Browsing by Author "Wu, Chun-Hsien"

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A reconfigurable quadri-polarization diversity aperture-coupled patch antenna
(2007-03-01)
Wu, Yi-Fan
;
Wu, Chun-Hsien
;
Lai, Don-Yen
;
Chen, Fu-Chiarng
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電信工程研究所
We present a novel reconfigurable quadri-polarization diversity aperture-coupled patch antenna which can provide four polarization states. By controlling the do bias voltage of the pin-diodes on the feeding network, we can reconfigure the proposed antenna to provide a pair of orthogonal linear polarizations and a pair of orthogonal circular polarizations. Numerical and experimental results validate our design. This novel antenna provides potential polarization diversity features for wireless local area networks and multiple-input multiple-output systems.
Real-Time Instruction-Cycle-Based Dynamic Voltage Scaling (iDVS) Power Management for Low-Power Digital Signal Processor (DSP) with 53% Energy Savings
(2012)
Peng, Shen-Yu
;
Lee, Yu-Huei
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Wu, Chun-Hsien
;
Huang, Tzu-Chi
;
Chen, Ke-Horng
this paper presents an instruction-cycle-based dynamic voltage scaling (iDVS) power management strategy for a low-power processor design. The iDVS technique is fully compatible with conventional DVS scheduler algorithms. Furthermore, an additional iDVS design flow embedded in the standard cell lib flow is proposed to implement the iDVS-based DSP. In addition, the fast-response bidirectional asynchronous wave-pipeline (BAWP) digital low-dropout (LDO) regulator is also presented to improve the iDVS performance. The iDVS-based DSP chip implemented in an HH-NEC 0.18 mu m standard CMOS process demonstrates 53% energy savings over that without the iDVS technique.
Transient Improvement by Window Transient Enhancement and Overshoot Suppression Techniques in Current Mode Boost Converter
(2011-10-01)
Luo, Yean-Kuo
;
Chiou, Chao-Chang
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Wu, Chun-Hsien
;
Chen, Ke-Horng
;
Hsu, Wei-Chou
In this paper, a current mode boost converter using window transient enhancement (WTE) and overshoot suppression (OSS) technique is presented for digital still camera (DSC) applications. The peak-to-peak transient overshoot voltage demand of a DSC motor driver is generally within 4%-5% of the regulated value. However, conventional boost converters usually fail to pass this criterion during large load transient. The OSS technique reduces the overshoot voltage when load current changes from heavy to very light. Experimental results show that compared with the use of a conventional current mode boost converter, the use of the technique reduces drop voltage about 62% and overshoot voltage about 51% when the load current has a load step of 400 mA. Moreover, the settling time improves to 43%, which is better than in the conventional case of a 400 mA load current step. The overhead of the silicon area is about 4.5% to achieve the overshoot reduction. The estimated high performance demonstrates that it is suitable for DSC applications.