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Issue 44 May 1, 2012
Laurent Desclos Ethertronics
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TA B L E O F C O N T E N T S TABLE OF CONTENTS
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Laurent Desclos ETHERTRONICS Interview with Laurent Desclos - President and CEO
Featured Products Understanding Wireless Power - Part II BY DAVE BAARMAN AND JOSHUA SCHWANNECKE WITH VLSI
9 11
Adaptive inductive coupled mid-range systems provide the flexibility needed for a dynamic wireless system.
Characterize Linear Voltage Regulators with an SMU
19
BY ROBERT GREEN WITH KEITHLEY
How source measurement unit instruments can make the job of characterizing linear voltage regulators much easier.
RTZ - Return to Zero Comic
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INTERVIEW
Ethertronics
Can you give us background about yourself and how you got into engineering? When I was in high school, my older brother brought some electronic kits home. I was following him, trying to
understand how they worked. Later on, in order to have some pocket money in college, I went to work for a friend in an appliance and radio repair shop. Sometimes I would use what I was learning during the
Laurent Desclos - President and CEO
day, and try to implement it during the weekends. I learned a lot at that time from my teachers and friends. I graduated from the National Institute of Applied Sciences in France with a degree in electronics. After that, I went on to perform my civil duties in Gabon, Africa for a year and half. I was there as a teacher, helping students prepare for French engineering schools’ entrance exams. At the same time, I was given the opportunity to work on the national telecommunications network and earth stations in Africa. It was fun and I had the chance to go into the jungle to check on telecom sites and perform maintenance, as well as become familiarized with basic telecom knowledge. It was my first taste of being abroad and getting to know a different culture. I then came back to France for three years to pursue a PhD in
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FEATURED INTERVIEW
Laurent Desclos
INTERVIEW
At the end of my PhD, I wanted to work abroad again. I got a job as a researcher at NEC Japan and designed a few components at 24 GHz and 60 GHz for their wireless LAN division. I had a lot of support and freedom to do really cool stuff, but at that time, I think I was young and not ready for the cultural shock. I stayed there for about one and half years and then decided to come back to France, where I worked for two years for the French Army through a consulting company. I was studying Electromagnetic compatibility for new systems and their influence on the civilian world, as well as the implication of the newly deployed DCS system on the radio relays already in the field. I learned a lot on the propagation models and systems at that time. I also had a few interactions with SFR, or Bouygues Telecom, when they just started their deployment. Nobody at that time had a cell phone in France, which was funny. After two years in France, I was contacted by NEC Japan to come back. Since I was a better negotiator and also a bit more mature, I negotiated a position doing GaAs design at 60 GHz, managing a group designing front-end and components in CMOS and BiCMOS, and also started my own little lab on antenna research.
Was this the first time you became self-employed? We worked independently, but were funded by NEC. It was a really fun time. We were the first ones to develop a working solution, which was an RF transceiver for 2.4 -5 GHZ applications. My boss at that time gave me a lot of freedom and
Ethertronics is like a big university for new engineers with support from proprietary tools and experienced engineers. I learned and produced quite a lot. We had several successes and published and patented a few things that are still used. Then we transferred the lab to the research center in Princeton, New Jersey. I went to Princeton for a year, and then was contacted by one of my former students to join Ethertronics. I accepted right after meeting the two founders. That’s pretty much where I started with Ethertronics in 2000. Tell me a little about Ethertronics--what’s your mission and the industry you are targeting? We are targeting the whole wireless industry. All wireless devices need antennas. From the beginning, the vision of the company has been to create a better user experience.
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We started as a company focused on providing good support for our customers (OEMs, ODMs) by manufacturing antennas to meet their mobile device needs. It was around the 2005-2007 timeframe when we saw that the device form factor was shrinking while the number of bands to cover was increasing. We needed to develop better antennas to deal with these smaller form factors. We knew that we needed to transition from traditional passive antennas to antennas that had more of a systems perspective in mind, since this is critical for next-generation devices. We knew that we needed to support our customers not only on the antenna side but also on the system side. Much of our focus since that time has been on developing active antenna systems, whereby the antenna system and modem interact with each other to provide more “smarts” to the RF system. On the system side, it is interesting to bridge the gap for us on the multidisciplinary level, including antenna software, chip and communication system levels. I am very much convinced that there is a place for a company creating this ecosystem. Do you find that most of the antennas you design are custom designs for an application, or final products that people design in? We offer both custom and standard antennas. Most of the designs are custom, based on the OEM’s needs. Cell phones all have different designs, with components such as the speaker and camera in different locations. We consult with the OEM to come up with the best antenna
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FEATURED INTERVIEW
electromagnetism, applied to radar cross section. At the same time, to support my family as well as my curiosity, I taught electronics at the same college that I graduated from. Additionally, I took a job in IT support and worked for fun on the design of some chip on GaAs.
INTERVIEW
Of the markets for which you design antennas, what is your largest? The cell phone market is our biggest. Last year, it was about 80% of our total business. Where do you think the wireless market will be expanding into and what type of market are you hoping to capture in the future? Cell phones have been around for a long time and will continue with good growth. I think that the M2M market is an interesting one. More and more people are coming up with new applications for wireless all the time. With the increasing number of wireless devices, there is more demand to be able to coordinate all of these different devices operating within a given room. Antenna Systems will be very important as they are better able to coordinate the multiple signals from different devices. I think the medical field also has a lot of growth potential. Do you have a lab where you work on your antennas or do you use outside labs for that? We have design centers around the world allowing us to be close to our customers. Our headquarters
are in the U.S., with design centers in China, Korea, Taiwan, and Denmark. Ethertronics is structured as a global platform company, where everything is similar for the customer regardless of the location. All of our facilities have their own internal labs to characterize antennas. Each site is equipped with the same classical equipment
With our combination of experience and simulation tools, we can foresee issues within the device’s design and help our customers to resolve them. including anechoic chambers (near and far) and network analyzers; making it easy to pass projects from one office to another. The main R&D work is done at the corporate headquarters in San Diego. Additionally, our offices in Korea and Taiwan and to some extent China and Denmark also support R&D efforts. So you have multiple worldwide offices? Yes, that was one of the things that we targeted when this company was started. We wanted to make sure that we were close to our customers and the products throughout the
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entire design process. Let’s take for example a customer in Europe. They may start the design there, but then they need to transfer the design to an ODM in Taiwan, and then they transfer the manufacturing operation to China. So you need to be able to follow your customer through the entire process and provide them with the highest levels of support every step of the way. It’s kind of interesting because it needs to be seamless to the customer, but they need to know that you are there at every step of the process. When we started, we were three people. Now we are more than 190 people, with more than 80 percent as engineers, across the globe with manufacturing support in Korea and China. Can you tell us about some of your numerous patents? Any time you are awarded a patent, it is novel. I have more than 130 patents issued or pending. One of my first patents was during my PhD; addressing devices for blind people. Approximately 20 of the patents were with NEC. For Ethertronics, I don’t see them as just single patents with a single innovation. Instead, I see them more as building an edifice. What is more important than the number of patents is the strategy behind them. How they all work together and defend the “Ethertronics territory” against competitors. For Ethertronics, it was an interesting exercise. While building the company as a global platform company, I was also building a patent strategy based on where I foresaw bigger companies and competitors going.
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FEATURED INTERVIEW
design for their device’s layout. It’s almost like you become not only a design engineer but also a service engineer; consulting with them on where to place the antenna and all other components in the device so that they have the best device in the end. We also offer standard, off-theshelf antennas for M2M, medical, security and many other markets.
INTERVIEW
Do you use simulation tools to characterize the antenna when you are designing? We have our own proprietary IMD (Isolated Magnetic Dipole) antenna technology. IMD is a self-resonant antenna and as such, doesn’t suffer from surroundings as much as other antennas. It is scalable for different frequency bands. We understand how IMD works and how it interacts within the device. We use internal, proprietary simulation tools that allow us to simulate the environment for the antennas.
One of the problems in the industry is that people don’t understand the tools that they are using, and they don’t understand the disconnect between the antennas and the products they are designing them for, how do your simulation tools help to solve this problem? Our simulation tools help us to scale quickly and assist new engineers learning the technology. Ethertronics is like a big university for new engineers with support from proprietary tools and experienced engineers. As the new people get more design experience under their belts and understand the technology better, they don’t need the simulation tools. As their experience continues to grow, they then help the next generation of new engineers to learn the technology.
them. What direction do you see your business heading in the next few years? In December, we hit the 500 million unit mark for shipped antennas. We see a significant amount of growth over the next few years. However, I want to control the growth and not become an integrator or a “part slapper.” We are really oriented toward the future and solving issues for our customers. Applied R&D orientation is always a good direction for us. This is a critical time for our business. Our patented active antenna systems solutions set us apart from other companies in the space. ■
With our combination of experience and simulation tools, we can foresee issues within the device’s design and help our customers to resolve
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Ethertronics’ early patents were based on passive antenna solutions and some active antennas around switching and hardware. Now the patents are much more elaborate and are focused on the RF system including chips and algorithms. Integration of antennas into the RF system is paramount for success of advanced mobile devices.
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F E AT U R E D P R O D U C T S STMicroelectronics, a global semiconductor leader serving customers across the spectrum of electronics applications and the leading supplier of MEMS (Micro-Electro-Mechanical Systems) for consumer and portable applications 1, today unveiled the world’s first motion sensor that measures very high accelerations along all three axes at ultra-low current consumption. ST’s H3LIS331DL accelerometers address the need for precise shock detection up to 400 g2 in space- and powerconstrained applications, from car black boxes to medical monitoring devices and sports equipment. There is a need to detect and measure high-g shocks in a broad range of applications. Whereas existing high-g shock-detection solutions are mostly based on single- or dual-axis, power-hungry ‘airbag-type’ sensors, ST’s new high-g accelerometers deliver both the threedimensional precision and ultra-low current consumption optimized for battery-operated applications.For more information, please click here.
Pico Projector System Solution Intersil Corporation, a world leader in the design and manufacture of high-performance analog and mixed signal semiconductors, introduced the Pico-qHD™, the world’s lowest cost pico projector system, and the industry’s smallest production-ready LED-based LCoS Pico Projector solution. Developed for low power and cost-sensitive embedded or accessory pico projector applications, Intersil’s Pico-qHD provides a fully integrated reference design that includes a high volume production optical engine, hardware, firmware and customizable design files. The low cost system solution utilizes Micron’s E330 compact 5.5 cubic centimeter qHD optical engine , allowing for easy integration into a wide range of applications, including Micron’s recently announced portable PoP Video™ pico projector mobile device accessory. Built on an inexpensive 1.7 inch by 2 inch PCB, the Pico-qHD is designed to meet the low manufacturing cost requirements of consumer applications such as digital cameras, smartphones, tablets, video players and other handheld products. Driven by such applications, Pacific Media Associates forecasts pico projector sales of 58 million units per year by 2015. For more information, please click here.
RF Multi-Measurement Signal Analyzer LEDtronics®, Inc., the industry’s most innovative LED lamp manufacturer since 1983, announces a series of T5 tube-style LED lamps as direct replacement for 12V xenon and halogen T3/T4 subminiature glass bulbs from 4 to 15 watts, including Xenon 1205X (5W) and Halogen lamps 774 (8W), 891 (8W, 12.8V) and 773 (8W). The LEDtronics LEDG4BP-2W series of lamps work with high-frequency power supplies for 12VDC or 12VAC, and consume only 0.8 watts at 12VAC, and 1.4 watts at 12VDC voltage input — this adds up to 90% reduction in power consumption. These subminiature lamps come with a dual-pin G4 base and are available in 3000K warm white or 5500K pure white light colors. They are a perfect fit in applications such as pendant lamps, under-cabinet lighting, landscape lighting, electric signs, scoreboards, step lights, puck downlights, RVs, boats, car bulbs, ceiling fans and anywhere T3 or T4 halogen bulbs are used. A removable 5.2mm lead spacer is included. For more information, please click here.
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Understanding Wireless Power PART 2 Dave Baarman Director Of Advanced Technologies
Joshua Schwannecke Research Scientist
ADAPTIVE INDUCTIVE COUPLING Adaptive inductive coupling leverages the physics of magnetic induction. However, the technology is presently applied in near-field and mid-range configurations at the highest design efficiency in applications of less than several inches. This tunes the power and coils closely to realize performance levels comparable to present wired power usage while charging or powering devices at the present wired rates. Near-field adaptive inductive coupling has proven that tuning improves system Q dramatically which, in turn, maximizes the system efficiency. This is also understood as a critical factor for maximizing the magnetic field and therefore transfers power as discussed above. If systems are NOT being tuned to account for almost every situation, the physics behind wireless power is NOT being maximized. This is the primary issue that prevented Tesla and other early pursuers of the technology from succeeding. The difficulty of realizing the influencing factors in highly resonant systems is very subtle. This same methodology can be applied when the transmitter and receiver are highly tuned as in mid-range wireless power systems.
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Adaptive inductive coupled mid-range systems provide the flexibility needed for such a dynamic system. Another value of adaptive coupling systems is that they can provide power more efficiently at any distance. Tuning any of these systems for maximum performance in a given operating environment improves performance. Without this capability, the depth and breadth of applications becomes limited because the cost of efficiency is not only measured in the cost of additional parts but also in the operating cost. Social pressures amplify this as the sheer number of devices could have a significant global impact if this is not taken into consideration. One of many consumer expectations for wireless power is that wireless power transmitters for laptops also power cell phones, headsets, MP3 players, toys, and many other devices. This becomes a tuning and power control issue allowing devices to receive the necessary power required for each device. When this is considered in terms of broadcast power, the maximum power needs to be available while the other devices become less efficient. The same is true with close proximity with the
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TECHNICAL ARTICLE
MEASUREMENT AND UNDERSTANDING Figure 1 below represents one of the most challenging aspects of wireless power at low voltages. In the ACto-DC power supply or charger, low voltage along with typical semiconductor losses are some of the most significant losses. Notice this is measured from the wall to the battery or load for a complete picture. Losses occur at each of these junctures A1, A2 and A3 respectively.
–
Line Voltage
(120v-60hz)
A1
–
+
V1
+
–
–
+
V3 –
A3
Battery Cell
Figure 1: Measuring a traditional low voltage system and contributing losses.
There has been a lack of understanding regarding the efficiency of systems, most especially near-field, faredge or mid-range and RF wireless power systems. Current measurements are based on conversions and/ or coil-to-coil efficiency, which would exclude other key system factors that greatly impact the efficiency of a total solution. The full system must be considered to give a clear picture of actual efficiency to consumers (see Figures 2, 3 and 4 below). These measurements are a key factor in which wireless power types are judged in terms of global feasibility and mass adoption.
Ongoing work is seeking to improve and innovate solutions while citing the most influential published resources available today. The following is a very basic summary of some of this work. • RF Harvesting
–
Charge Controller
V2
DC Supply
A2
+
Efficiency
• 94+% at 1.4KW at 8mm (AC to AC load system eff.) 11, 12
+
THE HIDDEN CONCERNS WITH WIRELESS POWER
• Near Field – AC to AC
+
As with broadcast power, orientation can be an issue for adaptive inductive coupling. Using multi-axis coils or arrays to maximize omnidirectional coupling as well as the position within the field and high Q can minimize gaps. However, with adaptive inductive coupling, some of these challenges become significantly easier. To illustrate the complexity of the challenge when considering broadcast solutions, consider current cellular reception and other RF communications. This becomes even more complicated when placing coils or arrays in a device. Device shielding used to meet other regulatory requirements becomes effective in limiting wireless power performance. Placement and proximity to other materials and devices limits the performance and alters coupling to the source. Using near-field or mid-range configurations can offer many implementation solutions while securing a surface for transmission and reception of power in a known configuration in which both manufacturers and consumers are familiar. When this is expanded over distance, the difficulty of guaranteeing power is compounded by these complications and burdens device manufacturers with an additional layer of design considerations. The future will most likely offer additional solutions, but the eminent solution is to control some of these variables as we simplify the implementation. Meanwhile, these additional considerations are just being realized and may impose additional limitations to the design requirements.
• 75% at 60 Watts at 1m (coil to coil eff.) 9, 10
WIRELESS POWER
AC Input
Rectifier
Drivers
Coil
Controller
Current Sense
Coil
Voltage Conditioning
Load
• 50-70% at <100mw (conversion eff.) 3 • Near Field (far edge) eff. between source coil and load 4 • 50% at 60 Watts at 2m (coil to coil eff.) 5, 6, 7 – 15% (AC to AC load system eff.) 8
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Communications and Monitor
Figure 2: Conversion is important, but only in one part of the system. A typical measurement referred to in RF systems.
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TECHNICAL ARTICLE
exception that power for maximum efficiency with each device can be managed independently. Think of this as a power control and communications channel.
TECHNICAL ARTICLE AC Input
Rectifier
Drivers
Coil
Coil
COIL to COIL Controller
Current Sense
Figure 3: Coil-to-coil efficiency or coupling factor is very important but is only one part of the system.
AC Input
Rectifier
Drivers
Controller
Current Sense
Coil
Coil
AC to AC SYSTEM
Figure 4: System efficiency has many elements that directly effect overall efficiency numbers, and the full system must be considered to give a clear picture of capabilities.
PERFORMANCE Along with efficiency, performance is arguably the most important factor in bringing wireless power to a mass market. The consumer solution is the greatest challenge wireless power faces. Providing a “wow” factor while keeping a solution safe, affordable and easy to use is a barrier for complex technology solutions. The variability of consumer use cases, environments and user habits form yet another layer to the challenge. Regardless of whether broadcast or adaptive coupling systems are leveraged, the solutions will need the ability to adapt and respond to the myriad of variables associated with performance, which will be generated at the consumer level. If the technology does not have this capability to adapt, the technology and, ipso facto, the industry will be limited in its ability to meet demand and provide value. THE IMPORTANCE OF A STANDARD IN UNDERSTANDING WIRELESS POWER Given the unique features and benefits of both broadcast and adaptive inductive coupling solutions, as well as the recent case studies surrounding other globally accepted technologies like Bluetooth™ and Wi-Fi™, the logical course of action is to evaluate and agree on the most effective wireless power solution(s) to ensure rapid, mass
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Without a standard to converge the consumer demand with a technical solution, wireless power simply presents more adapters and power supplies that are not interoperable – more cords, cables and adapters that are limited by their usage without diversification across products and brands. THE MANUFACTURERS POINT OF VIEW There must be an engagement of equipment companies to understand and integrate wireless power worldwide. This is an essential yet time-consuming step. Each manufacturer has stringent requirements that forge new technologies into real industry solutions. A technology that appears to be a solution in the lab may have significant issues integrating into product, coexisting with other technologies and meeting regulatory or companyspecific standards. Without this step, a technology can only advance if viable solutions are realized. It can take years to fulfill these requirements as each respective company has a lot at stake if these efforts go unfulfilled. Consider the technological readiness level as an enabling or limiting trigger. This process is amplified as multiple companies introduce overlapping and extended expectations which further refine the end solution. The ability of a technology to survive this gauntlet is the very essence of enabling adoption. The lessons learned then fold back into the standard—teaching others to execute while allowing invention. In an effort to position in the marketplace, some technology companies attempt to forgo this process as it is expensive and time-consuming. This can position a technology well within consumers’ eyes yet fall short of both consumer and manufacturer needs. We have all seen immature technology that fails to deliver or meet the unspoken expectation. Only a few technologies are so successful that they dictate the market, which is usually company-specific and does not require collaboration from other companies. In order to have the highest integrity in a technology solution, embracing this gauntlet and knowing these requirements for success is imperative. Attempting to circumvent this process does little more than delay scrutiny and limits the market at the same time.
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adoption, which is already in motion through the efforts of the members of the Wireless Power Consortium13.
TECHNICAL ARTICLE
ADAPTIVE SOLUTIONS Adapters must be viewed as bridging solutions for legacy products and development of supporting infrastructure. This has a specific market size and function for people to test and experiment. This market represents a very small portion of the device market, yet it serves a very important role. It provides an arena for additional functions and designs to educate and delight consumers. However, if these solutions are NOT interoperable with a standard, they will limit their own ability to penetrate the market and will ultimately frustrate consumers who are looking for a universal, interoperable solution. INFRASTRUCTURE These market segments require a key component to drive adoption and one overarching unspoken trigger. The key component is a standard. As each manufacturer starts down the development road, they commit design, intellectual property and resources to a momentum in a specific direction. This adds to the device manufacturer’s gauntlet as these infrastructure manufacturers add additional consumer need, regulatory requirements and company-specific requirements. The technology must hold up to these consumer and manufacturer needs to be validated for product viability in infrastructure. This creates a convergence of requirements that should be introduced as important elements to further refine a standard. If independent developers and proprietary device manufacturers overlook this very important consideration, the rate of mass adoption for wireless power may be severely limited. The overarching unspoken trigger is the momentum of solutions within the massive space of device and infrastructure manufacturers. At some point, the number of adopters moving forward will drive the tipping point. When this happens, adopters will look for stability in the technology and solution offerings. A global standard with major manufacturer participation delivers the message that they overcame a large number of challenges and that there is an organization in place to address future challenges and the evolution of the technology. This
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clarity will give infrastructure manufacturers confidence in investing in a viable solution, which will ultimately translate to adoption. CONCLUSIONS Wireless power solutions today provide hope for additional freedoms in the future, but many hurdles still stand in the way. Some of these hurdles will be adjusting to the wide range of expected operating requirements yet undefined by consumer use. Meanwhile, consumers are looking for simple comparisons within the advancements of wireless power technologies, while a steady stream of media confuses coil-to-coil efficiency or conversion efficiency with system efficiency, which is a dramatic misconception. It must be recognized that wireless power is making the transition from a technology to an industry – products are commercially available, and a wireless power standard is evolving. In the near term, consumers will both accept and adopt more products. Though the real stability of any one technology is defined as a solution that allows the most flexibility through multiple commercial applications while meeting consumer expectations, the ultimate scenario is for the best solutions to meld together as wireless power evolves as a whole. As scenarios continue to play out and the industry continues to be defined, there are several key considerations that need to be fully explored: • The safety of broadcasted power remains unknown. Research and additional studies continue to pour in with oftentimes confusing or conflicting results that appear to be inconclusive. Close proximity wireless power can be designed to be as safe as existing power supplies allowing a conservative first step in the evolution of wireless power. • Range of power or scalability can be addressed with near-field technologies, but broadcast power harvesting is somewhat limited by regulatory standards as a supplemental source of energy requiring the device to be very low in power or tightly shielded to the surface. Regulatory issues may also play a significant role in broadcasting power. Present rules may not be the long-term regulations as these technologies are tested, but they are the rule today. The compliance and compatibility of wireless power
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This is not to say that other technologies and methods will not evolve in this very same way. However, the surest approach to increase the likelihood for mass adoption involves engaging key influential technologies that are suitable for market demands.
Primary
Secondary 1
Secondary 2
TECHNICAL ARTICLE
Diameter
TECHNICAL ARTICLE
Secondary 3
Peak Efficiency
1 Diameter
2 3
Distance
Distance
Primary
Secondary 1
Secondary 2
Secondary 3
Diameter
Diameter
Figure 5: Shows that distance impacts coil to coil efficiency. This also shows that for all near-field or mid-range systems a peak efficiency range is fairly close proximity although the range is extended. This figure is not drawn to scale.
Distance
1
2
3
Distance
Figure 6: Shows a simple example of maintaining efficiency by comparing several progressively larger coils to achieve the same level. This figure is not drawn to scale.
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• Efficiency is a crucial aspect of almost any wireless power system. It will define usage, reliability, cost, integration size and mass adoption appeal. Efficiency is being compared in many ways in an attempt to understand the wireless power opportunity. It is important to understand this matrix of offerings within the limits, capabilities, complicating factors and range of use. With that being said, it is apparent today that the highest efficiency possible is desirable. It seems logical to assume that the highest efficiency will not be achieved without intelligence and adjustability in any case or technology mentioned. Performance versus impact will always be a commercial decision within this realm. It is important to understand that efficiencies powering actual product account for additional systems and losses that are typically not represented in laboratory or advertised numbers. This can lead to misleading assumptions and comparisons. It is important to understand these predictably elusive aspects of wireless power. • The system coil geometries discussed earlier show that anything not matched very well will have additional system losses. These ratios determine part of the final system efficiency. A system’s ability to tune the needed elements will be a critical aspect of future designs to maximize system efficiency. • Although many exciting applications are imminent, the most practical implementation of mid-range inductive power technologies appears to be moving closer in proximity for stability in the system, installation, use case and environment. This is also where we see peak efficiency as shown in Figure 5. • Although mid-range solutions can extend power transfer, the peak efficiency range is extended in a much smaller range. This will be pragmatic for the initial commercialization while the technology evolves. Higher frequencies and larger fields
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provide specific benefits and also bring additional regulatory and susceptibility issues that require further investigation and consideration. In Figure 6, you can also see that the diameter of the coils associated with the primary over distance have a specific efficiency relationship. • Solutions to real world problems are important. For example, overcoming industrial design challenges like the misconception that industrial metal camera cases cannot be wirelessly charged will need to be addressed by innovative solutions such as charging through the display. These creative results should be shared with the wireless power community to advance the development of the technology and encourage newer, more efficient user-friendly solutions to reach the global marketplace. The best solution will have the capability of interfacing and controlling power using any or all of these technologies. Appendix 1. AcuPOLL® Research, Inc., August 2008 “Project Alamo River” 2. Eberhard Waffenschmidt and Toine Staring, “Limitation of inductive power transfer for consumer applications”,Submitted as synopsis to European Power Electronics (EPE) Conference 2009, Barcelona, Spain, 8-10 September, 2009. 3. AIP Industrial Physics Forum (November 13, 2006). Retrieved from: http://powercastco.com/PDF/HarvesterDataSheetv2.pdf 4. Aristeidis Karalis, J.D.Joannopoulos, and Marin Soljacic (2006). “Wireless Non-Radiative Energy Transfer.” 5. AIP Industrial Physics Forum (November 13, 2006). Retrieved from: http://powercastco.com/PDF/HarvesterDataSheetv2.pdf 6. Hadley, Franklin (Version from November 19, 2008). Retrieved from: http://web.mit.edu/isn/newsandevents/wireless_power.html 7. Eberhard Waffenschmidt and Toine Staring, “Limitation of inductive power transfer for consumer applications”, Submitted as synopsis to European Power Electronics (EPE) Conference 2009, Barcelona, Spain, 8-10 September, 2009. 8. Hadley, Franklin (Version from November 19, 2008). Retrieved from: http://web.mit.edu/isn/newsandevents/wireless_power.html 9. Intel Labs (Accessed October 2009). ”Wireless Resonant Energy Link.” Retrieved from: http://seattle.
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devices will also impact these considerations. Many manufacturers will ask new electromagnetic compatibility questions when 210V/m fields interact with products14. In any interoperable wireless power system, the range of scalability and power will be needed to adjust various elements of the system dynamically to maximize efficiency as operating parameters change.
TECHNICAL ARTICLE 10. Eberhard Waffenschmidt and Toine Staring, “Limitation of inductive power transfer for consumer applications”, Submitted as synopsis to European Power Electronics (EPE) Conference 2009, Barcelona, Spain, 8-10 September, 2009. 11. http://www.ecoupled.com 12. Eberhard Waffenschmidt and Toine Staring, “Limitation of inductive power transfer for consumer applications”, Submitted as synopsis to European Power Electronics (EPE) Conference 2009, Barcelona, Spain, 8-10 September, 2009. 13. http://www.wirelesspowerconsortium.com 14. Aristeidis Karalis, J.D.Joannopoulos, and Marin Soljacic (2006). “Wireless Non-Radiative Energy Transfer.” About the Author David Baarman is the Director of Advanced Technologies at Fulton Innovation and the lead inventor of eCoupled™ intelligent wireless power technology. Mr. Baarman is responsible for the technical supervision and development of eCoupled technology and other Fulton Innovation technologies. Mr. Baarman joined Amway in 1997, where he first pioneered the use of intelligent inductive coupling in the eSpring™ Water Purifier. With over 20 years of leadership experience in
the development of consumer and industrial products, Mr. Baarman took the technology behind eSpring and developed it to power everyday technologies, including consumer electronics, with a diverse range of power needs. Mr. Baarman’s efforts have led to national and global recognition of eCoupled technology and the acquisition of former competitor, Splashpower, in May 2008. Mr. Baarman has more than 350 U.S. and foreign patents that are granted or pending. Joshua Schwannecke is a Research Scientist with the Advanced Technologies Group at Fulton Innovation. Josh has more than five years of experience with wireless power and developing solutions using eCoupled technology. He has developed wireless power solutions for the Amway eSpring Water Purifier and other devices including hearing aids, phones, headsets, laptops, and power tools. He also works closely with Fulton’s partner companies to research wireless power solutions for prototype products. Mr. Schwannecke holds a Masters in Electrical Engineering from Michigan State University and has received an excellence award for coil design and optimization. He holds one granted patent and has eight published patent applications. ■
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intel-research.net/research.php#wrel
Get the Datasheet and Order Samples http://www.intersil.com
PWM DC/DC Controllers with VID Inputs for Portable GPU Core-Voltage Regulator ISL95874, ISL95875, ISL95876
Features
The ISL95874, ISL95875, ISL95876 ICs are Single-Phase Synchronous-Buck PWM regulators featuring Intersil’s proprietary R4 Technology™. The wide 3.3V to 25V input voltage range is ideal for systems that run on battery or AC-adapter power sources. The ISL95875 and ISL95876 are low-cost solutions for applications requiring dynamically selected slew-rate controlled output voltages. The soft-start and dynamic setpoint slew-rates are capacitor programmed. Voltage identification logic-inputs select four (ISL95875, ISL95876) resistor-programmed setpoint reference voltages that directly set the output voltage of the converter between 0.5V and 1.5V, and up to 5V with a feedback voltage divider.
• Input Voltage Range: 3.3V to 25V
Compared with R3 modulator, the R4 modulator has equivalent light-load efficiency, faster transient performance, accurately regulated frequency control and all internal compensation. These updates, together with integrated MOSFET drivers and Schottky bootstrap diode, allow for a high-performance regulator that is highly compact and needs few external components. The differential remote sensing for output voltage and selectable switching frequency are another two new functions. For maximum efficiency, the converter automatically enters diode-emulation mode (DEM) during light-load conditions, such as system standby.
• Output Voltage Range: 0.5V to 5V • Precision Regulation - Proprietary R4™ Frequency Control Loop - ±0.5% System Accuracy Over -10°C to +100°C • Optimal Transient Response - Intersil’s R4™ Modulator Technology • Output Remote Sense • Extremely Flexible Output Voltage Programmability - 2-Bit VID Selects Four Independent Setpoint Voltages for ISL95875 and ISL95876 - Simple Resistor Programming of Setpoint Voltages • Selectable 300kHz, 500kHz, 600kHz or 1MHz PWM Frequency in Continuous Conduction • Automatic Diode Emulation Mode for Highest Efficiency • Power-Good Monitor for Soft-Start and Fault Detection
Applications • Mobile PC Graphical Processing Unit VCC Rail • Mobile PC I/O Controller Hub (ICH) VCC Rail • Mobile PC Memory Controller Hub (GMCH) VCC Rail
RVCC CVCC
EN
PHASE
SREF
PGOOD
CIN QHS
12 11
LO
10 QLS
9
VO
CBOOT
8
5
ROFS
VIN
3.3V TO 25V
RPGOOD
13 VCC
14 PVCC
15 LGATE
UGATE
OCSET
4 CSOFT
ROFS1
GPIO
BOOT
7
3
RTN
FB
2
GND
6
1
RFB1
FSEL
RTN1
PGND
16
CPVCC
ROCSET
+5V
VOUT 0.5V TO 3.3V CO
CSEN
RTN1
RO
RFB
0
FIGURE 1. ISL95874 APPLICATION SCHEMATIC WITH ONE OUTPUT VOLTAGE SETPOINT AND DCR CURRENT SENSE
March 2, 2012 FN7933.1
Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2011, 2012 All Rights Reserved. All other trademarks mentioned are the property of their respective owners.
Characterize
Linear Voltage Regulators with an SMU Robert Green
Senior Market Development Manager
S
ource measurement unit instruments (or SMU instruments) can make the job of characterizing linear voltage regulators—both conventional and low dropout (LDO) regulators—easier. Because SMU instruments source, measure, and sink voltage and current, you can use the simple test setup shown in Figure 1 to measure a regulator’s basic electrical parameters, including line regulation, load regulation, dropout voltage, and quiescent current. SMU1 sources voltage and measures current on the LDO regulator’s input side. To measure the current with this setup, set the output voltage of SMU1 to a desired input test voltage. Set the current limit to a value higher than the voltage regulator’s maximum possible input current to account for the regulator’s rated current consumption.
A
SMU2 connects to the regulator’s output side, where it can act as a load and measure current. In this instance, SMU2’s output voltage is programmed to a value that is lower than the regulator’s expected output voltage, which forces SMU2 to sink current from the regulator, thereby acting as a load.
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TECHNICAL ARTICLE Out
Voltage Regulator
SMU1
TECHNICAL ARTICLE
In
SMU2
GND
A
CIN
COUT
Source V Measure I
A Source V Measure I
Figure 1
Line-regulation test A line-regulation test measures a regulator’s ability to maintain the specified output voltage under a constant load as the input voltage is varied. During this test, the output of SMU1 sweeps from a low voltage to a high voltage, while SMU2 sinks a constant current. Typically, the output voltage should vary less than 100mV. Load-regulation test A load-regulation test measures a regulator’s ability to maintain the specified output voltage under varying load current, while the input voltage remains constant. The LDO regulator’s output voltage should vary less than 100mV. For this test, SMU1 outputs a fixed input voltage. SMU2 once again sources a fixed voltage less than the regulator’s expected output voltage so that it will sink current. By setting SMU2’s current limit to different levels, you can simulate different load magnitudes and measure how well the regulator operates under varying loads.
which is the input voltage value at which the output starts to fall below its specified, regulated output level. Quiescent current Quiescent current is the difference between a regulator’s input current and its output current. To measure quiescent current, set SMU1 to sweep the regulator’s input voltage range. Once again, configure SMU2 to sink by programming its voltage to a value lower than the output voltage of the regulator. While sweeping the input voltage, measure both the input current and output current. The difference in the two measurements is the regulator’s quiescent current. By varying the programmed current limit of SMU2, you can determine how the quiescent current varies as a function of the output current. The SMU instrument’s versatility makes these types of measurements a snap. Also keep in mind that you can make these measurements manually, as you might do in a development lab, or automatically, as you might do in production.
Dropout voltage test
About the Author
To measure a regulator’s dropout-voltage, SMU1 sweeps from a maximum input voltage to a voltage below the regulator’s expected drop out voltage, while SMU2 acts as a load and sinks the output current. To configure SMU2 to act as a load, program SMU2 to source a voltage lower than the expected output voltage of the regulator. Set the current limit to create the desired constant load condition. Measuring both the input and output voltages will allow you to determine easily the dropout voltage,
Robert Green is a Senior Market Development Manager at Keithley Instruments focusing on low level measurement applications. During his 20-year career at Keithley, Mr. Green has been involved in the definition and introduction of a wide range of products including picoammeters, electrometers, digital multimeters, and temperature measurement products. He received a B.S. in Electrical Engineering from Cornell University and an M. S. in Electrical Engineering from Washington University, St. Louis, Missouri. ■
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