IoT reference designs optimize energy savings

Article By : Maurizio Di Paolo Emilio

In a future where most objects will be connected via Internet, devices and sensors will have to work wirelessly and without batteries.

In a future where most objects will be connected via Internet, devices and sensors will have to work wirelessly and without batteries. This is important to reduce energy consumption and environmental pollution.

Atmosic has unveiled the ATM3 series of IoT reference designs, developed specifically to optimize energy savings with photovoltaic energy harvesting and make the design of Bluetooth-connected devices flexible. The reference designs integrate Atmosic’s M3 Bluetooth 5 system-on-chip (SoC) with energy harvesting technology.

With Atmosic’s technology, connected devices can last for years on a battery, if they need a battery to operate at all, David Su, CEO at Atmosic, told EE Times Europe. “The lifetime of the device varies depending on the implementation and several other factors, but in general connected devices can last for several years without the need for battery replacement or charging.”

Reference design solutions make life easier for the designer, which in turn optimizes time-to-market for the company’s business. The three reference designs – one for remote controls, another for keypads and the third for beacons/sensors – will be released in the second quarter of 2021.

Solar energy

At its most basic level, an IoT sensor must be able to collect information, express that information in a digital format and transmit it down the chain, whether to a nearby peripheral device for collection and processing or directly to the back-end. Every part of that process has an energy cost, and although advances in technology have greatly increased energy efficiency in both processing and transmission, energy is still one of the main limiting factors in the design of IoT devices.

Battery technology is advancing more slowly than that of processors, chips, and sensors. This is one reason why some companies are looking for other methods to power their IoT devices. One option is solar energy. With increasingly efficient solar cells, it is fairly easy to add appropriately sized panels to small devices, and the cost of these panels has also fallen recently (figure 1).

Solar cell technology has advanced significantly in the last few years especially for small form factors. The efficiencies continue to improve, and various technology options for the material are now available. Atmosic is working with various solar cell manufacturers for reference solutions. The latest challenge manufacturers are working on is trying to make small, flexible solar cells that will enable interesting use cases,” said Su.

Figure 1: Battery Devices (Source: Atmosic)

Atmosic refence design

Thanks to the energy efficiency of solar energy harvesting, reference designs used in low-power IoT can not only have ‘forever’ battery life, but also offer the possibility of removing the battery. Atmosic highlighted how focusing on every aspect of low-power design will dramatically reduce, and in many cases eliminate, IoT’s reliance on batteries.

“Battery-free designs offer a number of advantages for both consumer and industrial applications. Consider a factory that uses Bluetooth beacons to keep track of thousands of assets. Changing all those batteries is time intensive, plus the cost of all those batteries will add up fast. By using battery-free designs, companies can cut down on maintenance time and enjoy big cost savings,” said Su.

He added, “Battery-free designs are ideal for devices that are relatively small in size and use less power, like keyboards and remotes. The bigger a device is, the more power it will use, so its photovoltaic cell will need to be proportionally larger. That’s why it’s more challenging to design larger and more power-intensive devices with energy harvesting, while also meeting other design requirements like size and aesthetics. However, as technology continues to advance, we’ll see battery-free designs become viable for a much wider variety of connected devices.”

Atmosic’s photovoltaic technology maximizes the energy capture of solutions with a very compact photovoltaic cell (the miniature equivalent of a solar panel) that fits compactly within the end product design to capture ambient sunlight or indoor light, possibly stored in a battery (figure 2).

Figure 2: Atmosic’s Applications

For example, in industrial beacon implementations, hundreds and even thousands of beacons can be deployed in a manufacturing plant, shopping mall or entertainment venue, eliminating labor and battery costs. For personal applications such as remote controls and keypads, the reliable operation of the device is a huge advantage while also providing numerous environmental benefits by reducing battery dependency among the growing number of IoT devices deployed worldwide.

The ATM3 remote control reference design provides three distinct storage configurations to allow for product design customization, including integrated standard coin cell battery with no supercapacitor, standard coin cell with a supercapacitor, rechargeable coin cell with no supercapacitor.

At the heart of the ATM3 reference design is a power management unit (PMU) integrated directly on the BLE chip for space and cost-efficiency. The intelligent PMU has a direct connection to the photovoltaic (PV) cell to maximize collection efficiency.

“While Atmosic’s new ATM3 series of IoT reference designs are expressly designed for photovoltaic energy harvesting, Atmosic’s M3 SoC enables devices to manage multiple energy inputs for the battery and harvested energy from various external sources including photovoltaic, RF, thermal, and kinetic. This means that manufacturers can use our M3 SoC to design products that draw power from multiple energy sources; in implementations where a particular source of energy might not be sufficient, having multiple energy sources will help the device to run longer,” said Su.

Atmosic’s low power BLE and efficient photovoltaic energy harvesting reduce the size of the photovoltaic cell, which has to be very small, offering a sleek and compact design for industrial applications.

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