Disruptive extreme low-power SOTB Technology, which stands for Silicon on Thin Buried Oxide, has been used by Renesas Electronics to produce their latest RE range of MCU’s. This self-powering technology is just the start of an innovative suite of sustainable energy technology to come from them.

At its core is extreme low active and standby power, speed, scalability, high performance analog with low noise, and high immunity to disruption from particle radiation. All of which, allows the technology to overcome significant technical challenges of self-powering devices requiring far less in-rush current (the power needed to start up a device) than a traditional micro-controller.

The technology breaks the previous trade-off between getting either low active current or low standby current consumption – previously you could only choose one. With SOTB, you get both without compromise. This means that the RE micro-controller’s implemented on the SOTB technology, can utilise a combination of extreme low stand-by and active power usage, switching efficiently between modes, and reducing the consumption requirements.

Additionally, SOTB supports high operating frequency for high performance and small silicon node geometry for high-density memory. This is a recipe for very capable, extreme low-power applications that run from harvested ambient energy – no batteries required. The RE01 microcontroller, developed by Renesas, also implements an on-chip energy harvesting controller allowing easy connection to solar cells and other harvesting technologies.

Our dependency on batteries is ever-growing, accelerated by the billions of IoT devices that are in operation and continue to emerge. The latest battery technology has taken great leaps in the past five years. Battery life has improved significantly, and energy density has been boosted to new levels previously thought unreachable. But these advancements have come at a cost. These improvements were only possible thanks to an increasingly exotic list of new compounds; these compounds come from across the world and are considered dangerous to mine, and even more dangerous when out of the ground. Lithium has incredibly explosive properties, and other key metals such as cobalt, cadmium and manganese are also hazardous when handled.

At the forefront of tackling the growing dependencies on batteries is SOTB technology. It dramatically reduces power consumption in both the active and standby states, eliminating the need for battery replacement or recharging, enabling self-sustaining and eco-friendly products that last forever.

Renesas collaborated with selected global and regional partners in providing a range of solutions and software using RE MCUs to focus on core technologies such as energy harvesting and power management, in order to accelerate customers’ development in battery maintenance-free IoT applications.

In this case, AND Technology Research used it’s revolutionary c2 product development platform to build a Battery-less SOTB demonstrator in partnership with Renesas. It ran on harvested energy alone using a Renesas RE microcontoller that features integrated energy harvesting control circuitry. A supercap is used as the main power storage, enabling the system to be completely charged and discharged repeatedly for years without a battery. A Bluetooth Low Energy (BLE) Module is used to send data collected from the sensors to a phone and features a photovoltaic cell used to harvest energy from ambient light. Built-in temperature, light, and humidity sensors connected to the SOTB MCU PMOD Type 2 connector enables the ability to attach additional peripherals.

“AND Technology Research and Dracula Technologies were the ideal partners to help us investigate how we can use the our RE microcontrollers, implemented on the unique SOTBTM ultra-low power process to enable truly battery-less IoT sensors, both reducing the maintenance required and also greatly extending the product lifetime of IoT sensors, as well as addressing many of the concerns around the continued use of many battery technologies”

Graeme Clark, Renesas Marketing Manager

Any energy harvesting method could have been implemented to harvest energy that otherwise might have been wasted, such as light, heat, vibration or more. For this SOTB demonstrator, the Dracula LAYER® technology was selected as the energy harvester of choice. The printed technology generates energy from ambient light using organic photoactive inks which are made from only organic materials. It doesn’t require rare earth elements required for batteries.

At the forefront of our product development process for energy-related products is the new ground-breaking SOTB technology, allowing us to continue building technology that has sustainability at its core.

Combining this with our c2 development platform, developed from over 40 years’ experience working in the IoT industry, reduces development time by up to 50% and allows for creation, connection, and deployment of robust, disruptive digitally connected products that are bespoke.

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