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IEEE Transactions on Biomedical Circuits and Systems

Kok-Hin Teng, Tong Wu, Xiayun Liu, Zhi Yang, Chun-Huat Heng
An 8-channel wireless neural signal processing IC, which can perform real-time spike detection, alignment, and feature extraction, and wireless data transmission is proposed. A reconfigurable BFSK/QPSK transmitter (TX) at MICS/MedRadio band is incorporated to support different data rate requirement. By using an Exponential Component-Polynomial Component (EC-PC) spike processing unit with an incremental principal component analysis (IPCA) engine, the detection of neural spikes with poor SNR is possible while achieving 625× data reduction...
March 3, 2017: IEEE Transactions on Biomedical Circuits and Systems
Pengpeng Chen, Huazhong Yang, Rong Luo, Bo Zhao
It is promising for wearable devices to go to a miniature size to alleviate the load of human body. One way to miniaturize the communication nodes on human body is to remove the bulky components such as antenna and crystal. Galvanically-coupled body channel communication (GC-BCC) has a great advantage over conventional wireless communications in reducing the size of wearable devices because it reuses the monitoring electrodes for signal transmission in place of antennas. To remove the crystal as well, the receiver must be immune to different types of frequency misalignments...
March 2, 2017: IEEE Transactions on Biomedical Circuits and Systems
Ahmed Soltan, Brian McGovern, Emmanuel Drakakis, Mark Neil, Pleun Maaskant, Mahbub Akhter, Jun Su Lee, Patrick Degenaar
Optical neuron stimulation arrays are important for both in-vitro biology and retinal prosthetic biomedical applications. Hence, in this work, we present an 8100 pixel high radiance photonic stimulator. The chip module vertically combines custom made gallium nitride μLEDs with a CMOS application specific integrated circuit. This is designed with active pixels to ensure random access and to allow continuous illumination of all required pixels. The μLEDs have been assembled on the chip using a solder ball flip-chip bonding technique which has allowed for reliable and repeatable manufacture...
February 13, 2017: IEEE Transactions on Biomedical Circuits and Systems
Hugo Cruz, Hong-Yi Huang, Ching-Hsing Luo, Shuenn-Yuh Lee
This paper presents a 10-channel time-of-flight application-specific integrated circuit (ASIC) for positron emission tomography in a 90 nm standard CMOS process. To overcome variations in channel-to-channel timing resolution caused by mismatch and process variations, adaptive biases and a digital-to-analog converter (DAC) are utilized. The main contributions of this work are as follows. First, multistage architectures reduce the total power consumption, and detection bandwidths of analog preamplifiers and comparators are increased to 1 and 1...
February 13, 2017: IEEE Transactions on Biomedical Circuits and Systems
Adriana N Vest, Li Zhou, Xuechen Huang, Viktoria Norekyan, Yaniv Bar-Cohen, Ramen H Chmait, Gerald Eli Loeb
We have developed a rechargeable fetal micropacemaker in order to treat severe fetal bradycardia with comorbid hydrops fetalis. The necessarily small form factor of the device, small patient population, and fetal anatomy put unique constraints on the design of the recharging system. To overcome these constraints, a custom high power field generator was built and the recharging process was controlled by utilizing pacing rate as a measure of battery state, a feature of the relaxation oscillator used to generate stimuli...
February 13, 2017: IEEE Transactions on Biomedical Circuits and Systems
Manuel Delgado-Restituto, Alberto Rodriguez-Perez, Angela Darie, Cristina Soto-Sanchez, Eduardo Fernandez-Jover, Angel Rodriguez-Vazquez
This paper reports an integrated 64-channel neural spike recording sensor, together with all the circuitry to process and configure the channels, process the neural data, transmit via a wireless link the information and receive the required instructions. Neural signals are acquired, filtered, digitized and compressed in the channels. Additionally, each channel implements an auto-calibration algorithm which individually configures the transfer characteristics of the recording site. The system has two transmission modes; in one case the information captured by the channels is sent as uncompressed raw data; in the other, feature vectors extracted from the detected neural spikes are released...
February 13, 2017: IEEE Transactions on Biomedical Circuits and Systems
T Marisa, T Niederhauser, A Haeberlin, R A Wildhaber, R Vogel, J Goette, M Jacomet
A new pseudo asynchronous level crossing analogue-to-digital converter (adc) architecture targeted for low-power, implantable, long-term biomedical sensing applications is presented. In contrast to most of the existing asynchronous level crossing adc designs, the proposed design has no digital-to-analogue converter (dac) and no continuous time comparators. Instead, the proposed architecture uses an analogue memory cell and dynamic comparators. The architecture retains the signal activity dependent sampling operation by generating events only when the input signal is changing...
February 7, 2017: IEEE Transactions on Biomedical Circuits and Systems
Lennart Leicht, Benjamin Eilebrecht, Soren Weyer, Steffen Leonhardt, Daniel Teichmann
Recording biosignals without the need for direct skin contact offers new opportunities for ubiquitous health monitoring. Electrodes with capacitive coupling have been shown to be suitable for the monitoring of electrical potentials on the body surface, in particular ECG. However, due to triboelectric charge generation and motion artifacts, signal and thus diagnostic quality is inferior to galvanic coupling. Active closed-loop humidification of capacitive electrodes is proposed in this work as a new concept to improve signal quality...
January 25, 2017: IEEE Transactions on Biomedical Circuits and Systems
Hang Wong, Wei Lin, Laure Huitema, Eric Arnaud
This paper presents a multi-polarization reconfigurable antenna with four dipole radiators for biomedical applications in body-centric wireless communication system (BWCS). The proposed multi-dipole antenna with switchable 0°, +45°, 90° and -45° linear polarizations is able to overcome the polarization mismatching and multi-path distortion in complex wireless channels as in BWCS. To realize this reconfigurable feature for the first time among all the reported antenna designs, we assembled four dipoles together with 45° rotated sequential arrangements...
January 23, 2017: IEEE Transactions on Biomedical Circuits and Systems
Kaveh Mohammad, Douglas J Thomson
A simple high frequency capacitance sensor with 180 aF sensitivity is designed for a wide range of microfluidic applications. The sensor is implemented utilizing differential ring oscillators operating at [Formula: see text] MHz with a differential signal at [Formula: see text] MHz. The sensor occupies [Formula: see text] cm × 2 cm on a printed circuit board. The sensor is tuned using two precision variable capacitors and has a full scale range of [Formula: see text] pF. The sensor was able to detect less than 1% Isopropyl Alcohol in DI water and to detect 15 μm polystyrene spheres flowing over 25 μm lines and spaces coplanar electrodes in a microfluidic channel...
January 23, 2017: IEEE Transactions on Biomedical Circuits and Systems
Elliot Greenwald, Christoph Maier, Qihong Wang, Robert Beaulieu, Ralph Etienne-Cummings, Gert Cauwenberghs, Nitish Thakor
An 8-channel current steerable, multi-phasic neural stimulator with on-chip current DAC calibration and residue nulling for precise charge balancing is presented. Each channel consists of two sub-binary radix DACs followed by wide-swing, high output impedance current buffers providing time-multiplexed source and sink outputs for anodic and cathodic stimulation. A single integrator is shared among channels and serves to calibrate DAC coefficients and to closely match the anodic and cathodic stimulation phases...
January 16, 2017: IEEE Transactions on Biomedical Circuits and Systems
Saeed Haghiri, Arash Ahmadi, Mehrdad Saif
Glial cells, also known as neuroglia or glia, are non-neuronal cells providing support and protection for neurons in the central nervous system (CNS). They also act as supportive cells in the brain. Among a variety of glial cells, the star-shaped glial cells, i.e., astrocytes, are the largest cell population in the brain. The important role of astrocyte such as neuronal synchronization, synaptic information regulation, feedback to neural activity and extracellular regulation make the astrocytes play a vital role in brain disease...
February 2017: IEEE Transactions on Biomedical Circuits and Systems
Miao Meng, Mehdi Kiani
Ultrasound has been recently proposed as an alternative modality for efficient wireless power transmission (WPT) to biomedical implants with millimeter (mm) dimensions. This paper presents the theory and design methodology of ultrasonic WPT links that involve mm-sized receivers (Rx). For given load (RL) and powering distance (d), the optimal geometries of transmitter (Tx) and Rx ultrasonic transducers, including their diameter and thickness, as well as the optimal operation frequency (fc) are found through a recursive design procedure to maximize the power transmission efficiency (PTE)...
February 2017: IEEE Transactions on Biomedical Circuits and Systems
Adrian Zurbuchen, Andreas Haeberlin, Alois Pfenniger, Lukas Bereuter, Jakob Schaerer, Frank Jutzi, Christoph Huber, Juerg Fuhrer, Rolf Vogel
Energy harvesting devices are widely discussed as an alternative power source for todays active implantable medical devices. Repeated battery replacement procedures can be avoided by extending the implants life span, which is the goal of energy harvesting concepts. This reduces the risk of complications for the patient and may even reduce device size. The continuous and powerful contractions of a human heart ideally qualify as a battery substitute. In particular, devices in close proximity to the heart such as pacemakers, defibrillators or bio signal (ECG) recorders would benefit from this alternative energy source...
February 2017: IEEE Transactions on Biomedical Circuits and Systems
Dai Jiang, Dominik Cirmirakis, Matthew Schormans, Timothy A Perkins, Nick Donaldson, Andreas Demosthenous
This paper presents a passive phase-shift keying (PPSK) modulator for uplink data transmission for biomedical implants with simultaneous power and data transmission over a single 13.56 MHz inductive link. The PPSK modulator provides a data rate up to 1.35 Mbps with a modulation index between 3% and 38% for a variation of the coupling coefficient between 0.05 and 0.26. This modulation scheme is particularly suited for biomedical implants that have high power demand and low coupling coefficients. The PPSK modulator operates in conjunction with on-off-keying downlink communication...
February 2017: IEEE Transactions on Biomedical Circuits and Systems
Rune Kaald, Trym Eggen, Trond Ytterdal
Fully digitized 2D ultrasound transducer arrays require one ADC per channel with a beamforming architecture consuming low power. We give design considerations for per-channel digitization and beamforming, and present the design and measurements of a continuous time delta-sigma modulator (CTDSM) for cardiac ultrasound applications. By integrating a mixer into the modulator frontend, the phase and frequency of the input signal can be shifted, thereby enabling both improved conversion efficiency and narrowband beamforming...
February 2017: IEEE Transactions on Biomedical Circuits and Systems
Fu-Yu Beverly Chen, David M Budgett, Yuhui Sun, Simon Malpas, Daniel McCormick, Peter S Freestone
Optogenetics allows control of neuronal activity with unprecedented spatiotemporal precision, and has enabled both significant advances in neuroscience and promising clinical prospects for some neurological, cardiac, and sensory disorders. The ability to chronically stimulate light-sensitive excitable cells is crucial for developing useful research tools and viable long-term treatment strategies. Popular optogenetic stimulation devices often rely on bench-top light-sources tethered via an optical fibre to the research animal, or significant componentry protruding externally from animal...
February 2017: IEEE Transactions on Biomedical Circuits and Systems
Yoon-Jee Kim, Sung-Eun Cho, Ji-Yong Um, Min-Kyun Chae, Jihoon Bang, Jongkeun Song, Taeho Jeon, Byungsub Kim, Jae-Yoon Sim, Hong-June Park
A 64-channel RX digital beamformer was implemented in a single chip for 3-D ultrasound medical imaging using 2-D phased-array transducers. The RX beamformer chip includes 64 analog front-end branches including 64 non-uniform sampling ADCs, a FIFO/Adder, and an on-chip look-up table (LUT). The LUT stores the information on the rising edge timing of the non-uniform ADC sampling clocks. To include the LUT inside the beamformer chip, the LUT size was reduced by around 240 times by approximating an ADC-sample-time profile w...
February 2017: IEEE Transactions on Biomedical Circuits and Systems
Zhiyuan Chen, Man-Kay Law, Pui-In Mak, Rui P Martins
In this paper, an ultra-compact single-chip solar energy harvesting IC using on-chip solar cell for biomedical implant applications is presented. By employing an on-chip charge pump with parallel connected photodiodes, a 3.5 × efficiency improvement can be achieved when compared with the conventional stacked photodiode approach to boost the harvested voltage while preserving a single-chip solution. A photodiode-assisted dual startup circuit (PDSC) is also proposed to improve the area efficiency and increase the startup speed by 77%...
February 2017: IEEE Transactions on Biomedical Circuits and Systems
Mehrdad A Ghanad, Michael M Green, Catherine Dehollain
An implantable local temperature monitoring system for a laboratory mouse is presented. Magnetic coupling is used to remotely power the passive implant. The temperatures of two local points are monitored by thermistors. A low-power readout circuit is implemented by directly amplifying and resolving the sensor response in the time domain. A free-running oscillator operating at 868 MHz transmits the sensor data to the base station. The average power dissipation of the implant is decreased by time interleaving between the sensor readout and the data communication...
February 2017: IEEE Transactions on Biomedical Circuits and Systems
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