Browsing by Author "Chang, Chih-Wei"

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120V/ns Output Slew Rate Enhancement Technique and High Voltage Clamping Circuit in High Integrated Gate Driver for Power GaN FETs
(2015)
Yang, Hsiang-An
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Chiu, Chao-Chang
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Lai, Shin-Chi
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Chen, Jui-Lung
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Chang, Chih-Wei
High power density is a key point that power converters endeavor to pursue. However, it is rare that gate driver of power converter can switch under high supply voltage with a fast operation frequency. In this paper, a half-bridge driver with the slew rate enhancement (SRE) technique is proposed and its switching frequency can be increased to 25MHz under a 700V supply voltage. Besides, the proposed high voltage clamping circuit ensures all circuits operating in a safe region without any overvoltage problems in the bootstrap operation. With specifically developed high voltage high speed (HVHS) process, high-side and low-side circuits can be well shielded by the isolation well which is embedded in the level shifter device to minimize chip size.
87% Overall High Efficiency and 11 mu A Ultra-Low Standby Current Derived by Overall Power Management in Laptops With Flexible Voltage Scaling and Dynamic Voltage Scaling Techniques
(2016-04-01)
Yang, Shang-Hsien
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Chiu, Chao-Chang
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Chang, Chih-Wei
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Chen, Chen-Min
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Meng, Che-Hao
The proposed overall power management in laptops can improve overall power conversion efficiency by the flexible voltage scaling (FVS) technique in cooperation with conventional dynamic voltage scaling (DVS) technique. The FVS technique separates the controller into two parts. One is a simple primary side controller and the other is emerged into the power management unit in the laptop for getting direct power control from the microprocessor. 12% light load efficiency and 7% peak efficiency are improved compared to conventional design with the DVS technique only but without the FVS technique. Furthermore, green mode is proposed to effectively reduce chip quiescent current to 11 mu A and to suppress power loss to 10 m W in ultra-light load, which is much smaller than 500 mW standby power defined by the restriction of Energy Star Standard and 40 mW of state-of-art commercial products.
A Buck Power Factor Correction Converter with Predictive Quadratic Sinusoidal Current Modulation and Line Voltage Reconstruction
(2016-09)
Yang, Shang-Hsien
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Meng, Che-Hao
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Chiu, Chao-Chang
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Chang, Chih-Wei
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Chen, Ke-Horng
A buck power factor correction (PFC) converter operating in continuous conduction mode (CCM) is influenced by the dead zone, which introduces distortion related to the input line voltage. Such phenomenon limits the maximum power factor (PF) and the minimum total harmonic distortion (THD) achievable. By deriving a methodology to achieve predictive line voltage reconstruction (PLVR), the influence of the dead zone is mitigated. With the prediction of quadratic sinusoidal current modulation ((PSCM)-C-2), the line current is shaped into sinusoid waveform that is in-phase with input line voltage, crucial for. Consequently, the proposed CCM buck PFC can achieve high PF, low THD, and efficiency simultaneously. A test chip was fabricated in 0.5-mu m Bipolar-CMOS-DMOS (BCD) process. The experimental results show a peak PF of 0.95 and a peak efficiency of 98% at 110 Vac.
A Compact Power Management for Next Generation Intensive Care Unit with 91% Conversion Efficiency
(2014-01-01)
Chiu, Chao-Chang
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Yang, Hsiang-An
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Su, Yi-Ping
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Chang, Chih-Wei
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Meng, Che-Hao
the proposed single-inductor dual-output (SIDO) converter with energy-conservation mode (ECM) control is designed for next generation intensive care unit. The energy-conservation mode (ECM) control generates two different energy delivery paths for dual buck outputs with only one inductor. In addition, the superposition technique is used to achieve a minimized inductor current level. The average inductor current is equal to the summation of two output loads. The measurement results shows the 91% peak efficiency can he derived.
A double-sided, single-chip integration scheme using through-silicon-via for neural sensing applications
(2015-02-01)
Chang, Chih-Wei
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Chou, Lei-Chun
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Huang, Po-Tsang
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Wu, Shang-Lin
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Lee, Shih-Wei
We present a new double-sided, single-chip monolithic integration scheme to integrate the CMOS circuits and MEMS structures by using through-silicon-via (TSV). Neural sensing applications were chosen as the implementation example. The proposed heterogeneous device integrates standard 0.18 mu m CMOS technology, TSV and neural probe array into a compact single chip device. The neural probe array on the back-side of the chip is connected to the CMOS circuits on the front-side of the chip by using low-parasitic TSVs through the chip. Successful fabrication results and detailed characterization demonstrate the feasibility and performance of the neural probe array, TSV and readout circuitry. The fabricated device is 5x5 mm(2) in area, with 16 channels of 150 mu m-in-length neural probe array on the back-side, 200 mu m-deep TSV through the chip and CMOS circuits on the front-side. Each channel consists of a 5x6 probe array, 3x14 TSV array and a differential-difference amplifier (DDA) based analog front-end circuitry with 1.8 V supply, 21.88 mu W power consumption, 108 dB CMRR and 2.56 mu Vrms input referred noise. In-vivo long term implantation demonstrated the feasibility of presented integration scheme after 7 and 58 days of implantation. We expect the conceptual realization can be extended for higher density recording array by using the proposed method.
A Fully Integrated 8-Channel Closed-Loop Neural-Prosthetic SoC for Real-Time Epileptic Seizure Control
(2013-01-01)
Chen, Wei-Ming
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Chiueh, Herming
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Chen, Tsan-Jieh
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Ho, Chia-Lun
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Jeng, Chi
A Fully Integrated Wireless SoC for Motor Function Recovery After Spinal Cord Injury
(2017-06-01)
Lo, Yi-Kai
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Kuan, Yen-Cheng
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Culaclii, Stanislav
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Kim, Brian
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Wang, Po-Min
This paper presents a wirelessly powered, fully integrated system-on-a-chip (SoC) supporting 160-channel stimulation, 16-channel recording, and 48-channel bio-impedance characterization to enable partialmotor function recovery through epidural spinal cord electrical stimulation. A wireless transceiver is designed to support quasi full-duplex data telemetry at a data rate of 2 Mb/s. Furthermore, a unique in situ bio-impedance characterization scheme based on time-domain analysis is implemented to derive the Randles cell electrode model of the electrode-electrolyte interface. The SoC supports concurrent stimulation and recording while the high-density stimulator array meets an output compliance voltage of up to +/- 10 V with versatile stimulus programmability. The SoC consumes 18 mW and occupies a chip area of 5.7 mm x 4.4 mm using 0.18 mu m high-voltage CMOS process. In our in vivo rodent experiment, the SoC is used to perform wireless recording of EMG responses while stimulation is applied to enable the standing and stepping of a paralyzed rat. To facilitate the system integration, a novel thin film polymer packaging technique is developed to provide a heterogeneous integration of the SoC, coils, discrete components, and high-density flexible electrode array, resulting in a miniaturized prototype implant with a weight and form factor of 0.7 g and 0.5 cm(3), respectively.
A Low-Power Bio-Potential Acquisition System with Flexible PDMS Dry Electrodes for Portable Ubiquitous Healthcare Applications
(2013-03-01)
Chen, Chih-Yuan
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Chang, Chia-Lin
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Chang, Chih-Wei
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Lai, Shin-Chi
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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 Metal-Only-ECO Solver for Input-Slew and Output-Loading Violations
(2010-02-01)
Lu, Chien-Pang
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Chao, Mango Chia-Tso
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Lo, Chen-Hsing
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Chang, Chih-Wei
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電子工程學系及電子研究所
To reduce the time-to-market and photomask cost for advanced process technologies, metal-only engineering change order (ECO) has become a practical and attractive solution to handle incremental design changes. Due to limited spare cells in metal-only ECO, the new added netlist may often violate the input-slew and output-loading constraints and, in turn, delay or even fail the timing closure. This paper presents a framework, named metal-only ECO slew/cap solver (MOESS), to resolve the input-slew and output-loading violations by connecting spare cells onto the violated nets as buffers. MOESS performs two buffer-insertion schemes in a sequential manner to first minimize the number of inserted buffers and then resolve timing violations, if any. The experimental results based on industrial designs demonstrate that MOESS can resolve more violations with fewer inserted buffers and less central processing unit runtime compared to an electronic design automation vendor's solution.
A mild and general method for preparation of alpha-glycosyl chlorides
(2009-08-05)
Chang, Chih-Wei
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Chang, Shih-Sheng
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Chao, Chin-Sheng
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Mong, Kwok-Kong T.
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應用化學系
A mild and efficient chlorination method for production of glycosyl chlorides is first described which employs inexpensive trichlorotriazine (TCT) and DMF as a chlorination reagent and is compatible with typical acid-labile hydroxyl protecting functions. The scope and limitations, reaction mechanism and its application in the sequential glycosylations are discussed. (C) 2009 Elsevier Ltd. All rights reserved.
A new glycosylation method based on 8-quinolyl glycosides
(2006-12-01)
Chang, Chih-Wei
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Ho, Tse-Lok
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應用化學系
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Department of Applied Chemistry
A synthesis of two 8-quinolyl glycosides (1 a, 2a) and demonstration of their service as glycosyl donors are described. These stable compounds react with various alcohols in the presence of metal salts at 60 degrees C for 16-48 h to furnish the coupling products in excellent yields (88-96%).
A Power-Efficient Bio-Potential Acquisition Device with DS-MDE Sensors for Long-Term Healthcare Monitoring Applications
(2010-05-01)
Chang, Chia-Lin
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Chang, Chih-Wei
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Huang, Hong-Yi
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Hsu, Chen-Ming
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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.
A TSV-Based Bio-Signal Package With mu-Probe Array
(2014-02-01)
Chou, Lei-Chun
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Lee, Shih-Wei
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Huang, Po-Tsang
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Chang, Chih-Wei
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Chiang, Cheng-Hao
Bio-signal probes providing stable observation with high quality signals are crucial for understanding how the brain works and how the neural signal transmits. Due to the weak and noisy characteristics of bio-signals, the connected interconnect length between the sensor and CMOS has significant impact on the bio-signal quality. In addition, long interconnections with wire bonding technique introduce noises and lead to bulky packaged systems. This letter presents an implantable through-silicon via (TSV) technology to connect sensors and CMOS devices located on the opposite sides of the chip for brain neural sensing applications. With the elimination of traditional wire bonding and packaging technologies, the quality of bio-signal can be greatly improved.
A TSV-Based Heterogeneous Integrated Neural-Signal Recording Device with Microprobe Array
(2014-01-01)
Chou, Lei-Chun
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Lee, Shih-Wei
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Cheng, Chuan-An
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Huang, Po-Tsang
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Chang, Chih-Wei
Highly integrated and miniaturized neural sensing microsystems are crucial for brain function investigation and neural prostheses realization. This paper presents a TSV-based heterogeneous integrated neural-signal recording device with microprobe array. By TSV, microprobe array and CMOS circuit make connection on the opposite sides of the chip. By measurement results on electrical characteristics of devices and TSV, this recording device is ready for bio-medical applications.
A Wireless and Batteryless Microsystem with Implantable Grid Electrode/3-Dimensional Probe Array for ECoG and Extracellular Neural Recording in Rats
(2013-04-01)
Chang, Chih-Wei
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Chiou, Jin-Chern
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電機資訊學士班
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Undergraduate Honors Program of Electrical Engineering and Computer Science
This paper presents the design and implementation of an integrated wireless microsystem platform that provides the possibility to support versatile implantable neural sensing devices in free laboratory rats. Inductive coupled coils with low dropout regulator design allows true long-term recording without limitation of battery capacity. A 16-channel analog front end chip located on the headstage is designed for high channel account neural signal conditioning with low current consumption and noise. Two types of implantable electrodes including grid electrode and 3D probe array are also presented for brain surface recording and 3D biopotential acquisition in the implanted target volume of tissue. The overall system consumes less than 20 mA with small form factor, 3.9 x 3.9 cm(2) mainboard and 1.8 x 3.4 cm(2) headstage, is packaged into a backpack for rats. Practical in vivo recordings including auditory response, brain resection tissue and PZT-induced seizures recording demonstrate the correct function of the proposed microsystem. Presented achievements addressed the aforementioned properties by combining MEMS neural sensors, low-power circuit designs and commercial chips into system-level integration.
Applications of neural network models for structural health monitoring based on derived modal properties
(2018-12-01)
Chang, Chia-Ming
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Lin, Tzu-Kang
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Chang, Chih-Wei
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土木工程學系
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Department of Civil Engineering
Structural health monitoring is required to interpret damaged structures in terms of locations and severity, even remaining performance of the damaged members. Therefore, this study proposes a new artificial intelligence-based structural health monitoring strategy based on neural network modeling. A neural network model is developed in accordance with a numerical model which is derived from the identified modal properties under ambient vibrations. The stochastic subspace system identification is first implemented to derive the natural frequencies and mode shapes of a healthy structure. These natural frequencies and mode shapes are then employed to derive a simplified model of this structure, allowing changing stiffness terms to construct various damage patterns. A neural network model is trained and built by the modal properties of the structure with these damage patterns. After a critical event occurs (e.g., earthquakes), this neural network model can be employed to estimate the damage patterns in terms of stiffness reduction. In this study, a numerical example consisting of two damage scenarios is carried out. This example studies a seven-story building with a single and multiple damaged columns in order to evaluate performance of the proposed structural health monitoring strategy. Moreover, the proposed structural health monitoring strategy is also applied to an experimental test of a scaled twin-tower building with weak braces in some floors. Partially modal properties of the structure are obtained from the stochastic subspace system identification, while a simplified model is developed in accordance to the identified modal properties of the healthy building. Then, a neural network model is established based on this simplified model. After seismic events, this neural network model is employed to carry damage detection of this building in terms of damage locations and levels. As a result, the proposed artificial intelligence-based structural health monitoring strategy is quite effective to locate damage if the identified modal properties are relatively accurate.
Compact spectrometer system based on a gradient grating period guided-mode resonance filter
(2016-05-16)
Lin, Hsin-An
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Hsu, Hsin-Yun
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Chang, Chih-Wei
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Huang, Cheng-Sheng
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機械工程學系
We demonstrate a compact spectrometer system by using a gradient grating period guided-mode resonance filter-mounted on a linear photodetector array-that exhibits spatially dependent resonance characteristics; a specific incident wavelength is reflected such that the underlying array pixels measure minimum intensity. A precalibrated transmission efficiency matrix is used to determine each pixel's transmission efficiency for specific wavelengths. Unknown spectral information can be calculated from the measured intensity. Grating periods of 250-388 nm in 2-nm increments are used in each 100-cycle period. Device length is 2.23 mm. Spectral range of 506-700 nm is measurable with 1-nm resolution. (C) 2016 Optical Society of America
Cooling Stimulation on Cerebral Cortex for Epilepsy Suppression with Integration of Micro-Invasive Electrodes and TE Coolers
(2013)
Chiou, Jin-Chern
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Chou, Lei-Chun
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Tsai, Shang-Wei
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Hou, Kuan-Chou
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Chang, Chih-Wei
Epilepsy suppression with cooling stimulation is the primary purpose for this study. In this dissertation, cooling stimulation was implemented and demonstrated on cerebral cortex of rats. Electrodes with needle structure was designed and fabricated by using MEMS technology to minimize the size of device. A TE cooler was used to create cooling source and it can be control via electrical current. A cooler component was integrated with an electrode and a TE cooler, in addition, a thermal sensor was also combined with it to detect temperature variation, which was affected by cooling cerebral cortex. The cooler components were implanted on surface of cerebral with deep brain stimulation and the thermal sensors were penetrated into cortex to measure temperature variation which can verify the functions of cooler components. In our experimental results, electrodes with needle structure can improve efficiency of epilepsy suppression due to the particular structure. Duration, frequency and average single time of epileptic waveforms were used to identify to performance of suppression.
Demonstration of Implantable Grid Electrode/3-Dimensional Probe Array for ECOG and Extracellular Neural Recording on Rat
(2012)
Chou, Lei-Chun
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Chang, Chih-Wei
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Chiou, Jin-Chern
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電機工程學系
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Department of Electrical and Computer Engineering
This demonstration presents implantable grid electrodes array and three dimensional microprobe array for neural sensing on free-behaved laboratory rats. A flexible grid electrode array is fabricated for ECoG signal acquiring brain surface signal with 12-um thick parylene-C substrate and platinum sensing electrode. Flexible electrode array provides perfectly fitted to brain surface curvature. The 3D probe array are fabricated by MEMS process with new stacking method for 3D biopotential acquisition in the implanted target volume of tissue. Practical in-vivo recordings including auditory response, brain resection tissue and PZT-induced seizures recording demonstrate the correct function of the proposed neural recording devices.
Design and Fabrication of Compact Spectrometer based on Gradient Grating Period Guided-Mode Resonance Filter
(2017-01-01)
Lin, Hsin-An
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Hsu, Hsin-Yun
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Chang, Chih-Wei
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Huang, Cheng-Sheng
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機械工程學系
We designed and fabricated a compact spectrometer based on a gradient grating period guided-mode resonance filter (GGP-GMRF). The GGP-GMRF of 2.23 mm long consisted of gratings with periods varying from 250-388 nm in 2-nm increments. With such compact size, the device can measure spectrum ranging from 506 to 700 nm.