other content about our technology & solutions
other content about our technology & solutions
A Top-Down Approach to Building Batteryless Self-Powered Systems for the Internet-of-Things
This paper presents a top-down methodology for designing batteryless systems for the Internet-of-Things (IoT).
We start by extracting features from a target IoT application and the environment in which it will be deployed. We then present strategies to translate these features into design choices that optimize the system and improve its reliability. We look into how to use these features to build the digital sub-system by determining the blocks to implement, the digital architecture, the clock rate of the system, the memory capacity, and the low power states. We also review how these features impact the choice of energy harvesting power management units.
A 116nW Multi-Band Wake-Up Receiver with 31- bit Correlator and Interference Rejection
This paper presents a 116nW wake-up radio complete with crystal reference, interference compensation, and baseband processing, such that a selectable 31-bit code is required to toggle a wake-up signal.
The front-end operates over a broad frequency range, tuned by an off-chip bandselect filter and matching network, and is demonstrated in the 402-405MHz MICS band and the 915MHz and 2.4GHz ISM bands with sensitivities of -45.5dBm, -43.4dBm, and -43.2dBm, respectively. Additionally, the baseband processor implements automatic threshold feedback to detect the presence of interferers and dynamically adjust the receiver’s sensitivity, mitigating the jamming problem inherent to previous energy-detection wake-up radios. The wake-up radio has a raw OOK chip-rate of 12.5kbps, an active area of 0.35mm2 and operates using a 1.2V supply for the crystal reference and RF demodulation, and a 0.5V supply for subthreshold baseband processing.
A 236nW -56.5dBm-Sensitivity Bluetooth Low-Energy Wakeup Receiver with Energy Harvesting in 65nm CMOS
Batteryless operation and ultra-low-power (ULP) wireless communication will be two key enabling technologies as the IC industry races to keep pace with the IoE projections of 1T-connected sensors by 2025.
Bluetooth Low-Energy (BLE) is used in many consumer IoE devices now because it offers the lowest average power for a radio that can communicate directly to a mobile device. The BLE standard requires that the IoE device continuously advertises, which initiates the connection to a mobile device. Sub-1s advertisement intervals are common to minimize latency. However, this continuous advertising results in a typical minimum average power of 10’s of μW at low duty-cycles. This leads to the quoted 1-year lifetimes of event-driven IoE devices (e.g. tracking tags, ibeacons) that operate from coin-cell batteries. This minimum power is too high for robust, batteryless operation in a small form-factor.
A 6.45 μW Self-Powered IoT SoC with Integrated Energy-Harvesting Power Management and ULP Asymmetric Radios
A 1 trillion node internet of things (IoT) will require sensing platforms that support numerous applications using power harvesting to avoid the cost and scalability challenge of battery replacement in such large numbers. Previous SoCs achieve good integration and even energy harvesting, but they limit supported applications, need higher end-to-end harvesting efficiency, and require duty-cycling for RF communication. This paper demonstrates a highly integrated, flexible SoC platform that supports multiple sensing modalities, extracts information from data flexibly across applications, harvests and delivers power efficiently, and communicates wirelessly.
A Battery-less 507nW SoC with Integrated Platform Power Manager and SiP Interfaces
A 507nW self-powered SoC is demonstrated for ultra-low power (ULP) internet-of-things (IoT) applications. The SoC includes ULP system-in-package (SiP) interfaces that enable its harmonious integration with a radio transmitter (TX) and a non-volatile memory (NVM). The energy harvesting platform power manager (EH-PPM) powers the SoC as well as off-chip components and is optimized for low quiescent power. It supplies the SoC with 0.5V, 1.0V, and 1.8V and can also power ULP sensors and the SiP components while running an example shipping-integrity tracking algorithm. A power monitor (PM) cold-boots the SoC from NVM and adapts the system’s power consumption. The tight integration between the SoC’s blocks enables sub-µW operation.
A 10 mV-Input Boost Converter With Inductor Peak Current Control and Zero Detection for Thermoelectric and Solar Energy Harvesting With 220 mV Cold-Start and 14.5 dBm, 915 MHz RF Kick-Start
A boost converter for thermoelectric energy harvesting in 130 nm CMOS achieves energy harvesting from a 10 mV input, which allows wearable body sensors to continue operation with low thermal gradients. The design uses a peak inductor current control scheme and duty cycled, offset compensated comparators to maintain high efficiency across a broad range of input and output voltages. The measured efficiency ranges from 53% at Vi = 20mV to a peak efficiency of 83% at Vi = 300mV. A cold-start circuit starts the operation of the boost converter from 220 mV, and an RF kick-start circuits starts it from -14.5 dBm at 915 MHz RF power.