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Power Supply Safety and Compliance This section presents articles on Safety & Compliance relevant to both designers and users of power supply products. These articles discuss compliance requirements related to safety, electromagnetic compliance (EMC), energy efficiency, and other areas affecting power supply approvals regionally and globally for diverse applications and markets. The articles discuss compliance issues from the design stage through pre-compliance and final compliance testing. Some articles are deeply technical, others relate case studies involving power supply customers. These article were previously published in the Spotlight on Safety & Compliance column of the How2Power Today newsletter, which is sponsored by Power Integrations. These articles were authored by Kevin Parmenter, Chair, and James Spangler, Co-chair, PSMA Safety and Compliance Committee. Bios of these authors are also presented here. This section also presents some other safety and compliance related resources. 
New JEDEC Guidelines Help Designers To Realistically Predict Stability Of SiC MOSFETs In Applications With the recent publication of JEDEC guidelines for SiC MOSFETs, the promised benefits of silicon carbide (SiC) MOSFETs can now be fully realized and consistently demonstrated through recognized industry guidelines. Concurrently, newly introduced high-voltage SiC MOSFETs have improved threshold voltage stability that can be validated by the new testing procedure. This article will provide background on the SiC market, discuss the JEDEC guidelines and testing performed by Infineon and conclude with details on newly implemented test procedures. Read the full article…
A Guide To Power Electronics Design For Off-Battery Automotive (Part 1): EMC And Line Transient Requirements Given the increasing number of power electronic systems integrated within vehicle designs, it is essential to consider the complicated electrical and electromagnetic environment in which these systems operate. All vehicle OEMs and most component suppliers to the OEMs perform tests to verify the electromagnetic compatibility (EMC) of their devices. This includes three types of immunity—conducted, radiated and electrostatic discharge—which you should understand before tackling an automotive power design. Read the full article…
A Highly Valuable Guide To EMC Troubleshooting And Pre-Compliance Testing
Anyone who is aware of EMC topics knows Ken Wyatt. He is one of the top talents in the field after acquiring over 35 years of experience. He has shared this experience in many books, articles and videos. Besides being a consultant and author, he is also a well-known lecturer. Ken’s latest book, Workbench Troubleshooting EMC Emissions, is a follow-up to his earlier work in volume 1, “Create Your Own EMC Troubleshooting Kit”. Here in volume 2 the goal is to give the reader simple techniques for mitigating conducted and radiated emissions and troubleshooting the same. Read the full story…
Comprehensive Reference On Transient Protection Includes Supercaps
The book is composed of ten chapters and five detailed appendices. The first chapter sets the stage for the rest of the discussion and suggests the scope of the book by providing a review of the different types of transients. These include voltage surges and power line disturbances such as sags and overvoltage conditions. Lighting surges are covered in discussions with various protection devices. Supercapacitors are introduced as a new way to absorb energy. Their ability to absorb electrical energy as a protection device is presented. This book would be useful for beginning engineers, experienced engineers as a review, and for engineers doing failure mode analysis. Read the full story…
One Month Left To Download EMC + SIPI 2021 Proceedings Due to COVID-19, the EMC + SIPI symposium was held virtually again this year, from July 27 through August 20, 2021. As always, this year’s conference program was full of useful information relating to EMC, signal integrity and power integrity topics. Members of the IEEE EMC Society were recently sent a reminder that they have until December 15, 2021 to access the conference proceedings here. If you are not a member of the EMC Society, but are already an IEEE member, you can join the society for a modest fee. See the society membership page. This article is a short overview and summary of the EMC + SIPI 2021 symposium to help you to navigate the workshops, tutorials and technical papers that are available in this year’s proceedings. Read the full article…
Safety Compliance Testing: It’s A Business, So Shop Around Over the years I have worked with various safety, compliance, and certification agencies and NRTLs (Nationally Recognized Testing Laboratories) and similar types of labs. In the past, some of these agencies were not-for-profit organizations which were funded by insurance companies to enhance safety and minimize losses from coverage of fires and damages caused by unsafe conditions in products. Today many or all the NRTLs are businesses who charge like lawyers in billable hours. This approach to safety and compliance certification has changed how test labs conduct business to the point where your success in obtaining certifications for your new product in a timely and cost effective manner will depend on which laboratory you choose to work with. And in my experience, your success will also depend on who you get assigned to at that particular NRTL. Read the full article…
A Standalone Controller Eases Compliance With USB PD Standards USB Power Delivery (PD) poses new power requirement challenges because of the variety of voltage and current combinations available—5 V, 9 V, 15 V, 20 V, 28 V, 36 V, 48 V and 1.5 A, 3 A, and 5 A, etc.—to supply the wide range of power levels the USB PD standard can provide. The power source and the inline devices communicate their power capabilities and power needs, respectively, in proper voltage and current levels before the source provides power over the USB cable. Some solutions require multiple ICs, including port detectors, microcontrollers and chargers for power delivery. While these solutions work, they take up space on a board, increase the solution cost, and require custom firmware, which can be time-consuming to create. A standalone PD controller can help address these challenges by managing the power negotiations without firmware development. Read the full article…
Predicting Mission Life Performance And Reliability Of Rad-Hard Power Electronics In space applications, understanding equipment reliability and performance over the mission lifetime remains a critical concern for system designers, especially for long duration, interplanetary and other critical missions. To achieve confidence in space systems requires rigorous design, strict qualification and radiation testing, and controlled manufacturing and screening to eliminate manufacturing defects and infant failures. Providing performance validation over the life of the mission is addressed through extensive design analyses validated by empirical data. Doing the detailed end-of-life performance assessment requires time, resources and expertise in radiation-hardened (rad-hard) electronics. This article will explain IR HiRel’s design analysis methodology for its rad-hard hermetic hybrid dc-dc converters that power spacecraft electrical subsystems. This method provides end-of-life verification of the dc-dc converter specifications and performance in accordance with MIL-PRF-38534 Class K. Read the full article…
Safety On The Bench: Hazards And Precautions In The Power Electronics Lab It’s no mystery that we, as power electronics engineers go through tremendous pains and trials to deliver a product that fulfills the mission requirements demanded by the application and the market. These requirements include reliability, environmental, safety and electromagnetic radiation, conduction and susceptibility constraints, and in some cases heavy ion, gamma ray and neutron events. We take all efforts to assure that the path of least resistance is upheld for the circuitry. This is the path of most resistance for us, but this is the duty. The standards can vary from ambiguous to crystal clear across space, mil, medical, aerospace, defense, consumer, automotive, industrial. But what happens on the bench in the lab during prototype and evaluation stages—before the codified standards apply? Shouldn’t that be safe too? Read the full article…
Why Aren’t Many Resistors UL Rated? Electronics in various types of applications and markets will occasionally require a UL rating. UL recognition for a component can range from the flammability level, to a complex set of tests designed to demonstrate whether the part will fail without creating fire, explosion, significant heat, or other detrimental or dangerous results. When seeking resistors for such applications, our customers frequently ask, why aren’t there more UL-rated resistors available? This article discusses the cost factors that influence whether resistors carry a UL rating. It also explains how fusible, failsafe resistors offer an alternative to UL-rated components. But first, let’s look at why UL-rated resistors are considered for applications requiring a UL rating and where they fit in the two approaches to obtaining a UL listing for the customer’s end product. Read the full article…
WBG Semiconductors Pose Safety And EMI Challenges In Motor Drive Applications For years we’ve been told that silicon (Si) power MOSFETs and IGBTs have largely reached their performance limits and that wide-bandgap (WBG) power semiconductors such as SiC and GaN MOSFETs will soon take over. One area where this is supposed to happen is in variable-speed motor drives, where SiC MOSFETs are competing with silicon IGBTs to be the power switch of choice for driving permanent magnet synchronous motors (PMSMs). GaN FETs are also being positioned for use in these applications. Despite the hype, there are serious obstacles to overcome in making the WBG power switches viable in motor drive applications. Read the full article…
Safety And Compliance Are Mostly Learned In The Real World, Not The Classroom Recently I came across an article written a few years ago by Lou Frenzel, titled “7 Critical Things They Don’t Teach You in EE School”. The topics Frenzel focused on were “power supplies, pc board design, video, motors, test and measurement, wireless and digital signal processing” and he noted some of the reasons why each of these areas are important for EEs, why universities tend not to teach about them (at least in undergrad programs) and how engineers are largely left to learn these subjects on their own. In reading about these neglected subjects, I could not help but add safety and compliance issues to the list. As with the topics that Frenzel discussed, knowledge of safety and compliance requirements and practices is critical to performing our jobs as electronics engineers. Yet so many aspects of S&C are never addressed in engineering studies. Read the full article…
EMC+SIPI Talks Reveal More About EMI Filter Design For Flyback Converters While many of the presentations at EMC+SIPI 2020 addressed EMI and EMC issues broadly, some of the talks had a power electronics focus. This article focuses on two such presentations on EMI filter design by Michael Schutten and Cong Li of GE Research. which offered practical information on filter design for low-power flyback converters. Not only were these talks interesting on their own, they also were similar to work that I (Jim) and my co-authors presented at the Power Electronics Technology conference in 2002. All of these talks explained and demonstrated how the various components used in an EMI filter affect the line-conducted noise. In this article, we’ll discuss and compare these presentations to highlight what power supply designers can learn from them. Read the full article…
Materials Compliance: Avoiding Product Recalls With Platform Technology “The electronics industry is famous for jumping into the latest societal crisis, imposing new regulations. This has progressed to where OEMs must make materials declarations for every component in their products as to their compliance with RoHS, WEEE, REACH and California prop 65— to name a few. Disclosure requirements are manifold and penalties are severe,” says Safety & Compliance columnist Kevin Parmenter. “This has created a tsunami of customer requests for information from their component manufacturers, distributors and others. Keeping up with the requests can be overwhelming for both the suppliers and their customers. In this S&C column, Valerie Kuntz and Neil Smith explain how platform data technology offers relief from the compliance tracking and reporting burden, enabling companies to manage changing materials compliance requirements in an orderly fashion.” Read the full article…
Keeping Up With IEC 62368 The UL/EN/IEC 62368 standard is a merger of two standards—UL/EN/IEC 60065 Audio and Video Equipment and UL/EN/IEC 60950 Information and Communication Equipment. Most designers probably have some familiarity with 62368 because the industry has been transitioning to this standard for several years. There’s another regulatory milestone looming as the legacy standards in the European Union are about to be withdrawn on December 20, 2020. As this deadline approaches, many designers may still need to come up to speed on what the standard requires, and understand what variations of the standard are being applied as well as aspects of the standard that are still in flux. With that in mind, we present a brief overview and update on UL/EN/IEC 62368. Read the full article…
EMC+SIPI Symposium Shares Valuable Tutorials Virtually Each year the IEEE EMC Society holds its annual conference devoted to electromagnetic compatibility, signal integrity and power integrity. As is the case with many events, the IEEE EMC + SIPI Symposium is going virtual this year with all presentations being given online. As a result, in lieu of the traditional one-week format, conference sessions have been spread out over the course of a month, from August 3rd through the 28th. This virtual format could be a boon for many attendees as it allows individuals to attend more sessions live. Nevertheless, the conference is so large that you cannot attend every presentation live. So the IEEE EMC Society has made a provision for those who register to view the sessions on-demand from September 1-30, 2020. The authors are both in the process of attending the symposium. This article contains their overview of the week one sessions with Jim’s comments on those he has attended. Read the full article…
Mounting Bridge Rectifiers: Compliance Needs Make It Complicated Among the various types of semiconductor devices, bridge rectifiers are somewhat unusual in that they are subject to safety agency certifications such as UL. These devices have agency approvals because they often connect to the ac mains in their applications. In addition, higher-power bridge rectifiers are usually mounted on a chassis or heatsink, such that they become part of the isolation safety barrier and therefore subject to creepage and clearance considerations as well as hi-pot testing. There are also maximum touch temperatures that affect rectifier usage. The requirements for isolation and heat removal are often in conflict. This article discusses techniques and strategies for satisfying these requirements—real world best practices—and highlights some of the pitfalls to avoid when mounting bridge rectifiers in your applications. Read the full article…
Power Supply Book Also Explains EMI And EMC Requirements
Paul Lee’s very practical book on the broader subject of power supplies also contains very useful information on EMI and EMC. “Power Supplies Explained” provides explanations on the causes of electromagnetic interference in its various forms, techniques for identifying and mitigating the sources of EMI, applicable regulations, and other details that can help working engineers get their products to market faster. In his review of the chapter on EMI and EMC, Kevin recaps what readers can learn from this discussion while also sharing his experiences in getting power converters to pass regulatory requirements. Read the full article…
New EU Appliance Regulations Add Complexity, Reform Product Labeling In Europe there are newer, updated regulations for energy efficiency targeting consumer white goods which we could see adopted as best practices globally. The new regulations also include changes in the labeling for appliances. The main purpose of these labeling changes is to allow the consumers to make better purchasing decisions. Ultimately, the goal of these changes in energy efficiency and labeling requirements is to achieve energy efficiency objectives for the region. Besides modifying efficiency requirements, the new EU regulations also impose limits on audible noise since many appliances contain motors. These changes in EU appliance regulations are the subject of an upcoming webinar by Power Integrations on “EU Ecodesign and Energy Labeling Directives,” which will be presented by David Chen. This article highlights some of the key regulatory changes to be discussed in this webinar. Read the full article…
The Ever Evolving And Complex World Of Materials Compliance And Declarations Compliance concerns are not just about staying on the right side of social and environmental regulations. These issues impact the long-term viability of your organization and its ability to sell products. The two most adhered-to regulatory standards are EU REACH and EU RoHS. However, attention to the health of citizens and the environment has led to the implementation of guidance and regulation around the world. There are guidelines and regulations that apply on a regional level, but also those that are country specific and, within the U.S., even state-level regulations. These rules may apply differently in various countries of manufacture and there may be differences with respect to the end markets. In this article, we will provide a brief overview of the major materials compliance directives and regulations that are enforced across the globe. Then, we will provide further background on conflict minerals and explain the regulatory requirements imposed on the use of such materials in the U.S. Read the full article…
PFC (Part 2): How Current Harmonics Cause Distortion And The Role of the Delta-Wye Transformer The first part of this article reviewed the evolution of power factor correction (PFC) requirements and discussed the IEC 61000-3-2 PFC standard. Here in part 2, the relationship between line frequency harmonics and distortion is analyzed, and we explain how the delta-wye transformer corrects this distortion on the power grid. Read the full article…
Power Factor Correction (Part 1): Why We Need It And How It Evolved The application of power factor correction (PFC) in switched-mode power supplies is well established and the circuits used to implement active PFC are widely known. Along with knowledge of PFC circuits and components, many engineers likely have an awareness of the PFC standards that govern product compliance. But when it comes to why these PFC requirements are in place and what were the industry or market conditions that drove their adoption, the record is not so clear. Here in part 1 we review the history of how PFC evolved and the technical requirements it produced. This discussion includes a review of the IEC 61000-3-2 power factor standard and the limits it imposes on harmonics generated by non-resistive loads, and where PFC is currently required. Read the full article…
APEC 2020 Resources Help Engineers Address Power Supply Safety and Compliance Needs APEC season is coming up soon and this means the brightest minds and top suppliers in the power electronics industry will be gathered in one place. This year the IEEE Applied Power Electronics Conference (APEC 2020) will be in New Orleans, March 15-19 and as always, we will be there to participate. Over 300 exhibitors will be there this year showcasing their latest technologies and practical solutions to proximate problems in our industry. From a safety and compliance standpoint, this unique collection of suppliers and service providers presents a special opportunity to obtain the components, tools and advice we need as engineers to meet our regulatory requirements. Read the full article…
X-Capacitor Discharge Must Satisfy Both Safety And Energy Efficiency Rules Many products including power supplies and household products are connected to the ac line. Within these products we find the X capacitors used to provide line filtering. If no measures are taken to discharge these capacitors, they can retain a high-voltage charge even after ac power is removed from the product. There are regulations to prevent the consumer from being shocked if their fingers should touch the metal prongs of the ac power plug while they are removing it from the outlet. Satisfying these safety requirements for the discharge of X capacitors would be straightforward were it not for the energy efficiency standards, which are pervasive and over time are becoming more demanding. This article discusses both the safety and energy efficiency requirements, looks at the different circuit approaches to discharging X capacitors and how well they do in terms of satisfying the energy efficiency regulations. Read the full article…
Maintaining Battery Safety And Life Of Battery Are Top Priorities In Battery Charger Design Over the years, various rechargeable battery chemistries have been developed including sealed lead acid (SLA), NiCd, NiMH, Li-ion, Li-ion polymer and lithium iron phosphate (LFP or LiFePO4). All of the rechargeable chemistries have advantages and disadvantages, but they’ve all had safety issues related to charging. In this article, we’ll discuss the risks to battery safety and long operating life posed by charging errors, and describe the techniques used in charger design to prevent these errors. We’ll also identify some of the governing standards. This information may be of value both to those designing battery chargers as well as those who are specifying battery charger products. Read the full article…
Selecting An AC Line Filter For Switching Power Supply Applications While guidelines have been written on how to select EMI line filters, many system engineers still aren’t aware that they need EMI filters. When they do realize they need one, they often select a filter without regard to their actual filtering needs. They may also ignore the impact of the filter on other requirements (such as leakage current), and issues such as customer support. In this article, the authors identify some of the popular bad practices being used to choose EMI line filters, explain why they’re wrong and provide a quick guide to proper filter selection that will help designers avoid the common pitfalls. They identify the key criteria you’ll need for filter selection including rules of thumb and key specs that will guide designers in making good choices. Armed with this information, designers will be better equipped to apply the EMI selection guides and tools already available. Read the full article…
Explaining The ROI Of Compliance Efforts To Your Colleagues In this column, we frequently stress the need to plan for compliance requirements—all types including safety, EMC, energy efficiency and environmental/restricted materials—early in the product design cycle or process. We stress the need to know the requirements and to perform pre-compliance testing as you go through the different design stages. But knowing we should do these things, and getting our companies to agree to do them are different things. So often there is resistance from other members of a design team, or other colleagues in the organization, to take the necessary extra steps to ensure that compliance needs are considered throughout product development. How do we overcome this resistance? A paper presented at the recent IEEE EMC + SIPI 2019 conference provides guidance on how compliance advocates can convince their colleagues in engineering and management of the value, or more specifically, the return on investment (ROI) of addressing compliance needs early and throughout the product design process. Read the full article…
Will Your Products Be Ready For Next Wave Of European Efficiency Regulations? In a previous Spotlight on Safety & Compliance column, the author alerted designers and product planners that products sold in Europe would be required to have continuously higher efficiency to comply with 2020, 2030, and 2050 EU reduced energy consumption requirements as compared with the 2016 estimated EU power consumption level. The EU Commission created two framework directives: Ecodesign, and the corresponding Energy Labelling, which have driven efficiency improvement in the appliance category products over the past two decades. Resulting product efficiencies have increased by 40% in some cases. Read the full article…
Forms Vs. Function: Battling The Paperwork Deluge On Restricted Substances Almost once a week or more the phone rings or an email arrives, usually from a top name brand company or on behalf of one, asking about our product’s compliance with environmental and hazardous materials regulations. I [Kevin] work for a semiconductor manufacturer, so the requests concern components we’re supplying to a customer. But anyone supplying any components, subassemblies or finished electronic instruments or equipment could be subject to such inquiries. The request comes from a far off land because it’s been outsourced to someone to get a form filled out. The good news is that people are paying attention to restricted materials regulations. However the bad news is that many customers are inflexible in the way they work with their suppliers to gather the needed information. In this article, the authors describe the problem, suggest some possible solutions, and point to some helpful resources. Read the full article…
Measuring Common-Mode And Differential-Mode EMI Currents Line-conducted EMI current is composed of two elements: common mode (CM) current and differential mode (DM) current. Either one of these contributors to line-conducted EMI may be responsible for a unit failing EMC testing. And without knowing why a unit is failing, coming up with a solution can become a time-confusing exercise in trial and error. On the other hand, by measuring CM and DM EMI currents separately, engineers can identify why their products are exceeding the specified EMI limits and quickly tailor an EMI filter solution to pass EMC testing. Although the techniques for measuring CM and DM currents are well documented in the literature, many power supply engineers are still unfamiliar with them and therefore do not make these measurements. In this article, the authors review the literature regarding measurement of CM and DM EMI currents, offer an overview of the different measurement techniques and point to the references where readers can delve more into the details of making the measurements. Read the full article…
An Introduction To Medical Regulations: Understanding The 60601 Standard This article aims to give an initial introduction to the rules and regulations that govern safety and compliance in medical equipment. This basic information does not go into details of medical power supplies. Rather, an attempt is made to enlighten those not familiar with the medical regulations and standards, including designers and specifiers of medical power supplies. In particular, we aim to shed light on the importance of medical equipment immunity from radiated and conducted electromagnetic emissions. Medical regulations are complex because they apply to the safety of both patients and medical practitioners. The 60601 standard, which is the focus here, applies to most locations throughout the world, and anywhere medical equipment is used: operating rooms, hospital rooms, intensive care units, nurseries, senior care facilities and even households. Read the full article…
Pre-Compliance Testing Is Necessary For All Products For some companies, pre-compliance testing may seem like a source of unnecessary expense or extra steps in an already time-constrained product development schedule. Or it may be something they’ve given no thought to at all. But when the risks associated with not performing pre-compliance testing are considered, it becomes clear that pre-compliance testing is a means of avoiding unwanted increases in product development cost. Pre-compliance testing alerts the design, engineering management and marketing teams that an issue may be lurking in the weeds and informs them of the potential problem before the product ships. By applying pre-compliance testing prior to production, excessive redesign costs, and production delays can be avoided. Read the full article…
Knowing The Link Between Product Regulations And Product Standards Can Put You Ahead Of The Competition A regulation is a rule or directive created and maintained by an authority such as a country, federation of countries, states, or provinces. Enforcement is by law. Content is available to the public for free. A standard is a document created by consensus and approved by a recognized body or organization for common or repeated use. Standards may be international or regional. Most standards are available to the public for a fee levied by the organization. Enforcement occurs when a label is attached to the product indicating compliance. Regulations precede and influence certain performance and test standards. This article explains how company standards staff and design engineers can monitor and influence a regulation far in advance of any standard(s) creation thus better positioning their company products for success under the new regulation. Beginning with an historical example, the author chose the European Union (EU) and the relationship between the Ecodesign efficiency regulation and the relevant IEC standard(s). Read the full article…
Materials Compliance: Just as Critical As Electrical Safety & EMC For most power electronics engineers, and perhaps for hardware designers in general, environmental regulations have not been high on the list of design considerations. Other compliance requirements have usually demanded more attention. But that situation may be changing and now even power supply designers may need an awareness of the regulations governing restricted materials. According to one expert who spoke at a recent webinar on materials compliance in electronics, in terms of recall issues, materials compliance deserves the same priority as electrical safety and even more than EMC. The materials compliance area is expanding in scope and the repercussions of not meeting the standards are higher than ever before as the authors explain. Read the full story…
Roadmap Charts Compliance Trends And Requirements For Power Supplies The Power Sources Manufacturers Association (PSMA) devotes a section of its Power Technology Roadmap (PTR) to reporting on relevant trends in power supply safety and compliance. For those unfamiliar with the PTR, it is a document published every two years “to provide a consolidated outlook of trends in power conversion technology for the next two to five years.” In the latest version of the roadmap, PTR 2019, which is due to be released at APEC, the section on Safety & Compliance describes how power supply compliance has become more challenging since the last PTR was published. Although certain requirements such as those for safety and EMC, have always been in conflict, it has become harder to strike the necessary balance in power supply development as both the safety and the EMC requirements become more stringent. There are also more stringent environmental requirements coming from RoHS, WEEE and conflict material legislation. Read the full story…
Proper Design Of The Power Supply’s Input EMI Filter Protects Against Power Line Transients In this article, author James Spangler examines the standards that address a power supply’s ability to withstand ac power line transients including those induced by lightning. He shares the results of his research on what standards apply and how they were developed. He then discusses the role that the EMI filter stage plays in providing protection against power line transients and how designers can determine whether changes or additions to this protection are required to meet the applications’ requirements. Read the full story…
Low-Wattage Energy Efficient Power Supplies Got Their Start In White Goods This article recaps how the process for developing energy efficient low-wattage power supplies began with the energy systems used in refrigerators back in the 1970s. Besides giving some insight into how low-power energy efficient power supplies developed, this article will help to explain how appliances became energy efficient. It also discusses why there are no efficiency standards specifically for the power supplies used in white goods. Read the full story… Isolation Standards Say Little About Isolator Performance There is confusion concerning which standards apply to the various types of optocouplers, optodrivers, and isolators used in gate drive and power supply circuits. There is also a general misconception that isolation standards set requirements for isolator performance beyond the input-to-output voltage isolation. In this article, the authors review the different isolator device types, identify some of the major isolation standards, and then discuss the requirements imposed on the different isolator device types. Read the full story…
The DoE Views USB Chargers As External Power Supplies The authors recently discovered that the USB-powered battery charger used by their cell phones and tablets is considered an external power supply (EPS), and not a battery charger under DoE rules. This became clear when reading the result of the appeals submitted to the DoE by a number of companies who charge the internal batteries using a USB Power Delivery system. This articles analyzes this ruling, discusses why USB chargers are viewed as EPSs, and what constitutes a battery charger under DoE regulations. Read the full story… ISPCE 2018 Drilled Deeply Into Today’s Compliance Issues In the vast world of conferences there are only a handful centric to the areas of safety and compliance as relevant to the electronics field. The annual IEEE Symposium on Product Compliance Engineering (ISPCE) is one of these events. In fact, for those with a stake in safety and compliance issues, it’s a must attend event. Kevin was among the approximately 250 participants at this year’s symposium in San Jose where ISPCE addressed all of the proximate issues in this field. Read the full story… Beware The Pitfalls Of Power Suppy Hipot Testing A dielectric withstanding voltage test—commonly referred to as a hipot test—determines the ability of equipment with an installed power supply to protect against electrical shock. However, for switching power supplies, the hipot test should be considered a destructive test. This article explains why that’s the case and how power supply users can avoid damaging power supplies through improper application of hipot tests. Read the full story… Level VI DoE Rules And Regulations For External Power Supplies—Where To Find Them The DoE energy efficiency standard currently in effect for external power supplies (EPSs) is known as Level VI. Although we have seen a number of articles stating the rules in some form, they do not provide a reference to where the rules are located and typically omit many details concerning their application. This article provides the URL where designers can actually find the Level VI energy efficiency rules with some discussion on related information. Read the full story… New Isolation Technologies Close The Gap With Optos On Compliance This year, the subject of isolation received special attention at APEC 2018 in two industry sessions and in a lively rap session where the merits of magnetic, capacitive and the incumbent optical isolation methods were debated. One of the key takeaways from these sessions was that alternative technologies are supplanting optocouplers in new designs. If you’ve not paid much attention to the new isolation technologies up until now, you might want to take another look. Read the full story… PCB Board Layout Is Critical When The Power Supply And MCU Live On The Same Board In many simple industrial and consumer products there is printed circuit board (PCB) that contains both a microcontroller (MCU) and a simple off-line power supply. In such cases, there are typically two sources of EMI: line conducted EMI from the power supply and radiated EMI from the MCU. When there is a failure in EMC testing, the customer’s first reaction is often to blame the power supply. But very likely, it is not the power supply causing the failure, but rather a poor PCB layout that caused the data lines to radiate. After reviewing some of the basic requirements of PCB design, we go step-by-step through the details of layout of a PCB for an MCU. Read the full story… A Power Supply Can’t Fix All EMC Woes, Yet Partnering With The Right Power Supply Experts Early Can Recently I was called by a customer who was failing EMC in the test lab. They were using one of our competitor’s power supplies and we had been talking with them about using ours. It was hard to ascertain if our pitch was falling on deaf ears or not. But now, with their product failing compliance testing, suddenly we were important to them as evidenced by them calling me after hours. With their product in the test lab there was real urgency as the money meter was running with the test lab charging them by the hour as the customer tried to get their product to pass EMC. This is their story and the lessons learned. Read the full story… The Next Stage Of The Design Specification For Production: Energy Efficiency This article is written to supply information on energy efficiency standards, which may be needed to complete the design of your product. Marketers and anyone who creates new product specifications need to review the energy efficiency specifications, before sending the document(s) to the engineering department. In this article, we introduce a specialized, free energy efficiency database that engineers can access to determine which energy efficiency requirements apply in their power supply or end equipment applications and also to keep up-to-date on changes in these requirements. Read the full story… Getting to Know IEC 62368-1—How Does A TV/Stereo Standard Affect My Industrial Power Electronics Design? The prescriptive requirements of IEC 60950-1 intended for information technology equipment have existed for a long time. Independent of IEC 60950-1 is the IEC 60065 specification, which applies to audiovisual equipment, projectors, TVs and similar equipment. Now this is all changing as these two standards are being harmonized into a hazard-based specification known as IEC 62368-1. As with 60950-1 and 60065, the scope of 62368-1 includes internal and external power supplies. As the deadlines for transitioning to this new standard approach, power supply designers need to come up to speed on 62368-1 requirements. Read the full story… Understanding LISNs Is Essential To EMI Pre-Compliance Testing A line impedance stabilization network (LISN) is a circuit used for testing power supply line conducted emissions produced by either a power supply or some other type of product that contains a power supply. Since there are multiple standards that require conducted emissions testing, if you are designing power supplies, chances are you’ll need to know enough about LISNs to perform pre-compliance testing of your product. In this column, the authors explain the basics of how LISNs work and are used, identify some of the applicable standards, and then analyze the differences between the LISNs specified by two FCC standards to help engineers understand when these differences affect testing and when they don’t. Read the full story… Power Supply Standards: Which Ones Apply In Your Application? When an engineer begins a program, one confronting issue emerges—which standards or regulations must the product meet? The number of potentially applicable standards is quite large, covering a range of issues including safety, energy efficiency, electromagnetic compatibility, material toxicity and environmental considerations. In many instances, multiple standards apply, are sometime conflicting, and are often changing. These challenges motivated creation of the PSMA’s Safety and Compliance database. Here in this first Spotlight on Safety & Compliance Column, Kevin and Jim take readers on a tour of the database. Read the full story… About the Authors of How2Power Today’s Spotlight on Safety & Compliance
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Workbench Troubleshooting EMC Emissions (Volume 2): Simple Techniques for Radiated and Conducted Emissions Troubleshooting and Pre-Compliance Testing (EMC Troubleshooting Trilogy), Kenneth Wyatt, available from Amazon, 2021, 240 pages.
Power Supplies Explained, Paul Lee, G3ZKO, published by the Radio Society of Great Britain, September 11, 2018, 531 pages, $24.95 from ARRL, also available for Kindle from Amazon.
Kevin Parmenter is an IEEE Senior Member and has over 20 years of experience in the electronics and semiconductor industry. Kevin is currently vice president of applications engineering in the U.S.A. for Excelsys, an Advanced Energy company. Previously, Kevin has served as director of Advanced Technical Marketing for Digital Power Products at Exar, and led global product applications engineering and new product definition for Freescale Semiconductors AMPD - Analog, Mixed Signal and Power Division. Prior to that, he worked for Fairchild Semiconductor in the Americas as senior director of field applications engineering and held various technical and management positions with increasing responsibility at ON Semiconductor and in the Motorola Semiconductor Products Sector. Kevin serves on the board of directors of the PSMA and was the general chair of APEC 2009. Kevin has also had design engineering experience in the medical electronics and military electronics fields. He holds a BSEE and BS in Business Administration, is a member of the IEEE, and holds an Amateur Extra class FCC license (KG5Q) as well as an FCC Commercial Radiotelephone License. 
James Spangler is a Life Member of the IEEE with over 40 years of electronics design experience and is president of Spangler Prototype Inc. (SPI). His power electronics engineering consulting firm’s priority is helping companies to place products into production, assisting them to pass government regulations and agency standards such as UL, FCC, ANSI, IES, and the IEC. 
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