Browsing by Author "Luo, Ching-Hsing"

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A Low-Power Bio-Potential Acquisition System with Flexible PDMS Dry Electrodes for Portable Ubiquitous Healthcare Applications
(2013-03-01)
Chen, Chih-Yuan
;
Chang, Chia-Lin
;
Chang, Chih-Wei
;
Lai, Shin-Chi
;
Chien, Tsung-Fu
This work describes a bio-potential acquisition system for portable ubiquitous healthcare applications using flexible polydimethylsiloxane dry electrodes (FPDEs) and a low-power recording circuit. This novel FPDE used Au as the skin contact layer, which was made using a CO2 laser and replica method technology. The FPDE was revised from a commercial bio-potential electrode with a conductive snap using dry electrodes rather than wet electrodes that proposed reliable and robust attachment for the purpose of measurement, and attaching velcro made it wearable on the forearm for bio-potential applications. Furthermore, this study proposes a recording device to store bio-potential signal data and provides portability and low-power consumption for the proposed acquisition system. To acquire differential bio-potentials, such as electrocardiogram (ECG) signals, the proposed recording device includes a low-power front-end acquisition chip fabricated using a complementary metal-oxide-semiconductor (CMOS) process, a commercial microcontroller (MSP430F149), and a secure digital (SD) card for portable healthcare applications. The proposed system can obtain ECG signals efficiently and are comfortable to the skin. The power consumption of the system is about 85 mW for continuous working over a 3 day period with two AA batteries. It can also be used as a compact Holter ECG system.
A Power-Efficient Bio-Potential Acquisition Device with DS-MDE Sensors for Long-Term Healthcare Monitoring Applications
(2010-05-01)
Chang, Chia-Lin
;
Chang, Chih-Wei
;
Huang, Hong-Yi
;
Hsu, Chen-Ming
;
Huang, Chia-Hsuan
This work describes a power-efficient bio-potential acquisition device for long-term healthcare applications that is implemented using novel microelectromechanical dry electrodes (MDE) and a low power bio-potential processing chip. Using micromachining technology, an attempt is also made to enhance the sensing reliability and stability by fabricating a diamond-shaped MDE (DS-MDE) that has a satisfactory self-stability capability and superior electric conductivity when attached onto skin without any extra skin tissue injury technology. To acquire differential bio-potentials such as ECG signals, the proposed processing chip fabricated in a standard CMOS process has a high common mode rejection ratio (C. M. R. R.) differential amplifier and a 12-bit analog-to-digital converter (ADC). Use of the proposed system and integrate simple peripheral commercial devices can obtain the ECG signal efficiently without additional skin tissue injury and ensure continuous monitoring more than 70 hours with a 400 mAh battery.
All Digital Phase-Locked Loop Using Active Inductor Oscillator and Novel Locking Algorithm
(2011)
Huang, Tzu-Chi
;
Huang, Hong-Yi
;
Liu, Jen-Chieh
;
Cheng, Kuo-Hsing
;
Luo, Ching-Hsing
A fast locking all-digital phase-locked loop (ADPLL) with the active inductor oscillator is proposed. An LC-tank DCO with a tunable active inductor can obtain a wider operational frequency range, smaller area and higher signal quality. The proposed frequency and phase locking algorithm can achieve good jitter performance, high frequency accuracy, and low circuit complexity. The ADPLL is designed using a 0.18 um CMOS process. The operational frequency range of the ADPLL is from 318 MHz to 458 MHz. The RMS and the peak-to-peak jitters at 402 MHz are 4.2 ps and 94 ps, respectively. The core size is 390x390 um(2). The power consumption is 5.4 mW at 416 MHz.
Broadband Loop Antenna on Soft Contact Lens for Wireless Ocular Physiological Monitoring
(2014)
Ting, Ssu-Han
;
Jeng, Bo-Ming
;
Chen, Wen-Shan
;
Chiou, Jin-Chern
;
Luo, Ching-Hsing
This paper presents a novel loop antenna with broadband for wireless ocular physiological monitoring (WOPM). The antenna is fabricated on a thin-film poly-para-xylylene C (parylene C) substrate with a small thickness of 11 mu m and dimension of pi x 6.5 x 6.5 mm(2). With the advantage of small size, the proposed antenna is suitable to apply to the soft contact lens and transmit the signal in microelectromechanical Systems (MEMS). Because the pig's eye and human's eye have similar parameters of conductivity and permittivity, the experimental results are obtained by applying the proposed antenna on the pig's eye and cover from 1.54 to 6GHz for ISM band (2.4 and 5.8GHz) applications. The measured antenna radiation patterns, antenna gains, and radiation efficiency will be demonstrated in this paper, which are suitable for application of wireless ocular physiological monitoring.
Design of Miniaturized Antenna and Power Harvester Circuit on the Enucleated Porcine Eyes
(2014-01-01)
Cheng, Hui-Wen
;
Yu, Tsung-Chi
;
Huang, Hong-Yi
;
Ting, Ssu-Han
;
Huang, Tzuen-Hsi
This letter describes a prototype of a miniaturized rectifying antenna (rectenna) design for the wireless powering of an ocular device. In contrast to the conventional on-lens loop antenna, this letter presents a loop antenna with stepped structures for optimal impedance to the rectifier. The return loss of the antenna less than -15 dB at 3 GHz is accomplished in a contact lens with a diameter ranging from 10 to 15 mm. Additionally, the radio frequency (RF) rectifier and voltage-boosting network (VBN) are optimized to enhance the power conversion efficiency (PCE) by using the voltage boosting technique. Experimental results indicate that the optimal rectifier, which is fabricated with the TSMC 0.18-mu m process, produces a dc output voltage of 2.94 V and a conversion efficiency of 31% across a resistive 3.5 k Omega load with an input power of +9 dBm. Moreover, the rectenna under the experiment with an enucleated porcine eye can be powered wirelessly with a transmitting device at a distance of 4 cm. The output power is 2.01 mW with a transmitting power of +32 dBm for the wireless ocular physiological monitoring (WOPM) system. Importantly, this letter demonstrates the feasibility of an optimal miniaturized on-lens rectenna design, capable of overcoming the RF power attenuation on the ocular tissue to increase the delivering distance and reduce the transmitting power.
Design of Miniaturized Antenna and Power Harvester Circuit on the Enucleated Porcine Eyes
(2014-01-01)
Cheng, Hui-Wen
;
Yu, Tsung-Chi
;
Huang, Hong-Yi
;
Ting, Ssu-Han
;
Huang, Tzuen-Hsi
This letter describes a prototype of a miniaturized rectifying antenna (rectenna) design for the wireless powering of an ocular device. In contrast to the conventional on-lens loop antenna, this letter presents a loop antenna with stepped structures for optimal impedance to the rectifier. The return loss of the antenna less than -15 dB at 3 GHz is accomplished in a contact lens with a diameter ranging from 10 to 15 mm. Additionally, the radio frequency (RF) rectifier and voltage-boosting network (VBN) are optimized to enhance the power conversion efficiency (PCE) by using the voltage boosting technique. Experimental results indicate that the optimal rectifier, which is fabricated with the TSMC 0.18-mu m process, produces a dc output voltage of 2.94 V and a conversion efficiency of 31% across a resistive 3.5 k Omega load with an input power of +9 dBm. Moreover, the rectenna under the experiment with an enucleated porcine eye can be powered wirelessly with a transmitting device at a distance of 4 cm. The output power is 2.01 mW with a transmitting power of +32 dBm for the wireless ocular physiological monitoring (WOPM) system. Importantly, this letter demonstrates the feasibility of an optimal miniaturized on-lens rectenna design, capable of overcoming the RF power attenuation on the ocular tissue to increase the delivering distance and reduce the transmitting power.
Power-efficient wireless sensor for physiological signal acquisition
(2009-04-01)
Chang, Chia-Lin
;
Chang, Chih-Wei
;
Hsu, Chen-Ming
;
Luo, Ching-Hsing
;
Chiou, Jin-Chern
This work presents a power-efficient wireless sensor implemented using microelectromechanical system (MEMS)-based dry electrodes (MDE) and a ZigBee protocol chip for physiological signal acquisition. To improve signal quality with low electrode-skin interface impedance, a silicon-based MDE is fabricated via micromachining technology. The proposed wireless sensor can provide four different channels for up to 10 kHz bandwidth, 10-bit resolution biomedical signal transmissions. Different from other systems, the proposed wireless sensor employs a novel power management method for physiological signals to reduce power consumption. The proposed wireless sensor successfully transmits electrocardiogram (ECG) signals and four-channel electroencephalogram (EEG) signals with power consumptions of 92.7 and 56.8 mW respectively. It consumes 46% less power than the original sensor without power management (173 mW) in ECG acquisition and 67% less power in EEG acquisition. The circuit printed-circuit-band area in the proposed wireless sensor is 3.5 x 4.5 cm, suitable for various portable biomedical applications. (C) 2009 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3124190]
The Novel research of Intraocular Pressure Tonometer by Using Inductance sensor
(2012)
Tang, Yu-Shun
;
Jeng, Wei-De
;
Huang, Ting-Wei
;
Ou-Yang, Mang
;
Chiou, Jin-Chern
This article mainly discusses the theoretical derivation and the estimate of the intraocular pressure (IOP) sensor by using inductance. The inductance changes associate with the variation of anterior corneal curvature radius due to the differences of IOP. The value of inductance is transformed by the LC oscillator, and the signal is transmitted by antenna, and finally read by the exterior readout circuit to achieve IOP measuring. The result show that the estimative values of inductance is close to the measured values, and the percentage of inductance variation is about 0.08% per 1 mmHg. Because of the low percentage, it makes much harder to realize readout circuit. In the future, the alteration of structure and material are considered to increase the percentage of varying inductance.