Energy Harvesting Spotlight: Maxim Claims “Smallest Solar Harvesting Solution”
IoT designers are commonly plagued with the issue of long-term deployment. Energy-harvesting paradigms, including a new solar harvesting device from Maxim, may be a promising supplement to battery cells.
Deploying Internet of Things (IoT) devices for long-term service remains a complex challenge—despite high-density batteries, high-efficiency power converters, and low-power electronics. To power IoT devices, designers are faced with power considerations addressing three specific states of operation: quiescent, steady-state, and pulse/burst modes of operation.
For example, in a fire alarm, a small steady-state current draw is best handled by primary battery chemistry, where shelf life can be reasonably extrapolated based on the total integrated power requirements of the device relative to the primary cell energy density.
However, for IoT devices that change modes between the three states, it can be difficult for designers to quantify long-term energy demands. Maxim Integrated hopes to remedy this challenge with a recently-announced solar energy-harvesting solution, the MAX20361.
Energy Harvesting for IoT
Energy-harvesting technology, combined with rechargeable (secondary) battery cells, can capture and transform several potential sources of power into a useful electrical form for IoT devices.
Basic architecture of a solar photovoltaic cell. Image used courtesy of Hindawi
Some common sources of harvested energy include:
- Piezoelectric and static electricity
- Solar energy
Maxim Unveils the "Smallest Solar Harvesting Solution"
Last week, Maxim Integrated announced the “smallest solar harvesting solution” on the market with the release of the MAX20361 single/multi-cell solar harvester, equipped with power tracking capabilities.
Targeting space-constrained devices (thus limiting battery size), Maxim claims its solution is 50% smaller and more efficient than previous designs.
Maxim Integrated says the MAX20361EVKIT offers designers the opportunity to test out the features of the newest chipset. Image used courtesy of Maxim Integrated
“This device offers exciting possibilities for a new supplemental power source to continually charge the battery of a device,” said Frank Dowling, director of the Industrial and Healthcare Business Unit at Maxim Integrated.
Compared to the closest competitor, the new energy-harvesting solution is said to be 50% smaller and 5% more efficient. Image used courtesy of Maxim Integrated
“For example, if you can harvest just 30 mW of solar power per day on a 300 mAHr battery system, which typically runs for three weeks, you can, as a result, extend that runtime by over 50 percent.”
Conserving Energy for Transport Tracking
IoT sensors with longer runtimes become more attractive for supply chain management companies looking for transport tracking services, like those offered by the LoRaWAN wireless network. For instance, companies like TagoIO and Semtech, both members of the LoRa Alliance, collaboratively benefit from the energy-harvesting designs developed by Maxim Integrated.
However, transport analytics is not the only service to benefit from solar harvesting technology.
Electronic Clothes: Fashionable or Faux-Pas?
Wearables are another market in which researchers are investigating the potential use of solar energy harvesting. The goal here is to develop a “self-sustaining unit” to be worn on the human body.
A solar energy-harvesting wearable, developed by researchers Petar Jokic and Michele Magno. Image used courtesy of Petar Jokic and Michele Magno
This is especially true as electronics have made their way into wardrobes, whether for fashion—re: ugly Christmas sweaters with flashing LEDs—or for function, like solar-charged battery packs for charging cellphones on-the-go.
In these solar-powered or solar-supplemented wearable designs, designers are principally concerned with the maximum power point.
Maximum power from a solar cell is found at the “knee-point” between open-circuit voltage and short-circuit current. Image used courtesy of Petar Jokic and Michele Magno
Maxim Integrated’s new chipset is built with maximum power point tracking (MPPT), which could improve the availability of steady power to the device.
Developers Get Creative to Remotely Power IoT
The market for IoT and wearable technology will continue to demand that developers extend operational life. Beyond solar, researchers have recently posited that 5G might be used as a power grid. The researchers developed a flexible, high-gain energy-harvesting antenna based on a Rotman lens.
Whether using solar or electromagnetic energy harvesting, the question is no longer focused on whether designers can incorporate these energy sources. Rather, suppliers like Maxim Integrated are exploring how EEs can optimize sustainable power designs.
What experience do you have with incorporating energy harvesting in your designs? Do you have a story in which your battery technology didn’t last as long as you needed it? Share it in the comments below.