Pub Date : 2025-01-21DOI: 10.1109/TBCAS.2025.3531995
Asif Iftekhar Omi;Anyu Jiang;Baibhab Chatterjee
In the context of implantable bioelectronics, this work provides new insights into maximizing biomedical wireless power transfer (BWPT) via the systematic development of inductive links. This approach addresses the specific challenges of power transfer efficiency (PTE) optimization within the spatial/area constraints of bio-implants embedded in tissue. Key contributions include the derivation of an optimal self-inductance with S-parameter-based analyses leading to the co-design of planar spiral coils and L-section impedance matching networks. To validate the proposed design methodology, two coil prototypes— one symmetric (type-1) and one asymmetric (type-2)— were fabricated and tested for PTE in pork tissue. Targeting a 20 MHz design frequency, the type-1 coil demonstrated a state-of-the-art PTE of $sim$ 4% (channel length = 15 mm) with a return loss (RL) $>$ 20 dB on both the input and output sides, within an area constraint of $<$ 18$times$18 mm${}^{2}$. In contrast, the type-2 coil achieved a PTE of $sim$ 2% with an RL $>$ 15 dB, for a smaller receiving coil area of $<$ 5$times$5 mm${}^{2}$ for the same tissue environment. To complement the coils, we demonstrate a 65 nm test chip with an integrated energy harvester, which includes a 30-stage rectifier and low-dropout regulator (LDO), producing a stable $sim$ 1V DC output within tissue medium, matching theoretical predictions and simulations. Furthermore, we provide a robust and comprehensive guideline for advancing efficient inductive links for various BWPT applications, with shared resources in GitHub available for utilization by the broader community.
{"title":"Efficient Inductive Link Design: A Systematic Method for Optimum Biomedical Wireless Power Transfer in Area-Constrained Implants","authors":"Asif Iftekhar Omi;Anyu Jiang;Baibhab Chatterjee","doi":"10.1109/TBCAS.2025.3531995","DOIUrl":"10.1109/TBCAS.2025.3531995","url":null,"abstract":"In the context of implantable bioelectronics, this work provides new insights into maximizing biomedical wireless power transfer (BWPT) via the systematic development of inductive links. This approach addresses the specific challenges of power transfer efficiency (PTE) optimization within the spatial/area constraints of bio-implants embedded in tissue. Key contributions include the derivation of an optimal self-inductance with S-parameter-based analyses leading to the co-design of planar spiral coils and L-section impedance matching networks. To validate the proposed design methodology, two coil prototypes— one symmetric (type-1) and one asymmetric (type-2)— were fabricated and tested for PTE in pork tissue. Targeting a 20 MHz design frequency, the type-1 coil demonstrated a state-of-the-art PTE of <inline-formula><tex-math>$sim$</tex-math></inline-formula> 4% (channel length = 15 mm) with a return loss (RL) <inline-formula><tex-math>$>$</tex-math></inline-formula> 20 dB on both the input and output sides, within an area constraint of <inline-formula><tex-math>$<$</tex-math></inline-formula> 18<inline-formula><tex-math>$times$</tex-math></inline-formula>18 mm<inline-formula><tex-math>${}^{2}$</tex-math></inline-formula>. In contrast, the type-2 coil achieved a PTE of <inline-formula><tex-math>$sim$</tex-math></inline-formula> 2% with an RL <inline-formula><tex-math>$>$</tex-math></inline-formula> 15 dB, for a smaller receiving coil area of <inline-formula><tex-math>$<$</tex-math></inline-formula> 5<inline-formula><tex-math>$times$</tex-math></inline-formula>5 mm<inline-formula><tex-math>${}^{2}$</tex-math></inline-formula> for the same tissue environment. To complement the coils, we demonstrate a 65 nm test chip with an integrated energy harvester, which includes a 30-stage rectifier and low-dropout regulator (LDO), producing a stable <inline-formula><tex-math>$sim$</tex-math></inline-formula> 1V DC output within tissue medium, matching theoretical predictions and simulations. Furthermore, we provide a robust and comprehensive guideline for advancing efficient inductive links for various BWPT applications, with shared resources in GitHub available for utilization by the broader community.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":"19 2","pages":"300-316"},"PeriodicalIF":0.0,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143545232","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 : 2025-01-17DOI: 10.1109/TBCAS.2025.3530790
Chen Zhang;Zhijie Huang;Changchun Zhou;Ao Qie;Xin an Wang
Many electrocardiogram (ECG) processors have been widely used for cardiac monitoring. However, most of them have relatively low energy efficiency, and lack configurability in classification leads number and inference algorithm models. A multi-lead ECG coprocessor is proposed in this paper, which can perform efficient ECG anomaly detection. In order to achieve high sensitivity and positive precision of R-peak detection, a method based on zero-crossing slope adaptive threshold comparison is proposed. Also, a one-dimensional convolutional neural network (1-D CNN) based classification engine with reconfigurable processing elements (PEs) is designed, good energy efficiency is achieved by combining filter level parallelism and output channel parallelism within the PE chains with register level data reuse strategy. To improve configurability, a single instruction multiple data (SIMD) based central controller is adopted, which facilitates ECG classification with configurable number of leads and updatable inference models. The proposed ECG coprocessor is fabricated using 55 nm CMOS technology, supporting classification with an accuracy of over 98%. The test results indicate that the chip consumes 62.2 nJ at 100 MHz, which is lower than most recent works. The energy efficiency reaches 397.1 GOPS/W, achieving an improvement of over 40% compared to the reported ECG processors using CNN models. The comparison results show that this design has advantages in energy overhead and configurability.
{"title":"An Energy-Efficient Configurable 1-D CNN-Based Multi-Lead ECG Classification Coprocessor for Wearable Cardiac Monitoring Devices","authors":"Chen Zhang;Zhijie Huang;Changchun Zhou;Ao Qie;Xin an Wang","doi":"10.1109/TBCAS.2025.3530790","DOIUrl":"10.1109/TBCAS.2025.3530790","url":null,"abstract":"Many electrocardiogram (ECG) processors have been widely used for cardiac monitoring. However, most of them have relatively low energy efficiency, and lack configurability in classification leads number and inference algorithm models. A multi-lead ECG coprocessor is proposed in this paper, which can perform efficient ECG anomaly detection. In order to achieve high sensitivity and positive precision of R-peak detection, a method based on zero-crossing slope adaptive threshold comparison is proposed. Also, a one-dimensional convolutional neural network (1-D CNN) based classification engine with reconfigurable processing elements (PEs) is designed, good energy efficiency is achieved by combining filter level parallelism and output channel parallelism within the PE chains with register level data reuse strategy. To improve configurability, a single instruction multiple data (SIMD) based central controller is adopted, which facilitates ECG classification with configurable number of leads and updatable inference models. The proposed ECG coprocessor is fabricated using 55 nm CMOS technology, supporting classification with an accuracy of over 98%. The test results indicate that the chip consumes 62.2 nJ at 100 MHz, which is lower than most recent works. The energy efficiency reaches 397.1 GOPS/W, achieving an improvement of over 40% compared to the reported ECG processors using CNN models. The comparison results show that this design has advantages in energy overhead and configurability.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":"19 2","pages":"317-331"},"PeriodicalIF":0.0,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143545036","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 : 2025-01-09DOI: 10.1109/TBCAS.2025.3527652
Muhammad Abrar Akram;Aida Aberra;Soon-Jae Kweon;Sohmyung Ha
This paper presents a new potentiostat circuit architecture for interfaces with amperometric electrochemical biosensors. The proposed architecture, which is based on a digital low-dropout regulator (DLDO) structure, successfully eliminates the need for transimpedance amplifier (TIA), control amplifier, and other passive elements unlike other typical potentiostat topologies. It can regulate the required electrode voltages and measure the sensor currents ($textit{I}_{textit{SENSE}}$) at the same time by using a simple implementation with clocked comparators, digital loop filters, and current-steering DACs. Three different configurations of the proposed potentiostat are discussed including single-side regulated (SSR) potentiostat, dual-side regulated (DSR) potentiostat, and differential sensing DSR potentiostat with a background working electrode. These proposed potentiostats were designed and fabricated in a 180 nm complementary metal-oxide semiconductor (CMOS) process, occupying an active silicon areas of 0.0645 mm${}^{2}$, 0.1653 mm${}^{2}$, and 0.266 mm${}^{2}$, respectively. Validation results demonstrate that the proposed potentiostats operate on a wide sampling frequency range from 100 Hz to 100 MHz and supply voltage range from 1 V to 1.8 V. The proposed DSR potentiostat achieves a minimal power consumption of 3.7 nW over the entire dynamic range of 129.5 dB.
{"title":"An Ultra-Low-Power Amplifier-Less Potentiostat Design Based on Digital Regulation Loop","authors":"Muhammad Abrar Akram;Aida Aberra;Soon-Jae Kweon;Sohmyung Ha","doi":"10.1109/TBCAS.2025.3527652","DOIUrl":"10.1109/TBCAS.2025.3527652","url":null,"abstract":"This paper presents a new potentiostat circuit architecture for interfaces with amperometric electrochemical biosensors. The proposed architecture, which is based on a digital low-dropout regulator (DLDO) structure, successfully eliminates the need for transimpedance amplifier (TIA), control amplifier, and other passive elements unlike other typical potentiostat topologies. It can regulate the required electrode voltages and measure the sensor currents (<inline-formula><tex-math>$textit{I}_{textit{SENSE}}$</tex-math></inline-formula>) at the same time by using a simple implementation with clocked comparators, digital loop filters, and current-steering DACs. Three different configurations of the proposed potentiostat are discussed including single-side regulated (SSR) potentiostat, dual-side regulated (DSR) potentiostat, and differential sensing DSR potentiostat with a background working electrode. These proposed potentiostats were designed and fabricated in a 180 nm complementary metal-oxide semiconductor (CMOS) process, occupying an active silicon areas of 0.0645 mm<inline-formula><tex-math>${}^{2}$</tex-math></inline-formula>, 0.1653 mm<inline-formula><tex-math>${}^{2}$</tex-math></inline-formula>, and 0.266 mm<inline-formula><tex-math>${}^{2}$</tex-math></inline-formula>, respectively. Validation results demonstrate that the proposed potentiostats operate on a wide sampling frequency range from 100 Hz to 100 MHz and supply voltage range from 1 V to 1.8 V. The proposed DSR potentiostat achieves a minimal power consumption of 3.7 nW over the entire dynamic range of 129.5 dB.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":"19 5","pages":"993-1004"},"PeriodicalIF":4.9,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143545042","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 the TENSmini, a compact and wearable device (38 $times$ 38 $times$ 21 mm${}^{3}$, weighing only 31 g), designed for home-based self-management of overactive bladder syndrome (OAB). The device integrates two conductive textile electrodes into a sock, which can be washed and reused. It is wirelessly controlled with mobile devices to generate current pulses with adjustable frequency from 1 to 100 Hz, pulse width of 50 to 250 $mu$s, and amplitude of up to 60 mA. A safety-enhanced drive circuit with galvanic isolation and automatic detection mechanism monitors electrode connections, prevents over-current, and protects users against open-circuit conditions. We report on the electrical properties of the conductive textile electrodes and present results from a real-world study involving ten human participants. The findings confirm that the wearable device effectively stimulates the tibial nerve and performs comparable to a clinical-grade stimulator. In general, the proposed system shows potential for OAB management due to its wearability, improved safety features, and long-term reusability.
{"title":"Smart Wearable TENS Device for Home-Based Overactive Bladder Management","authors":"Wei Ju;Aidan McConnell-Trevillion;David Alejandro Vaca-Benavides;Sadeque Reza Khan;Susan D. Shenkin;Kianoush Nazarpour;Srinjoy Mitra","doi":"10.1109/TBCAS.2025.3527343","DOIUrl":"10.1109/TBCAS.2025.3527343","url":null,"abstract":"We present the TENS<italic>mini</i>, a compact and wearable device (38 <inline-formula><tex-math>$times$</tex-math></inline-formula> 38 <inline-formula><tex-math>$times$</tex-math></inline-formula> 21 mm<inline-formula><tex-math>${}^{3}$</tex-math></inline-formula>, weighing only 31 g), designed for home-based self-management of overactive bladder syndrome (OAB). The device integrates two conductive textile electrodes into a sock, which can be washed and reused. It is wirelessly controlled with mobile devices to generate current pulses with adjustable frequency from 1 to 100 Hz, pulse width of 50 to 250 <inline-formula><tex-math>$mu$</tex-math></inline-formula>s, and amplitude of up to 60 mA. A safety-enhanced drive circuit with galvanic isolation and automatic detection mechanism monitors electrode connections, prevents over-current, and protects users against open-circuit conditions. We report on the electrical properties of the conductive textile electrodes and present results from a real-world study involving ten human participants. The findings confirm that the wearable device effectively stimulates the tibial nerve and performs comparable to a clinical-grade stimulator. In general, the proposed system shows potential for OAB management due to its wearability, improved safety features, and long-term reusability.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":"19 5","pages":"981-992"},"PeriodicalIF":4.9,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143545253","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 : 2025-01-08DOI: 10.1109/TBCAS.2025.3526762
Swagat Bhattacharyya;Jennifer O. Hasler
Integrate-and-fire (I&F) neurons used in neuromorphic systems are traditionally optimized for low energy-per-spike and high density, often excluding the complex dynamics of biological neurons. Limited dynamics cause missed opportunities in applications such as modeling time-varying physical systems, where using a small number of neurons with rich nonlinearities can enhance network performance, even when rich neurons incur a marginally higher cost. By adding additional coupling into the gate of one transistor within an I&F neuron, we parsimoniously achieve a highly nonlinear system capable of exhibiting rich dynamics and chaos. The dynamics of this novel neuron include regular spiking, fast spiking, and chaotic chattering, and can be tuned via the neuron parameters and input current. We implement and experimentally demonstrate the behavior of our chaotic neuron and its subcircuits on a 350 nm field-programmable analog array. Experimental insights inform a compact simulation model, which validates experimental results and confirms that the additional coupling incites chaos. Results are corroborated with comparisons to traditional I&F neurons. Our chaotic circuit achieves the lowest area (0.0025 mm2), power draw (1.1-2.6 W), and transistor count (6T) of any nondriven chaotic system in integrated CMOS thus far. We also demonstrate the utility of our neuron for neuroscience exploration and hardware security.
{"title":"A Six-Transistor Integrate-and-Fire Neuron Enabling Chaotic Dynamics","authors":"Swagat Bhattacharyya;Jennifer O. Hasler","doi":"10.1109/TBCAS.2025.3526762","DOIUrl":"10.1109/TBCAS.2025.3526762","url":null,"abstract":"Integrate-and-fire (I&F) neurons used in neuromorphic systems are traditionally optimized for low energy-per-spike and high density, often excluding the complex dynamics of biological neurons. Limited dynamics cause missed opportunities in applications such as modeling time-varying physical systems, where using a small number of neurons with rich nonlinearities can enhance network performance, even when rich neurons incur a marginally higher cost. By adding additional coupling into the gate of one transistor within an I&F neuron, we parsimoniously achieve a highly nonlinear system capable of exhibiting rich dynamics and chaos. The dynamics of this novel neuron include regular spiking, fast spiking, and chaotic chattering, and can be tuned via the neuron parameters and input current. We implement and experimentally demonstrate the behavior of our chaotic neuron and its subcircuits on a 350 nm field-programmable analog array. Experimental insights inform a compact simulation model, which validates experimental results and confirms that the additional coupling incites chaos. Results are corroborated with comparisons to traditional I&F neurons. Our chaotic circuit achieves the lowest area (0.0025 mm<sup>2</sup>), power draw (1.1-2.6 W), and transistor count (6T) of any nondriven chaotic system in integrated CMOS thus far. We also demonstrate the utility of our neuron for neuroscience exploration and hardware security.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":"19 5","pages":"1005-1017"},"PeriodicalIF":4.9,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143545026","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 : 2025-01-08DOI: 10.1109/TBCAS.2025.3526813
Sunglim Han;Hoyong Seong;Sein Oh;Jimin Koo;Hanbit Jin;Hye Jin Kim;Sohmyung Ha;Minkyu Je
This paper presents a 72-channel resistive-sensor interface integrated circuit (IC). The proposed IC consists of 8 sensor oscillator units and a reference clock generator. The sensor oscillator (S-OSC) units generate pulses with pulse widths dependent on the sensor input values, and the pulses are oversampled by the reference clock using frequency dividers. The time-domain signals are fed to the time-to-digital converters (TDCs) and converted to digital values. Each S-OSC unit is time-multiplexed to measure the resistance values from 9 sensors. Multiple phases from a highly energy-efficient phase-locked loop (PLL) are used for the TDCs, resulting in a signal-to-quantization-noise ratio (SQNR) that exceeds the intrinsic signal-to-noise ratio (SNR) of the sensor oscillators. This results in an effective number of bits (ENOB) of 9.3 bits at 310 pJ per channel. The maximum ENOB that can be achieved with a division ratio (N) of 256 is 14.1 bits and can be adjusted by changing N. Using this time-domain interface approach, the IC converts the sensor resistances directly into time, extending its measurement capabilities to 10 M$Omega$. The proposed IC, designed and fabricated in a 180-nm CMOS process with an active area of 0.015 mm${}^{2}$, consumes only 15.07 $mu$W per channel, resulting in a channel-specific Walden figure of merit (FoM) of 0.48 pJ per conversion step. In addition, by tuning N, the IC achieves an outstanding Schreier FoM of 159.8 dB in high-resolution scenarios.
本文提出了一种72通道电阻式传感器接口集成电路。该集成电路由8个传感器振荡器单元和一个参考时钟发生器组成。传感器振荡器（S-OSC）单元产生脉冲宽度取决于传感器输入值的脉冲，脉冲由使用分频器的参考时钟过采样。时域信号被馈送到时间-数字转换器（tdc）并转换成数字值。每个S-OSC单元都是时间复用的，用于测量来自9个传感器的电阻值。tdc采用了高能效锁相环（PLL）的多相，导致信号-量化-噪声比（SQNR）超过传感器振荡器的固有信噪比（SNR）。这导致在每通道310 pJ时的有效位数（ENOB）为9.3位。当分割比(N)为256时，最大ENOB为14.1位，可通过改变N来调整。采用这种时域接口方法，IC将传感器电阻直接转换为时间，将其测量能力扩展到10 M $Omega$。该IC采用180nm CMOS工艺设计和制造，有源面积为0.015 mm ${}^{2}$，每个通道仅消耗15.07 $mu$ W，导致每个转换步骤的特定通道瓦尔登优点系数（FoM）为0.48 pJ。此外，通过调整N，该IC在高分辨率场景下实现了159.8 dB的出色施雷埃FoM。
{"title":"A Time-Domain Multi-Channel Resistive-Sensor Interface IC With High Energy Efficiency and Wide Input Range","authors":"Sunglim Han;Hoyong Seong;Sein Oh;Jimin Koo;Hanbit Jin;Hye Jin Kim;Sohmyung Ha;Minkyu Je","doi":"10.1109/TBCAS.2025.3526813","DOIUrl":"https://doi.org/10.1109/TBCAS.2025.3526813","url":null,"abstract":"This paper presents a 72-channel resistive-sensor interface integrated circuit (IC). The proposed IC consists of 8 sensor oscillator units and a reference clock generator. The sensor oscillator (S-OSC) units generate pulses with pulse widths dependent on the sensor input values, and the pulses are oversampled by the reference clock using frequency dividers. The time-domain signals are fed to the time-to-digital converters (TDCs) and converted to digital values. Each S-OSC unit is time-multiplexed to measure the resistance values from 9 sensors. Multiple phases from a highly energy-efficient phase-locked loop (PLL) are used for the TDCs, resulting in a signal-to-quantization-noise ratio (SQNR) that exceeds the intrinsic signal-to-noise ratio (SNR) of the sensor oscillators. This results in an effective number of bits (ENOB) of 9.3 bits at 310 pJ per channel. The maximum ENOB that can be achieved with a division ratio (N) of 256 is 14.1 bits and can be adjusted by changing N. Using this time-domain interface approach, the IC converts the sensor resistances directly into time, extending its measurement capabilities to 10 M<inline-formula><tex-math>$Omega$</tex-math></inline-formula>. The proposed IC, designed and fabricated in a 180-nm CMOS process with an active area of 0.015 mm<inline-formula><tex-math>${}^{2}$</tex-math></inline-formula>, consumes only 15.07 <inline-formula><tex-math>$mu$</tex-math></inline-formula>W per channel, resulting in a channel-specific Walden figure of merit (FoM) of 0.48 pJ per conversion step. In addition, by tuning N, the IC achieves an outstanding Schreier FoM of 159.8 dB in high-resolution scenarios.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":"19 2","pages":"291-299"},"PeriodicalIF":0.0,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761421","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 : 2025-01-03DOI: 10.1109/TBCAS.2024.3525071
Yegeun Kim;Changhun Seok;Yoontae Jung;Soon-Jae Kweon;Sohmyung Ha;Minkyu Je
This paper proposes a motion-artifact-tolerant multi-channel biopotential-recording IC. A simple counter-based digital-assisted loop (DAL), implemented entirely with digital circuits, is proposed to track motion artifacts. The DAL effectively tracks motion artifacts without signal loss for amplitudes up to 120 mV with a 10 Hz bandwidth and can accommodate even larger motion artifacts, up to 240 mV, with a 5 Hz bandwidth, demonstrating its robustness across various conditions and motion artifact ranges. The IC includes four analog front-end (AFE) channels, and they share the following programmable gain amplifier (PGA) and analog-to-digital converter (ADC) in a time-multiplexed manner. It supports a programmable gain from 20 dB to 54 dB. Furthermore, the chopper with an analog DC-servo loop (DSL) is added to cancel out electrode DC offsets (EDO) and achieve a low noise level by removing the 1/f noise. The proposed IC fabricated in a 0.18-$mu$m CMOS technology process achieves an input-referred noise (IRN) of 0.71 $mu$V${}_{textrm{rms}}$ over a bandwidth of 0.5 to 500 Hz and a signal-to-noise-and-distortion ratio (SNDR) of 63.34 dB. It consumes 5.74 $mu$W of power and occupies an area of 0.40 mm${}^{textrm{2}}$ per channel. As a result, the proposed IC can record various biopotential signals thanks to its artifact-tolerant and low-noise characteristics.
{"title":"A Motion-Artifact-Tolerant Biopotential-Recording IC With a Digital-Assisted Loop","authors":"Yegeun Kim;Changhun Seok;Yoontae Jung;Soon-Jae Kweon;Sohmyung Ha;Minkyu Je","doi":"10.1109/TBCAS.2024.3525071","DOIUrl":"10.1109/TBCAS.2024.3525071","url":null,"abstract":"This paper proposes a motion-artifact-tolerant multi-channel biopotential-recording IC. A simple counter-based digital-assisted loop (DAL), implemented entirely with digital circuits, is proposed to track motion artifacts. The DAL effectively tracks motion artifacts without signal loss for amplitudes up to 120 mV with a 10 Hz bandwidth and can accommodate even larger motion artifacts, up to 240 mV, with a 5 Hz bandwidth, demonstrating its robustness across various conditions and motion artifact ranges. The IC includes four analog front-end (AFE) channels, and they share the following programmable gain amplifier (PGA) and analog-to-digital converter (ADC) in a time-multiplexed manner. It supports a programmable gain from 20 dB to 54 dB. Furthermore, the chopper with an analog DC-servo loop (DSL) is added to cancel out electrode DC offsets (EDO) and achieve a low noise level by removing the 1/f noise. The proposed IC fabricated in a 0.18-<inline-formula><tex-math>$mu$</tex-math></inline-formula>m CMOS technology process achieves an input-referred noise (IRN) of 0.71 <inline-formula><tex-math>$mu$</tex-math></inline-formula>V<inline-formula><tex-math>${}_{textrm{rms}}$</tex-math></inline-formula> over a bandwidth of 0.5 to 500 Hz and a signal-to-noise-and-distortion ratio (SNDR) of 63.34 dB. It consumes 5.74 <inline-formula><tex-math>$mu$</tex-math></inline-formula>W of power and occupies an area of 0.40 mm<inline-formula><tex-math>${}^{textrm{2}}$</tex-math></inline-formula> per channel. As a result, the proposed IC can record various biopotential signals thanks to its artifact-tolerant and low-noise characteristics.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":"19 2","pages":"280-290"},"PeriodicalIF":0.0,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143545024","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 : 2024-12-31DOI: 10.1109/TBCAS.2024.3523913
Guoao Liu;Yuanqi Hu
In this paper, a wireless power transfer (WPT) system composed of a voltage-mode fully integrated resonance regulating rectifier (IR${{}^{3}}$) and an on-chip antenna running at 402 MHz has been designed for bioimplants in deep tissue. The proposed IR${{}^{3}}$, including a 200 pF decoupling capacitor, is implemented in a 0.22 mm${{}^{2}}$ active area in the 180-nm CMOS process. A charging duration based regulation compensation circuit offers a low ripple factor of 0.3% at a 1.8 V output voltage and a high voltage conversion efficiency (VCE) of 1.73 to overcome the low inductive coupling coefficient (under 0.01) due to the deep implant scenario. And a clock gating VCDL-based on-&-off delay compensation scheme is proposed to compensate for the phase error of the IR${{}^{3}}$. Performing rectification and regulation simultaneously in a single stage, the IR${{}^{3}}$ effectively enhances power conversion efficiency. The whole system achieves a power conversion efficiency (PCE) of 65% with a 1.5 mW load. In addition, digital control-based compensation circuits also improve its transient response performance, the 1% setting time is only 6.9 $mu$s when the load changes from 65 $mu$W to 1.5 mW.
{"title":"A 402 MHz and 1.73-VCE Resonance Regulating Rectifier With On-Chip Antennas for Bioimplants","authors":"Guoao Liu;Yuanqi Hu","doi":"10.1109/TBCAS.2024.3523913","DOIUrl":"10.1109/TBCAS.2024.3523913","url":null,"abstract":"In this paper, a wireless power transfer (WPT) system composed of a voltage-mode fully integrated resonance regulating rectifier (IR<inline-formula><tex-math>${{}^{3}}$</tex-math></inline-formula>) and an on-chip antenna running at 402 MHz has been designed for bioimplants in deep tissue. The proposed IR<inline-formula><tex-math>${{}^{3}}$</tex-math></inline-formula>, including a 200 pF decoupling capacitor, is implemented in a 0.22 mm<inline-formula><tex-math>${{}^{2}}$</tex-math></inline-formula> active area in the 180-nm CMOS process. A charging duration based regulation compensation circuit offers a low ripple factor of 0.3% at a 1.8 V output voltage and a high voltage conversion efficiency (VCE) of 1.73 to overcome the low inductive coupling coefficient (under 0.01) due to the deep implant scenario. And a clock gating VCDL-based on-&-off delay compensation scheme is proposed to compensate for the phase error of the IR<inline-formula><tex-math>${{}^{3}}$</tex-math></inline-formula>. Performing rectification and regulation simultaneously in a single stage, the IR<inline-formula><tex-math>${{}^{3}}$</tex-math></inline-formula> effectively enhances power conversion efficiency. The whole system achieves a power conversion efficiency (PCE) of 65% with a 1.5 mW load. In addition, digital control-based compensation circuits also improve its transient response performance, the 1% setting time is only 6.9 <inline-formula><tex-math>$mu$</tex-math></inline-formula>s when the load changes from 65 <inline-formula><tex-math>$mu$</tex-math></inline-formula>W to 1.5 mW.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":"19 5","pages":"968-980"},"PeriodicalIF":4.9,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143543911","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 : 2024-12-23DOI: 10.1109/TBCAS.2024.3521033
Qing Yang;Hadi Lotfi;Frederik Dreyer;Michal Kern;Bernhard Blümich;Jens Anders
Low-field nuclear magnetic resonance (NMR) instruments are an indispensable tool in industrial research and quality control. However, the intrinsically low spin polarization at low magnetic fields severely limits their detection sensitivity and measurement throughput, preventing their widespread use in biomedical analysis. Overhauser dynamic nuclear polarization (ODNP) effectively addresses this problem by transferring the spin polarization from free electrons to protons, significantly enhancing sensitivity. In this paper, we explore the potential of using ODNP for signal enhancement in a custom-designed portable chip-based DNP-enhanced NMR platform, which is centered around a miniaturized microwave (MW) transmitter, a custom-designed NMR-on-a-chip transceiver, and two application-specific ODNP probes. The MW transmitter provides frequency synthesis, signal modulation, and power amplification, providing sufficient output power for efficient polarization transfer. The NMR-on-a-chip transceiver combines a radio frequency (RF) transmitter with a fully differential quadrature receiver, providing pulsed excitation and NMR signal down-conversion and amplification. Two custom-designed ODNP probes are used for proof-of-concept DNP-enhanced NMR relaxometry and spectroscopy measurements. The presented chip-based ODNP platform achieves a maximum MW output power of $34 textrm{dBm}$, resulting in a signal enhancement of $-162$ using the relaxometry ODNP probe with $1.4 mutextrm{L}$ of $10 textrm{mM}$ non-degassed TEMPOL solution, and an enhancement of $-63$ with the spectroscopy ODNP probe using $50 textrm{nL}$ of the same solution. The proton polarization was increased from $0.5times 10^{-6}$ to $81times 10^{-6}$ at a low field of $0.16 textrm{T}$. Proof-of-concept measurements on radical-doped tattoo inks and acetic acid verify the potential of our chip-based ODNP platform for the analysis of biologically and medically relevant parameters such as relaxation times, chemical shifts, and hyperfine interactions.
{"title":"A Portable Chip-Based Overhauser DNP Platform for Biomedical Liquid Sample Analysis","authors":"Qing Yang;Hadi Lotfi;Frederik Dreyer;Michal Kern;Bernhard Blümich;Jens Anders","doi":"10.1109/TBCAS.2024.3521033","DOIUrl":"10.1109/TBCAS.2024.3521033","url":null,"abstract":"Low-field nuclear magnetic resonance (NMR) instruments are an indispensable tool in industrial research and quality control. However, the intrinsically low spin polarization at low magnetic fields severely limits their detection sensitivity and measurement throughput, preventing their widespread use in biomedical analysis. Overhauser dynamic nuclear polarization (ODNP) effectively addresses this problem by transferring the spin polarization from free electrons to protons, significantly enhancing sensitivity. In this paper, we explore the potential of using ODNP for signal enhancement in a custom-designed portable chip-based DNP-enhanced NMR platform, which is centered around a miniaturized microwave (MW) transmitter, a custom-designed NMR-on-a-chip transceiver, and two application-specific ODNP probes. The MW transmitter provides frequency synthesis, signal modulation, and power amplification, providing sufficient output power for efficient polarization transfer. The NMR-on-a-chip transceiver combines a radio frequency (RF) transmitter with a fully differential quadrature receiver, providing pulsed excitation and NMR signal down-conversion and amplification. Two custom-designed ODNP probes are used for proof-of-concept DNP-enhanced NMR relaxometry and spectroscopy measurements. The presented chip-based ODNP platform achieves a maximum MW output power of <inline-formula><tex-math>$34 textrm{dBm}$</tex-math></inline-formula>, resulting in a signal enhancement of <inline-formula><tex-math>$-162$</tex-math></inline-formula> using the relaxometry ODNP probe with <inline-formula><tex-math>$1.4 mutextrm{L}$</tex-math></inline-formula> of <inline-formula><tex-math>$10 textrm{mM}$</tex-math></inline-formula> non-degassed TEMPOL solution, and an enhancement of <inline-formula><tex-math>$-63$</tex-math></inline-formula> with the spectroscopy ODNP probe using <inline-formula><tex-math>$50 textrm{nL}$</tex-math></inline-formula> of the same solution. The proton polarization was increased from <inline-formula><tex-math>$0.5times 10^{-6}$</tex-math></inline-formula> to <inline-formula><tex-math>$81times 10^{-6}$</tex-math></inline-formula> at a low field of <inline-formula><tex-math>$0.16 textrm{T}$</tex-math></inline-formula>. Proof-of-concept measurements on radical-doped tattoo inks and acetic acid verify the potential of our chip-based ODNP platform for the analysis of biologically and medically relevant parameters such as relaxation times, chemical shifts, and hyperfine interactions.","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":"19 2","pages":"257-269"},"PeriodicalIF":0.0,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143544942","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 : 2024-12-19DOI: 10.1109/TBCAS.2024.3519932
{"title":"2024 Index IEEE Transactions on Biomedical Circuits and Systems Vol. 18","authors":"","doi":"10.1109/TBCAS.2024.3519932","DOIUrl":"https://doi.org/10.1109/TBCAS.2024.3519932","url":null,"abstract":"","PeriodicalId":94031,"journal":{"name":"IEEE transactions on biomedical circuits and systems","volume":"18 6","pages":"1385-1410"},"PeriodicalIF":0.0,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10810376","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858944","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：