Browsing by Author "Wang, Shih-Wei"

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A 80V Output Voltage Boost Converter with Low Voltage Ripple for Avalanche Photodiode(APD)
(2011)
Yang, Yao-Yi
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Hsieh, Chun-Yu
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Huang, Tzu-Chi
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Lee, Yu-Huei
;
Wang, Shih-Wei
The Avalanche Photodiodes (APDs) are widely used in a variety of optical application requiring high sensitivity, such as long-distance optical communication and optical distance measurement, because the APDs can detect the low level light. APDs accompanied with the Transimpedance Amplifier (TIA) are utilized on the receiver side in the communication system. The trend of integrating the active optical components faces the challenge of integrating different voltage levels. In general, the operation voltage of TIA is usually 1.8 V or 3.3 V. However, the APD requires a high reverse-biasing voltage of 40 V - 80 V. Therefore, a high conversation-ratio boost converter must be included to provide the high voltage to bias the APD. Besides, output voltage ripple must be minimized to decrease the influence on communication signals. Experimental results show the 80 V output voltage boosted from the input voltage of 2.5 V. The output voltage ripple is 2 mV under the condition of 1 mA load current.
A Low Quiescent Current Asynchronous Digital-LDO With PLL-Modulated Fast-DVS Power Management in 40 nm SoC for MIPS Performance Improvement
(2013-04-01)
Lee, Yu-Huei
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Peng, Shen-Yu
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Chiu, Chao-Chang
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Wu, Alex Chun-Hsien
;
Chen, Ke-Horng
A low quiescent current asynchronous digital-LDO (D-LDO) regulator integrated with a phase-locked loop (PLL)-modulated switching regulator (SWR) that achieves the near-optimum power management supply for core processor in system-on-chip (SoC). The parallel connection of the asynchronous D-LDO regulator and the ripple-based control SWR can accomplish fast-DVS (F-DVS) operation as well as high power conversion efficiency. The asynchronous D-LDO regulator controlled by bidirectional asynchronous wave pipeline realizes the F-DVS operation, which guarantees high million instructions per second (MIPS) performance of the core processor under distinct tasks. The use of a ripple-based control SWR operating with a leading phase amplifier ensures fast response and stable operation without the need for large equivalent-series-resistance, thus reducing the output voltage ripple for the enhancement of supply quality. The fabricated chip occupies 1.04 mm(2) in 40 nm CMOS technology. Experimental results show that a 94% peak efficiency with a voltage tracking speed of 7.5 V/mu s as well as the improved MIPS performance by 5.6 times was achieved.
A Self-Orthogonal Code and Its Maximum-Likelihood Decoder for Combined Channel Estimation and Error Protection
(2008)
Wu, Chia-Lung
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Chen, Po-Ning
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Han, Yunghsiang S.
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Wang, Shih-Wei
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電信工程研究所
Recent researches have confirmed that better system performance can be obtained by jointly considering channel equalization and channel estimation in the code design, when compared with the system with individually optimized devices. However, the existing codes are mostly searched by computers, and hence, exhibit no good structure for efficient decoding. In this paper, a systematic construction for the codes for combined channel estimation and error protection is proposed. Simulations show that it can yield codes of comparable performance to the computer-searched best codes. In addition, the structural codes can now be maximum-likelihoodly decodable in terms of a newly derived recursive metric for use of the priority-first search decoding algorithm. Thus, the decoding complexity reduces considerably when compared with that of the exhaustive decoder. In light of the rule-based construction, the feasible codeword length that was previously limited by the capability of code-search computers(1) can now be further extended, and therefore facilitates their applications.
Amphiregulin promotes cisplatin chemoresistance by upregulating ABCB1 expression in human chondrosarcoma
(2020-05-31)
Huang, Yu-Wen
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Lin, Chih-Yang
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Tsai, Hsiao-Chi
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Fong, Yi-Chin
;
Han, Chien-Kuo
Chondrosarcomas are well known for their resistance to chemotherapeutic agents, including cisplatin, which is commonly used in chondrosarcomas. Amphiregulin (AR), a ligand of epidermal growth factor receptor (EGFR), plays an important role in drug resistance. We therefore sought to determine the role of AR in cisplatin chemoresistance. We found that AR inhibits cisplatin-induced cell apoptosis and promotes ATP-binding cassette subfamily B member 1 (ABCB1) expression, while knockdown of ABCB1 by small interfering RNA (siRNA) reverses these effects. High phosphoinositide 3-kinase (PI3K), Akt and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappa B) phosphorylation levels were observed in cisplatin-resistant cells. Pretreating chondrosarcoma cells with PI3K, Akt and NF-kappa B inhibitors or transfecting the cells with p85, Akt and p65 siRNAs potentiated cisplatin-induced cytotoxicity. In a mouse xenograft model, knockdown of AR expression in chondrosarcoma cells increased the cytotoxic effects of cisplatin and also decreased tumor volume and weight. These results indicate that AR upregulates ABCB1 expression through the PI3K/Akt/NF-kappa B signaling pathway and thus contributes to cisplatin resistance in chondrosarcoma.
An Energy-Recycling (ER) Technique for Reducing Power Consumption of Field Color Sequential (FCS) RGB LEDs Backlight Module
(2009)
Huang, Ming-Hsin
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Tsai, Yueh-Chang
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Wang, Shih-Wei
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Wu, Dian-Rung
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Chen, Ke-Horng
A single driving module with field color sequential (FCS) LCD technology needs to dynamically switch output voltage between 40 V for 12 series G-and B-color LEDs and 26 V for 12 series R-color LEDs at related time cluster. Thus, an energy-recycling (ER) technology is proposed to accelerate voltage settling and save compressed energy when the driving voltage is pressed from 40 V to 26 V. Only one recycling capacitor and one Schottky diode are added into the power structure of synchronous boost converter for composing the proposed ER technology. A proposed energy-recycling mode (ERM) controller is plugged into a boundary current mode (BCM) controller to control energy delivering and recycling. The proposed ER technology was fabricated by TSMC 0.25 mu m 2.5/5 V BCD process. Experimental results demonstrate fast and efficient tracking performance of driving voltage is achieved.
CCN6-mediated MMP-9 activation enhances metastatic potential of human chondrosarcoma
(2018-09-20)
Tzeng, Huey-En
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Tang, Chih-Hsin
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Wu, Sz-Hua
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Chen, Hsien-Te
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Fong, Yi-Chin
Chondrosarcomas are primary malignant bone tumors that have a poor prognosis. WNT1-inducible signaling pathway protein-3 (WISP-3, also termed CCN6) belongs to the CCN family of proteins and is implicated in the regulation of various cellular functions, such as cell proliferation, differentiation, and migration. It is unknown as to whether CCN6 affects human chondrosarcoma metastasis. We show how CCN6 promotes chondrosarcoma cell migration and invasion via matrix metallopeptidase-9 (MMP)-9 expression. These effects were abolished by pretreatment of chondrosarcoma cells with PI3K, Akt, mTOR, and NE-KB inhibitors or short interfering (si)RNAs. Our investigations indicate that CCN6 facilitates metastasis through the PI3K/Akt/mTOR/NE-KB signaling pathway. CCN6 and MMP-9 expression was markedly increased in the highly migratory JJ012(S10) cell line compared with the primordial cell line (JJ012) in both in vitro and in vivo experiments. CCN6 knockdown suppressed MMP-9 production in JJ012(S10) cells and attenuated cell migration and invasion ability. Importantly, CCN6 knockdown profoundly inhibited chondrosarcoma cell metastasis to lung. Our findings reveal an important mechanism underlying CCN6-induced metastasis and they highlight the clinical significance between CCN6 and MMP-9 in regard to human chondrosarcoma. CCN6 appears to be a promising therapeutic target in chondrosarcoma metastasis.
Dynamic Sawtooth Compensation (DSC) Technique with Self-tuning Mode Selection (SMS) for Current-Mode Buck-Boost Converter
(2012)
Su, Yi-Ping
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Wang, Shih-Wei
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Lee, Yu-Huei
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Chen, Ke-Horng
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電控工程研究所
the current-mode Buck-Boost (BB) converter with the proposed dynamic sawtooth compensation (DSC) technique is able to improve transient response and system stability. To prevent the system switches between buck and boost operations once input and output are nearly equivalent, self-tuning mode selection (SMS) is proposed to decrease output ripple and redundant power consumption by eliminating the mode misjudgment. The duty cycle is decided by the output of error amplifier and sawtooth signal, which can be adequately adjusted to ensure small output ripple and thus to improve efficiency. Besides, the DSC and SMS technique can reduce the inductor current level and the numbers of switching to decrease switching and conduction losses for high efficiency. The converter with the switching frequency of IMHz was fabricated in IP3M 0.25-mu m CMOS process. The input voltage is in the range of 2.7V to 4.8V for battery-powered devices. The efficiency is higher than 88% when load ranges from 100mA to 400mA.
Fast Transient (FT) Technique With Adaptive Phase Margin (APM) for Current Mode DC-DC Buck Converters
(2012-10-01)
Lee, Yu-Huei
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Huang, Shao-Chang
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Wang, Shih-Wei
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Chen, Ke-Horng
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電控工程研究所
This paper proposes a fast transient (FT) control with the adaptive phase margin (APM) to achieve good transient response in current-mode DC-DC buck converters at different load conditions. The overshoot/undershoot voltage and the transient recovery time are effectively reduced. The APM control can always maintain the system phase margin at an adequate value under different load conditions. That is, the compensation pole-zero pair is adapted to load current to extend the system bandwidth and get an adequate phase margin. Experimental results show the overshoot/undershoot voltage is smaller than 60 mV (3%) and transient period is smaller than 12 mu s as load current suddenly changes from 100 to 500 mA, or vice versa. Compared with conventional designs without any fast transient technique, the undershoot voltage and recovery time are enhanced by 45% and 85%, respectively.
On the Optimal Power Allocation for Additive Color Noise Parallel Channels with Limited Access Constraint
(2011)
Wang, Shih-Wei
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Chen, Po-Ning
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Wang, Chung-Hsuan
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Chang, Wen-Chieh
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電機工程學系
In this paper, we consider an (N, K)-limited access system consisting of N parallel additive noise channels with spatial dependency, where the receiver starts to decode the information being transmitted when at least K out of N channel outputs are received. We investigate the optimal power allocation that maximizes the minimum mutual information among all possible cases of partial reception. A universal guideline is then obtained for a group of permutation-invariant channels, in which the system mutual information remains unchanged when permuting the parameters that characterize the partial reception and signal-to-noise power ratio (SNR) of channels, that a channel with less noise power should have larger SNR. When all N channels belong to a permutation-invariant group, we also have that the optimal power allocation problem can be transformed to an equivalent problem for K parallel channels without limited access constraint via a water-filling noise-power-redistribution process. The merit of this transformation can be more evidently seen when the channel input-noise pairs are reduced to be spatially independent with distributions scaled from a common random vector, for which the optimal power allocation solution can be simply obtained by a two-phase water-filling process.
Optimal Power Allocation for (N, K)-Limited Access Channels
(2012-06-01)
Wang, Shih-Wei
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Chen, Po-Ning
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Wang, Chung-Hsuan
;
電子物理學系
;
Department of Electrophysics
In this paper, we consider a system that consists of independent parallel channels, where the receiver starts to decode the information being transmitted when it has access to at least K of them. We refer to this system as the (N, K)-limited access channel. No prior knowledge for the distribution about which transmissions will be received is assumed. In addition, both the channel inputs and channel disturbances can be arbitrary, except that the mutual information function for each channel is assumed strictly concave with respect to the input power. Hence, the channel capacity below which the code rate is guaranteed to be attainable by a sequence of codes with vanishing error can be determined by the minimum mutual information among any K out of N channels. We then investigate the power allocation that maximizes this minimum mutual information subject to a total power constraint. As a result, the optimal solution can be determined via a systematic algorithmic procedure by performing at most K single-power-sum-constrained maximizations. Based on this result, the closed-form formula of the optimal power allocation for an (N, K)-limited access channel with channel inputs and additive noises, respectively, scaled from two independent and identically distributed random vectors of length N is subsequently established, and is shown to be well interpreted by a two-phase water-filling principle. Specifically, in the first noise-power redistribution phase, the least N - K noise powers (equivalently, second moments) are first poured (as noise water) into a tank consisting of K interconnected unit-width vessels with solid base heights, respectively, equal to the remaining K largest noise powers. Afterward, those W vessels either with noise water inside or with solid base height equal to the new water surface level are subdivided into N - K + W vessels of rectangular shape with the same heights (as the water surface level) and widths in proportion to their noise powers. In the second signal-power allocation phase, the heights of vessel bases will be first either lifted or lowered according to the total signal power and channel mutual information functions, followed by the usual signal-power water-filling scheme. The two-phase water-filling interpretation then hints that the degree of "noisiness" for a general (possibly, nonadditive and non-Gaussian) limited access channel might be identified by composing the derivative of the mutual information function with its inverse.
Phomaketide A Inhibits Lymphangiogenesis in Human Lymphatic Endothelial Cells
(2019-04-01)
Tai, Huai-Ching
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Lee, Tzong-Huei
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Tang, Chih-Hsin
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Chen, Lei-Po
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Chen, Wei-Cheng
Lymphangiogenesis is an important biological process associated with cancer metastasis. The development of new drugs that block lymphangiogenesis represents a promising therapeutic strategy. Marine fungus-derived compound phomaketide A, isolated from the fermented broth of Phoma sp. NTOU4195, has been reported to exhibit anti-angiogenic and anti-inflammatory effects. However, its anti-lymphangiogenic activity has not been clarified to date. In this study, we showed that phomaketide A inhibited cell growth, migration, and tube formation of lymphatic endothelial cells (LECs) without an evidence of cytotoxicity. Mechanistic investigations revealed that phomaketide A reduced LECs-induced lymphangiogenesis via vascular endothelial growth factor receptor-3 (VEGFR-3), protein kinase C (PKC), and endothelial nitric oxide synthase (eNOS) signalings. Furthermore, human proteome array analysis indicated that phomaketide A significantly enhanced the protein levels of various protease inhibitors, including cystatin A, serpin B6, tissue factor pathway inhibitor (TFPI), and tissue inhibitor matrix metalloproteinase 1 (TIMP-1). Importantly, phomaketide A impeded tumor growth and lymphangiogenesis by decreasing the expression of LYVE-1, a specific marker for lymphatic vessels, in tumor xenograft animal model. These results suggest that phomaketide A may impair lymphangiogenesis by suppressing VEGFR-3, PKC, and eNOS signaling cascades, while simultaneously activating protease inhibitors in human LECs. We document for the first time that phomaketide A inhibits lymphangiogenesis both in vitro and in vivo, which suggests that this natural product could potentially treat cancer metastasis.
Power Management With a Low-Ripple High-Conversion-Ratio 80-V Output Voltage Boost Converter for Avalanche Photodiode System
(2013-07-01)
Yang, Yao-Yi
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Wang, Shih-Wei
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Hsieh, Chun-Yu
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Huang, Tzu-Chi
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Lee, Yu-Huei
Avalanche photodiodes (APDs) accompanied with the transimpedance amplifiers (TIAs) are often utilized as receivers in the communication system. A drawback of APDs is that the avalanche gain depends on temperature and varies with the bias voltage, leading to a decrease in the quality of communication. Moreover, the bias voltage for a high avalanche gain is up to 80 V, implying that a power module is inevitably required and raises the difficulty of integration. Therefore, a power management is proposed to provide an 80-V voltage and compensates the temperature dependence for a constant avalanche gain. The low-ripple high-conversion-ratio boost converter eliminates the LC resonance resulted from the nonideal effect of diodes to supress the output voltage ripple, implying that a high quality of bias voltage is guaranteed. Experimental results show that the output voltage ripple is 2.12 mV under the condition of 1-mA load current. A 97% accuracy of avalanche gain is proved to guarantee the high quality of APDs.
Power-Tracking Embedded Buck-Boost Converter With Fast Dynamic Voltage Scaling for the SoC System
(2012-03-01)
Lee, Yu-Huei
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Huang, Shao-Chang
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Wang, Shih-Wei
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Wu, Wei-Chan
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Huang, Ping-Ching
A power-tracking embedded buck-boost converter with a fast dynamic voltage scaling (F-DVS) function is proposed to power the system-on-a-chip (SoC) system. To meet the power request of the SoC for different operation functions, fast up/down-tracking is implemented to achieve the F-DVS function. Recycling energy is also derived to minimize power dissipation during the down-tracking period. In addition, the peak current control and valley current control methods are utilized in the buck and boost operations, respectively, to minimize the effect of switching noise in high switching operation for compact solution. Moreover, the self-tuning pulse skipping mechanism extends the effective duty cycle to achieve voltage regulation and improves efficiency when the input voltage is close to that of the output. Through F-DVS, the tracking speed from 3 to 2 V and vice versa are 15 and 20 mu s, respectively, with a high switching frequency of 5 MHz.
ZnO Nanoparticles Induced Caspase-Dependent Apoptosis in Gingival Squamous Cell Carcinoma through Mitochondrial Dysfunction and p70S6K Signaling Pathway
(2020-03-01)
Wang, Shih-Wei
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Lee, Chien-Hsing
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Lin, Ming-Shen
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Chi, Chih-Wen
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Chen, Yu-Jen
Zinc oxide nanoparticles (ZnO-NPs) are increasingly used in sunscreens, food additives, pigments, rubber manufacture, and electronic materials. Several studies have shown that ZnO-NPs inhibit cell growth and induce apoptosis by the production of oxidative stress in a variety of human cancer cells. However, the anti-cancer property and molecular mechanism of ZnO-NPs in human gingival squamous cell carcinoma (GSCC) are not fully understood. In this study, we found that ZnO-NPs induced growth inhibition of GSCC (Ca9-22 and OECM-1 cells), but no damage in human normal keratinocytes (HaCaT cells) and gingival fibroblasts (HGF-1 cells). ZnO-NPs caused apoptotic cell death of GSCC in a concentration-dependent manner by the quantitative assessment of oligonucleosomal DNA fragmentation. Flow cytometric analysis of cell cycle progression revealed that sub-G1 phase accumulation was dramatically induced by ZnO-NPs. In addition, ZnO-NPs increased the intracellular reactive oxygen species and specifically superoxide levels, and also decreased the mitochondrial membrane potential. ZnO-NPs further activated apoptotic cell death via the caspase cascades. Importantly, anti-oxidant and caspase inhibitor clearly prevented ZnO-NP-induced cell death, indicating the fact that superoxide-induced mitochondrial dysfunction is associated with the ZnO-NP-mediated caspase-dependent apoptosis in human GSCC. Moreover, ZnO-NPs significantly inhibited the phosphorylation of ribosomal protein S6 kinase (p70S6K kinase). In a corollary in vivo study, our results demonstrated that ZnO-NPs possessed an anti-cancer effect in a zebrafish xenograft model. Collectively, these results suggest that ZnO-NPs induce apoptosis through the mitochondrial oxidative damage and p70S6K signaling pathway in human GSCC. The present study may provide an experimental basis for ZnO-NPs to be considered as a promising novel anti-tumor agent for the treatment of gingival cancer.