Experimental Demonstration of STT-MRAM-based Nonvolatile Instantly On/Off System for IoT Applications: Case Studies

Abstract

Energy consumption has been a big challenge for electronic devices, particularly, for the battery-powered Internet of Things (IoT) equipment. To address such a challenge, on one hand, low-power electronic design methodologies and novel power management techniques have been proposed, such as nonvolatile memories and instantly on/off systems; on the other hand, the energy harvesting technology by collecting signals from human activity or the environment has attracted widespread attention in the IoT area. However, the system with self-powered energy harvesting may suffer frequent energy failures or fluctuating energy conditions, which degrade system reliability and user experience. Therefore, how to make the system under unreliable power inputs operate correctly and efficiently is one of the most critical issues for the energy harvesting technology. In this paper, we built an instantly on/off system based on nonvolatile STT-MRAM for IoT applications, which can instantly power on/off under different conditions of the harvested energy. The system powers on and operates normally when the harvested energy is enough (over the preset threshold); otherwise, the system powers off and stores the operational data back to the nonvolatile STT-MRAM. We described implementations of the hardware/software co-designed architecture (with image acquisition as an example) based on the commercialized 32MB STT-MRAM, and experimentally demonstrated the system functionality and efficiency under five typical energy harvesting scenarios, including radio-frequency (RF), thermal, solar, piezoelectric and WIFI. Our experimental results show that the power consumption and data restore time were reduced by 15.1 \(\% \) and 714 times respectively in comparison with the DRAM-based counterpart.

A Detailed Study of SOT-MRAM as an Alternative to DRAM Primary Memory in Multi-Core Environment

“…Importantly, they have shared specific timing and power details, offering valuable insights for further research. Work in [18] examines the effects of commercially available STT-MRAM and DRAM on energy harvesting in IoT systems. The study evaluates different scenarios and finds that using STT-MRAM results in a 15% decrease in power consumption and a 714x faster data restoration time.…”

Design of a spin–orbit-torque-based self-terminated nonvolatile register for a write/leakage-energy-minimized backup operation

“…3,4) Nonvolatile (NV) logic, where internal data are stored in NV-devices is a fundamental solution for this issue. [5][6][7][8][9] Because all the data can be retained in NV-devices without power supply, the use of NV-logic has high potential for realizing the ultra-low-power edge-IoT device by temporarily shutting down the power supply of the unused modules. An NV-register which is composed of several NV flip-flops (NV-FFs) [10][11][12][13][14] is a key component of the NV-logic LSI as it stores various temporal data into NV devices before power down.…”

Ultra High-Density SOT-MRAM Design for Last-Level On-Chip Cache Application

“…Spin-transfer torque magnetic random-access memory (STT-MRAM) has garnered significant interest as an excellent prospect for on-chip cache memory applications, owing to its advantageous attributes, such as high integration density, low leakage power consumption, inherent nonvolatility, and compatibility with the complementary metaloxide-semiconductor (CMOS) fabrication process [1][2][3][4][5][6][7][8][9][10].…”