Summary
- We are developing battery-less IoT devices powered by energy harvesting.
- To minimize power consumption, we are developing new technologies: (1) a novel compressed sensing technology, and (2) a proprietary power supply circuit (LDO regulator).
- (1) Novel compressed sensing technology: By leveraging the “sparsity” inherent in biological signals and signals from nature, we aim to create a sensing system that satisfies both high compression and high fidelity.
- (2) Proprietary power supply circuit: We have developed a new low dropout (LDO) regulator circuit. Despite its ultra-low power consumption, it achieves a high level of power supply stability, which is among the best in the world.
- We are developing a wearable EEG device that operates using minute temperature differences as an energy source.
- Our technologies are expected to contribute to the battery-less operation of IoT and wearable devices, reducing battery usage, enabling long-term operation, and facilitating device miniaturization.
- Developer explains in the video: https://youtu.be/Z7Jy3mnk_ko (Please use the subtitle function to watch).
Background & Technology
Associate Professor Daisuke Kanemoto and his team at the Graduate School of Engineering, Osaka University, are developing technologies to promote energy efficiency in IoT devices and wearable devices. Their research aims to address technical challenges such as extending operating time, miniaturizing batteries, and achieving battery-less operation using energy harvesters.
This time, we introduce two of the power-saving technologies developed in their research:
(1) Proprietary compressed sensing technology focusing on signal characteristics. By performing reconstruction processing that utilizes the features of the sensed signal, this technology achieves high compression, high-precision reconstruction, and accelerated compression processing for the sensing system. It has been demonstrated that this approach significantly improves accuracy compared to conventional reconstruction techniques.
(2) Proprietary LDO regulator. This independently developed technology achieves both power savings and high power supply stability for LDO regulators commonly used in electronic circuits of IoT and wearable devices. It significantly suppresses power supply fluctuations (PSRR: Power Supply Rejection Ratio) at the desired frequency while maintaining low power consumption. For more details, please refer to our website below.
https://bionauts.jp/?p=2448
Furthermore, to demonstrate the applicability of the above technologies (1) and (2) to IoT and sensor devices, the researchers have developed a prototype of a wireless EEG measurement device. This prototype reduces the power consumption of the A/D converter and wireless transmitter to the world’s lowest level of 97 μW per channel. Due to the significant reduction in power consumption, it was demonstrated that the device could operate using only the slight energy generated from a temperature difference of 2 degrees Celsius, such as the difference between body temperature and ambient temperature (for more details, refer to the “paper” below).
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Figure 1. Here is a photo of the developed wireless EEG device (“Kogaku” vol. 52, Oct. 2023, p.440). On the left side, a thermoelectric conversion element generates energy by applying a 2-degree temperature difference, created considering the difference between body temperature and ambient temperature. The EEG signal is output from a signal generator for the experiment, and it was confirmed that not only low power consumption (97 μW/channel) was achieved, but also that the reconstructed waveform closely resembled the original signal.
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Figure 2. Overview diagram of the wireless EEG device under development:
Researcher
Associate Professor Daisuke Kanemoto (Graduate School of Engineering, Osaka University)
Patent & Publication
(1) Novel compressed sensing technology
・Patent PCT/JP2023/002981
・Paper: https://doi.org/10.1109/ISCAS46773.2023.10181822
(2) Proprietary LDO regulator
・Patent PCT/JP2022/037552
・Paper: https://iopscience.iop.org/article/10.35848/1347-4065/ad1f0e
Expectation
- For those facing challenges with wireless, miniaturized, and low-power IoT and wearable devices.
- For those looking forward to developing devices through energy harvesting.
- For those interested in data compression technology for wireless communication and sensing circuit systems.
Please consider adopting this technology for your company’s new business ventures and next-generation technology development. We can establish a collaborative framework through technical guidance, joint research, and patent licensing agreements. We encourage you to start by exchanging ideas with the professor (via online meeting).
Project.DA-03294a