Browsing by Author "Chang, Che-Wei"

Now showing 1 - 7 of 7

Applying Expert Diagnosis Model to Collaborative Design Systems
(2011-04-01)
Wu, Cheng-Ru
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Chang, Che-Wei
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Chen, Chiu-Chin
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資訊管理與財務金融系註：原資管所+財金所
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Department of Information Management and Finance
Thin film transistor liquid crystal display (TFT-LCD) industry need to control the development budget. The alarm management system (AMS) can test machine alarm. This study uses the grey relational analysis (GRA) the expert evaluation model to measure software quality management system of alarm in order to reduce system failures.
Design of Wide-IF-Band CMOS Mixer with LO Multiplier
(2013)
Tsai, Han-Ting
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Tseng, Pei-Ling
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Chang, Che-Wei
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Hu, Robert
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Jou, Christina F.
This paper reports the development of K-band wide-IF-band CMOS mixer with LO multiplier suitable for wideband applications. To achieve such broad bandwidth, several design techniques-such as current-reuse differential-pair with LC resonance circuit, and simultaneous in-band gain peaking and off-band gain tailoring-have been analyzed and employed. The on-wafer measurement of this 17.4-26.1GHz TSMC 0.18 mu m CMOS mixer with LO doubler shows a -1dB conversion gain, 11dB noise figure, -6dBm input-referred 1dB compression point, 40dB RF-IF isolation, and 45dB LO-IF isolation at 8.7GHz. The chip size is 1400 x 1300 mu m(2).
Digital Primary-Side Sensing Control for Flyback Converters
(2009)
Chang, Che-Wei
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Lin, Yu-Tzung
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Tzou, Ying-Yu
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電機工程學系
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Department of Electrical and Computer Engineering
Primary-side sensing (PSS) technique can be used for the output voltage or current regulation by employing an auxiliary winding. However, the sensed voltage may be corrupted by switching noise due to leakage inductance, winding resistance, and nonlinearity of the magnetic core, therefore the sensed voltage can only achieve limited accuracy. With the advance of power control IC realization technology, more complicated control and estimation algorithms can be realized by using analog, digital, or mixed-signal technologies. This paper introduces a digital control method to make the influence of nonideal factors as low as possible. A key factor for accurate voltage sensing is the determination of sampling instant on the auxiliary winding. A prototype of a DCM DC/DC flyback converter with digital signal processor has been realized to verify the proposed digital PSS scheme.
Full-Duplex Constructive Relay for Wireless Multicast
(2018-01-01)
Chang, Che-Wei
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Lin, Kate Ching-Ju
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資訊工程學系
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Department of Computer Science
Full-duplex relaying has attracted a lot of attention recently due to its capability of receiving and forwarding simultaneously in the same frequency band. However, most of the existing designs focus on unicast communication and customize the relaying algorithm so as to maximize the receiving signal strength of a particular user. In this work, we aim at developing a full-duplex constructive forwarding system for wireless multicast. As different multicast members typically have heterogeneous channel state information, it is especially challenging to find a forwarding processing strategy that works fine for all the multicast members. To overcome this issue, we propose two models, one for maximizing the worst SNR of the multicast members while the other optimizing the overall reception quality, which is especially suitable for video multicast. We evaluate our designs via trace-driven simulations. The results demonstrate that we can consistently improve the worst SNR by 2-3 dB and the gain is especially significant for a large coverage network area.
Pioneering e-supply chain integration in semiconductor industry: a case study
(2008-03-01)
Hwang, Bang-Ning
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Chang, Shih-Chi
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Yu, Hsiao-Cheng
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Chang, Che-Wei
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交大名義發表
Taiwan Semiconductor Manufacturing Company (TSMC) is the largest semiconductor foundry in the world. Advanced Semiconductor Engineering Inc. (ASE) is the world's leader in semiconductor assembly and testing. From 1998 to 2004, the two companies completed electronic integration of I I key business processes through the Internet. The result is a seamless interface between TSMC, ASE and their joint customers. They can now obtain accurate, timely information on their product status and respond appropriately when needed. While the direct economic benefits are estimated to be around US$ 10 million through productivity increase over a total investment of about US$ 2 million, the indirect benefits of this initiative could be on the order of US $100 million if the joint customers' benefits are considered. In collaboration with the RosettaNet organization, TSMC and ASE leveraged their pioneering experiences to define three data exchange standards which can then be widely adopted in the semiconductor industry. This case study is a demonstration of how two leading companies in their respective fields can join forces to make a difference in creating value for the entire semiconductor industry, which in turn benefits society at large. With the momentum continuing to build and the sphere of influence continuing to expand, it is anticipated that TSMC, ASE and the entire sector will upgrade their competitiveness in terms of cost, quality, responsiveness and customer orientation.
Primary-Side Sensing Error Analysis for Flyback Converters
(2009)
Chang, Che-Wei
;
Tzou, Ying-Yu
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電控工程研究所
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Institute of Electrical and Control Engineering
Primary-side sensing (PSS) technique can be used for output voltage or current regulation by employing an auxiliary winding for the sensing of the output voltage without using an additional opto-coupler for output feedback isolation. However, the sensed voltage may be corrupted by switching noises due to leakage inductance, winding resistance, uncertainty of winding parameters, and nonlinearity of the magnetic core, therefore, the sensed voltage can only achieve limited accuracy. This paper makes an error analysis of the PSS technique due to the leakage inductance and other key parameters when applying to flyback converters. Computer simulation has been carried out to verify the proposed error analysis method. The developed error analysis method can be used to improve the design of the flyback transformer and PSS algorithm for the development of more advanced digital primary-side controller in applications to flyback converters.
The Intelligent Message Estimator for Wireless Network Control Systems
(2010)
Chang, Che-Wei
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Lai, Chien-Liang
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Hsu, Pau-Lo
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電機工程學系
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Department of Electrical and Computer Engineering
The data dropout and the time delay in networked control systems (NCS) degrade their performance greatly, especially under the wireless applications. In this study, both the message estimator and the traffic monitor designed for the wireless network control system (WiNCS) are proposed. Instead of the event-trigger NCS, the output feedback signal is sent by the timing trigger and the received node implemented with a message estimator for effectively compensating those lost data. Different estimators applied to the WiNCS have been discussed and results indicate that the Taylor estimator is preferred with easy implementation on a light-traffic network. Moreover, with the heavy-load network, the intelligent message estimator (IME) is suitable to cope with the unstable problem occurred in the Taylor estimator. Experimental results show that the Taylor estimator reduced the output error 30.1 % within a light-traffic network, and the IME reduced the output error 74.7% even with a heavy network load. Finally, when the network traffic is heavy enough, the sampling time of the WiNCS must be adjusted according to the data dropout rate based on the network traffic monitor to further decrease the dropout rate.