A 1.02 μW Battery-Less, Continuous Sensing and Post-Processing SiP for Wearable Applications

Lukas, Christopher J.; Yahya, Farah B.; Breiholz, Jacob; Roy, Abhishek; Chen, Xing; Patel, Harsh; Liu, Ningxi; Kosari, Avish; Li, Shuo; Kamakshi, Divya Akella; Ayorinde, Oluseyi; Wentzloff, David D.; Calhoun, Benton H.

doi:10.1109/tbcas.2019.2894775

Cited by 24 publications

(10 citation statements)

References 19 publications

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“…The experimental study shows that the device mounted on the various parts of the body can generate electricity through normal body movements (e.g., 2.5 V (foot), 1.98 V (ankle), 1.05 V (knee), 0.75 V (wrist), and 0.48 V (neck)). Its capacity to generate a peak power of 40 µW with a power density of 0.106 mW cm −3 shows the capability for powering small electronic components and wearable sensors (e.g., voltage supervisors [339] or ECG monitoring system-on-chips [340] ).…”

Section: Transparent Piezoelectric Energy Harvestermentioning

confidence: 99%

Advanced Soft Materials, Sensor Integrations, and Applications of Wearable Flexible Hybrid Electronics in Healthcare, Energy, and Environment

et al. 2019

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glasses, watches, wristbands, or belts, are either fully or partially composed of planar and rigid materials, which require the use of obtrusive, hard supports or additional bendable strips to be mounted on the human body. Therefore, clinical devices that use the existing wearables cause discomfort and limit monitoring of human physiological data in the laboratory. This is the big limitation factor to overcome despite the ever-growing market for wearables in broader screenings outside of the clinic. By this account, it is necessary to replace the bulky and rigid plastics and metal components in the sensors and electronics with skin-like materials for enhanced wearability and functionality.The concept of WFHE poses a possible solution to address the aforementioned difficulties by providing user comfort, compliant mechanics, soft integration, multifunctionality, and smart diagnostics with embedded machine learning algorithms. Specifically, such electronics would provide stable and intimate contact to the soft human skin without adding any mechanical and thermal loadings or causing skin breakdown. Current development strategies and approaches for advanced WFHE focus on soft, flexible form factors, nonirritating and nontoxic characteristics, fully autonomous energy components, seamless wireless communications, Recent advances in soft materials and system integration technologies have provided a unique opportunity to design various types of wearable flexible hybrid electronics (WFHE) for advanced human healthcare and humanmachine interfaces. The hybrid integration of soft and biocompatible materials with miniaturized wireless wearable systems is undoubtedly an attractiveprospect in the sense that the successful device performance requires high degrees of mechanical flexibility, sensing capability, and user-friendly simplicity. Here, the most up-to-date materials, sensors, and system-packaging technologies to develop advanced WFHE are provided. Details of mechanical, electrical, physicochemical, and biocompatible properties are discussed with integrated sensor applications in healthcare, energy, and environment. In addition, limitations of the current materials are discussed, as well as key challenges and the future direction of WFHE. Collectively, an all-inclusive review of the newly developed WFHE along with a summary of imperative requirements of material properties, sensor capabilities, electronics performance, and skin integrations is provided. Wearable Flexible Hybrid ElectronicsThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.

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Section: Transparent Piezoelectric Energy Harvestermentioning

confidence: 99%

Advanced Soft Materials, Sensor Integrations, and Applications of Wearable Flexible Hybrid Electronics in Healthcare, Energy, and Environment

et al. 2019

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“…In conventional operation, I OUT-avg is equal to the peak current (I OUT-peak ) and is determined by V OUT and ES/load impedance. With discontinuous charging, since current is delivered only during t NOL , I OUT-avg becomes a function of d NOL as shown in (8), where R L is the load resistance. This introduces d NOL as a new control variable that will be utilized in this technique.…”

Section: A Design Featuresmentioning

confidence: 99%

“…Therefore, reducing f SW would not be possible in conventional continuous operation. To keep V OUT in (9) constant and prevent P ROUT in (10) from increasing, the additional control variable d NOL is reduced to lower the I OUT-avg in (8). The lower losses result in achieving peak PCE at a lower P IN .…”

Section: B Theoretical Analysis Of Maximum Efficiency At Desired Inpmentioning

confidence: 99%

“…In healthcare, implantable or wearable wireless sensor network (WSN) nodes can be used to constantly monitor vital signs such as pulse, blood pressure, oxygen saturation, and ECG signals of persons at risk such as the elderly [5], [6]. They can also be used to detect falls in elderly patients and help manage chronic conditions [7], [8]. To enable this, WSN nodes are equipped with a microcontroller and transceiver, as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

“…For example, a 2.6mm x 3mm solar cell may produce 20nW-200µW depending on illuminance [18]. This wide variation is especially challenging for implantable devices located in body areas exposed to light, such as inside the eye or under the skin [1], [8]. Second, WSN nodes are deployed in harsh environments and energy must be harvested from ultra-low power levels.…”

Section: Introductionmentioning

confidence: 99%

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An Input Power-Aware Efficiency Tracking Technique With Discontinuous Charging for Energy Harvesting Applications

2020

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This paper proposes a discontinuous charging technique for switched-capacitor converters that improves the power conversion efficiency (PCE) at low power levels and extends the input power harvesting range at which high PCE is achievable. Discontinuous charging delivers current to energy storage only during clock non-overlap time. This enables tuning of the output current to minimize converter losses based on the available input power. Based on this fundamental result, an input power-aware, two-dimensional efficiency tracking technique for Wireless Sensor Network (WSN) nodes is presented. In addition to conventional switching frequency control, clock non-overlap time control is introduced to adaptively optimize PCE according to the sensed ambient power levels. The proposed technique is designed and simulated in 90nm CMOS with post-layout extraction. Under the same input and output conditions, the proposed system maintains at least 45% PCE at 4µW input power, as opposed to a conventional continuous system which requires at least 18.7µW to maintain the same PCE. Therefore, the input power harvesting range is extended by 1.5x. The technique is applied to a wearable WSN implementation utilizing the IEEE 802.15.4-compatible GreenNet communications protocol. This allows the node to meet specifications and achieve energy autonomy when deployed in environments where the input power is 49% lower than what is required for conventional operation.

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Design and analysis of batteryless cardiac pacemaker through combining thermoelectric generators along with DC‐DC converter

Shwetha¹,

Lakshmi

2021

Int Trans Electr Energ Syst

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Implantable cardiac pacemakers are equipped with batteries to provide power supply that have a limited lifetime. Battery-based implantable cardiac pacemakers need surgical intervention to replace batteries. This is an undesirable condition that can increase the risk of complications and costs for patients. To overcome the above shortcomings, a batteryless cardiac pacemaker is introduced, which harvests energy from the body temperature. In this article, a batteryless cardiac pacemaker is designed, which is powered by sustainable energy sources. Hence, thermoelectric generators (TEGs) are considered the sustainable renewable energy source that powers up cardiac pacemakers with effective reduction in dimension without limiting the capacity. Then, power electronic converters adapted with TEGs has enhanced the ability of controlling environmental conditions as well as maximizing energy harvesting. Therefore, a DC-DC converter is designed with TEG to solve environmental conditions issues of TEG. In this proposed methodology, a TEG with three different types of DC-DC converters is designed and validated to analyze the performance of converters such as boost converter, buck converter, and buckboost converter. The proposed design was analyzed based on a case example and simulated using Cadence Capture CIS. Finally, a prototype of our design was developed to evaluate the experimental outcome. Four modules are designed and validated: general pacemaker, TEG with pacemaker, TEG with boost converter, TEG with buck converter, and TEG with buck-boost List of Symbols and Abbreviations: ρ, density; Q, heat flux; Q, volumetric heat; C P , specific heat at consonant pressure; j !

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A 1.02 μW Battery-Less, Continuous Sensing and Post-Processing SiP for Wearable Applications

Cited by 24 publications

References 19 publications

Advanced Soft Materials, Sensor Integrations, and Applications of Wearable Flexible Hybrid Electronics in Healthcare, Energy, and Environment

Advanced Soft Materials, Sensor Integrations, and Applications of Wearable Flexible Hybrid Electronics in Healthcare, Energy, and Environment

An Input Power-Aware Efficiency Tracking Technique With Discontinuous Charging for Energy Harvesting Applications

Design and analysis of batteryless cardiac pacemaker through combining thermoelectric generators along with DC‐DC converter

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