Pub Date : 2024-03-28DOI: 10.1109/TBCAS.2024.3401821
{"title":"TechRxiv: Share Your Preprint Research with the World!","authors":"","doi":"10.1109/TBCAS.2024.3401821","DOIUrl":"https://doi.org/10.1109/TBCAS.2024.3401821","url":null,"abstract":"","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10540338","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141164706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-21DOI: 10.1109/TBCAS.2024.3380055
Shuenn-Yuh Lee;Zhan-Xian Liao;I-Ting Feng;Hao-Yun Lee;Chou-Ching Lin
This study proposes a charge-mode neural stimulator for electrical stimulation systems that utilizes a capacitor-reuse technique with a residual charge detector and achieves active charge balancing simultaneously. The design is mainly used for epilepsy suppression systems to achieve real-time symptom relief during seizures. A charge-mode stimulator is adopted in consideration of the complexity of circuit design, the high voltage tolerance of transistors, and system integration requirements in the future. The residual charge detector allows users to understand the current stimulus situation, enabling them to make optimal adjustments to the stimulation parameters. On the basis of the information on actual stimulation charge, active charge balancing can effectively prevent the accumulation of mismatched charges on electrode impedance. The capacitor- and phase-reuse techniques help realize high integration of the overall stimulator circuit in consideration of the commonality of the use of a capacitor and charging/discharging phase in the stimulation circuit and charge detector. The proposed charge-mode neural stimulator is implemented in a TSMC 0.18 µm 1P6M CMOS process with a core area of 0.2127 mm 2 . Measurement results demonstrate the accuracy of the stimulation’s functionality and the programmable stimulus parameters. The effectiveness of the proposed charge-mode neural stimulator for epileptic seizure suppression is verified through animal experiments.
{"title":"Charge-Mode Neural Stimulator With a Capacitor-Reuse Residual Charge Detector and Active Charge Balancing for Epileptic Seizure Suppression","authors":"Shuenn-Yuh Lee;Zhan-Xian Liao;I-Ting Feng;Hao-Yun Lee;Chou-Ching Lin","doi":"10.1109/TBCAS.2024.3380055","DOIUrl":"10.1109/TBCAS.2024.3380055","url":null,"abstract":"This study proposes a charge-mode neural stimulator for electrical stimulation systems that utilizes a capacitor-reuse technique with a residual charge detector and achieves active charge balancing simultaneously. The design is mainly used for epilepsy suppression systems to achieve real-time symptom relief during seizures. A charge-mode stimulator is adopted in consideration of the complexity of circuit design, the high voltage tolerance of transistors, and system integration requirements in the future. The residual charge detector allows users to understand the current stimulus situation, enabling them to make optimal adjustments to the stimulation parameters. On the basis of the information on actual stimulation charge, active charge balancing can effectively prevent the accumulation of mismatched charges on electrode impedance. The capacitor- and phase-reuse techniques help realize high integration of the overall stimulator circuit in consideration of the commonality of the use of a capacitor and charging/discharging phase in the stimulation circuit and charge detector. The proposed charge-mode neural stimulator is implemented in a TSMC 0.18 µm 1P6M CMOS process with a core area of 0.2127 mm\u0000<sup>2</sup>\u0000. Measurement results demonstrate the accuracy of the stimulation’s functionality and the programmable stimulus parameters. The effectiveness of the proposed charge-mode neural stimulator for epileptic seizure suppression is verified through animal experiments.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140186738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-20DOI: 10.1109/TBCAS.2024.3379208
Kai Cui;Xiaoya Fan;Yanzhao Ma
This paper presents an energy-efficient wireless power receiver for implantable electrical stimulation applications, which can achieve one-step adiabatic bipolar-supply that is generated by a hybrid single-stage dual-output regulating (SSDOR) rectifiers. The structure using only four switches overcomes the disadvantages that the two output voltage values in the traditional dual-output rectifiers are close to each other. A constant-current (CC) controlled adiabatic dynamic voltage scaling (DVS) technique is proposed to minimize the voltage headroom of the stimulating drivers and improve the stimulation efficiency significantly. In addition, the receiver adopts only one general constant on-time (COT) low-frequency control to adjust the stimulation current, reducing both the power consumption and the complexity of the control circuits. The proposed receiver has been fabricated in a 0.18 $mu$ m BCD process with $pm$ 6 V voltage compliance and 2.5 mA maximum stimulating current. With a current range from $pm$ 1.5 mA to $pm$ 2.5 mA, the measured maximum average headroom voltage is only 80 mV and the peak total efficiency of the receiver is 85.6 $%$ . The functionalities of the proposed receiver have been successfully verified through $in ,vitro$ experiments.
本文介绍了一种用于植入式电刺激应用的高能效无线电源接收器，该接收器可通过混合式单级双输出调节（SSDOR）整流器实现一步绝热双极供电。这种仅使用四个开关的结构克服了传统双输出整流器两个输出电压值相互接近的缺点。此外，还提出了一种恒流（CC）控制绝热动态电压缩放（DVS）技术，以最大限度地减少激励驱动器的电压净空，显著提高激励效率。此外，接收器只采用一个通用的恒定导通时间（COT）低频控制来调节激励电流，从而降低了功耗和控制电路的复杂性。该接收器采用 0.18 μm BCD 工艺制造，电压符合±6 V 标准，最大刺激电流为 2.5 mA。在 ±1.5 mA 至 ±2.5 mA 的电流范围内，测得的最大平均净空电压仅为 80 mV，接收器的峰值总效率为 85.6%。拟议接收器的功能已通过体外实验成功验证。
{"title":"An Energy-Efficient Wireless Power Receiver With One-Step Adiabatic-Bipolar-Supply Generating for Implantable Electrical Stimulation Applications","authors":"Kai Cui;Xiaoya Fan;Yanzhao Ma","doi":"10.1109/TBCAS.2024.3379208","DOIUrl":"10.1109/TBCAS.2024.3379208","url":null,"abstract":"This paper presents an energy-efficient wireless power receiver for implantable electrical stimulation applications, which can achieve one-step adiabatic bipolar-supply that is generated by a hybrid single-stage dual-output regulating (SSDOR) rectifiers. The structure using only four switches overcomes the disadvantages that the two output voltage values in the traditional dual-output rectifiers are close to each other. A constant-current (CC) controlled adiabatic dynamic voltage scaling (DVS) technique is proposed to minimize the voltage headroom of the stimulating drivers and improve the stimulation efficiency significantly. In addition, the receiver adopts only one general constant on-time (COT) low-frequency control to adjust the stimulation current, reducing both the power consumption and the complexity of the control circuits. The proposed receiver has been fabricated in a 0.18 \u0000<inline-formula><tex-math>$mu$</tex-math></inline-formula>\u0000m BCD process with \u0000<inline-formula><tex-math>$pm$</tex-math></inline-formula>\u00006 V voltage compliance and 2.5 mA maximum stimulating current. With a current range from \u0000<inline-formula><tex-math>$pm$</tex-math></inline-formula>\u00001.5 mA to \u0000<inline-formula><tex-math>$pm$</tex-math></inline-formula>\u00002.5 mA, the measured maximum average headroom voltage is only 80 mV and the peak total efficiency of the receiver is 85.6\u0000<inline-formula><tex-math>$%$</tex-math></inline-formula>\u0000. The functionalities of the proposed receiver have been successfully verified through \u0000<inline-formula><tex-math>$in ,vitro$</tex-math></inline-formula>\u0000 experiments.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140178353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-18DOI: 10.1109/TBCAS.2024.3378973
Yuming He;Stan van der Ven;Hua-Peng Liaw;Chengyao Shi;Pietro Russo;Marios Gourdouparis;Mario Konijnenburg;Stefano Traferro;Martijn Timmermans;Carolina Mora Lopez;Pieter Harpe;Eugenio Cantatore;Elisabetta Chicca;Yao-Hong Liu
Intracortical brain-computer interfaces offer superior spatial and temporal resolutions, but face challenges as the increasing number of recording channels introduces high amounts of data to be transferred. This requires power-hungry data serialization and telemetry, leading to potential tissue damage risks. To address this challenge, this paper introduces an event-based neural compressive telemetry (NCT) consisting of 8 channel-rotating Δ-ADCs, an event-driven serializer supporting a proposed ternary address event representation protocol, and an event-based LVDS driver. Leveraging a high sparsity of extracellular spikes and high spatial correlation of the high-density recordings, the proposed NCT achieves a compression ratio of >11.4×, while consumes only 1 µW per channel, which is 127× more efficient than state of the art. The NCT well preserves the spike waveform fidelity, and has a low normalized RMS error <23% even with a spike amplitude down to only 31 µV.
{"title":"An Event-Based Neural Compressive Telemetry With >11× Loss-Less Data Reduction for High-Bandwidth Intracortical Brain Computer Interfaces","authors":"Yuming He;Stan van der Ven;Hua-Peng Liaw;Chengyao Shi;Pietro Russo;Marios Gourdouparis;Mario Konijnenburg;Stefano Traferro;Martijn Timmermans;Carolina Mora Lopez;Pieter Harpe;Eugenio Cantatore;Elisabetta Chicca;Yao-Hong Liu","doi":"10.1109/TBCAS.2024.3378973","DOIUrl":"10.1109/TBCAS.2024.3378973","url":null,"abstract":"Intracortical brain-computer interfaces offer superior spatial and temporal resolutions, but face challenges as the increasing number of recording channels introduces high amounts of data to be transferred. This requires power-hungry data serialization and telemetry, leading to potential tissue damage risks. To address this challenge, this paper introduces an event-based neural compressive telemetry (NCT) consisting of 8 channel-rotating Δ-ADCs, an event-driven serializer supporting a proposed ternary address event representation protocol, and an event-based LVDS driver. Leveraging a high sparsity of extracellular spikes and high spatial correlation of the high-density recordings, the proposed NCT achieves a compression ratio of >11.4×, while consumes only 1 µW per channel, which is 127× more efficient than state of the art. The NCT well preserves the spike waveform fidelity, and has a low normalized RMS error <23% even with a spike amplitude down to only 31 µV.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140159847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-16DOI: 10.1109/TBCAS.2024.3401846
Yemin Kim;Junhyuck Lee;Byunghun Lee
Active implantable medical devices (AIMDs) rely on batteries for uninterrupted operation and patient safety. Therefore, it is critical to ensure battery safety and longevity. To achieve this, constant current/constant voltage (CC/CV) methods have been commonly used and research has been conducted to compensate for the effects of built-in resistance (BIR) of batteries. However, conventional CC/CV methods may pose the risk of lithium plating. Furthermore, conventional compensation methods for BIR require external components, complex algorithms, or large chip sizes, which inhibit the miniaturization and integration of AIMDs. To address this issue, we have developed a pulse charger that utilizes pulse current to ensure battery safety and facilitate easy compensation for BIR. A comparison with previous research on BIR compensation shows that our approach achieves the smallest chip size of 0.0062 mm 2 and the lowest system complexity using 1-bit ADC. In addition, we have demonstrated a reduction in charging time by at least 44.4% compared to conventional CC/CV methods, validating the effectiveness of our system’s BIR compensation. The compact size and safety features of the proposed charging system make it promising for AIMDs, which have space-constrained environments.
有源植入式医疗设备 (AIMD) 依靠电池实现不间断运行和患者安全。因此，确保电池的安全性和使用寿命至关重要。为此，人们普遍采用恒流/恒压（CC/CV）方法，并开展了补偿电池内置电阻（BIR）影响的研究。然而，传统的 CC/CV 方法可能会带来镀锂的风险。此外，传统的 BIR 补偿方法需要外部元件、复杂的算法或较大的芯片尺寸，这阻碍了 AIMD 的微型化和集成化。为了解决这个问题，我们开发了一种脉冲充电器，利用脉冲电流确保电池安全，并方便对 BIR 进行补偿。与以往的 BIR 补偿研究相比，我们的方法实现了 0.0062 mm2 的最小芯片尺寸，并使用 1 位 ADC 实现了最低的系统复杂性。此外，与传统的 CC/CV 方法相比，我们已证明充电时间至少缩短了 44.4%，这也验证了我们系统的 BIR 补偿效果。建议的充电系统体积小巧、安全可靠，因此很有希望应用于空间有限的 AIMD。
{"title":"Ultra-Compact Pulse Charger for Lithium Polymer Battery With Simple Built-in Resistance Compensation in Biomedical Applications","authors":"Yemin Kim;Junhyuck Lee;Byunghun Lee","doi":"10.1109/TBCAS.2024.3401846","DOIUrl":"10.1109/TBCAS.2024.3401846","url":null,"abstract":"Active implantable medical devices (AIMDs) rely on batteries for uninterrupted operation and patient safety. Therefore, it is critical to ensure battery safety and longevity. To achieve this, constant current/constant voltage (CC/CV) methods have been commonly used and research has been conducted to compensate for the effects of built-in resistance (BIR) of batteries. However, conventional CC/CV methods may pose the risk of lithium plating. Furthermore, conventional compensation methods for BIR require external components, complex algorithms, or large chip sizes, which inhibit the miniaturization and integration of AIMDs. To address this issue, we have developed a pulse charger that utilizes pulse current to ensure battery safety and facilitate easy compensation for BIR. A comparison with previous research on BIR compensation shows that our approach achieves the smallest chip size of 0.0062 mm\u0000<sup>2</sup>\u0000 and the lowest system complexity using 1-bit ADC. In addition, we have demonstrated a reduction in charging time by at least 44.4% compared to conventional CC/CV methods, validating the effectiveness of our system’s BIR compensation. The compact size and safety features of the proposed charging system make it promising for AIMDs, which have space-constrained environments.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140961387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present a mm-sized, ultrasonically powered lensless CMOS image sensor as a progress towards wireless fluorescence microscopy. Access to biological information within the tissue has the potential to provide insights guiding diagnosis and treatment across numerous medical conditions including cancer therapy. This information, in conjunction with current clinical imaging techniques that have limitations in obtaining images continuously and lack wireless compatibility, can improve continual detection of multicell clusters deep within tissue. The proposed platform incorporates a 2.4 × 4.7 mm 2 integrated circuit (IC) fabricated in TSMC 0.18 µm, a micro laser diode (µLD), a single piezoceramic and off-chip storage capacitors. The IC consists of a 36 × 40 array of capacitive trans-impedance amplifier-based pixels, wireless power management and communication via ultrasound and a laser driver all controlled by a Finite State Machine. The piezoceramic harvests energy from the acoustic waves at a depth of 2 cm to power up the IC and transfer 11.5 kbits/frame via backscattering. During Charge-Up, the off-chip capacitor stores charge to later supply a high-power 78 mW µLD during Imaging . Proof of concept of the imaging front end is shown by imaging distributions of CD8 T-cells, an indicator of the immune response to cancer, ex vivo, in the lymph nodes of a functional immune system (BL6 mice) against colorectal cancer consistent with the results of a fluorescence microscope. The overall system performance is verified by detecting 140 µm features on a USAF resolution target with 32 ms exposure time and 389 ms ultrasound backscattering.
{"title":"Toward a Wireless Image Sensor for Real-Time Fluorescence Microscopy in Cancer Therapy","authors":"Rozhan Rabbani;Hossein Najafiaghdam;Micah Roschelle;Efthymios Philip Papageorgiou;Biqi Rebekah Zhao;Mohammad Meraj Ghanbari;Rikky Muller;Vladimir Stojanović;Mekhail Anwar","doi":"10.1109/TBCAS.2024.3374886","DOIUrl":"10.1109/TBCAS.2024.3374886","url":null,"abstract":"We present a mm-sized, ultrasonically powered lensless CMOS image sensor as a progress towards wireless fluorescence microscopy. Access to biological information within the tissue has the potential to provide insights guiding diagnosis and treatment across numerous medical conditions including cancer therapy. This information, in conjunction with current clinical imaging techniques that have limitations in obtaining images continuously and lack wireless compatibility, can improve continual detection of multicell clusters deep within tissue. The proposed platform incorporates a 2.4 × 4.7 mm\u0000<sup>2</sup>\u0000 integrated circuit (IC) fabricated in TSMC 0.18 µm, a micro laser diode (µLD), a single piezoceramic and off-chip storage capacitors. The IC consists of a 36 × 40 array of capacitive trans-impedance amplifier-based pixels, wireless power management and communication via ultrasound and a laser driver all controlled by a Finite State Machine. The piezoceramic harvests energy from the acoustic waves at a depth of 2 cm to power up the IC and transfer 11.5 kbits/frame via backscattering. During \u0000<italic>Charge-Up,</i>\u0000 the off-chip capacitor stores charge to later supply a high-power 78 mW µLD during \u0000<italic>Imaging</i>\u0000. Proof of concept of the imaging front end is shown by imaging distributions of CD8 T-cells, an indicator of the immune response to cancer, \u0000<italic>ex vivo,</i>\u0000 in the lymph nodes of a functional immune system (BL6 mice) against colorectal cancer consistent with the results of a fluorescence microscope. The overall system performance is verified by detecting 140 µm features on a USAF resolution target with 32 ms exposure time and 389 ms ultrasound backscattering.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140066385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, a novel fixed-window level-crossing analog-to-digital converter (LCADC) is proposed for the ECG monitoring application. The proposed circuit is implemented using fewer comparators and reference levels compared to the conventional structure, which results in a decrease in complexity and occupied silicon area. Also, the power consumption is reduced considerably by decreasing the activity of the comparator. Simulation results show a 5-fold reduction in activity by applying the standard ECG signals to the proposed structure. The proposed circuit is implemented in 0.18 µm CMOS technology using a 0.9 V supply voltage. Measurement results show a 5.9 nW power consumption and a 7.4-bit resolution. The circuit occupies a 0.05846 mm 2 silicon area. A typical level-crossing-based R-peak-detection algorithm is applied to the output samples of the LCADC, which shows the effectiveness of using this type of sampling.
{"title":"An Ultra-Low Power Fixed-Window Level Crossing ADC for ECG Recording","authors":"Mahdi Ghasemi;Nassim Ravanshad;Hamidreza Rezaee-Dehsorkh","doi":"10.1109/TBCAS.2024.3376642","DOIUrl":"10.1109/TBCAS.2024.3376642","url":null,"abstract":"In this paper, a novel fixed-window level-crossing analog-to-digital converter (LCADC) is proposed for the ECG monitoring application. The proposed circuit is implemented using fewer comparators and reference levels compared to the conventional structure, which results in a decrease in complexity and occupied silicon area. Also, the power consumption is reduced considerably by decreasing the activity of the comparator. Simulation results show a 5-fold reduction in activity by applying the standard ECG signals to the proposed structure. The proposed circuit is implemented in 0.18 µm CMOS technology using a 0.9 V supply voltage. Measurement results show a 5.9 nW power consumption and a 7.4-bit resolution. The circuit occupies a 0.05846 mm\u0000<sup>2</sup>\u0000 silicon area. A typical level-crossing-based R-peak-detection algorithm is applied to the output samples of the LCADC, which shows the effectiveness of using this type of sampling.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140112518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-11DOI: 10.1109/TBCAS.2024.3375794
Reepa Saha;Zohreh Kaffash;S. Abdollah Mirbozorgi
This paper presents a novel resonance-based, adaptable, and flexible inductive wireless power transmission (WPT) link for powering implantable and wearable devices throughout the human body. The proposed design provides a comprehensive solution for wirelessly delivering power, sub-micro to hundreds of milliwatts, to deep-tissue implantable devices (3D space of human body) and surface-level wearable devices (2D surface of human skin) safely and seamlessly. The link comprises a belt-fitted transmitter (Belt-Tx) coil equipped with a power amplifier (PA) and a data demodulator unit, two resonator clusters (to cover upper-body and lower-body), and a receiver (Rx) unit that consists of Rx load and resonator coils, rectifier, microcontroller, and data modulator units for implementing a closed-loop power control (CLPC) mechanism. All coils are tuned at 13.56 MHz, Federal Communications Commission (FCC)-approved industrial, scientific, and medical (ISM) band. Novel customizable configurations of resonators in the clusters, parallel for implantable devices and cross-parallel for wearable devices and vertically oriented implants, ensure uniform power delivered to the load, PDL, enabling natural Tx power localization toward the Rx unit. The proposed design is modeled, simulated, and optimized using ANSYS HFSS software. The Specific Absorption Rate (SAR) is calculated under 1.5 W/kg, indicating the design’s safety for the human body. The proposed link is implemented, and its performance is characterized. For both the parallel cluster (implant) and cross-parallel cluster (wearable) scenarios, the measured results indicate: 1) an upper-body PDL exceeding 350 mW with a Power Transfer Efficiency (PTE) reaching 25%, and 2) a lower-body PDL surpassing 360 mW with a PTE of up to 20%, while covering up to 92% of the human body.
{"title":"Multi-resonator Wireless Inductive Power Link for Wearables on the 2D Surface and Implants in 3D Space of the Human Body","authors":"Reepa Saha;Zohreh Kaffash;S. Abdollah Mirbozorgi","doi":"10.1109/TBCAS.2024.3375794","DOIUrl":"10.1109/TBCAS.2024.3375794","url":null,"abstract":"This paper presents a novel resonance-based, adaptable, and flexible inductive wireless power transmission (WPT) link for powering implantable and wearable devices throughout the human body. The proposed design provides a comprehensive solution for wirelessly delivering power, sub-micro to hundreds of milliwatts, to deep-tissue implantable devices (3D space of human body) and surface-level wearable devices (2D surface of human skin) safely and seamlessly. The link comprises a belt-fitted transmitter (Belt-Tx) coil equipped with a power amplifier (PA) and a data demodulator unit, two resonator clusters (to cover upper-body and lower-body), and a receiver (Rx) unit that consists of Rx load and resonator coils, rectifier, microcontroller, and data modulator units for implementing a closed-loop power control (CLPC) mechanism. All coils are tuned at 13.56 MHz, Federal Communications Commission (FCC)-approved industrial, scientific, and medical (ISM) band. Novel customizable configurations of resonators in the clusters, parallel for implantable devices and cross-parallel for wearable devices and vertically oriented implants, ensure uniform power delivered to the load, PDL, enabling natural Tx power localization toward the Rx unit. The proposed design is modeled, simulated, and optimized using ANSYS HFSS software. The Specific Absorption Rate (SAR) is calculated under 1.5 W/kg, indicating the design’s safety for the human body. The proposed link is implemented, and its performance is characterized. For both the parallel cluster (implant) and cross-parallel cluster (wearable) scenarios, the measured results indicate: 1) an upper-body PDL exceeding 350 mW with a Power Transfer Efficiency (PTE) reaching 25%, and 2) a lower-body PDL surpassing 360 mW with a PTE of up to 20%, while covering up to 92% of the human body.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140103055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-08DOI: 10.1109/TBCAS.2024.3374891
Yuying Li;Yijie Li;Hao Li;Zhiliang Hong;Jiawei Xu
Non-invasive, closed-loop brain modulation offers an accessible and cost-effective means of evaluating and modulating one’s mental and physical well-being, such as Parkinson’s disease, epilepsy, and sleep disorders. However, wearable EEG systems pose significant challenges for the analog front-end (AFE) circuits in view of µV-level EEG signals of interest, multiple sources of interference, and ill-defined skin contact. This paper presents a direct-digitization AFE tailored for dry-electrode scalp EEG recording, characterized by wide input dynamic range (DR) and high input impedance. The AFE utilizes a second-order 5-bit delta-delta sigma (Δ-ΔΣ) ADC to shape DC electrode offset (DEO) and low-frequency disturbances while retaining high accuracy. A non-inverting pseudo-differential instrumentation amplifier (IA) embedded in the ADC ensures high input impedance (Z in ) and common-mode rejection ratio (CMRR). Fabricated in a standard 0.18-μm CMOS process, the AFE delivers 700-mV pp input signal range, 95.3-dB DR, 87-dB SNDR, and 800-MΩ input impedance at 50 Hz while consuming 88.4µW from a 1.2 V supply. The benefits of high DR and high input impedance have been validated by dry-electrode EEG measurement.
{"title":"An 800MΩ-Input-Impedance 95.3dB-DR Δ-ΔΣ AFE for Dry-Electrode Wearable EEG Recording","authors":"Yuying Li;Yijie Li;Hao Li;Zhiliang Hong;Jiawei Xu","doi":"10.1109/TBCAS.2024.3374891","DOIUrl":"10.1109/TBCAS.2024.3374891","url":null,"abstract":"Non-invasive, closed-loop brain modulation offers an accessible and cost-effective means of evaluating and modulating one’s mental and physical well-being, such as Parkinson’s disease, epilepsy, and sleep disorders. However, wearable EEG systems pose significant challenges for the analog front-end (AFE) circuits in view of µV-level EEG signals of interest, multiple sources of interference, and ill-defined skin contact. This paper presents a direct-digitization AFE tailored for dry-electrode scalp EEG recording, characterized by wide input dynamic range (DR) and high input impedance. The AFE utilizes a second-order 5-bit delta-delta sigma (Δ-ΔΣ) ADC to shape DC electrode offset (DEO) and low-frequency disturbances while retaining high accuracy. A non-inverting pseudo-differential instrumentation amplifier (IA) embedded in the ADC ensures high input impedance (Z\u0000<sub>in</sub>\u0000) and common-mode rejection ratio (CMRR). Fabricated in a standard 0.18-μm CMOS process, the AFE delivers 700-mV\u0000<sub>pp</sub>\u0000 input signal range, 95.3-dB DR, 87-dB SNDR, and 800-MΩ input impedance at 50 Hz while consuming 88.4µW from a 1.2 V supply. The benefits of high DR and high input impedance have been validated by dry-electrode EEG measurement.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140066384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a low-power frequency-domain functional near-infrared spectroscopy (FD-fNIRS) readout circuit for the absolute value measurement of tissue optical characteristics. The paper proposes a mixer-first analog front-end (AFE) structure and a 1-bit $Sigma$ - $Delta$ phase-to-digital converter (PDC) to reduce the required circuit bandwidth and the laser modulation frequency, thereby saving power while maintaining high resolution. The proposed chip achieves sub-0.01 ${}^{circ}$ phase resolution and consumes 6.8 mW of power. Nine optical solid phantoms are produced to evaluate the chip. Compared to a self-built high-precision measurement platform that combines a network analyzer with an avalanche photodiode (APD) module, the maximum measuring errors of the absorption coefficient and reduced scattering coefficient are 10.6% and 12.3%, respectively.
{"title":"An Energy-Efficient FD-fNIRS Readout Circuit Employing a Mixer-First Analog Frontend and a $Sigma$-$Delta$ Phase-to-Digital Converter","authors":"Zhouchen Ma;Cheng Chen;Yuxiang Lin;Liang Qi;Yongfu Li;Xia Bi;Mohamad Sawan;Guoxing Wang;Jian Zhao","doi":"10.1109/TBCAS.2024.3372887","DOIUrl":"10.1109/TBCAS.2024.3372887","url":null,"abstract":"This paper presents a low-power frequency-domain functional near-infrared spectroscopy (FD-fNIRS) readout circuit for the absolute value measurement of tissue optical characteristics. The paper proposes a mixer-first analog front-end (AFE) structure and a 1-bit \u0000<inline-formula><tex-math>$Sigma$</tex-math></inline-formula>\u0000-\u0000<inline-formula><tex-math>$Delta$</tex-math></inline-formula>\u0000 phase-to-digital converter (PDC) to reduce the required circuit bandwidth and the laser modulation frequency, thereby saving power while maintaining high resolution. The proposed chip achieves sub-0.01\u0000<inline-formula><tex-math>${}^{circ}$</tex-math></inline-formula>\u0000 phase resolution and consumes 6.8 mW of power. Nine optical solid phantoms are produced to evaluate the chip. Compared to a self-built high-precision measurement platform that combines a network analyzer with an avalanche photodiode (APD) module, the maximum measuring errors of the absorption coefficient and reduced scattering coefficient are 10.6% and 12.3%, respectively.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140029817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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