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EEWeb PULSE INTERVIEW

EEWebIssue 79

January 1, 2013

Electrical Engineering Community eeweb.com

Bug ProcessingMachine

TECHNICAL ARTICLE

MCU Wars 2.5 - Importance of Code Quality in an RTOS

SPECIAL FEATURE

Vice President,Asset ManagementQuanta Technology

NicholasAbi-Samra

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Nicholas Abi-Samra QUANTA TECHNOLOGY

Interview with Nicholas Abi-Samra - Vice President, Asset Management

Two experts in RTOS sit down to discuss the quality of the code in each of their RTOS products and the great lengths they go through to get their RTOS certified.

RTZ - Return to Zero Comic

Featured Products

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MCU Wars 2.5: The Importance of Code

Product Review: TS1101 Bidirectional Current-

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Why thinking of your verification environment as a bug processing machine can cause you to consider aspects of verification beyond the test benches and tests.

14The Bug Processing MachineBY RAY SALEMI WITH MENTOR GRAPHICS CORPORATION

Quality in an RTOS

Sense Amplifier Demo Board from Touchstone

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Nicholas

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Nicholas Abi-Samra

Quanta Technology

Quanta Technology is a high-growth, independent consult-ing company providing business and technical expertise to energy utilities and assisting in deploying practical solu-tions to improve their business performance. In this first is-sue of Pulse for 2013, we spoke with Nicholas Abi-Samra, the Vice President at Quanta Technology leading the Asset Management practice at the firm. Nicholas shared some insights on power delivery maintenance, the aging power infrastructure, and effects of extreme weather events on the power grid.

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How did you get into electronics and engineering, and when did you start?

I have been intrigued with electronics and electrical systems since childhood. That is why I went into electrical engineering. My idol as a child was my father, who owned a number of electronics shops, and who was the inventor of several electrical and electronic devices. One of his inventions in the early 1960’s was a voice-activated, phone answering system.

How did you end up in Electrical Power Engineering?

In graduate school I developed a passion for Electric Power Engineering, an area which had less emphasis in favor of the more popular engineering fields, such as Electronics and Digital Systems. In the USA, only a handful of engineering schools had reputable programs in power engineering, and this, unfortunately, is still the case today. This lack of emphasis on power engineering is a problem for the industry, though it does create an opportunity for engineering students. We also have a problem with what we call the “aging workface” in power engineering.

Can you elaborate on the aging workforce issue?

The U.S. Department of Labor has estimated that as much as 50 percent of the nation’s utility workforce (engineers, technicians and line workers) will retire in the next five to 10 years. The challenges associated with replacing the technical and institutional knowledge of these electric power professionals will be huge. The potential impact on day-to-day utility operations of this knowledge transfer will also be significant.

We are hearing a lot about deployments of smart grid technology, and issues such as distribution automation. Can you elaborate more on that?During the coming five years we should expect that the smart grid deployments by utilities will create a large number of positions for engineering graduates. These positions will be created across various categories, but most will be in electrical engineering. Smart grid is universally understood to be the key enabling technology for the nation’s ambitions towards renewable energy development, electric vehicle adoption, and energy efficiency improvements. The opposite is also true in my opinion; without smart grid investments, many electrical engineering jobs in the electrical utility industry will either be deferred or not created. The smart grid will do for the electrical utility sector what the Internet has done for the communications sector.

Based on what you just said, do you have any advice for young engineering students who have not decided on a specialization?

Yes! Specialize in Electric Power Engineering with an emphasis on smart grid technology! I always try to get this message across to engineering students at universities and high schools.

Could you tell us a little bit about your company, Quanta Technology?Quanta Technology, http://quanta-technology.com/, is the independent consulting arm of Quanta Services. The industry looks towards us as the expertise-based consulting firm which covers the power systems

from end-to-end, from power generation, transmission, and distribution, all the way down to end-use customers. We cover system, planning, engineering, operations and asset management. We have a very talented staff of 120 workers, many of whom are renowned in our industry. Headquartered in Raleigh, we also have offices in Boston, Chicago, Oakland, Toronto, and Rotterdam.

You mentioned you are affiliated with Quanta Services. Can you explain who they are?Quanta Services, Inc. (http://www.quantaservices.com), is a publicly traded company (NYSE:PWR), with over 19,000 employees. It represents the largest union and non-union field forces in the energy industry. Quanta Services also owns one of the largest construction fleets

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The smart grid will do for the electrical utility sector what the Internet has done for the communications sector.

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in the industry, and enables rapid deployment to support emergency power restoration. The company’s headquarters are in Houston.

You lead the Asset Management practice at Quanta Technology; can you tell us more about asset management? Well, Asset Management is interpreted in many different ways in the utility industry, but everybody agrees is very important, no matter how you look at it. For some, asset management means the management and maintenance of the capital equipment that makes up the power system, such as the transformers, breakers, poles, etc. To others, asset management refers to the risk assessment and mitigation associated with energy delivery infrastructure. Some view asset management as the management

of the capital investment required to own, operate and maintain the electric delivery infrastructure. To Quanta Technology, asset management covers all these things.

Can you tell us more about the maintenance practices for the different grid components?

Maintenance management is a complicated business. Maintenance budgets are continually scrutinized by fiscal managers in an ongoing effort to trim dollars, and asset managers are under constant pressure to squeeze every last bit of productivity out of every maintenance dollar.

In the power grid we have literally millions of components. For example, large utilities may have several hundred thousand distribution transformers (better known as pad mounted transformers) mounted on

poles or on the ground. Maintaining these components can vary by utility, but there four main approaches:

• Run-to-failure - In this approach there is no intervention or maintenance. A component is simply replaced when the component it fails.

• Time-based maintenance - Inspection follows a certain pre-determined schedule, and thus a piece of equipment may be inspected whether it needs it or not. Simple approach… but not the most efficient and may not catch a problem in time to fix it.

• Reliability centered maintenance (RCM) – RCM is a process which combines reliability analysis with a review of maintenance history to develop a recommended maintenance plan.

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The smart grid will do for the electrical utility sector what the Internet has done for the communications sector.

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• Condition-based maintenance (CBM) - Maintenance is performed when the need arises, that is, after one or more indicators show that equipment is going to fail or that equipment performance is deteriorating.

Developing and implementing a maintenance philosophy is a critical step in an overall asset management strategy. The decisions of when and how to use a specific maintenance philosophy are best made based on information of degradation modes and the characteristics of specific equipment (as well as associate failure rates and patterns). A good approach to deal with maintenance strategies should be based on component life cycles and a life cycle management approach for the delivery infrastructure. At Quanta Technology, we assist our clients in defining and implementing maintenance programs based on current equipment condition and operational factors that define the maintenance requirement.

What challenges do you foresee in your industry?I would have to say that the first is the aging power infrastructure and the second is the impact of extreme weather on it. The second is highly related to the first.

What do you mean by aging power Infrastructure?

Many utility systems in the United States, Canada, and the rest of the world, were originally built many decades ago - 50, 60, 70, or even older. As a piece of electrical system equipment (such as a transformer or a circuit breaker) gets older, it deteriorates due to the wear and tear of continued service or weathering. At some point, the equipment becomes worn out. It will

either fail outright, or weakened in condition and could no longer stand against extreme weather events. Such failures cause interruptions in service and require expensive emergency repairs and system restoration work. Failed pieces of equipment have to be replaced with new ones, so even in the oldest area of any utility system, there is a mix of equipment pieces of different age -- some quite old, and some much newer. In some places, however, over three quarters of the equipment is original -- in spite of being five or more decades old. Next time you drive by an established community, have a closer look at those distribution wood poles and the transformers on top of them… some of these have been there before many of your readers have been born.

Does this mean we are going fall over an aging power Infrastructure cliff sometime soon?

Oh no, it does not. Some of the old equipment is still in very good condition despite its age, and is expected to provide satisfactory service for years to come. Some of the equipment, however, albeit a small percentage, is badly deteriorated (perhaps not to extent that it shows visible signs of imminent failure, but to the extent that it cannot do its original job dependably) and needs to be replaced. Replacing that equipment before it fails is more easily said than done. That is because finding the future “bad actors” in a power system is a quite challenge. In many cases, badly deteriorated equipment does not give obvious signs of its undependability. Tests can be done to improve the knowledge that the utility has on its equipment condition, yet these tests

are not entirely dependable. Tests are perhaps only 80-90% accurate in depicting the bad actors, and also sometimes lead to false positives.

- Ages in any infrastructure, particularly an old one, are well mixed- An aged infrastructure is made up of survivors- Equipment starts failing from the moment it is installed- Failure rate increases very gradually as a function of age- Not all equipment fails at the same age- Finally, it’s not age, but the condition of the equipment which matters the most

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At Quanta Technology we use our industry and equipment knowledge to assist our clients in defining and implementing maintenance programs based on current equipment condition and operational factors that define the maintenance requirement. Developing and implementing a maintenance philosophy is a critical step in an overall asset management strategy.

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I can talk hours on this subject, as it is something we specialize in at Quanta Technology, but here are some takeaways:

Many of these aging systems are not just aged, but obsolete. They weren’t designed to meet today’s service reliability needs or peak load levels. While they have been augmented over the decades, they are at or beyond their limit in many regards. Simple renewal of equipment and structures will not really give utilities what they need to face the future, particularly with regard to providing the 21st century “Smart” electric service many utilities and regulators envision. One can envision renewed systems, built to different design guidelines, incorporating different system layouts, with circuit automated switching and technologies. The problem is how to make an orderly, affordable transition from the existing aged, obsolete system to that new design. The transition must be made in a way that is both affordable and demonstrably justifiable to customers, investors, and ratepayers alike.

How about the impacts of extreme weather on power systems?

This is a very hot topic in the industry today, especially after superstorm Sandy. First let us define extreme weather. Extreme weather includes unusual, severe or unseasonal weather, or weather at the extremes of the historical distribution—the range that has been seen in the past. Some like to think of this as weather which occurs only 5% or less of the time.

Some attribute the increase in extreme weather events to man-made global warming. Recent studies indicate an increasing threat from extreme weather. One senior vice president from a major utility noted that they are seeing the “storm of the century” every year now.

A report published this summer by National Oceanic and Atmospheric Administration (NOA), indicated that July 2012 was the hottest month on record for the contiguous United States. It also showed that over 63% of the contiguous United States also experienced “moderate to exceptional” drought conditions. It also indicated that the period between January 2012 and July 2012 was the warmest first seven months of any year on record for the contiguous United States, with most places seeing record and near-record temperatures.

Most recently, Hurricane Sandy affected 24 states, with particularly severe damage in New Jersey and New York. Its storm surge hit New York City flooding streets, tunnels and subway lines and cutting power in and around the city with damage in the US is estimated at over $60 billion. A sizable of portion of this damage is in the power infrastructure. Sandy underlined the fragility of the aging power infrastructure.

As extreme weather and fires have become more and more common over the past few years, aging power infrastructures and equipment - which have not been designed to such extremes - will be expected see relentless attacks. The aging infrastructure makes the power systems more vulnerable to failures that could damage human health and safety. Failures from components affected by extreme weather can cause interruptions in service to the utility’s customers, and require expensive emergency repairs and system restoration work. This comes at a time that all of us are requiring a higher level of reliability and security.

There are some common approaches to hardening the power

- Ages in any infrastructure, particularly an old one, are well mixed- An aged infrastructure is made up of survivors- Equipment starts failing from the moment it is installed- Failure rate increases very gradually as a function of age- Not all equipment fails at the same age- Finally, it’s not age, but the condition of the equipment which matters the most

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At Quanta Technology we use our industry and equipment knowledge to assist our clients in defining and implementing maintenance programs based on current equipment condition and operational factors that define the maintenance requirement. Developing and implementing a maintenance philosophy is a critical step in an overall asset management strategy.

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EEWeb PULSE INTERVIEW grid against extreme weather events which can be used across many different utilities. Yet, each utility is unique and some tailored measures need to be considered. Quanta Technology provides a wide range of assistance to electric utility companies for hardening their systems against extreme weather. Quanta Services provides emergency restoration services for many extreme weather events such as ice storms, hurricanes and wildfires. It has a fleet of more than 5,000 off-road vehicles to get the experienced work crew, emergency generators and materials needed to restore power following the outages.

You mentioned condition-based maintenance earlier; can you elaborate on that in the context of aging assets?

Today’s utility environment includes expectations of higher reliability, lower costs and increased earnings, increased investment in environmentally friendly technologies, rapid fuel price escalation, and the challenge of aging in both the work force and the utility infrastructure. On top of that, there is regulatory and fiscal pressure to extend the life of existing power delivery assets through better understanding of the assets conditions, knowledge of operational issues that significantly impact the remaining life of the assets, and implementation of maintenance practices to support the operating objectives. Addressing aging infrastructure is difficult in traditional utility budgeting processes. Our experts are experienced in quantifying the future impact of aging equipment and developing justified multi-year plans that are acceptable to regulators. We provide services to

evaluate the current condition of power delivery assets such as power transformers, circuit breakers, and other substation infrastructure as well as distribution networks, cable systems and pole plants to assist utilities in their decision processes around capital equipment operations, refurbishment, and replacement.

What are some of the hardest situations you faced professionally?

Well, that is an interesting question. I have to say these have to be associated with appearing at large facility, like a large power generating nuclear plant, after a major incident, like a fire. My job responsibilities included root-cause analysis of the failure of major equipment, and investigating blackouts in the USA and overseas. These typically are very interesting to investigate (as no two are ever alike usually), but never-the-less they are not the most pleasant situations utilities face! When you arrive on-site of the incident, you get to meet people who are not in their best moods! Tensions are high as everybody scrambles to put the plant back in operation or system back together. Needless to say, you cannot make any mistakes and you have to think fast on your feet to find what went wrong in a hurry and under immense pressure. Those had to be some of the hardest situations I had faced, and I had many of them.

Do you have any note-worthy engineering recognition? Some of the awards that I was fortunate and honored to have, are:

• George Westinghouse Signature Award of Engineering Excellence, Westinghouse Electric’s highest

recognition award (two-time winner)

• Chauncey Starr Award, EPRI’s highest recognition award (three-time winner)

On the professional side, I served as the General Chair and Technical Program Coordinator for the IEEE Power & Energy General Meeting. Over 500 different organizations from over 50 countries were represented, h t tp : / /www.pes-gm.org/2012/images/general/Nick-Welcome-Letter-GM-2012.pdf. This year we had a record-breaking conference with 1,289 accepted publications which were critically-peer reviewed by 21 technical committees. We offered 170 technical sessions with topics ranging from developments and experiences in fields related to power generation, transmission, distribution, end-use, and of course, smart grid. I encourage readers to go to the conference site, http://www.pes-gm.org/2012/, and watch the videos from our amazing keynote speakers. In addition, we have over 30 hours of videos of very deep dives into many topics from we called Super Sessions from world experts. It was really a great honor for me to be affiliated with such a great event in electrical power engineering.

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Noncontact Temperature Measurement SystemRaytek, a worldwide provider of infrared (IR) thermometry, has introduced the Raytek Equipment Monitoring System with DataTemp® Multidrop software, a noncontact temperature measurement system that provides round-the-clock condition monitoring of actively powered components or operating machinery in support of predictive and preventive maintenance programs. Early detection of heat-related faults and failures, along with maintenance performed as needed and not when estimated, result in reduced maintenance costs and less waste from unexpected downtime. For more information, please click here.

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The Bug

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The BugProcessingMachine

Ray SalemiSenior Verification ConsultantMentor Graphics Corporation

The holiday season is upon us and once again we must field the question, “What do you do for a living?”

We RTL design and verification engineers usually think of this as a throwaway question, a conversation starter, small talk. But when we consider the question more closely we see that it contains the key to RTL success.

What do we do for a living? We process RTL bugs. We find ‘em and fix ‘em (some of us write RTL, but that quickly devolves into finding and fixing bugs). This is a key insight, because if we think of our daily activity as finding and fixing bugs, we realize that our success as a design team hinges on our ability to process as many bugs as possible in a day. The goal of processing as many bugs as possible in a day requires that we think of our verification environment not as a test bench, but as a bug processing machine.

Thinking of your verification environment as a bug processing machine causes you to consider aspects of verification beyond the testbench and tests. Instead you need to think of all the things it takes to increase bug processing productivity. You need to find ‘em and fix ‘em faster. Let’s consider each of the pieces in a bug processing machine.

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Regression ScriptSuccessful RTL development requires a daily cycle of bug processing. This means that you want to be able to run simulations overnight, come into work in the morning, and look through your simulation output for bugs. This is the “find ‘em” part of the day.

Running tests overnight is the single biggest thing you can do to improve your bug processing productivity. It beats the heck out of coming into work, starting a simulation, and getting a cup of coffee.

One can write regression scripts in a variety of languages. Python is a common language. If you use ModelSim or Questa from Mentor Graphics, you can download an example of a TCL regression script at http://www.fpgasimulation.com/downloads/fpgasimulation_examples.zip (Look in the folder called “Chapter26”).

Bug TrackingA bug processing system cannot exist without a bug tracking system. You’re likely to find, and fix, two broad categories of bugs:

• Testbench Bugs—Sadly, this happens even to the best of us. Testbench bugs can vary from problems with the regression script, to incorrect testbench behavior. Flagging spurious RTL bugs is a common testbench bug. Another is RTL functionality that isn’t reflected in the test bench.

• RTL Bugs—This is what we’re here for! To find and fix RTL bugs. As we add tests to the regression system,

we’ll find more bugs, go into the bug tracking system.

Google shows us that there are at least ten free bug tracking systems available. They all work like big state machines for bugs. The bugs come in with some open state, move to an assigned state, then a fixed state, and finally a closed state after they’ve successfully run through regression.

Bug tracking allows you to capture important metrics such as the number of open bugs, the bug arrival rate, and the bug fix rate.

Source ControlSource control allows teams to work together on a design and merge the results back together in a controlled way. It also allows an individual engineer to save versions of a design in case of some disastrous deletion of code or misunderstanding about functionality.

There are many source control systems, and all of them are hated by different engineers for different reasons. There’s no getting around it. My personal favorite is GIT because individual engineers can use it without having to set up a central server, but your company may already have one in place.

Regression scripts work together with source control. On a properly working engineering team, the team members will run a short regression to make sure that they haven’t introduced bugs before checking their work into a central branch.

Source Control systems can also create useful metrics in terms of files being modified and bugs being fixed.

Bug tracking allows you to capture important metrics such as the number of open bugs, the bug arrival rate, and the bug fix rate.

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Some source control systems integrate with bug tracking systems so that you can see the release that fixed a certain bug (or introduced another one).

Coverage ModelsOne can think of an RTL design as a large black box full of bugs. You don’t know how many bugs are in the box, and you don’t know where they are, but you want to find them all.

The only way to do this is to create a list of things that need to be verified before you can say that your debug work is completed. This is a coverage model.

Some coverage models are simply test plans: the engineers say, ”We’ve fully tested the design when we’ve run all these tests.” Other coverage models measure the stimulus to the design: “We’ve fully tested this design when we’ve tested all these scenarios.” Other coverage models look at signals or data in the design and measure whether they’ve been tested: “We’ve fully tested this design when all the FIFOs have been filled at least once.” Finally some coverage models measure code coverage to determine when the design is fully tested.

Your design goals will drive your coverage model, but you need to have a coverage model before you can claim to have fully tested a design.

The Test BenchFinally, we have the test bench. I’m discussing the test bench last because it is usually the thing that an RTL team will develop first. In fact, many teams may think that their bug processing machine is complete when they’ve written the test case. This is not true.

The test bench provides the core functionality that supports all the other parts of the bug processing machine. It allows regression scripts to run multiple tests. It records coverage and creates coverage reports. It catches bugs by stimulating the DUT and comparing the results to known good output. That said, it is not the complete solution to bug processing.

You can write test benches many ways. Recent trends are to write test benches in SystemVerilog using the Universal Verification Methodology (UVM), but you can also write test benches in simple SystemVerilog, VHDL, or even C++. There are many ways to do the job.

Processing BugsThe key to bug-free RTL is to create a complete bug processing machine that helps you find bugs and fix them as quickly as possible. We’ve discussed the pieces of that bug processing machine in this article. The key to success is to recognize that you need all these pieces in place to deliver bug-free RTL as quickly as possible.

Your design goals will drive your coverage model, but you need to have a coverage model before you can claim to have fully tested a design.

About the AuthorRay Salemi is a veteran of the EDA industry and has been working with Hardware Description Languages since he joined Gateway Design Automation—the company that invented Verilog. Over the course of his career he has worked at Cadence, Sun Microsystems, and Mentor Graphics. Ray is currently a Senior Verification Consultant with Mentor Graphics.

Ray earned a BS in Computer Systems Engineering with a minor in English from the University of Massachusetts at Amherst. He earned his MBA from Babson College. He has used this unusual combination of skills to publish several books including the management book “Leading After a Layoff”, the engineering book “FPGA Simulation”, and, most recently, the humorous book “Robot Haiku”.

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Episode 2.5Importance of CodeQuality in an RTOS

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Episode 2.5Importance of CodeQuality in an RTOS

In this episode of MCU Wars, Jean Labrosse of Micrium and Richard Barry of FreeRTOS dis-cuss the quality of code in each of their RTOS products and the great lengths they go through to get their RTOS certified.

This series was filmed at DevCon 2012 by Renesas in Anaheim, California. DevCon pro-vides an environment for valuable technical information exchange and access to Renesas’ technology experts and partenrs from around the world.

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Could you elaborate a little more about the quality of code in each of your RTOSs?

Jean

Richard

It’s something that Jean and I take great pride in—the quality of the software that we provide. Again, even though it’s open source, it’s developed through a

strict coding standard. As I mentioned earlier, there is a safety-critical version,

although it’s not the same now, but it grew out of the same product and is being reengineered. As far as the quality goes, it does prove the quality of the product. One thing I didn’t mention earlier is that on the show floor yesterday, we were actually launching an RX version of that and the product is called SafeRTOS, which comes with a whole load of certification documentation for both medical, European and American standards. Quality is one of our key attributes we like to promote.

I would probably say the same thing for our product as well. MicroC/OS-II has been certified for a DO-178B Level A, which is the most stringent certification

from the FAA point of view and were flown in highly safety-critical applications.

In fact, like I mentioned before, MicroC/OS-II has been used on the Mars Rover and we got a statement from NASA and JPL that basically said they did not change a single line of code to use it in the Mars Rover. That really speaks highly of it. We also have FDA certification, or at least pre-market approval, for FDA and, of course, the industrial safety body, so it’s very robust. When you say quality, to us, quality doesn’t just mean it works, it means it’s also impeccable and that we are extremely meticulous about following the coding standard and that everything is lined up.

This is another reason to have the source code available. If you’re giving people source code, you are letting yourself bare, especially when so many

thousands of people are downloading it and looking at it. We have to concentrate

on the quality for that reason, if nothing else. Of course, Jean and I have different opinions on coding style—Jean will obviously claim that his is superior to mine, and I am obviously going to claim that mine is superior—but at the end of the day, it’s purely about the end user. It’s a subjective thing and you can’t please every user at

the same time. Coming back to the certification, people really shouldn’t underestimate the amount of effort and time and expense that goes into that. The documentation that’s provided and the official certification that you have to go through for certain government bodies goes back to what we were saying about people doing it themselves; sure they can, but it’s going to cost them 10 times the cost and four times the time to do it, so these are very high quality products.

To give you an example: just to certify MicroC/OS-II is about 6,000 pages of documentation and they have to run every single function, F-statement,

switch statement, and they need to verify that all boundary conditions are verified

100% and gone through the total code coverage. They also have to verify the comments, making sure that by putting a comment in the code, you are commenting on

Richard

Jean

When you say quality, to us, quality just doesn’t mean it works, it means it’s also impeccable and that we are extremely meticulous about following the coding standard and that everything is lined up.

“

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To view this episode of MCU Wars and other EEWeb videos:

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Concluded in Episode 6...the proper thing, so that’s also an important thing. 6,000 pages of documentation is a phenomenal amount of work and millions of dollars.

You don’t want to be doing that yourself when you can buy it. Going back to the code coverage—in the SafeRTOS product, we use MCDC, which I’m sure

Jean will be familiar with, but anyone outside of the aerospace industry won’t

necessarily know what it means, but it is the highest level of code coverage that you can possibly provide. Every single route through the code, when you have multiple decisions in a condition, you have to have every single combination of everything to show that there is nothing that’s being generated that is not doing anything. The effort is intense.

Richard

When you say quality, to us, quality just doesn’t mean it works, it means it’s also impeccable and that we are extremely meticulous about following the coding standard and that everything is lined up.

”

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Dave BaarmanDirector Of

Advanced Technologies

Making WirelessTruly Wireless:

Need For UniversalWireless Power

Solution

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laudantium, totam rem aperiam,

eaque ipsa quae ab illo inventore

veritatis et quasi architecto beatae vitae

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Dual 15A/Single 30A Step-Down Power ModuleISL8225MThe ISL8225M is a fully-encapsulated step-down switching power supply that can deliver up to 100W output power from a small 17mm square PCB footprint. The two 15A outputs may be used independently or combined to deliver a single 30A output. Designing a high-performance board-mounted power supply has never been simpler -- only a few external components are needed to create a very dense and reliable power solution.

Automatic current sharing and phase interleaving allow up to six modules to be paralleled for 180A output capability. 1.5% output voltage accuracy, differential remote voltage sensing and fast transient response create a very high-performance power system. Built-in output over-voltage, over-current and over-temperature protection enhance system reliability.

The ISL8225M is available in a thermally-enhanced QFN package. Excellent efficiency and low thermal resistance permit full power operation without heat sinks or fans. In addition, the QFN package with external leads permits easy probing and visual solder inspection.

Related Resources• See AN1789 “ISL8225MEVAL2Z 6-Phase, 90A Evaluation

Board Setup Procedure”

• See AN1790 “ISL8225MEVAL3Z 30A, Single Output Evaluation Board Setup Procedure”

• See AN1793, “ISL8225MEVAL4Z Dual 15A/Optional 30A Cascadable Evaluation Board”

• See ISL8225M 110A Thermal Performance Video

Features• Fully-encapsulated dual step-down switching power supply

• Up to 100W output from a 17mm square PCB footprint

• Dual 15A or single 30A output

• Up to 95% conversion efficiency

• 4.5V to 20V input voltage range

• 0.6V to 6V output voltage range

• 1.5% output voltage accuracy with differential remote sensing

• Up to six modules may be paralleled to support 180A output current

• Output over-voltage, over-current and over-temperature protection

• Full power operation without heat sinks or fans

• QFN package with exposed leads permits easy probing and visual solder inspection

Applications• Computing, networking and telecom infrastructure

equipment

• Industrial and medical equipment

• General purpose point-of-load (POL) power

FIGURE 1. COMPLETE 30A STEP-DOWN POWER SUPPLY FIGURE 2. SMALL FOOTPRINT WITH HIGH POWER DENSITY

1.2V@30A4.5V TO 20VVOUT

4.7µF

4x22µF

ISL8225M

VIN1

VSEN2-

VSEN1+EN/FF1EN/FF2

VMON2

VMON1

SGN

D

PGN

D

VOUT1

VSEN1-

MO

DE

COMP2

COMP1

VIN

OFF 1kΩ5x100µF

470pF

1kΩ

VCC

RSET

NOTE: ALL PINS NOT SHOWN ARE FLOATING.

VIN2 VOUT2VIN2

ON

17mm 17mm

7.5mm

December 3, 2012FN7822.0

Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2012All Rights Reserved. All other trademarks mentioned are the property of their respective owners.

Get the Datasheet and Order Eval Boards

http://www.intersil.com

EEWeb PULSE PRODUCT REVIEW

24 EEWeb | Electrical Engineering Community

Review of the

TS1101 Bidirectional Current-Sense Amplifier Demo BoardFrom Touchstone

by Gary CrowellEEWeb

This review will hopefully show you what Touchstone Semiconductor’s TS1101 bi-directional, symmetrical, high-side current sense amplifier can do. The TS1101 boasts super low 1uA power consumption, and no dead band when the current changes direction. This should allow for simpler designs, save power, and board space in your designs.

The TS1101 is made for low current, high-side current-sensing amplification in products like cell phones, notebooks, tablets, power management systems, motor control, load protection, and smart battery packs and chargers.

What you get with the development board is a TS1101, resistor, and capacitor soldered to a PCB along with some test point pins. There are also large pads for soldering your connections to the board, however where

there are pads, they left off the pins that are easier to clip or connect to.

The TS1101 also features a low input offset voltage of less than 100uV, much lower than some of the competing parts on the market. This part has four available gain options of 25/50/100/200 V/V amplification, so you can choose one that works best in your application.

Figure 1: TS1101 Bidirectional Current-Sense Amplifier Circuit

Figure 2: Connecting to the TS1101 Board

Figure 3: The TS1101 is available with different gain options

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The expression for the TS1101’s output voltage is given by:

Vout=Iload x 50mOhm x Rout/Rgain[A/B]

Plugging in the values:

for the TS1101-100: 400ma x 50mOhm x 10kOhm/100Ohm = 2V

for the TS1101-200: 200ma x 50mOhm x 20kOhm/100Ohm = 2V

When connected to a 6V supply and 15-ohm or 30-ohm load the TS1101-100 and TS1101-200 demo boards’ Vout should be 2V.

In conclusion, the Touchstone TS1101 is a neat little current sensing amplifier that takes up little real estate in its SOT23-5 package and can take the place of 2 uni-directional CSA’s while providing better performance. The TS1101 offers a variety of gains for your applications, consumes very little power, and is very accurate.

Figure 4: The TS1101 features

Figure 5: My results at 6V

Figure 6: My results over a range of voltages for TS1101-100

Figure 7: The TS1101 at work

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