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JAN 2014 David Chen

CEO & Co-founder of Jade Sky Technologies


LED Adoption Jade Sky’s LED ICs are paving the way for mass consumer adoption

plus SmarteXite LED Dimmer

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Lighting Electronics









Bright Lights Ahead: The Future of Smart Lighting

A Look at EMI in Offline-Powered LED Lamps

Interview with David Chen CEO & Co-founder of Jade Sky

The Quest for Mass LED Adoption


Lighting Electronics

Bright Lights Ahead: Dialog Semiconductor talks the future of smart lighting The opportunities are limitless. Smart lighting is proving to be one of the most effective and innovative opportunities in energy savings. Some industry experts predict that within 10 years, LED lights will deliver more environmental and economic benefits than any other clean technology, including high-voltage power transmission, electric vehicles, smart grids and renewable power. Lighting control systems enable consumers to dim, brighten and change the color of bulbs easily. These systems can be controlled via a smartphone or tablet application. However, despite the strong outlook for the rapid adoption of smart lighting, the technology that links the products remains largely proprietary, which ultimately hinders growth.




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To this end, Dialog has launched the smarteXite™ platform, the first LED driver technology to directly and easily support wireless connectivity, digital dimming and intelligent sensor control, enabling a new generation of highly flexible, programmable LED driver integrated circuits (ICs) for smart lighting applications. In addition, we have made the platform integrate with the devices that exist within the Internet of Things in order to make light a controllable part of our environment to increase comfort, save energy, and make life more convenient.

The smarteXite platform is a new generation of LED driver ICs that combines Dialog’s strengths in configurable power management with state-of-the-art digital signal processing design. The platform focuses on two main areas of innovation: a completely new approach in the way lamps can be dimmed with multiple lighting interfaces and a new way of developing and supporting the manufacturing process. The first device from the smarteXite family, the iW6401, offers a versatile “one size fits all” platform for a wide range of smart lighting LED applications. Intelligent color or proximity sensing devices can be directly connected and powered by the iW6401’s integrated power management unit, reducing external components and cost. With its fully data based configuration, the design time can be drastically reduced, and expensive and time consuming hardware redesign loops can be skipped completely. Configuration data can be accessed even after a retrofit lamp is fully assembled by using the mains supply terminals as a communication interface.


Why Smart Lighting? While smart lighting is an innovative technology, it hasn’t yet broken into mass adoption. However, we are starting to see that consumers want better control over their lighting for the ambience, energy and cost saving benefits. Furthermore, the physical and emotional benefits of smart lighting are countless. For example, with mood, accent and task lighting, consumers can avoid eye strain, increase energy levels and create a nicer ambience in their homes. With smarteXite, consumers are empowered to adjust lighting brightness levels, color and color temperature automatically according to the time of day or an individual consumer’s daily routine. Users can group lights or opt to have an “all light off” button so they can be sure they’ve turned off every light in every room. An additional feature of our LED drivers is improved thermal management. Heat

TECH ARTICLE is the enemy of LED bulbs, particularly in installations where airflow is restricted. Poor thermal design can result in overheating, which can dramatically reduce bulb operating life. Dialog’s technology monitors the temperature inside the sealed LED bulb and rather than just shutting the light off when conditions get too hot, it allows a “graceful,” stepped reduction of LED current that dims the bulb brightness until the temperature is reduced, and it does this in a way that is barely discernible to users.

The Need for a New Platform The transition of the lighting industry from traditional light sources to LED is a disruptive change and a tremendous challenge for companies who used to think in innovation cycles of 3-6 years. As new technology joins the fray, these cycle times are shortening, particularly for consumer products. At the same time manufacturers are maintaining a huge number of individual products (SKUs) split into various power levels, form factors, and features with regional differences. On top of this complexity, new LED models are rolled out at a continuous pace with improved performance and lower cost.

smarteXite empowers the industry by providing the right tools to master these challenges. A set of fully lighting-qualified functional IP modules on a common process technology serves as a tool-box to quickly combine new SoCs (systems on chip) and make them available at shortest time to market. Each of the modules is fully programmable in its internal functionality via a common interface and programming model. This makes the entire LED driver IC fully configurable on different levels of the LED lamp value chain. smarteXite supports final stage digital calibration on the production line where the bulb manufacturers can reconfigure the

With smarteXite, consumers are empowered to adjust lighting brightness levels, color and color temperature automatically according to the time of day or an individual consumer’s daily routine.


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The benefits of the new dimming technology are: • Resolves all compatibility problems with phase cut dimmers • Applicable worldwide • No audible noise • No reliability issues • No light flicker or shimmer • Up to 100m cable between dimmer and light source • Any number of lamps, limited only by total power • Much better electrical efficiency of the LED driver over traditional phase cut dimmers


illumination calibration settings like brightness and color via the A/C mains terminals. This allows lower tolerance LEDs to be used with less binning or waste of LEDs. The iW6401 can be configured to actively manage lamp temperature using either an on-chip or offchip temperature sensor and a configurable state temperature control.

Keeping to the Industry Standard In residential applications, the only established technology for dimming lamps is the commonly known “phase cut” technology. It works on the principle that the power of the AC mains voltage is reduced by cutting out some of its energy, hence reducing the brightness in incandescent lamps. LED lamps require specific technology to deal with this modified AC line voltage and only few control ICs are capable of doing this at high performance. However, such solutions offer simple brightness control and only a few lamps can be operated on one dimmer. With the advent of LED, new

TECH ARTICLE The smarteXite iW6401 is the first LED driver chip to integrate all functions needed to make an LED light source fully compliant with IEC62756.

possibilities require new technology. OSRAM, in cooperation with Europe’s largest dimmer maker, INSTA GmbH, have developed the new Ledotron™ dimmer technology. The target of this development was: • Full compliance with all worldwide EMI standards • Open, license-free protocol • Plug-and-play replacement of traditional dimmers • Group-addressable multi-channel protocol • Support of color control and tunable white •P  rotocol over power line using baseband modulation • IEC standardization • Serve as the “last mile” between home automation systems and light source The Ledotron Marketing Alliance, including partners OSRAM and INSTA, has been instrumental in establishing and encouraging the adoption of Ledotron systems. The Ledotron compatible dimmer is a 1:1 replacement of a traditional 2-wire phase cut dimmer. A constant phase cut at the very beginning of an AC mains cycle is provided for internal power supply of the dimmer. On the end of a mains half cycle, data bits are modulated in the base band; i.e. high bits are indicated by a reduced voltage. Standardization of this technology is ongoing under The International Electrotechnical Commission’s (IEC’s) guideline 62756-1, and is expected to be issued this year. Solutions based on Ledotron combine manual dimmer control with easy connection to the Internet of Things. In a typical Ledotron configuration, the maximum number of devices that can be connected to the dimmer is only limited by the peak power of the dimmer. The communication between the dimmer and lamps is done via baseband data modulation around the zero crossings of the AC mains voltage.

Designing a Ledotron compatible lamp from scratch is a complex and time-consuming task and requires deep knowledge and understanding of the underlying technology. The smarteXite iW6401 is the first LED driver chip to integrate all functions needed to make an LED light source fully compliant with IEC62756. As a plug-and-play solution, the designer of the LED driver does not have to interfere with the communication side as all signal processing is integral to the driver chip.

Conclusion LED lighting is an area that is about to explode in terms of volume as the majority of governments around the world begin to implement power regulations banning inefficient incandescent lighting and push more efficient, cleaner LED lighting. Dialog’s versatile “one size fits all” smarteXite technology enables better processing, which results in better, more precise and accurate control without the need for external filtering or signal conditioning. Our first product, the iW6401, is the world’s first programmable retrofit LED lamp driver IC, which allows the bulb to be configured via software, reducing the bill of materials, cost and time-to-market for our customers. With its multiple dimming interfaces, the platform is a future-proof true “smart-fit” solution ready for the digital revolution in lighting. ■

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A Theoretical Look at EMI in Offline Powered LED Lamps

by David Cuthbert EEWeb Contributing Author

In this article we’ll explore EMI (Electromagnetic Interference) in offline powered LED lamps, focusing on lamps having an ANSI standardized screw base as used in U.S. residences.


TECH ARTICLE ENERGY STAR速, the FCC, and EMI LED lamp manufacturers who are an ENERGY STAR速 partners must meet several requirements including Power Factor, FCC CFR Part 15 conducted and radiated EMI, Transient Protection per ANSI/IEEE C62.411991, and Product Safety per ANSI/UL 19932009. The standard design goal is to meet all of these requirements at minimum cost and to do this we want to minimize the EMI filter component count and not design for excessive EMI attenuation margin. Using SPICE simulation we can rough in the EMI filter design and get a feel for the tradeoffs before actual lab tests are performed.

The EMI Receiver and SPICE Simulation EMI plots using SPICE simulation FFT plots of EMI do not always match actual measurements. However, they are useful to rough in an EMI filter design and to get a feel for what each filter component does. FCC testing allows QP (Quasi-peak) or Average detection to be used and the EMI receiver is set to one or the other. However, a SPICE FFT frequency domain simulation plots the RMS amplitude of each spectral component and this can lead to a difference between measured and simulated EMI. Additionally, for an EMI noise source having only one spectral line in the EMI receiver RBW (Resolution Bandwidth) measured and simulated may agree. But, when more than one spectral line is in the receiver RBW, simulation will under-report the amplitude. To correct for this the simulated power in each spectral line (in the receiver RBW) is added together. For example, in a PF corrected flyback converter there may be 75 spectral lines spaced 120 Hz apart in a 9 kHz RBW. If each spectral line is of equal amplitude the correction factor to add to the simulated result is 10LOG(75) = 19 dB.

Fig. 1: DM noise model

Fig. 2: Equivalent DM noise model

DM Noise and an Equivalent DM Noise Source Due to fast voltage and current transitions a SPICE simulation of a PF controlled LED driver can take several minutes to run. To quickly rough in an EMI filter and to explore filter topology and component value tradeoffs faster simulation is needed. This can be done by replacing the LED driver circuit of Fig.1 with the equivalent noise source circuit of Fig. 2. The quickest simulation is had by using a sine wave current source and adjusting

Fig. 3: CM noise model


Lighting Electronics its frequency and amplitude so that the fundamental frequency signal at the LISN RX port is the same for both the LED driver circuit and the equivalent noise source circuits.

Fig. 4: Equivalent CM noise model

A Pi-filter is usually used with the capacitor at the switcher providing a local source of charge for switching current, a series inductor for switching frequency series impedance, and a capacitor across the AC line, or LISN, as shown in Fig. 1. Note that to be effective the line capacitor should exhibit an impedance considerably lower than the 100 ohm differential LISN impedance. For 100 kHz switching noise this capacitor can be 0.1 µF or greater. Note that the total filter capacitance can adversely impact the ENERGY STAR® Power Factor requirement of ≥0.70. For example, 1µF of filter capacitance across a 10 watt load having a PF of unity will cause the PF to be 0.9. Given these constraints the total filter capacitance for a 10 watt load should probably be no less than 0.1 µF and not greater than 1.0 µF.

Equivalent CM Noise Source

Fig. 5: Added DM inductor

The circuit of Fig. 3 models the CM noise current coupled between the switcher and ground via the LED-to-ground capacitance. While this capacitance is of the order of only 1 pF, enough noise current can be coupled to fail FCC conducted and radiated EMI by tens of decibels. As with the DM simulation the CM simulation can be a slow simulation and an equivalent noise model can significantly speed up the design process.

Fig. 6: Added CM choke

The CM noise SPICE model is shown in Fig. 3. The important component values are the transformer primary-to-secondary capacitance (XFMR C), the LED-to-ground capacitance (LED CM C), and the EMI Y-capacitance (Y-CAP). The fast dv/dt at the FET drain couples noise current through the transformer capacitance and LED-toground capacitance to ground and back through the LISN. The Y-cap provides a local path for most of the noise current to return to the source, which is the FET drain. The noise attenuation of the Y-cap is equal to the Y-cap capacitance divided by the transformer capacitance. Given a 1000 pF Y-cap and a 10 pF transformer the attenuation is 100X or 40 dB. For additional CM filtering a CM choke can be added. To be effective the CM choke


TECH ARTICLE impedance must be greater than the LED-toground impedance. Because the impedance of a practical choke may be around 5k ohms, and the LED-to-ground capacitance may be 1 pF, a CM choke might be effective only above 30 MHz. So, while a CM choke might not reduce conducted noise in the 0.15 – 30 MHz test range, it can reduce radiated noise in the 30 - 200 MHz range. The equivalent CM noise model of Fig. 4 can be modified with an additional DM inductor (Fig. 5) or a CM choke (Fig. 6).

Other EMI Mitigation Methods In addition to filtering there are additional ways to reduce EMI. The FET drain rise/fall times can be lengthened – thereby rolling off HF noise – by increasing the gate resistor value. The tradeoff is increased FET power dissipation. And ringing at the FET drain (caused by stray L and C) can be reduced by adding an RC snubber. And the transformer primary-to-secondary capacitive coupling can be reduced with an electrostatic shield but this is probably too expensive for a consumer LED lamp.

Fig. 7: Ring wave circuit

Radiated EMI Does passing FCC conducted EMI mean the product will pass FCC radiated EMI? Not necessarily. At 30 MHz the FCC class B conducted EMI limit line is 48 dBµV while the radiated EMI limit line is 29.5 dBµV/m at a distance of 10 meters. 48 dBµV across the 25 ohm CM LISN impedance is an RF current of 10 uA. Modeling a typical FCC test setup using EZNEC software, with 10 µA of 30 MHz RF current driving the “antenna” formed by the power cable, produces a radiated field of 30 dBµV/m. This is right at the radiated limit line and a few dB of conducted margin would be good to have.

Fig. 8: Voltage spike on the switching FET

Summary We’ve taken a basic look at EMI, how it’s generated by the LED driver, and how it can be controlled. We’ve also investigated how the EMI filter impacts Power Factor and how the EMI filter responds to transients. This information should provide you with the tools to minimize product cost while meeting the applicable ENERGY STAR®, requirements.

Transient Protection

About the Author

The ENERGY STAR® line transient protection specifies an ANSI/IEEE C.62.41-1991 100 kHz ring wave, Class A, 2.5 kV level. While enough EMI filter capacitance might be used to absorb this transient a clamp circuit employing a SPS/ TVSS can be a lower cost solution. The 100 kHz ring wave circuit of Fig. 7 produces a 180 volt spike across the switching FET (Fig. 8), requiring a higher voltage FET than if proper SPS/TVSS protection were used.

Dave Cuthbert is a consultant with expertise in EMC Design, Signal Integrity, RF, Antennas, Design Review, Power Electronics and Instrumentation and Measurement. ■

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Lighting Electronics


LED Adoption Jade Sky’s LED ICs are paving the way for mass consumer adoption

Jade Sky mission Co-foun driver th

Lighting industry



Co-founders, Eugene Cheung and David Chen

y Technologies is a Silicon Valley start-up that creates innovative LED IC solutions. The company's is to enable an effective, high-performance, and low-cost alternative to the 130+ year-old Edison bulb. nded by David Chen in 2010, Jade Sky leveraged its team's experience in power to develop a unique LED hat aims to accelerate consumer adoption.

g Electronics spoke with David Chen, current CEO of Jade Sky, about the recent boom in the LED lighting y, some of their new LED power products, and what it will take to achieve mass adoption of LED bulbs.


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“What we’ve done as a company is put chips out there focusing on the user experience so that people will start using LED lights—we want people actually to buy them, because they are delighted with the performance and energy savings. We want them to keep these devices and not return them.”

Can you tell us about your background and what motivated you to co-found Jade Sky Technologies? After graduating from MIT, I worked as a hardware engineer developing highefficiency power supplies for portable products such as GPS receivers and handhelds. Afterwards, for the next 15 years, I worked in systems engineering with an application focus, mainly serving customers on the technical side, which I greatly enjoyed. My co-founder, Eugene Cheung, is a seasoned chip designer who previously worked for several analog IC companies, specializing in power and communications. In 2010 we heard all about the difficulty of dimming in LED lighting, so we thought how perfect it was to work on this problem because we could marry our expertise in power to the very worthwhile development of LED lighting applications. Power and lighting were two sides of the same coin as we viewed it, because although both have similar aspects,


they each have their unique challenges. There are aspects in lighting that go beyond traditional power, so it was exciting for us to learn these new concepts while still being able to contribute our ways of thinking about power very comfortably. Most importantly, we thought that LED lighting provided a tremendous opportunity to do some good and to work on something that had such a great potential to save energy in the world. So, we founded the company.

When anyone gets ready to start a company they need to have a feel of how will they fit into the market. What was the state of the industry in power technology driving these LED products when you started the company? That is a great question. Back in 2010, when I was still with my previous company, we had a discussion to see if we wanted to go into LED lighting, but at that time, the management team made a decision not to focus in this area for fear of distraction from

COVER INTERVIEW their core products. However, the exercise gave me a chance to speak to various potential customers, where I learned of the tremendous frustration concerning LED driver electronics, especially in the area of dimming compatibility and in working smoothly with existing infrastructures. Back then, I thought that if my current company was not willing to work on this issue, I certainly knew people who could find solutions to this problem. It was really the start of how a lot of our thoughts came together. There were still a lot of technical hurdles that we needed to overcome at that time. People knew that there were LEDs, but the user experience was still terrible.

What products do you currently offer? Our products are quite simple, actually. They are driver chips or ICs that can be found in the electronic guts of any LED lighting product. If you open up an LED light bulb, you will see a PCB with electronic components

on it. In the heart of those components is a chip that basically controls the amount of current going to generate the light in the LEDs. Those chips are what we make, and we introduced the first of our products last year. Our first product is a dimmable driver IC that works with all existing types of dimmers, particularly TRIAC-type dimmers like the ones you typically find in the household.

How does your product compare to the existing players in the market that are getting bigger and bigger? What are the differentiating factors of your product in the market competition? Our differentiation is really in the end-user experience. If you design a light bulb that uses our driver chip inside, what you’ll find is that the light bulb will be able to work with any dimmer out there. If you go to a hardware store and you check in the lighting section, you will see in the packaging the word “dimmable,” but in reality, it’s more of a hit or a miss. You


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I was talking with the folks at the California Lighting Technology Center at UC Davis (CLTC), and they told me that while it is great to have a technology that enables energy savings or promotes energy efficiency, if nobody wants to use it, the adoption will be low. This has happened before with CFLs, so they don’t want the same mistake again with LED lights. The CLTC is particularly sensitive about the user experience. What we’ve done as a company is put chips out there focusing on the user experience so that people will start using LED lights—we want people actually to buy them, because they are delighted with the performance and energy savings. We want them to keep these devices and not return them. Eventually, the aim is to have real energy savings come from the mass adoption of LED lighting by making it easy for everyone to buy, use, and like LED lights.

What was the biggest challenge in getting this product to market?

purchase one and bring it home, you then try it out thinking that it’ll work because it tells you it’s dimmable, and if you’re lucky, it does. However, there is also a very big chance that you have the “wrong” type of dimmer, which will cause the LED bulb to flicker, to dim non-smoothly or in a limited range, or even to cause the light to be stuck on or off. By the time you have already spent money on the LED bulb, it is unlikely you will have actually gone to the LED bulb manufacturer’s website to check what type of dimmers are approved for compatibility, assuming you even know what dimmer model you have at home! Another differentiation is that an LED bulb using our chip really works like traditional incandescents in the sense of ease of use— it just works. It can dim from 100% down to 0%, and there is no early cut-off. Unlike incandescents, however, light is produced efficiently, which is what we bring to the table along with the excellent user experience.


I’ll give two answers—one will be on the business challenge and the other will be a bit more technical. I see that the biggest business challenge for us is simply what it has been for any start-up: breaking into the tier-1 customers. That has been a challenge because often times such customers seem not quite ready yet to switch to a fairly innovative approach like ours despite the demonstrated performance advantages. That is something that we are still working on and fortunately we are getting a lot of meetings and audiences. Some of the technical challenges are that LEDs want to be driven with a constant current. That’s really what they are designed to do both for reliability and performance. But if you look at the infrastructure for dimmers, TRIACbased dimmers are traditionally designed to work with resistive types of loading, and that is what incandescent-tungsten type of filaments are. They are basically resistors. If you take a constant-current type of load, and you match it to something that really wants to see a constant type of resistance, you can develop a lot of compatibility issues related to what current and voltages want to be at any particular moment for the input AC wave. What we do to address this challenge—


“You can view our chip as simply a building block, and the nice part of it is that with the selection of the properly rated components, you can scale up the power quite easily.”


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“Dimming is a big part of intelligent lighting. In daylight harvesting where you have a lot of outdoor lights and when there is ambient light available, you don’t really need to have full brightness. The applications are huge.”




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“What excites me about LED lighting is the tremendous energy savings that could be achieved by simply combining a great user experience with an inherently efficient lighting technology.”

and this is where our patents are relevant—is we use an approach that presents resistive loading to the dimmer but drives constant current to the LEDs. Whether you are looking at the input or the output, a seamless interface is provided by our chip, ideally matched to what is on each side. That is the technical challenge that we have overcome with our technology and chips.

Are there other types of applications aside from the traditional light bulb that most of your devices are based on? Right now, our bread and butter are in retrofit light bulbs, down lights, par lights and other various bulb form factors. However, we’re also looking to get into higher power applications, so we are developing reference designs that go into panels and tube lights that work around 16 W - 25 W. Beyond that, we are also partnering with some folks to work on outdoor lighting including parking lot lights and bulkhead lights for hallways, outdoor facilities, and housing complexes. We had some successes with housing projects in Hong Kong and Singapore in terms of outdoor bulkhead lights. We are also discussing projects involving streetlights that go around 100 Watts or so. You can view our chip as simply a building block, and the nice part of it is that with the selection of the properly rated components, you can scale up the power quite easily. The fundamental technology is the same, so the applications it can serve are very wide. Outside of lighting we are going into quite a few other applications as well. As it turns out, some of the technology used for lighting can go into high powerfactor supplies for various appliances, so we are expanding into that area as well.

In the application of streetlights or some of the other end applications, do you still apply the dimming technology? Dimming is a big part of intelligent lighting. In daylighting applications where you have a lot of outdoor lights and when there is ambient light available, you don’t really need to have full brightness. The idea of dimming automatically and intelligently when there’s existing light is actually a huge area of research for us. We are doing this research in partnership with companies that work on ambient light


COVER INTERVIEW sensors; we provide the driver building block for such systems because we dim so well. The applications are huge. Intelligent lighting can be placed in various commercial properties with tube lights, panel lights, and outdoor lights as well as in other industrial and commercial applications. Dimming matters a lot, but often for different reasons.

For engineers who want to use your product, what kind of resources can you offer them? The traditional lighting industry is interesting because they’re grappling with this shift to LED lighting. By shift, I mean the traditional R&D for lighting has been through what they call the use of metal benders, people who know how to form the external shell to make lights look pretty. With the move to LEDs, electrical engineers, who haven’t contributed much to traditional lighting, are now greatly needed by lighting companies in order to design LED lights. As a chip company, we are able to provide a full, ready-made design package to make it easy. Even with limited resources, these lighting companies and manufacturers can easily go to market really quickly. We provide design packages, which are essentially design blueprints that have the exact circuit schematics, PCB layouts, and bill of materials. Everything concerning the design is done and ready to go. A customer can literally just take it to the factory and get it made, or they can try various modifications if they want to. We are happy to do things to get folks to adopt this technology faster. Fortunately, light bulbs are not hugely complicated systems. We used to make power supply chips for routers, servers, switches and things like that, and I can’t imagine a chip vendor providing the entire design schematic for a router or server. In our case, the bulb design is within our engineering capability so we are able to provide the whole thing.

as far as 20 years. Each of us experienced working together at various companies previously, and now we are back together. It’s a group of friends who share the same passion, who respect each other’s capabilities and personal integrity, and without that, we couldn’t be successful. It is a tremendous gift not to be immersed in corporate politics and be the kind of company where we just put our heads down and make a lot of progress, and I think that’s awesome. Another reason is that LED technology and all the associated technical challenges are so fascinating. Going around on any given day and night, one is starting to see LED lighting everywhere. It is tremendously rewarding to be part of that, and I would say it is such a joy for me. I wish I started doing this earlier in my career!

There are a lot of very interesting directions that LED Lighting could possibly go, but what excites you the most about the future of LED lighting? I think intelligence will be huge—the potential of intelligence as related to LED lighting is very exciting. In terms of the technical aspect, having LED light sources that provide light where you want it, when you want it, and not needing a whole lot of intervention is great. The fact that you can have this as nodes within a network is also very exciting. Perhaps if we could go back to a core idea though, LED lighting is already much more efficient than what is installed right now. If one considers that fact in combination with the improved user experience that drives mass adoption, that is indeed the very key. What excites me is the tremendous energy savings that could be achieved by simply combining a great user experience with an inherently efficient lighting technology. ■

Every company is different—the phase, the expectation, and even the leadership. Can you tell us about the culture of your company? Our culture, to put it in one word, is simply fun. It is fun for two main reasons. One, we get to work with our friends—friends that go back


Lighting Electronics

The Quest for Mass

LED Adoption David Chen, CEO and Co-founder and Eugene Cheung, VP Engineering and Co-founder



Hot tungsten is a tough act to follow. Efforts to transition homes to high-efficiency light sources have been underway since at least 1992, when California utilities launched full-scale compact fluorescent lamp (CFL) rebate programs. The California Energy Commission estimates that as of 2010, only 21% of all residential lamp sockets in California had been refitted with CFLs, with the national residential average being just 11% (1, 2). The lethargic and incomplete market adoption of CFLs in the residential market demonstrates that just because a product produces sufficient light, proves cost effective, saves energy, and is supported by millions of dollars in marketing, the adoption of that technology is not ensured.


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Can LEDs return better market results than their CFL forebears? Yes, but not without making technology choices that prioritize user experience. One of the biggest challenges facing the lighting industry is how to effectively transition consumers and industry from 130 year old Edison incandescent light to more energy-efficient solid-state LED lighting choices. The Energy Independence & Security Act of 2007 set a future deadline for eliminating all general-service “Edison screw” incandescent light bulbs of 40 Watts and above in the United States by January 1, 2014. That future is upon us! Even with the backing of government legislation, the looming question for the LED lighting industry is whether the masses are actually ready to adopt these nascent LED lamps to retrofit over 3.3 billion Edison screw lamp sockets within the U.S. (of which about 97% are residential). This is an enormous opportunity to refit a fundamental technology if we can get consumers to welcome it into their homes. According to McKinsey & Company,”forecasts for LED uptake in the residential segment remain high, at almost 50 percent in 2016 and over 70 percent in 2020.

Architectural lighting remains the early adopter, and its LED market share is expected to reach close to 90 percent by 2020.” Unfortunately, LED lamps on the market thus far have been falling short on addressing some of the same user-experience issues that stunted the adoption of CFLs and consumers have little patience for yet another failed technology transition campaign. Even with legislation intervention, LED lighting manufacturers must persuade a somewhat reluctant public to leave their time-tested incandescents behind and transition to the new LED products over other less expensive lighting alternatives such as CFL and Halogen. We, as an industry, must take user experience seriously, and manufacture LED lamps that will delight the end customer. Despite dramatic improvements over CFLs in color quality, however, most current-generation LED lamps still grossly misbehave in the presence of dimmers and energy management sensors, with issues including non-linear output, very limited dimming range, visible flicker, strobing, and/or becoming stuck on or off. The color quality of the light quickly becomes rather irrelevant when the LED lamp itself is flashing or otherwise misbehaving. If it has an Edison screw base, it should work in any Edison socket, and if an LED lamp’s packaging states “dimmable”, it should be able to dim with any dimmer.

JST301 Chip Features:

• • • • • • • • • •


Smooth monotonic 0 to100% dimming range with no flicker Compatibility with all TRIAC dimmers: leading-edge, trailing-edge, digital, and with occupancy sensors Near-unity power factor without external PFC circuitry and independent of driver topology Support for isolated and non-isolated designs Adjustable switching frequency (50kHz-500kHz) for space constrained designs Spread-spectrum modulation for reduced EMI,  (-6dB typ.) Low quiescent current, 500uA Protection features for over-voltage, over-current, and over-temperature conditions Patented PFC architecture and dimming technology Higher system efficiency with reduced system cost and increased reliability


Typical Applications:

• • • •

Dimmable Retrofit LED Lamps and Luminaires, up to 30W Industrial and Commercial Lighting, T-lamps LED Driver Modules and Bricks Solid-state Signage

"We, as an industry, must take user experience seriously, and manufacture LED lamps that will delight the end customer. "

For LED lighting manufacturers, there is now a solution. The JST301 chip, using patented RetroBulb™ technology, delivers the experience expected by users familiar with the incandescent lamp along with the energy efficiency and reliability of solid-state lighting. Now, for the very first time, LED lighting OEMs can say NO to dimmer-compatibility charts, dimmer-testing overhead, customer dissatisfaction, purchase difficulties and returns. Jade Sky Technologies’ mission is to bring simplicity back to lighting for the end consumer by making a true retrofit LED bulb possible. Holding many patents, JST manufactures innovative power ICs that help ensure a smooth and comprehensive transition from incandescent to LED lighting.

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The JST301 chip with RetroBulb™ technology makes it possible for OEMs to create LED lighting products that have lower BOM cost (resulting in better consumer pricing), smaller physical area requirements, guaranteed-bydesign universal compatibility with all previously-installed dimmers and sensors, smooth, flicker-free deep-dimming with 100% down to 0% range, very high efficiency, and near unity power factor. ■


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