKE (VDE Association for Electrical, Electronic & Information Technologies), which resulted in a first revision of VDE 0884-10 in 2006. In 2011, an attempt to start work on the international equivalent standard, IEC 60747-17, failed when critical mass in participation was not achieved. Four experts from four different countries were needed at the time. In the summer of 2014, the German second edition of VDE 0884-10 was finalised. It includes significant improvements over the previous revision and the current optocoupler standard (details see below). Recently, this second edition was submitted to the International Electronic Commission (IEC) as a proposal for a new work item to be accepted, with enough experts nominated, during the general IEC meeting in November 2014. The lack of a dedicated standard for magnetic and capacitive couplers forced the industry to certify those products to the existing optocoupler standard (IEC 607475-5, or its predecessor IEC 60747-5-2) for almost a decade. Some test and certification labs accepted certifying magnetic and capacitive couplers on an exception basis to the above mentioned optocoupler standard by subjecting material to the same tests as the optocouplers. This practice was accepted by the industry. In May 2014, this practice was withdrawn by the DKE and therefore, no longer a certification option at the VDE test and certification lab. Furthermore, all existing certifications for magnetic and capacitive couplers that are issued based on IEC 60747-5-5 will be reissued based on VDE 0884-10 Ed.1, the published German

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Optocouplers

magnetic and capacitive isolation standard, and later based on Ed.2 (expected in December 2014). Other test and certification labs, especially outside of Germany, might be willing to continue to certify against the optocoupler norm, as the DKE decision is not binding to them. Nevertheless, the new VDE 0844-10 Ed.2 is a much stronger norm than the optocoupler norm, so there is little need to continue to use the optocoupler standard.

and magnetic isolators, the test voltage is accelerated to increased levels such as 5kV, 6kV, 7kV, and so on. Depending on the test voltage, it takes days, weeks, months and longer to force a breakdown of the isolation barrier. According to VDE 0884-10 Ed.2, at least one data point must exceed 10e7 seconds (116 days) before failure. Furthermore, the tests and test voltage have to be chosen for worst case conditions (temperature, waveform).

The improvements made to the VDE 0084-10 Ed.2 set an unprecedented new level of rigour in component standards. Table 1 shows the main differences. The working voltage is a key parameter on which engineers focus first to see the isolation performance of a coupler when high-voltage is applied across the isolation barrier over the product lifetime.

Based on the resulting Weibull chart, we get data points (X1, X2 … Xn) for a given failure rate (Table 1, row 5 for ppm rates). The resulting dependency for lifetime over stress voltage can be drawn (Figure 1). For SiO2 (silicon dioxide), the result is a linear curve. For thin film polymer, the result is a 1/V curve. At the point where the curve crosses the required lifetime (37.5 years for reinforced level – new mandate in latest VDE0884-10 Ed.2), we can draw a line down to the voltage scale to get the stress voltage for this lifetime point. This voltage is then divided by 1.2 (extrapolation factor for margin), which finally results in the working voltage, VIORM.

Optocouplers use the partial discharge (PD) test to determine the max working voltage (VIORM). This test lasts for one second in production and qualification of the device. Testing for VIORM is also performed for magnetic and capacitive couplers. However, a more modern method is used by taking the working voltage determined from a time dependent dielectric breakdown (TDDB) analysis. Table 1: Comparing the main differences between the standards for optocouplers and magnetic/capacitive couplers

The TDDB analysis is a well-known methodology in the semiconductor and other industries to gain knowledge about lifetime at accelerated stress test conditions. In automotive systems, for example, the acceleration is temperature to get lifetime estimations of product reliability at hightemperature operation. In the case of capacitive

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Failure rate

This procedure delivers scientifically rigorous lifetime estimation for 37.5 years of lifetime. The dependency of lifetime versus stress voltage can be clearly seen. It enables an accurate estimate of the max working voltage for a longer or shorter lifetime. This shows very high transparency and delivers high valued information directly into the hands of engineers who want to know more than just a working voltage value. In the case of the optocoupler standard, there is no lifetime

design

Optocouplers

estimation requirement at all outside of the partial discharge test. The VDE 0884-10 Ed.2 requires that the failure rate for a reinforced isolation barrier not exceed 1 ppm. This guarantees very high levels of quality right out of the gate. Basic isolation requirements are different, however, and require an isolation barrier failure rate below 1000 ppm. This might seem high for basic isolation, as certainly a >300 ppm delivery performance is seen as a catastrophic failure rate and would cause immediate line stops. But the 1000 ppm requirement outlined in VDE 0884-10 Ed.2 must be seen over the full rated lifetime of 26 years (20 x 1.3), at maximum working voltage and at worst case temperature. If we consider a linear distribution of 1000 ppm over 26 years, the result is ~38 ppm. Furthermore, the failure rate will not be constant over time, but increases toward the end of the lifetime. So, the effective rate during the expected operational time will be much lower than 38 ppm for basic isolators, even under worst case conditions. If we take the same approach for the

failure rate requirement of reinforced isolators (