Streamlining energy harvesting product development for battery-free IoT

The series includes the BG22E, MG22E, and FG22E models, which stand as Silicon Labs' most energy-efficient SoCs thus far. These SoCs support the creation of high-performance IoT devices utilising Bluetooth Low Energy (LE), 802.15.4-based, or Sub-Ghz wireless technologies. They are particularly suited for devices that operate on minimal power from external energy sources such as indoor or outdoor ambient light, ambient radio waves, and kinetic motion.

In addition, Silicon Labs has announced a partnership with e-peas to enhance the capabilities of its new xG22E Explorer Kit. This collaboration has led to the development of two specialised energy harvesting shields that integrate seamlessly with the Explorer Kit, enabling developers to fine-tune peripherals and debugging options to meet the specific requirements of their applications while achieving precise energy measurements. These shields are designed to optimally harvest and store energy from various sources. The first shield features e-peas' advanced AEM13920 dual-harvester, capable of simultaneously capturing energy from two separate sources – such as light, thermal gradients, and electromagnetic waves – without compromising energy conversion efficiency. The second shield, based on e-peas’ AEM00300, is tailored for harnessing energy from intermittent, pulsed sources.

"As the market for energy harvesting and low-power solutions grows, Silicon Labs remains dedicated to enhancing our wireless MCU and radio stack capabilities to advance the development of battery-free IoT solutions," said Ross Sabolcik, Senior Vice President for the Industrial and Commercial Business Unit at Silicon Labs. Our efforts to prioritise energy efficiency and increase device longevity underscore our commitment to fostering a more sustainable IoT ecosystem."

The expansion and widespread implementation of the Internet of Things (IoT) encounters a significant hurdle in powering devices that are both low in complexity and small in size. Conventional power sources such as mains electricity or batteries bring about issues of scalability and ongoing maintenance. The advent of Ambient IoT seeks to overcome these challenges by promoting a new category of connected devices that derive their power mainly from energy harvested from environmental sources such as radio waves, light, motion, and heat.

Silicon Labs aims to build a device that can address one of the significant challenges in Ambient IoT: creating a platform that can optimise its energy consumption and prolong its lifespan. The xG22E family comes equipped with several features designed to minimise energy use and make it the platform of choice for energy harvesting, including:

• Ultra-fast, low-energy cold start for applications starting from a zero-energy state to transmit packets and then rapidly return to sleep. An xG22E device wakes up in only eight milliseconds and uses only 150 micro-Joules, or roughly 0.003% of the energy needed to power a 60-watt equivalent LED lightbulb for one second
• Energy conserving deep sleep swift wake-up reduces wake-up energy by 78% compared to other Silicon Labs devices
• Power-efficient energy mode transition to smoothly transition in and out of energy modes by mitigating current spikes or inrush, which can harm energy storage capacity
• Multiple deep sleep wake-up options, such as RFSense, GPIO, and RTC wake-up sources from the deepest EM4 sleep mode, are ideal for extended storage

Energy harvesting and conservation technologies bring a host of advantages to various sectors, notably in reducing energy costs, cutting dependency on batteries, and shrinking operational carbon footprints through the shift in energy consumption sources and minimisation of battery waste. These technologies also enhance many existing IoT applications. For instance, electronic shelf labels, increasingly popular among global retailers, facilitate more precise pricing, inventory management, and loss prevention. Although such systems could involve thousands of labels per location, their low power requirements and intermittent connectivity needs make them ideal candidates for energy harvesting. By tapping into Ambient IoT energy sources, retailers can significantly reduce or completely eliminate their reliance on batteries for these labels. Similar applications in the consumer market include solar-powered television remote controls and portable, wireless switches for lights and appliances.