Browsing by Author "Lee, Chi-Yang"

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Architecture implementation of class-D amplifiers using digital-controlled multiphase-interleaved PWM technique
(2006)
Lin, Yu-Tzung
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Lee, Chi-Yang
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Tzou, Ying-Yu
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電控工程研究所
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Institute of Electrical and Control Engineering
The class-D amplifier has the advantages of having a high efficiency, a small-size and gains its wide applications in battery-powered audio systems. However, its output power is limited by the rating of its output transistors. This paper presents the development of a new architecture for the realization of a class-D audio amplifier using a digital-controlled multi-phase interleaved PWM converter to enhance its output power. This interleaved technique is widely used in DC-DC converters. A digital current control technique with interleaved PWM generation was developed to reduce the total harmonic distortion (THD) of the output current under lower PWM switching frequency. A comparative evaluation of a single-phase and a three-phase class-D amplifier structure is presented. Furthermore, the design and implementation of a digital control IC, including an ADC synchronous sampler, a digital compensator, and a phase-shift PWM generator, is introduced. Computer simulations and experimental verifications are given to illustrate the feasibility and performance of the proposed technique.
VR Lighting Design
(2017-01-01)
Lee, Chi-Yang
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Chang, Hsuan-Ming
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Lin, Chun-Heng
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Tsai, Ming-Han
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Lin, Wen-Chieh
Lighting design is a crucial process in video games, animation, interior design, and some other fields. Current lighting design systems support only direct lighting paradigm which requires fine-tuning each light's parameters to achieve a global lighting effect. In this study, we developed an integrated lighting design system which comprises direct, indirect, and inverse lighting design paradigms in VR enviromnent. The system provides designers with an immersive, intuitive, and effective way of lighting design.