In a world focused on sustainability, addressing the energy demands of urbanization is critical. Technologies that reduce energy waste while offering efficiency are essential. The IoT industry faces the challenge of adopting such solutions. This article explores how the EFR32xG22E (xG22E) series SoC from Silicon Labs supports energy harvesting to simplify battery-free IoT solutions.
Environmental Impact of Batteries
IoT devices rely on power, often from traditional batteries. However, batteries pose significant drawbacks. Over 15 billion discarded batteries enter landfills annually, contributing to approximately 900,000 tons of hazardous waste that pollutes soil and groundwater. In the U.S., households purchase over 90 batteries per year, most lasting less than a decade. By 2025, an estimated 25 billion IoT devices will be operational, requiring 6 million battery replacements daily.
Batteries present issues of inconvenient disposal, frequent replacement, and scalability challenges. These limitations affect device reliability and hinder the transition to battery-free, energy-efficient IoT applications.
Ambient IoT: A New Class of Devices
To address the challenges of traditional batteries and minimize environmental impact, the industry has introduced ambient IoT devices. These devices draw power from natural sources such as magnetic and electric fields, light, heat, kinetic energy, and sound, reducing reliance on batteries.
Ambient IoT enables devices to operate using natural energy, extending their lifespan and significantly lowering the environmental footprint of battery use.
xG22E SoC for Energy Harvesting
The xG22E series SoC is optimized for energy harvesting. It features an 8ms power-on reset (PoR) consuming 150 microjoules (¦ÌJ), and an EM4 mode wake-up in 1.83ms using 16.6 ¦ÌJ. The SoC offers high RF performance, multi-protocol support, and 2.4GHz operation. It integrates with various power management devices, enabling the use of technologies like supercapacitors.
With fast, low-energy cold starts, efficient deep-sleep wake-ups, and energy mode transitions, the xG22E minimizes harmful current spikes and protects energy storage, making it a reliable wireless SoC for remote applications.
Applications of xG22E Energy Harvesting
The xG22E SoC supports a range of applications, including:
- Smart Homes and Appliances: Energy harvesting in Zigbee-enabled devices like door sensors, faucets, and switches eliminates battery dependency and replacement costs.
- Gaming Electronics: Indoor solar-powered TV remotes and keyboards benefit from low-power Bluetooth SoCs.
- Smart Buildings: Kinetic energy harvesting for battery-free door handles and light switches using Zigbee Green Power reduces maintenance needs.
- Other Applications: Tire pressure monitoring sensors, asset tracking, electronic shelf labels, factory automation, predictive maintenance, and smart agriculture.
Collaboration for Energy Harvesting Solutions
Silicon Labs has partnered with e-peas, a provider of power management ICs (PMICs), to develop an energy harvesting shield kit for the xG22E Explorer Kit. The kit includes three shields optimized for the development board to prevent power leakage and facilitate external measurements.
The first shield supports testing with alternative battery chemistries and supercapacitors, offering multiple test points. The second targets kinetic/pulse harvesting with the e-peas AEM0300 PMIC for power buck conversion. The third uses the e-peas AEM13920 PMIC, enabling experimentation with dual energy harvesting sources.
The kit includes example applications for Bluetooth and Zigbee Green Power, along with guidance on PMIC configuration and code optimization for energy-based decisions.
