Browsing by Author "Tsai, Chia-Sheng"

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Charge pump circuit suitable for low-voltage process
(2005-07-07)
Ker, Ming-Dou
;
Tsai, Chia-Sheng
The present invention discloses a charge pump circuit suitable for a low-voltage process. The charge pump circuit is composed of stages of the voltage amplifying circuits connected each other, and the operation of two adjacent stages of voltage amplifying circuit is controlled by two opposite set of the timing signals. Each stage of the voltage amplifying circuit has a coupled pair of a first complementary MOS (CMOS) transistor and a second CMOS transistor switching in accordance with a timing signal and an inverse timing signal inputted into the first and second capacitors. Then, two diode devices guide charges to next stage, and a voltage higher than the integrated circuit voltage source is outputted. The present invention has advantage of high pumping gain, and the reliability issue of the gate oxide layer in the low-voltage process can be also solved.
Overview and design of mixed-voltage I/O buffers, with low-voltage thin-oxide CMOS transistors
(2006-09-01)
Ker, Ming-Dou
;
Chen, Shih-Lun
;
Tsai, Chia-Sheng
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電機學院
;
College of Electrical and Computer Engineering
Overview on the prior designs of the mixed-voltage I/O buffers is provided in this work. A new 2.5/5-V mixed-voltage I/O buffer realized with only thin gate-oxide devices is proposed. The new proposed mixed-voltage I/O buffer with simpler dynamic n-well bias circuit and gate-tracking circuit can prevent the undesired leakage current paths and the gate-oxide -reliability problem, which occur in the conventional CMOS I/O buffer. The new mixed-voltage I/O buffer has been fabricated and verified in a 0.25-mu m CMOS process to serve 2.5/5-V I/O interface. Besides, another 2.5/5-V mixed-voltage I/O buffer without the subthreshold leakage problem for high-speed applications is also presented in this work. The speed, power consumption, area, and-noise among these mixed-voltage I/O buffers are also compared and discussed. The new proposed mixed-voltage I/O buffers can be easily scaled toward 0.18- mu m (or below) CMOS processes to serve other mixed-voltage I/O interfaces, such as 1.8/3.3-V interface.
Single-component polyfluorene electrolytes bearing different counterions for white light-emitting electrochemical cells
(2013-02-01)
Tsai, Chia-Sheng
;
Yang, Sheng-Hsiung
;
Liu, Bo-Cun
;
Su, Hai-Ching
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照明與能源光電研究所
A series of polyfluorene (PF) electrolytes bearing Br, BF4-, or PF6- counterions were synthesized and characterized. 2,1,3-Benzoselenadiazole moieties were incorporated into polymer main chains to produce single-component white light-emitting polymers. The thermal stability of Br-containing ionic PF was decreased because of the Hofmann elimination occurred at higher temperature. By replacing Br with BF4- or PF6- counterions, the thermal stability of polymers was significantly improved. UV-vis absorption and photoluminescence spectra revealed that Br-containing ionic PF generates blue shift in methanol, while BF4 and PF6-containing ionic PFs show blue shift in acetonitrile. Electrochemical analysis revealed that oxidation potentials of BF4 and PF6-containing ionic PFs were decreased, resulting in increase in HOMO and LUMO levels. The optimized spin-coated light-emitting electrochemical cell (LEC) with the configuration of ITO/PEDOT/polymer/Ag showed a maximum luminescence efficiency of 1.56 lm/W at a low operation bias of 3 V. The single-component LEC device exhibited pure white light emission with CIE'1931 coordinates approaching (0.33, 0.33) and high color rendering index (CRI > 85), referring to its potential use in solid-state-lighting application. (C) 2012 Elsevier B.V. All rights reserved.
Synthesis of fluorene-based polyelectrolytes tethering different counterions for single-component white light-emitting electrochemical cells
(2013)
Yang, Sheng-Hsiung
;
Tsai, Chia-Sheng
;
Liu, Bo-Cun
;
Su, Hai-Ching
;
照明與能源光電研究所
A series of polyfluorene (PF) electrolytes bearing Br-, BF4-, or PF6- counterions were synthesized and characterized. 2,1,3-benzoselenadiazole moieties were incorporated into polymer main chains to produce single-component white light-emitting polymers. The thermal stability of Br-containing ionic PF was decreased because of the Hofmann elimination occurred at higher temperature. By replacing Br- with BF4- or PF6- counterions, the thermal stability of polymers was significantly improved. The emission intensity around 550 nm was decreased for ionic polyelectrolytes. The optimized spin-coated light-emitting electrochemical cell (LEC) with the configuration of ITO/PEDOT/polymer/Ag showed a maximum luminescence efficiency of 1.56 lm/W at a low operation bias of 3 V. The single-component LEC device exhibited pure white light emission with CIE\'1931 coordinates approaching (0.33, 0.33) and high color rendering index (CRI > 85), referring to its potential use in solid-state-lighting application.