• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.21 no.1
• /
• pp.53-60
• /
• 2010

This paper presents a novel gain control system composed of a feedback circuit, Two stage Low Noise Amplifier (LNA) using 0.18 um CMOS technology for 5.2 GHz. The feedback circuit consists of the seven function blocks: peak detector, comparator, ADC, IVE(Initial Voltage Elimination) circuit, switch, storage, and current controller. We focus on detecting signal and designing storage circuit that store the previous state. The power consumption of the feedback circuit in the system can be reduced without sacrificing the gain by inserting the storage circuit. The adaptive front-end system with the feedback circuit exhibits 11.39~22.74 dB gain, and has excellent noise performance at high gain mode. Variable gain LNA consumes 5.68~6.75 mW from a 1.8 V supply voltage.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 1990.10a
• /
• pp.47-52
• /
• 1990

This paper presents a cyclocoverter with a LC resonant circuit for a induction motor dr-ive. The cycloconverter can provide variab-le voltage and frequency three phase output while keeping the input displacement factor at 1.0. The input current wave forms are sinusoidal, and the wide output frequency ran-ge is appropriate for variable speed AC motor drives.

• Proceedings of the KIPE Conference
• /
• 2001.12a
• /
• pp.89-92
• /
• 2001

In conventional three-phase rectifiers, it was necessary to use a transformer to obtain low output voltage. In this paper, we propose a characteristic experimental of three-phase diode rectifiers circuit that achieves low voltage by using a very simple circuit configuration that does not have a transformer and does not need any complex control. We also describe the operation principle of the proposed circuit, and der?ive a theoretical formula for its current waveform. On the basis these theoretical values with experimentally obtained input output current characteristics, current amplification factor, and output voltage characteristics, allowed us to confirm the soundness of our theoretical analyses.

• Proceedings of the IEEK Conference
• /
• 2002.06b
• /
• pp.257-260
• /
• 2002

This paper describes the pixel of AMOLED(act ive matrix organic light emitting diode) driving circuit by poly-sl technology. The area per pixel is 278um$\times$278um in 120$\times$160(2.2 inch) Driving the OLEDS with active matrix leads to the lower voltage operation, the lower peak pixel currents and the display with much greater efficiency and brightness The role of the active matrix is to provide a constant current throughout the entire frame time and is eliminating the high currents encountered In the passive matrix approach, This design can support the high resolutions expected by the consumer because the current variation specification is norestricted. The pixel has been designed driving TFT threshold voltage cancellation circuit and wide aperture ratio circuit that communizes 4 pixel. The test simulation results and layout are 11% per threshold-current var Eat ion and 12.5% the aperture ratio of increase.

• Proceedings of the IEEK Conference
• /
• 2004.06a
• /
• pp.7-10
• /
• 2004

This paper describes techniques to implement low-cost adapt ive Pipelined LMS filter for ASIC implement ions of high communication receivers. Power consumpiton can be reduced using a careful selection of architectural, algorithmic, and VLSI circuit techlifue A Pipelined architecture for the strength-reduced algorithm is then developed via the relaxed look-ahead transformation. This technique, which is an approximation of the conventional look-ahead compution, maintains the functionality of the algorithm rather than the input-output behavior Convergence maiysis of the Proposed architecture has been presented and support via simulation results. The resulting pipelined adaptive filter achives a higher though put requires lower power as compared to the filter using the serial algorithm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2004.05b
• /
• pp.472-474
• /
• 2004

In this study, we investigated the characteristics of the input impedance and the gain of a ‘Folded dipole antenna with stub’ by the Method of Moments. The center frequency in this study is 200MHz, the radius of wire is 0.5nm, and the distance between two linear dipoles is 2cm. The inside variation of stub length within 18cm and the outside variation of stub length 4.5cm ive the value of SWR(Standing Wave Ratio) within 3. This means that the impedance matching between the ‘Folded dipole antenna with stub’ and receiver can easily be performed without a supplementary matching circuit.