Official Blog of Silicon Labs

      • IoT Hero Sengled Brings Style and Simplicity to Smart Connected Lighting

        deirdrewalsh | 05/144/2017 | 12:02 PM



        Charles Sun is the vice president of R&D at Sengled, a company that’s built its design philosophy around helping customers simplify their surroundings with innovative lighting products. We recently got to chat with Charles about some of the things Sengled is doing in the smart lighting arena.


        How did Sengled become a company, what was the impetus for its creation?

        Sengled has been dedicated to making daily life heathy, happy, and convenient through lighting products designed for simplicity and style.


        Aesthetic design seems to be an important element of the Sengled brand, what are some of the challenges that come with designing for ease-of-use as well as looks?

        Our goal isn’t to change light bulbs so dramatically that it becomes difficult for users to adopt them. In the design tone and manner, we try to keep the existing form factor and appearance consistent while incorporating modern characteristics of high-tech functionality. We try to transform a traditional light bulb or lamp into smart lighting seamlessly. However, there are several real challenges to overcome. In addition to meeting appearance standards for the design, we must solve the interaction problem of cooling the LEDs, managing the high-speed circuitry of the hardware and RF design to achieve the desired aesthetic, and meeting reliability and performance standards without increasing their size in comparison with the traditional lighting products.


        Tell us about some of the innovations you’ve pioneered, specifically with integrating audio and security into LEDs.

        Our multi-channel wireless speaker system, Pulse, is a synchronous multi-channel speaker light and the world's first one that can play with a mobile phone. It can support up to eight lights simultaneously while playing music and can adjust each light to the sound and volume for each speaker. Integrated with an IP Camera, our Snap can achieve 1080p HD real-time video viewing, video cloud storage, and high-precision motion detection with the full function of standard waterproof PAR38 lighting.


        How long has Silicon Labs been part of your solution, and can you tell us about the selection process? What made Silicon Labs the choice for you?

        We selected Silicon Labs in 2015 after evaluating five zigbee solution vendors. In making the decision, we carefully considered product performance, protocol stability and compatibility, as well as in-time technical and business support.


        You recently received the Innovation Award in Eco-Design and Sustainable Technologies category at CES, can you tell us about what sets Pulse Link and Element apart from such a busy market?


        Pulse Link is an extension of the Pulse family. It evolved from a multi-channel Bluetooth playback speaker system into a video playback system. Its typical application is for watching TV in living room. At present, most companies designing the connected bulb only provide the most basic connection and control functions. In addition to our modern design, excellent RF performance, and stable performance, the Element is our first energy-saving LED as well as the first in our tree planting plan. The Element combines built-in, cost-effective power detection circuitry and algorithms (has been granted US patent), making our products unique and in line with the current trend of energy-saving and carbon emission reduction.


        Finally, where do you see the IoT market heading in the next 5-10 years?

        Integrated IoT solution with lighting and security should be the focus of the future. If the product experience and price can be dramatically improved at the same time, the progress will be accelerated.

      • Students at Norwegian University of Science and Technology Race Toward Engineering Excellence

        Lance Looper | 05/139/2017 | 10:29 AM


        Revolve NTNU is an independent student organization at the Norwegian University of Science and Technology that consists of 64 team members working toward a common goal: to develop and build a racecar to compete in one of the largest engineering competitions in the world, Formula Student. This is their experience working toward the 2017 competition thus far.


        We are always pushing the limits for our automotive design, and testing of our design is essential for ensuring performance during competitions.




        The team uses a wireless telemetry setup in order to have easy, real-time access to our data. Revolve NTNU has experimented with multiple different technologies over the years, and used Wi-Fi for our 2016 system.


        For our 2017 telemetry system, we were looking for an additional radio system using a lower frequency than either Wi-Fi 2.4 or 5GHz. We contacted Silicon Labs and saw that they had offerings that combine sub-GHz frequencies and low power, an added benefit for a battery driven racecar. Silicon Labs has been an excellent ally in our project, providing chipsets and development kits, in addition to being able to provide help with our questions.




        The latest model, Gnist, powered by the Silicon Labs EFR32 Flex Gecko


        The intended use for the module provided with use of an EFR32 Flex Gecko is to transmit mainly the most important data from the car to the base station. As our car uses a self-made battery, there are a number of safety precautions in order to ensure safe usage of the car. The most important, therefore, is the state of each individual cell in the battery. If the temperature is too high, the car is will automatically stop. We want to know the state of the battery from where we are in the pit so we can warn the driver to slow down in order to reduce the temperature of the batteries before the car shuts down.


        The sub-GHz link provided by the EFR32 Flex Gecko is therefore required to provide an interference-free and longer-range alternative to the Wi-Fi system we used previously. We are also going to use the system to only broadcast the battery information to prevent problems maintaining the line as experienced with the Wi-Fi system. Other possibilities for the EFR32 include updating and tuning the car over-the-air by sending updates to the car wirelessly.


        Check out the Gnist riding on Trollstigen, Norway’s most famous national tourist car routes:


        Revolve NTNU has designed a custom circuit board using radio board inserts provided by Silicon Labs, greatly reducing the complexity, while maintaining the performance needed for our system. We are aiming for a range in excess of 500 meters with a bit rate of 500 kbit/s


        Learn more about the NTNU Revolve team and their exciting project here, and check out Silicon Labs’ Wireless solutions here.

      • May 2017 Member Spotlight: YK

        Siliconlabs | 05/139/2017 | 03:58 AM

        We are featuring one of the Silicon Labs Community members who is active or new in the community on a monthly basis to help members connect with each other.


        Meet our May member of the month: YK



        Q: Congrats on becoming our featured member of the month! Can you introduce yourself to our community members?


        My name is YiKai Chen from Climax Technology Co., LTD, Taipei, Taiwan. I am dedicated and interested in low power wireless protocols such as Zigbee, Contiki 6LowPan, Thread, BLE, z-Wave, DECT ULE, etc. We have worked on Zigbee products for more than 9 years and are using EM358x and EFR32 for our Zigbee products now.


        Q: How did you know about the Silicon Labs Community?



        When I start to use EM358x and EFR32, distributor suggests searching Silicon Labs Community when we have any question or problem. I used to work this way on another forum so I do the same thing on Silicon Labs Community.


        Q: What features, products, services would you like to see in the future from Silicon Labs?


        I would like to see more organized and detail documents about your products and more intelligent search for your products and application notes.


        Q: What advice would you give to someone new to the community?


        Be patient, search and read if there is any existing answer to your issue on the community. If not, don’t afraid to ask. We are willing to help.

      • Speed Does Not Kill: Power Supplies with Fast Switching Frequency Get Safer

        Lance Looper | 05/136/2017 | 10:00 AM

        The more power generated by a smaller power supply, the more cost effective it is and the less room it takes in the design. Designers can improve W/mm3 with faster switching. Switching technology using Gallium Nitride (GaN) or Silicon Carbide (SiC) allows faster switching rates than are currently available—up to 20 times faster.


        The technologies’ lateral structures, compared to vertical for silicon, make them low-charge devices capable of switching hundreds of volts in mere nano-seconds (ns). The challenge is that they require isolated gate drivers to work, and today’s technology typically cannot support the required noise immunity from their superfast switching.


        Faster Switching - SMPS Want It

        Fast power switching is most prevalent in switched mode power supplies (SMPS). SMPS convert their input power from ac to dc (ac-dc) or from dc to dc (dc-dc). In most cases, they also change voltage levels to suit the needs of the application.


        SMPS Graphic.png

        Typical ac-dc SMPS block diagram


        The new GaN and SiC technology switches faster and is more efficient than current switches. But their faster switching causes higher switching transients as shown in the figure below with a typical 600 V high side rail.

        Switching Transients.png

        Switching transients in a power converter


        GaN switching times are typically about 5ns, or about 10x - 20x faster than conventional systems. In this case, the 600 V high voltage rail results in a 120 kV/µs transient (600 V / 5 ns = 120 V/ns or 120 kV/µs).


        CMTI – Common Mode Transient Immunity – the Key Isolated Gate Driver Spec

        The isolated gate drivers controlling the power switches have to be designed to withstand these noise transients without creating glitches or latching-up. The ability of the driver to withstand these common mode noise transients is generally defined as CMTI (common mode transient immunity), and is expressed in units of kV/µs.



        What are the Isolated Gate Driver Options?

        Isolated gate drivers must preserve the integrity of the isolation from the primary to the secondary side. There are a number of isolated gate driver solutions available today:


        • Junction-isolated drivers – With 50 kV/µs for latch-up immunity (CMTI proxy), these are not suitable for new, fast-switching tech’s requirement.
        • Opto-coupled drivers – With 10-50 kV/µs for latch-up immunity (CMTI proxy), these are still not good enough.
        • Transformer-coupled drivers – Getting closer with 50-100 kV/µs for latch-up immunity (CMTI proxy), but these are still not adequate.
        • Capacitive-coupled drivers – She’s got it where it counts. These explicitly specify CMTI at 200 kV/µs (MIN) for signal integrity and 400 kV/µs (MAX) for latch-up immunity. These exceed the 120 kV/µs requirement.


        There are other advantages for these drivers. Their latency (propagation delay) can be as much as 10x better than popular optocoupled gate drivers, and their part-to-part matching can be more than 10x better. This provides the designer with another key advantage—the system’s overall modulation scheme can be fine-tuned for maximum efficiency (W/mm3) and safety without having to accommodate specification slop. They also support lower voltage operation (2.5 V compared to 5 V) and a wider operating temperature range.


        Plus, they offer advanced features such as input noise filters, asynchronous shutdown capability, and multiple configurations such as half bridge or dual independent drivers in a single package.

        Finally, they are rated to 60 years of operating life at high voltage conditions, longer than any other comparable solution.


        Power supply designers want to maximize their W/mm3 using the fastest power switching technology available. The latest GaN- and SiC-based switches are the fastest available technology today, but isolated require gate drivers with very high noise immunity (CMTI).


        The Si827x isolated gate drivers from Silicon Labs meet GaN’s and SiC’s noise immunity requirements with margin to spare (120 kV/µs required, 200 kV/µs supplied).



      • Chapter 6 Addendum: Input Modes Explained - Part 2

        lynchtron | 05/128/2017 | 10:00 AM



        In the last section, we introduced the GPIO as an input mode peripheral and the ADC for an analog detection of the input voltage.  In this section, we will configure the Analog Comparator (ACMP) to function as a discrete logic device, as both an input and output. 


        We will use the ACMP to level-shift the detected LED pulse of the last section from a weak signal to one that can be used as normal input logic to the MCU.

        Analog Comparator (ACMP)


        The Analog Comparator (ACMP) compares two analog input values and outputs a digital high or low signal depending on whether the positive input is higher than the negative input.  The inputs can be a pair of pins on the MCU, or an internal, software-controlled reference value with 64 divisions of the reference for one of the inputs. 


        The ACMP result can be read by software or optionally sent out to a physical pin.  By routing the digital output to a physical pin, the ACMP can be used as a discrete circuit element that can be utilized by external electronic circuitry, including external feedback, with no firmware required beyond the initial configuration.


        You could think of the ACMP as a slower and lower-resolution ADC.  Since the ACMP has an internal reference voltage that is configurable by software to 64 divisions of VCC (or 1.25v, or 2.5V internal references), you can sweep through those programmable reference levels to compare to the input at each reference value and thereby slowly determine the analog value of the input pin.

        The ACMP has eight available pins in its input mux that can be used for either the positive or negative input, each of which must be used one at a time. 


        To demonstrate the operation of the ACMP, we will use the ACMP as a discrete level shifter.  One of the things that the ACMP can do is shift the voltage of a signal from a low-voltage device so that you can interface it to a higher-voltage device.  We will once again use the light sensor on the starter kit to detect potentially faint pulses from a blinking LED and convert those pulses into full-swing 3.3V signals.

        To generate light pulses, we will configure a simple GPIO on PD1 to blink at a rate based on the TIMER0 CNT register, and then wire an LED to the PD1 pin with a 300-ohm resistor in series.  The necessary code to set up an LED blink rate is almost exactly that of the code to trigger the ADC in the previous section, except we simply configure the TIMER0 to trigger 10 times a second instead of once per second.  Then, inside the interrupt handler, we clear the interrupt and toggle the PD1 pin.  


              CMU_ClockEnable(cmuClock_TIMER0, true);
              CMU_ClockEnable(cmuClock_GPIO, true);
              // Create a timerInit object, based on the API default
              TIMER_Init_TypeDef timerInit = TIMER_INIT_DEFAULT;
              timerInit.prescale = timerPrescale1024;
              TIMER_IntEnable(TIMER0, TIMER_IF_OF);
              // Enable TIMER0 interrupt vector in NVIC
              // Set TIMER Top value
              TIMER_TopSet(TIMER0, ONE_SECOND_TIMER_COUNT / 10);
              TIMER_Init(TIMER0, &timerInit);
              // Wait for the timer to get going
              while (TIMER0->CNT == 0)
              // Excite the light sensor on PD6
              GPIO_PinModeSet(gpioPortD, 6, gpioModePushPull, 1);
              // Set up a GPIO output pin to push pull to the blink LED
              GPIO_PinModeSet(gpioPortD, 1, gpioModePushPull, 0);
        void TIMER0_IRQHandler(void)
              TIMER_IntClear(TIMER0, TIMER_IF_OF);
              GPIO_PinOutToggle(gpioPortD, 1);


        The voltage level detected by the light sensor from this blinking LED can be seen on an oscilloscope.


        The voltage swing generated by the light sensor (with the LED at about two inches from the light sensor) is between 500mV and 1V.  If we were to try to decipher the pulses from the light sensor with an ordinary GPIO pin in input mode, the voltage would never cross the thresholds needed to indicate a digital low/high transition.  Therefore, we will use the ACMP to “level shift” the light sensor output into full-swing 3.3V pulses on pin PE2.

        The following code will configure the ACMP to act as a discrete analog comparator, and will output the result on pin PE2. 


              CMU_ClockEnable(cmuClock_GPIO, true);
              CMU_ClockEnable(cmuClock_ACMP0, true);
              ACMP_Init_TypeDef acmp_init = ACMP_INIT_DEFAULT;
              acmp_init.fullBias = true;
              acmp_init.vddLevel = 10;
              /* Init and set ACMP0 channel on PC6 */
              ACMP_Init(ACMP0, &acmp_init);
              ACMP_ChannelSet(ACMP0, acmpChannelVDD, acmpChannel6);
              /* Set up GPIO as output on location 1, which is PE2, without inverting */
              ACMP_GPIOSetup(ACMP0, 1, true, false);
              GPIO_PinModeSet(gpioPortE, 2, gpioModePushPull, 0);
              /* Wait for warmup */
              while (!(ACMP0->STATUS & ACMP_STATUS_ACMPACT));

        The ACMP negative input reference required to sample the light sensor waveform is around 600mV (at least, that is what the ambient lighting conditions in the room required when I measured the above scope shot).  This can be achieved by setting the VDD reference type and using 11 divisions of 64 using the formula 11/64 * 3.3V = 567mV.  It is important to remember that this is an ambient light sensor, and that the baseline of this waveform will move as the amount of ambient light in the room changes.  Therefore, the value of 11 divisions of VDD could change depending on the ambient lighting conditions.  For example, a bright room might require a value of 24 for the VDD reference scaling factor.  It would be best to stop the LED blinking, sample the room ambient voltage, and then set the VDD reference just above the room ambient voltage value.


        In the oscilloscope waveforms, the original waveform from the light sensor is shown on channel 1, and the output of the ACMP is shown on channel 2.  The ACMP output waveform remains a steady 3.3V rail-to-rail voltage even as the distance between the LED and the light sensor varies over time, as shown in the waveform on the right.


        Note that once the analog comparator is set up as a discrete component, it will continue to function throughout interrupts, debug halts, and in energy modes EM0 through EM3. 


        It is also possible to sample the output of the comparator in software on ACMP0 Channel 6.  It can therefore be used to operate as a rudimentary ADC for quiescent signals by sweeping the negative input though all possible 64 steps to find which step triggers the output to go high.


        More details about the ACMP can be found in Application Note AN0020 Analog Comparator.

        The Voltage Comparator (VCMP) is a simplified instance of the ACMP that is tied directly to the VDD pin of the EFM32 MCU.  This gives your firmware the ability to detect the value of the supply voltage without using a GPIO pin or a channel of the ACMP.  More details about the VCMP peripheral can be found in Application Note AN0018 Supply Voltage Monitoring.  The application note also explains how to prepare for and react to dying battery situations.


        In the next section, we will use the TIMER and PCNT peripherals to count the input events, such as the pulses generated by a quadrature decoder or LED pulses.

      • IoT Hero Nanoleaf Breaks Down Barriers Between Doing Good, Looking Good, and Feeling Good

        deirdrewalsh | 05/123/2017 | 09:50 AM

        We were excited to recently sit down with Gimmy Chu, the CEO and a cofounder of Nanoleaf, a Smart Lighting company. With worldwide offices in Canada, Hong Kong, and China, Nanoleaf has been delivering never-before-seen lighting designs since 2012 with a passion for cutting-edge design and sustainability.


        Tell us a little about Nanoleaf; how do you describe your work to people?
        At our core, we are a smart lighting company on a mission for sustainability. We believe in creating smarter, more efficient lighting that offers a more exciting experience for consumers while also forging a more sustainable future for the planet. We often say that we want to break the barriers between doing good, looking good, and feeling good. We’ve focused a lot on thinking outside of the box when it comes down to product design as well; that is truly one of our passions.




        Your award-winning design work certainly speaks for itself. How did you even begin to approach smart lighting in the way that you do? You’re very unique.
        The other two cofounders and I were actually friends at university. We had a really strong bond. And a lot of that forged over the three of us building solar-powered cars together in a class. After graduation, the world pulled us in different ways. One of us went into pharmaceuticals, one into manufacturing in China, and I was on a more traditional corporate path of my own.


        Despite the distance, we kept in touch. And more important, we kept trying to brainstorm ways we could work together again, what we could try and make together that was completely different. Because that’s another one of our drivers: we want to make things that just don’t exist in the market. After many late-night Skype sessions, we landed on lighting as a great way to contribute to sustainability.


        Our first product we made together was actually a standard light bulb, but it was actually the most energy-efficient light bulb in the world; and we actually still offer a Classic Series of light bulb technology. But then the market demands of the IoT called us, and the necessity to play in a system where people could control their light bulbs, and where the light bulbs could talk to other devices as needed—that’s what we dove into.

        Our forays into the IoT spaces included the Smarter Kit we crowd-funded on Indiegogo—an Apple HomeKit-compatible offering. It was outfitted with a Nanoleaf Hub that allowed integration with Apple and a Nanoleaf Smart Ivy bulb. The Smart Ivy bulb still has more power than any other smart bulb on the market today. It’s a 60W equivalent bulb that uses only 7.5W of energy to produce 800 Lumens, and we managed to give it an Art Deco design no one had ever seen before in a light bulb.


        And our newest product offering is the Nanoleaf Aurora. It’s a set of modular LED panels that truly lets people customize and illuminate their space in ways that simply weren't possible before. You can control it and customize it completely to your taste and space—even with your voice. The Aurora was largely inspired by the idea of recreating natural light, so that people could experience the same warm soothing qualities indoors as well—especially during winter when there’s less sunlight hours.




        And what’s next for Nanoleaf? Where do you see Smart Lighting itself heading?
        We’re working on a new line that will launch this fall called the Aurora Rhythm. Like with everything we’ve done, we’re trying to push people to think outside the notion that lighting is just approximating a candle—the original home lighting product. Lighting has profound effects on your mood, energy levels, and overall well-being. It’s a very important aspect of living well every day, and we want to help improve that with each new product we release.


        Smarter-Kit -1.jpg


        Can you elaborate on your approximating a candle comment? That’s intriguing.
        Well, the thing about lighting in my opinion is that for a long time a light bulb was really just taking the idea of a candle flame and turning it upside down to hang from the ceiling, then connecting it to wires to light up a whole home. This idea of using light in a room is the box that people have placed lighting in. With today’s technology, we’ve eliminated these restrictions. The freedom of the Aurora panels lets people control and customize where they want their lighting, the shape and design, as well as the specific colors they want to set. It offers a full spectrum of lighting customizations to play with. Smart lighting is going to continue to push this boundary, as it should.




        What Silicon Labs product are you using at Nanoleaf, and why did you go with it?
        We’ve been using Silicon Labs since the beginning, and they’ve been integrated into several products now. The Smarter Kit I mentioned used your ZigBee SoCs and communications stack. These had a very low power implementation and were very easy to use. The Aurora used an 8-bit MCU. And the upcoming Aurora Rhythm slated for release this August is using the Bluetooth Blue Gecko SoC.


        I will also genuinely say that we’ve truly valued our partnership with Silicon Labs. Our R&D team has spent time with your R&D teams. The environment is collaborative with an openness to help each other and share knowledge. This kind of collaboration has helped us push boundaries and reach our goals. It’s been a trusted, pivotal partnership in my mind.


        Where do you see the collective IoT heading in the next 5–8 years in your opinion given your overall exposure to the space?
        Well, I think it’s safe to say that the standardization issue hopefully will get more resolution. A lot of entities out there still seem to be vested in a more proprietary approach to the IoT. Real standardization of the protocols everyone is following will really push the IoT to its next level of innovation in my opinion. The other thing to watch for is the progress of both voice recognition and AI within the space.



      • Computex Taipei 2017

        Nari | 05/123/2017 | 05:53 AM



        Location: Taipei International Convention Center (TICC), 2nd floor, 201F, Taipei, Taiwan

        Date: MAY 30 - JUNE 3, 2017


        Join us at Computex Taipei 2017 where we will be demoing everything you need to build a smarter, more connected world.   Meet and mingle with Silicon Labs experts, and see our live, hands-on demonstrations:



        Experience an end-to-end development solution for your IoT applications with Thunderboard Sense, with the wireless Gecko multi-protocol Bluetooth® low-energy and sub-GHz propriety radio. Easily sync through mobile app connectivity and cloud streaming.  


        With our Blue Gecko and voice over Bluetooth software and hardware, you can enhance your third party devices seamlessly with Apple HomeKit and Bluetooth LE applications.



        Reduce complexity of a connected mesh network design and minimize power consumption with Silicon Lab’s best-in-class wireless mesh software and tools. We will be demonstrating Smart Home and connected lighting solutions built with Mighty Gecko Multi-band, Multi-Protocol Wireless SoC.


        Stop by our hospitality suite (TICC, 2nd Floor, 201F) or sign up for a private booth tour by responding to this email or visiting  There are a limited number of slots available so be sure to sign up today!