U-blox Low Power GNSS Receiver Tapped for Smart Watch Design

Technologies from U‑blox and TransSiP have been selected for the recently announced PowerWatch 2 from MATRIX Industries. Power Watch 2 claims to be the world’s first GPS smartwatch that you never need to recharge. The smartwatch embeds the ultra‑small, ultra‑low power U‑blox ZOE‑M8B GNSS receiver. Meanwhile, TransSiP’s PI technology ensures energy harvested is used at maximum efficiency.

The PowerWatch 2 does away with cables and external batteries by continually topping up its battery using thermoelectric energy generated from body heat as well as solar energy. The watch can connect to your smartphone and display notifications on your wrist, while tracking activities and visualizing them using dedicated iOS and Android apps, as well as with popular third-party health and fitness platforms.

The PowerWatch 2 delivers location tracking using the low‑power U‑blox ZOE‑M8B GNSS receiver module that consumes as low as 12 mW. Packaged as a (System‑in‑Package), the 4.5 x 4.5 x 1.0 mm module helps achieve the watch’s comparatively low 16‑mm thickness. And concurrent reception of up to three GNSS constellations means that it delivers high accuracy positioning in challenging situations such as urban or dense forest environments and when swimming.

Satellite based positioning is typically the most power‑hungry process on a sports watch. Providing highly efficient conversion of harvested energy into a very quiet supply of DC power, TransSiP PI enhances the ability of the ZOE‑M8B GNSS receiver module incorporating U‑blox Super‑E technology, to strike an ideal balance between power and performance. Working on a tight power budget, the watch supports 30 minutes of continuous GNSS tracking per day, with unused time accumulating in the watch’s battery pack—powering two hours of location tracking every four days.

TransSiP | www.transsip.com

U‑blox | www.u‑blox.com

Tailored Solutions Tackle Design Needs for Wearables

Low Power Priorities

For wearable devices, every drop of power is precious. That’s driving designers of these embedded systems to attack the power challenge from multiple angles. Fortunately, a slew of analog, power and system ICs have emerged that address the wearable market’s particular needs.

By Jeff Child, Editor-in-Chief

While power is an important issue in any embedded system design, it’s especially critical in wearable devices. Today’s generation of wearable electronics require longer battery lives, more functionality and better performance—all in extremely small form factors. Wearables comprise a wide variety of products including smartwatches, physical activity monitors, heart rate monitors, smart headphones and more.
Today’s wearable electronic devices share some common design priorities. First, they have an extremely low budget for power consumption. And because they’re not suited to being powered by replaceable batteries, they usually require a way for the unit to be recharged. Meanwhile, most modern wearables require some kind of wireless connectivity.

Feeding those needs, chip vendors—primarily from the microcontroller (MCU) and analog sectors—over the past 12 months have announced a generous mix of solutions to help keep power consumption low, to aid recharging and to enable new capabilities while maintaining narrow power constraints. Chip and platform solutions aimed at wearables span the range from specialized power management ICs (PMICs), data converters and power regulator chips, to wireless charging solutions and even complete reference design platforms specially for wearables.

Wrist-Worn Health Gear

Wearables have evolved from being more than just fun devices for health and fitness. Using sophisticated sensors and other capabilities, devices are being designed to do virtual care monitoring, assess chronic conditions and evaluate overall well-being. Along just those lines, in September Maxim Integrated announced its Health Sensor Platform 2.0 (HSP 2.0) (Figure 1). This wrist-worn platform can be used for rapid prototyping, evaluation and development. It provides the ability to monitor electrocardiogram (ECG), heart rate and body temperature from a wrist-worn wearable, saving up to six months in development time, according to Maxim.

Figure 1
The Health Sensor Platform 2.0 is a wrist-worn platform that can be used for rapid prototyping, evaluation and development. It provides the ability to monitor electrocardiogram (ECG), heart rate and body temperature from a wrist-worn wearable.

In the past, system developers have found it challenging to derive precise ECG monitoring from the wrist—most alternatives require a wearable chest strap. Getting accurate body temperature typically requires using a thermometer at another location. Maxim has overcome these challenges in the HSP 2.0. by using its proprietary sensor and health monitoring technology.

Enclosed in a watch casing, the wrist-based form factor enables HSP 2.0 to provide basic functionality out of the box, with body-monitoring measurements starting immediately. Data can be stored on the platform for patient evaluation or streamed to a PC for analysis later. Unlike other wearables, the data measurements collected by the HSP 2.0 can be owned by the wearer. This alleviates data privacy concerns and enables users to conduct their own data analysis. Also, because HSP 2.0 is an open platform, designers can evaluate their own algorithms on the board. In addition, the modular format is future proof to quickly accommodate new sensors over time.

HSP 2.0 includes the following Maxim chips: the MAX32630 DARWIN low-power MCU for wearables; the MAX32664 ultra-low-power biometric sensor hub with embedded heart-rate algorithm; the MAX20303 PMIC; the MAX30205 human body temperature sensor with ±0.1°C accuracy; the MAX30001 single-channel integrated biopotential and bioimpedance analog front-end (AFE) solution; and the MAX86141 optical pulse oximeter and heart-rate sensor.

Energy Controller for Wearables

For its part, Renesas Electronics has been working on meeting extreme low power demands by applying innovations in semiconductor process development. In November the company unveiled an innovative energy-harvesting embedded controller that can eliminate the need to use or replace batteries in a device. Developed based on Renesas’ SOTB (silicon-on-thin-buried-oxide) process technology, the new embedded controller achieves extreme reduction in both active and standby current consumption. The extreme low current levels of the SOTB-based embedded controller enables system designers to completely eliminate the need for batteries in some of their products through harvesting ambient energy sources such as light, vibration and flow (Figure 2).

Figure 2
The extreme low current levels of the SOTB-based embedded controller enables system designers to completely eliminate the need for batteries in some of their products through harvesting ambient energy sources such as light, vibration and flow.

Although the solution was developed with IoT devices in mind, the controller is more broadly aimed at what they call the new market of maintenance-free, connected IoT sensing devices with endpoint intelligence. This includes health and fitness apparel, shoes, wearables, smart watches and drones. Renesas’ first commercial product using SOTB technology, the R7F0E embedded controller, is a 32-bit, Arm Cortex-based embedded controller. The device is capable of operating up to 64 MHz for rapid local processing of sensor data and execution of complex analysis and control functions.

The R7F0E consumes just 20 μA/MHz active current, and only 150 nA deep standby current, approximately one-tenth that of conventional low-power MCUs. According to the company, samples of the new R7F0E embedded controller are available now for beta customers, and samples are scheduled to be available for general customers from July 2019. Mass production is scheduled to start from October 2019.

LDO Regulator for Wearables

Achieving longer battery lives is a problem that can be attacked from many angles. Power regulator electronics are among those. With that in mind, Microchip Technology in October introduced a linear Low Dropout (LDO) regulator that extends battery life in portable devices up to four times longer than traditional ultra-low quiescent (IQ) LDOs. With an ultra-low IQ of 250 nA versus the approximately 1 µA operation of traditional devices, the MCP1811 LDO reduces quiescent current to save battery life, enabling end users to recharge or replace batteries less often (Figure 3).

Figure 3
With an ultra-low IQ of 250 nA versus the approximately 1 µA operation of traditional devices, the MCP1811 LDO regulator saves battery life, enabling end users to recharge or replace batteries less often.

Well suited for IoT and battery-operated applications such as wearables, remotes and hearing aids, the LDO reduces power consumption in applications by minimizing standby or shutdown current. Reducing standby power consumption is critical in remote, battery-powered sensor nodes, where battery replacement is difficult and operating life requirements are high. Available in package options as small as 1 mm x 1 mm, the MCP1811 consumes minimal board space to meet the needs of today’s compact portable electronic designs. Depending on the application and number of LDOs, designers can take advantage of the extra board space with a larger battery to further increase battery life.

An additional benefit the MCP1811 offers is faster load line and transient response when compared to other ultra-low IQ LDOs. Faster response times can accelerate wake-up speed in devices such as monitors or sensors that require immediate attention. Faster transient response can help designers avoid undervoltage and overvoltage lockout measures used in sensitive applications where transient spikes can lead to catastrophic results.

Secure Payments with Wearables

An important capability in a certain class of wearables is the ability to support electronic retail transactions directly from the wearable device. While this is arguably a whole separate technology category in itself, we’ll touch on a couple developments here. In November, Infineon Technologies announced an EMV-based payment solution for key chains, rings, wristbands, bracelets and other wearable devices.

The SECORA Pay W for Smart Payment Accessories (SPA) combines an EMV chip with the card operating system, payment applet as well as the antenna directly on the unit. As a turnkey solution it allows card vendors, device manufacturers, financial institutions or event organizers to quickly and cost-efficiently introduce fashion accessories for payment and even access.

Infineon’s SECORA Pay solutions portfolio comprises the SECORA Pay S for standard Visa and MasterCard payment cards, SECORA Pay X for applications with extended features such as multi-application, national debit and white label schemes or access management and SECORA Pay W for payment accessories. All SECORA turn-key solutions are pre-certified by Mastercard and Visa and will accelerate the deployment of contactless payment. The EMV Chip Specifications (www.emvco.com) define globally valid requirements for chip-based payment solutions and acceptance terminals. They enable secure contact- and contactless applications and the use of other emerging payment technologies.

Complete Payment SoC

Likewise a player in the contactless transaction market, STMicroelectronics (ST) back in October announced teaming up with Fidesmo to create a turnkey active solution for secure contactless payments on smart watches and other wearable technology. The complete payment system-on-chip (SoC) is based on ST’s STPay-Boost IC, which combines a hardware secure element to protect transactions and a contactless controller featuring proprietary active-boost technology that maintains reliable NFC connections even in devices made with metallic materials. Its single-chip footprint fits easily within wearable form factors (Figure 4).

Figure 4
The STPay-Boost IC combines a hardware secure element to protect transactions and a contactless controller featuring proprietary active-boost technology that maintains reliable NFC connections even in devices made with metallic materials. Its single-chip footprint fits easily within wearable form factors.

ST’s proprietary NFC-boosting active load modulation technology simplifies RF design and accelerates time to market by ensuring superior performance with little or no circuit optimization needed. A small-size antenna can sustain robust and reliable wireless connection, permitting smaller overall product dimensions and lower power consumption resulting in longer battery life.

Fidesmo’s MasterCard MDES tokenization platform completes the solution by allowing the user to load the personal data needed for payment transactions. Convenient Over-The-Air (OTA) technology makes personalization a simple step for the user without any special equipment. Kronaby, a Sweden-based hybrid smartwatch maker, has embedded the STPay-Boost chip in its portfolio of men’s and women’s smart watches that offer differentiated features such as freedom from charging and filtered notifications. The SoC with Fidesmo tokenization enables Kronaby watches to support a variety of services such as payments, access control, transportation and loyalty rewards.

Data Converters

Data converters also have role to play in efforts to meet the extreme low power needs of wearable devices. Along such lines, in December Texas Instruments (TI) introduced four tiny precision data converters (Figure 5). The new data converters enable designers to add more intelligence and functionality, while shrinking system board space. The DAC80508 and DAC70508 are eight-channel precision digital-to-analog converters (DACs) that provide true 16- and 14-bit resolution, respectively.

Figure 5
The DAC80508 and DAC70508 are eight-channel precision DACs that provide true 16- and 14-bit resolution, respectively. The ADS122C04 and ADS122U04 are 24-bit precision ADCs that feature a two-wire, I2C-compatible interface and a two-wire, UART-compatible interface, respectively.

The ADS122C04 and ADS122U04 are 24-bit precision analog-to-digital converters (ADCs) that feature a two-wire, I2C-compatible interface and a two-wire, UART-compatible interface, respectively. The devices are optimized for a variety of small-size, high-performance or cost-sensitive electronics applications such as wearables.

Both DACs include a 2.5-V, 5-ppm/°C internal reference, eliminating the need for an external precision reference. Available in a 2.4-mm-by-2.4-mm die-size ball-grid array (DSBGA) package or wafer chip-scale package (WCSP) and a 3-mm-by-3-mm quad flat no-lead (QFN)-16 package, these devices are up to 36% smaller than the competition, says TI. Meanwhile, the tiny, 24-bit precision ADCs are available in 3-mm-by-3-mm very thin QFN (WQFN)-16 and 5-mm-by-4.4-mm thin-shrink small-outline package (TSSOP)-16 options. The two-wire interface requires fewer digital isolation channels than a standard serial peripheral interface (SPI), reducing the overall cost of an isolated system. These precision ADCs eliminate the need for external circuitry by integrating a flexible input multiplexer, a low-noise programmable gain amplifier and other circuitry.

Memory Innovations

Among the latest innovations aimed at wearables from Cypress Semiconductor is an FRAM (ferroelectric random access memory)-based data logging solution. In November, Cypress introduced a nonvolatile data-logging solution with ultra-low power consumption. This solution is well suited for portable medical and wearable devices that demand nonvolatile memories to continuously log an increasing amount of user and sensor data while using as little power as possible.

Cypress’ Excelon LP FRAM is an energy-efficient device that provides instant-write capabilities with virtually unlimited endurance (Figure 6). This enables wearable systems to perform mission-critical data logging requirements while maximizing battery life. The Excelon LP series is available in a low-pin-count, small-footprint package that is suited for space-constrained, wearable applications.

Figure 6
The Excelon LP FRAM provides instant-write capabilities with virtually unlimited endurance. This enables wearable systems to perform mission-critical data logging requirements while maximizing battery life.

The Excelon LP series offers 4-Mb and 8-Mb industrial and commercial-grade densities with 50 MHz and 20 MHz Serial Peripheral Interface (SPI) performance. The series reduces power consumption with 100 nA hibernate and 1 µA standby modes that greatly improve a battery-powered product’s user experience by extending system operating time. The device’s inherent instant writes also eliminate power failure “data-at-risk” due to volatile data buffers in legacy memories. The family features wide voltage operation from 1.71 V to 3.6 V and is available in RoHS-compliant industry-standard packages that are pin compatible with EEPROMs and other nonvolatile memories. Excelon LP F-RAMs provide 1,000-trillion (1015) read/write cycle endurance with 10 years of data retention at 85°C or 151 years at 65°C.

Charging Wearables

A common aspect of wearable devices is that they tend not to be suited for replaceable batteries. As a result, they typically need to be recharged. Wireless (cordless) battery charging is beginning to take hold as a solution. Feeding such needs, in October Analog Devices announced its Power by Linear LTC4126 as an expansion of its offerings in wireless battery charging. The LTC4126 combines a wireless powered battery charger for Li-Ion cells with a high efficiency multi-mode charge pump DC-DC converter, providing a regulated 1.2 V output at up to 60 mA (Figure 7).

Figure 7
The LTC4126 combines a wireless powered battery charger for Li-Ion cells with a high efficiency multi-mode charge pump DC-DC converter, providing a regulated 1.2 V output at up to 60 mA.

Charging with the LTC4126 allows for a completely sealed end product without wires or connectors and eliminates the need to constantly replace non-rechargeable (primary) batteries. The efficient 1.2 V charge pump output features pushbutton on/off control and can directly power the end product’s ASIC. This greatly simplifies the system solution and reduces the number of necessary external components. The device is ideal for space-constrained low power Li-Ion cell powered wearables such as hearing aids, medical smart patches, wireless headsets and IoT devices.

The LTC4126, with its input power management circuitry, rectifies AC power from a wireless power receiver coil and generates a 2.7 V to 5.5 V input rail to power a full-featured constant-current/constant-voltage battery charger. Features of the battery charger include a pin selectable charge voltage of 4.2 V or 4.35 V, 7.5 mA charge current, automatic recharge, battery temperature monitoring via an NTC pin, and an onboard 6-hour safety charge termination timer. Low battery protection disconnects the battery from all loads when the battery voltage is below 3.0 V. The LTC4126’s charge pump switching frequency is set to 50 kHz/75 kHz to keep switching noise out of the audible range, ideal for audio related applications such as hearing aids and wireless headsets. The IC is housed in a compact, low profile (0.74 mm) 12-lead 2 mm × 2 mm LQFN package. The device is guaranteed for operation from –20°C to 85°C in E-grade.

Kit for Wireless Charging

Also facilitating building wireless chargers for wearables, ST for its part offers a kit-level solution. The ST plug-and-play wireless battery-charger development kit (STEVAL-ISB045V1) lets users quickly build ultra-compact chargers up to 2.5 W with a space-saving 20 mm-diameter coil, for charging small IoT devices and wearables such as smart watches, sports gear or healthcare equipment (Figure 8).

Figure 8
The ST plug-and-play wireless battery-charger development kit lets users quickly build ultra-compact chargers up to 2.5 W with a space-saving 20 mm-diameter coil, for charging small IoT devices and wearables such as smart watches, sports gear or healthcare equipment.

Built around the STWBC-WA wireless charging-transmitter controller, the kit comprises a charging base unit containing a transmitter board with the 20 mm coil already connected and ready to use. Getting started is easy, using the PC-based STSW-STWBCGUI software to configure the STWBC-WA and monitor runtime information such as power delivered, bridge frequency, demodulation quality and protocol status. The kit includes a dongle for running the GUI. The supporting ecosystem includes certified reference boards, software and detailed documentation to help developers quickly design chargers for wearables.

The STWBC-WA controller chip contains integrated drivers and natively supports full-bridge or half-bridge topologies for powering the antenna. The half-bridge option allows charging up to 1 W with a smaller-diameter coil for an even more compact form factor. The chip supports all standard wireless-charging features, including Foreign Object Detection (FOD) and active presence detection for safe charging, and uses digital feedback to adapt the transmitted power for optimum efficiency at all load conditions. Two firmware options give users the choice of a fast turnkey solution or customizing the application using APIs to access on-chip peripherals including an ADC, a UART and GPIOs.

Clearly there are many facets and angles to address the low power needs of wearables. As demands for more functionality rise, system developers will need to remain ever mindful of keeping battery life at the same lengths or longer. Fortunately, there seems to be no stopping the innovation among chip vendors targeting this growing wearables market.

RESOURCES

Analog Devices | www.analog.com
Cypress Semiconductor | www.cypress.com
Infineon Technologies | www.infineon.com
Maxim Integrated | www.maximintegrated.com
Microchip Technology | www.microchip.com
Renesas Electronics America | www.renesas.com
STMicroelectronics | www.st.com
Texas Instruments | www.ti.com

This article appeared in the March 344 issue of Circuit Cellar

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POWER MAKES IT POSSIBLE

Power Issues for Wearables
Wearable devices put extreme demands on the embedded electronics that make them work—and power is front and center among those demands. Devices spanning across the consumer, fitness and medical markets all need an advanced power source and power management technologies to perform as expected. Circuit Cellar Chief Editor Jeff Child examines how today’s microcontroller and power electronics are enabling today’s wearable products.

Power Supplies for Medical Systems
Over the past year, there’s been an increasing trend toward new products that have some sort of application or industry focus. That means supplies that include either certifications, special performance specs or tailored packaging intended for a specific application area such as medical. This Product Focus section updates readers on these technology trends and provides a product gallery of representative medical-focused power supplies.

DESIGN RESOURCES, ISSUES AND CHALLENGES

Flex PCB Design Services
While not exactly a brand-new technology, flexible printed circuit boards are a critical part of many of today’s challenging embedded system applications from wearable devices to mobile healthcare electronics. Circuit Cellar’s Editor-in-Chief, Jeff Child, explores the Flex PCB design capabilities available today and whose providing them.

Design Flow Ensures Automotive Safety
Fault analysis has been around for years, and many methods have been created to optimize evaluation of hundreds of concurrent faults in specialized simulators. However, there are many challenges in running a fault campaign. Mentor’s Doug Smith presents an improved formal verification flow that reduces the number of faults while simultaneously providing much higher quality of results.

Cooling Electronic Systems
Any good embedded system engineer knows that heat is the enemy of reliability. As new systems cram more functionality at higher speeds into ever smaller packages, it’s no wonder an increasing amount of engineering mindshare is focusing on cooling electronic systems. In this article, George Novacek reviews some of the essential math and science around cooling and looks are several cooling technologies—from cold pates to heat pipes.

MICROCONTROLLER PROJECTS WITH ALL THE DETAILS

MCU-Based Solution Links USB to Legacy PC I/O
In PCs, serial interfaces have now been just about completely replaced by USB. But many of those interfaces are still used in control and monitoring embedded systems. In this project article, Hossam Abdelbaki describes his ATSTAMP design. ATSTAMP is an MCS-51 (8051) compatible microcontroller chip that can be connected to the USB port of any PC via any USB-to-serial bridge currently available in the market.

Pet Collar Uses GPS and Wi-Fi
The PIC32 has proven effective for a myriad of applications, so why not a dog collar? Learn how Cornell graduates Vidya Ramesh and Vaidehi Garg built a GPS-enabled pet collar prototype. The article discusses the hardware peripherals used in the project, the setup, and the software. It also describes the motivation behind the project, and possibilities to expand the project in the future.

Guitar Video Game Uses PIC32
While music-playing video games are fun, their user interfaces tend leave a lot to be desired. Learn how Cornell students Jake Podell and Jonah Wexler designed and built a musical video game that’s interfaced with using a custom-built wireless guitar controller. The game is run on a Microchip PIC32 MCU and uses a TFT LCD display to show notes that move across the screen towards a strum region.

… AND MORE FROM OUR EXPERT COLUMNISTS

Non-Evasive Current Sensor
Gone are the days when you could do most of your own maintenance on your car’s engine. Today they’re sophisticated electronic systems. But there are some things you can do with the right tools. In his article, By Jeff Bachiochi talks about how using the timing light on his car engine introduced him to non-contact sensor technology. He talks about the types of probes available and how to use them to read the magnitude of alternating current (AC

Impedance Spectroscopy using the AD5933
Impedance spectroscopy is the measurement of a device’s impedance (or resistance) over a range of frequencies. Brian Millier has designed many voltammographs and conductivity meters over the years. But he recently came across the Analog Devices AD5933 chip made by which performs most all the functions needed to do impedance spectroscopy. In this article, explores the technology, circuit design and software that serve these efforts.

Side-Channel Power Analysis
Side-channel power analysis is a method of breaking security on embedded systems, and something Colin O’Flynn has covered extensively in his column. This time Colin shows how you can prove some of the fundamental assumptions that underpin side-channel power analysis. He uses the open-source ChipWhisperer project with Jupyter notebooks for easy interactive evaluation.

The Quest for Extreme Low Power

Input Voltage

–Jeff Child, Editor-in-Chief

JeffHeadShot

Over the next couple years, power will clearly rank as a major design challenge for the myriad of edge devices deployed in Internet of Things (IoT) implementations. Such IoT devices are wireless units that need to be always on and connected. At the same time, they need low power consumption, while still being capable of doing the processing power needed to enable machine intelligence. The need for extreme low power in these devices goes beyond the need for long battery life. Instead the hope is for perpetually powered solutions providing uninterrupted operation—and, if possible, without any need for battery power. For their part, microcontroller vendors have been doing a lot in recent years within their own labs to craft extreme low power versions of their MCUs. But the appetite for low power at the IoT edge is practically endless.

Offering a fresh take on the topic, I recently spoke with Paul Washkewicz, vice president and co-founder of Eta Compute about the startup’s extreme low power technology for microcontrollers. The company claims to offer the lowest power MCU intellectual property (IP) available today, with voltages as low as 0.3 V. Eta Compute has developed and implemented a unique low power design methodology that delivers up to a 10x improvement in power efficiency. Its IP and custom designs operate over severe variations in conditions such as temperature, process, voltage and power supply variation. Eta Compute’s approach is a self-timed technology supporting dynamic voltage scaling (DVS) that is insensitive to process variations, inaccurate device models and path delay variations.

The technology has been implemented in a variety of chip functions. Among these are M0+ and M3 ARM cores scaling 0.3 V to 1.2 V operation with additional low voltage logic support functions such as real-time clocking (RTC), Advanced Encryption Standard (AES) and digital signal processing. The technology has also been implemented in an A-D converter sensor interface that consumes less than 5 µW. The company has also crafted an efficient power management device that supports dynamic voltage scaling down to 0.25 V with greater than 80% efficiency.

According to the company, Eta Compute’s technology can be implemented in any standard foundry process with no modifications to the process. This allows ease of adoption of any IP and is immune to delays and changes in process operations. Manufacturing is straightforward with the company’s IP able to port to technology nodes at any foundry. Last fall at ARM TechCon, David Baker, Ph.D. and Fellow at Eta Compute, did a presentation that included a demonstration of a small wireless sensor board that can operate perpetually on a small 1 square inch solar cell.

Attacking the problem from a different direction, another startup, Nikola Labs, is applying its special expertise in antenna design and advanced circuitry to build power harvesting into products ranging from wearables to sensors to battery-extending phone cases. Wi-Fi routers, mobile phones and other connected devices are continually emitting RF waves for communication. According to the company, radio wave power is strongest near the source—but devices transmit in all directions, saturating the surrounding area with stray waves. Nikola Labs’ high-performance, compact antennae capture this stray RF energy. Efficient electronics are then used to convert it into DC electricity that can be used to charge batteries or energize ultra-low power devices.

Nikola’s technology can derive usable energy from a wide band of frequencies, ranging from LTE (910 MHz) to Wi-Fi (2.4 GHz) and beyond (up to 6 GHz). Microwatts of power can be harvested in an active ambient RF area and this can rise to milliwatts for harvesters placed directly on transmitting sources. Nikola Labs has demonstrated energy harvesting from a common source of RF communication waves: an iPhone. Nikola engineers designed a case for iPhone 6 that captures waste RF transmissions, producing up to 30 mW of power to extend battery life by as much as 16% without impacting the phone’s ability to send and receive data.

Whether you address the challenge of extreme low power from the inside out or the outside in—or by advancing battery capabilities—there’s no doubt that the demand for such technologies will only grow within the coming years. With all that in mind, I look forward to covering developments on this topic in Circuit Cellar throughout 2018.

This appears in the January (330) issue of Circuit Cellar magazine

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