Search

In the PCB industry, Cu is the most commonly used metal for circuit line and pad materials. In this study the etching behavior of Cu in two different cases. First, the etching behavior of Cu when connected with Au was studied. After the wiring process, soft etching is performed to remove the copper oxide layer formed on the circuit or pad. Cu is excessively etched by a galvanic coupling of Au and Cu. Electrochemical evaluation such as open circuit voltage (OCV) and polarization curve in two different solutions were analyzed. Optimum etching conditions in which over etching did not occur even in the galvanic couple of Au and Cu were confirmed. Second, the etching behavior of Cu-Invar-Cu (CIC) was studied. It is one of the core candidate materials to compensate the disadvantages of conventional PCB. In wet etching process, it is difficult to obtain uniform pattern due to different etching rates and etching characteristics of Cu and Invar. The etching rates and etching properties of Cu and Invar in FeCl 3 and CuCl 2 were compared. Finally, the optimum conditions for uniform patterning were obtained.

We report a 5.28-Gb/s serializer ASIC for uncompressed long-haul video interconnects. Our ASIC is based on the serializer architecture which maintains the constant output data rate for various resolutions of incoming video signals from VGA to UXGA. With this, a wide-band phase-locked-loop in a serializer and a continuous-rate clock-and-data-recovery circuit in a de-serializer are not necessary. The serializer ASIC contains clock-and-data-recovery circuits, de-multiplexers, a digital processing block, a phase-locked-loop, multiplexers. A VCSEL driver circuit is also integrated so that it can be used for long-haul transmission with multimode fiber. The ASIC produces 5.28-Gb/s serialized driving currents for VCSEL from parallel input signals. It occupies 3.45 mm2 and consumes 151.7 mW.

To implement a mobile radio system, wave-propagation models are necessary to determine propagation characteristics accurately, Currently, the empirical/theoretical prediction models for urban environments are fairly well-developed. But there is a lack of a suitable prediction model for mountain region. So in this paper, to develop the prediction model for mountain region, propagation environments are classified based on three basic mechanisms: reflection, diffraction, penetration(absorbtion and scattering), and measurements have been performed for the classified mountain regions including open area, forest and ridge. Using the measurement data, empirical modeling of propagation characteristics are performed, and then a prediction model for mountain region is proposed.

Power line communications provide a convenient and cost-effective solution for data transmission, because power mains are the most popular and widely distributed medium in the world. However, the time-variant and unpredictable channel environment for communication poses a major challenge. In this regard, we propose a robust power line modem based on adaptively signal detection techniques for networked home appliances. The modulation scheme used in this research is a chirped spread spectrum with a separate matched filter based on an adaptive threshold decision technique. In addition, we propose an adaptive retransmission technique based on flexible carrier frequency selection using a ram based look-up table (LUT) for improving carrier sense multiple access with collision avoidance (CSMA/CA) media access protocol. The proposed power line transceiver is realized in 0.35 mum CMOS technology and verified with networked various consumer electronic devices. The results show that the proposed power line communication modem is well qualified as a communication device for home automation .

In this paper, we propose the architecture of high-performance HOG feature extractor circuit for the driver assistance system. We have proposed the simplified hardwired methods for the square root of the gradient calculation and the division operation of the block normalization. Our HOG feature extractor circuit can process 37 frames per seconds for 640×480 VGA images in real-time.

The heat transfer characteristics of a low temperature latent heat storage system have been determined for circular finned and unfinned tubes using sodium acetate tribydrate as a phase change material (PCM). In the heat recovery stage, supercooling of PCM in the finned-tube system is larger than that in the unfinned-tube system. The heat-transfer coefficient between the PCM and the heat-transfer tube surface can be predicted from the steady-state heat conduction equation except the beginning of freezing with some degree of supercooling. The heat transfer is significantly reduced by the void cavities upon shrinkage of PCM in the finned-tube system. The enhancement of heat transfer by thin finned-tube over the unfinned-tube is found to be negligible. The heat-transfer coefficient in the thick finned-tube system is approximately two times higher than that in the unfinned-tube system. The heat transfer coefficients for the unfinned-tube and thick finned-tube systems are found to be 45 ~ 150 W/m2-K and 90 ~ 250 W/m2-K, respectively. The thermal performance for three different tube systems is found to be strongly affected by the inlet temperature but not by the flow rate of the heat transfer fluid. The amount of heat recovered has been correlated in terms of the Fourier, Stefan, and Reynolds numbers.

Heat transfer characteristics of a low temperature latent heat storage system have been determined for the circular finned and unfinned tubes using sodium acetate trihydrate as a phase change material (PCM). In the heat storage stage (melting process). the PCM heat transfer coefficient in the unfinned-tube system showed good agreement with the calculated value by the heat conduction equation. The heat transfer between the tube wall and the PCM was not enhanced by the fins in the thin-finned-tube system, whereas 2 times higher heat-transfer coefficient for the thick-finned-tube system over the unfinned-tube system was obtained. The experimentally determined heattransfer coefficients in the unfinned-tube and thick-finned-tube systems are in the ranges of 40–170 and 80–320 W/m2-k, respectively. The amount of heat storage for three systems has been correlated in terms of Fourier, Stefan and Reynolds numbers. The thermal performance of heat storage systems are found to be strongly dependent on the

Heat-transfer characteristics during melting of magnesium chloride hexahydrate (MgCl2·6H2O  MCHH) have been determined for circular finned- and unfinned-tube systems. The effects of inlet temperature and flow rate of the heat transfer fluid (HTF) on the heat-transfer characteristics have been determined. Heat transfer from the tube to the phase-change material (PCM) is strongly influenced by natural convection of melted PCM, especially in the unfinned-tube system. The measured melting-front velocities in the unfinned-tube system agree well with analytical predictions. The amounts of heat storage in three different systems have been correlated in terms of Fourier, Stefan, and Reynolds numbers to provide basic data for designing unfinned-and finned-tube heat-storage units.

Smart vehicle technologies such as ADAS are growing concern about. Especially, pedestrian and vehicle recognition system based on machine vision is a big issue. In this paper, we propose the hardwired HOG feature extractor circuit for real-time human and vehicle detection, and describe the hardware implementation results. Our HOG feature extractor supports weighted gradient value, 2D histogram interpolation and block normalization. We have used the simplified methods of the square root and division operation for the hardware implementation. Our HOG feature extractor circuit was verified on FPGA environment and can be processed 33 frames per seconds for 640×480 VGA images in real-time.

This paper presents an efficient pedestrian detection by Bin-interleaved Histogram of Oriented Gradients (Bi-HOG) for automotive applications. The state-of-art feature named HOG [5] is adopted as the basic feature. We arrange alternately even-bin cells and odd-bin cells in one block and then extract the only even-bin feature elements for even-bin cells and the only odd-bin feature elements for odd-bin cells. So the feature dimension of our Bi-HOG is a half size of HOG by bin-interleaved method like this. We experimentally demonstrate that SVM classifiers trained by Bi-HOG have the same detection performance on the DaimlerChrysler data set as one by the original HOG in our two-staged pedestrian detection system and considerably reduce storage requirement and simplify the computational complexity.

Heat-transfer characteristics have been determined for the circular finned and unfinned-tube units during the freezing of magnesium chloride hexahydrate (MgCl2 · 6H2O) used as a phase-change material (PCM) with a melting temperature of 116.7 °C. The effects on the heat-transfer characteristics have been determined of the inlet temperature and the flow rate of air used as the heat-transfer fluid (HTF). With the unfinned-tube unit, the heat-transfer coefficients obtained between the PCM and the tube are larger than the calculated values based on the theory of steady-state heat conduction due to the dendritical crystal growth of PCM. The ratio of the heat-transfer coefficient of the finned-to the unfinned-tube systems is about 3.5 within the finned section and decreases gradually far from the finned section with an increase in crystal volume. The total amounts of heat recovered have been correlated in terms of the Fourier, Stefan, and Reynolds numbers to provide basic design data for circular finned- and unfinned-tube heat-storage units.

In this paper, a wireless power transmission system was designed and demonstrated using an optimized rectenna circuit. To use wireless power transmission, the most important factor is the microwave-DC conversion efficiency. To improve the microwave-DC conversion efficiency, matching circuits from antenna to rectifier and rectifier to load were designed and fabricated in this research. And also, printed monopole antenna was designed and optimized with rectifying circuit at 2.4GHz. The return loss (S11) of the antenna is about −22.6dB. The return loss of rectifying circuit is −28.3dB. We obtained the microwave-DC conversion efficiency of 0.61mW, when input power is 24dBm.

In this paper, a 110 dB, 1.024 MHz fourth-order single-loop sigma-delta modulator has been presented with an over-sampling ratio of 128 and an overload factor of -6 dB for a bandwidth of 4 kHz. In particular, this Sigma-Delta modulator is well suited for atmospheric pressure sensor. The whole modulator consumes only 3-mW from a single 3.3 V supply in a 0.35-mum CMOS technology and chip size is 1.68 mm2.

This paper presents a novel driving scheme for AMOLED displays using a current mirror structure. For future low cost displays, the results are based on soluble-processed OTFTs. Since the characteristics of soluble-processed OTFTs are poor compared to pentacene-based OTFTs, the output current levels are controlled by adjusting the ratio of device dimensions. The simulation results show reliable uniformity between input data and OLED current. Also, successful compensation of OLED current due to threshold voltage variation is also shown.

Design description and measurement results of 0.18 mum CMOS direct conversion receiver front-end intended for use in a transceiver for 2.4 GHz band of 802.15.4 standard are presented. Front-end consists of LNA and two current-mode passive mixers. Single-ended RF drive of double-balanced I/Q mixers was used as a means of power dissipation reduction. The measurement showed the following performance: noise figure 7.3 dB, 1/f-noise corner 70 kHz, power gain 10 dB, input IP3 -8 dBm with DC current dissipation of 3.5 mA while operating from voltage supply of 1.8 V

We propose a ubiquitous computing processor, which contains an IEEE802.11b wireless LAN for a communication channel. The IEEE802.11b wireless LAN would play an important role in the first generation of ubiquitous computing systems. In this work, the hardwired IEEE802.11b wireless LAN base-band processor, which supports the AMBA interface, was implemented and verified within a verification environment. As a result of this verification, we demonstrated that the implemented wireless baseband processor supports the IEEE802.11b standard. Also, it shows that the IEEE802.11b wireless LAN could play the role of the basic download channel in the proposed ubiquitous processor.

Today the digital coded systems for either data transmission or data storage are much in common. The output of the channel or storage medium differs from its input because they are both sensitive to the errors that can result from impaired transmission. For that reason, Reed-Solomon (RS) codes are commonly used in various applications. In this paper, we propose the VLSI implementation of Reed-Solomon decoder with the development of an architecture featuring parallel and pipelined processing to improve the speed and low power design. We analyzed the RS decoding algorithm for the efficient parallel and pipelined structure and modified the Euclid's algorithm arithmetic part to apply the parallel structure. The overall RS decoder is compared to Shuo's. We show the 10% area efficiency increase over Shao's time domain decoder and three times faster operation. In addition, we approve the proposed RS decoders with Altera FPGA Flex 10K-50, and Implemented with LG 0.6 processing.

This paper presents how we use a soft Peripheral Component Interconnect (PCI) Intellectual Property (IP) for converting an Industry Standard Architecture (ISA) bus to a PCI bus in the personal computer (PC) data protection application specific integrated circuit (ASIC) design. To save design time and achieve a more efficient design, we use a verified PCI IP. The PCI IP was a soft IP and designed by Pheonix Technology. The total blocks consist of 3 major blocks: PCI IP block, user interface block, and PC data protection block. We verified the functioning of the PC data protection circuit with a supplied test environment by Pheonix Technology. So we built in a test environment easily. We cooperated with the ASIC foundry and IP vendor for IP integration using PCI IP. The operating frequency is 33 MHz. The size of EEPROM is 64 Kbytes and the size of the data bus is 32 bits. We fabricated the chip in a 0.5 /spl mu/m CMOS technology since the EEPROM was made by 0.5 /spl mu/m CMOS technology.