• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.4B
• /
• pp.624-628
• /
• 2000

In this paper, the phenomenon to show in CDMA handset in case of which CDMA handset do not meet Traffic Rho value of IS-98B specifications, which have minimum requirements of CDMA handset about electrical performance is analyzed. This paper proposed method to improve Traffic Rho through improving the matching circuit of TX IF SAW FILTER and deleting noise of LDO(Low Dropout Regulator) to generate 3.OV_TX in TX block. HP8924C(CDMA Mobile Station Tester Set) and HP8595E(Spectrum Analyzer) measures the improved CDMA waveform.

• Transactions on Electrical and Electronic Materials
• /
• v.17 no.3
• /
• pp.172-177
• /
• 2016

Miller feedback compensation is introduced in a low dropout regulator (LDO) in order to obtain a capacitor-free regulator and improve the fast transient response. The conventional LDO has a limited bandwidth because of the large-size output capacitor and parasitic gate capacitance in the power MOSFET. In order to obtain a stable frequency response without the output capacitor, LDO is designed with resistor-capacitor (R-C) compensation and this is achieved with a connection between the gain-stage and the power MOS. An R-C compensator is suggested to provide a pole and zero to improve the stability. The proposed LDO is designed with the 0.35 μm CMOS process. Simulation testing shows that the phase margin in the Bode plot indicates a stable response, which is over 100^o. In the load regulation, the transient time is within 55 μs when the load current changes from 0.1 to 1 mA.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.12
• /
• pp.2503-2510
• /
• 2015

This paper presents a single-phase energy measurement IC to measure electric power quantities. The entire IC includes two programmable gain amplifiers (PGAs), two ${\sum}{\Delta}$ modulators, a reference circuit, a low-dropout (LDO) regulator, a temperature sensor, a filter unit, a computation engine, a calibration control unit, registers, and an external interface block. The proposed energy measurement IC is fabricated with $0.18-{\mu}m$ CMOS technology and housed in a 32-pin quad-flat no-leads (QFN) package. It operates at a clock speed of 4,096 kHz and consumes 10 mW in 3.3 V supply.

• Journal of IKEEE
• /
• v.21 no.2
• /
• pp.154-157
• /
• 2017

This paper proposes the Low-Dropout regulator with two output. Each of the two output has feedback, and shared feedback loop. PMOS is added to solve the problem the occur when sharing the feedback loop. Thus eased the Load Transient Response. Also Using one of the bias citcuit and one of the pass transistor, Area is reduce by half compared to Existing Area that used to obtain output of two output.

• Journal of Power Electronics
• /
• v.15 no.6
• /
• pp.1673-1681
• /
• 2015

A low dropout (LDO) regulator with a wide-bandwidth is proposed in this paper. The regulator features a Human Body Model (HBM) 8kV-class high robustness ElectroStatic Discharge (ESD) protection circuit, and two error amplifiers (one with low gain and wide bandwidth, and the other with high gain and narrow bandwidth). The dual error amplifiers are located within the feedback loop of the LDO regulator, and they selectively amplify the signal according to its ripples. The proposed LDO regulator is more efficient in its regulation process because of its selective amplification according to frequency and bandwidth. Furthermore, the proposed regulator has the same gain as a conventional LDO at 62 dB with a 130 kHz-wide bandwidth, which is approximately 3.5 times that of a conventional LDO. The proposed device presents a fast response with improved load and line regulation characteristics. In addition, to prevent an increase in the area of the circuit, a body-driven fabrication technique was used for the error amplifier and the pass transistor. The proposed LDO regulator has an input voltage range of 2.5 V to 4.5 V, and it provides a load current of 100 mA in an output voltage range of 1.2 V to 4.1 V. In addition, to prevent damage in the Integrated Circuit (IC) as a result of static electricity, the reliability of IC was improved by embedding a self-produced 8 kV-class (Chip level) ESD protection circuit of a P-substrate-Triggered Silicon Controlled Rectifier (PTSCR) type with high robustness characteristics.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.21 no.4
• /
• pp.123-127
• /
• 2021

Millimeter-wave tracking radars should be operated in various environmental restrictions, thus they demand more computing power and smaller size compared to conventional tracking radars. This paper presents the design and implementation of the compact power supply for millimeter-wave tracking radar applications. To meet requirements of low voltage/high current and voltage accuracy for FPGA/DSP digital circuits, Point of Load (POL) converters are used in order to enhance power density and system efficiency. LDO (Low Dropout) is applied for the output voltage under the light load condition, then the single-input-multi-output power supply with max power of 375 W and 8 outputs is developed. The proposed power supply achieves output voltage accuracy of ±2 % and noise level of <50 mVpp % under full load conditions.

• Journal of Engineering Education Research
• /
• v.14 no.3
• /
• pp.3-8
• /
• 2011

Women in the predominantly male-oriented college of engineering which is afflicted by the high dropout rate and the low employment rate of coeds in their majoring fields because of the die-hard male dominant culture. In order to resolve the related problems, P University has been actively engaged in a movement called "Women into Engineering" (WIE) to raise the gender cognitive awareness and to train women engineers for highly qualified work force. As part of the movement, a subject called "Women in Engineering" that focuses on the gender cognitive perspective is effective to reduce the dropout rate and to land a job inside their fields by stimulating their interest in their specialty and masting soft/hard skills. The study was conducted a survey of the coeds who have completed the "Women in Engineering" course to evaluate the degree of satisfaction perceived, and a t-test through comparing the group of the coeds and a group of coeds who have not taken the course. The results showed statistically significant responses indicating that both groups of coeds would like to see WIE offer more basic engineering courses like "Women in Engineering". This may lay the foundation to offer other major engineering courses for juniors and seniors that emphasize the gender cognitive approach.

• Journal of Engineering Education Research
• /
• v.17 no.5
• /
• pp.8-12
• /
• 2014

Women in engineering subject were developed for women included engineering education in Korea. Women in the predominantly male-oriented college of engineering which is afflicted by the high dropout rate and the low employment rate of coeds in their majoring fields because of the die-hard male dominant culture. In order to resolve the related problems, Our University has been actively engaged in a movement called "Women into Engineering" (WIE) to raise the gender cognitive awareness and to train women engineers for highly qualified work force. As part of the movement, a subject called "Women in Engineering" that focuses on the gender cognitive perspective is effective to reduce the dropout rate and to land a job inside their fields by stimulating their interest in their specialty made soft/hard skills. The study was conducted a survey of the coeds who have completed the "Women in Engineering" course to evaluate the degree of satisfaction perceived, and a t-test through comparing the group of the coeds and a group of coeds who have not taken the course. The results showed statistically significant responses indicating that both groups of coeds would like to see WIE offer more basic engineering courses like "Women in Engineering." This may lay the foundation to offer other major engineering courses for juniors and seniors that emphasize the gender cognitive approach.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.6
• /
• pp.2729-2734
• /
• 2011

In this paper, an active replica Low-dropout(LDO) regulator with DC voltage matching circuit is presented. In order to match the voltage between replica and output of regulator, DC voltage matching circuit is designed. The active replica low dropout regulator has higher Power Supply Rejection(PSR) than that of conventional regulator. The designed DC voltage matching circuit can reduce the drawback that may be occurred in replica regulator. And using fully active element in regulator can reduce the chip area and heat noise with resistor. As results of HSPICE simulation with 0.35um CMOS parameter, the designed active replica LDO regulator achieves Power Supply Rejection, -28@10Hz better than -17@10Hz of conventional replica regulator without DC matching circuit. And the output voltage is 3V.

• Educational Technology International
• /
• v.17 no.2
• /
• pp.229-251
• /
• 2016

This study was designed to investigate the relationship between middle school students' smart media competency and online learning outcomes. The context of this study was on online inquiry-based mathematics and science learning environment, and four-hundred and fifty-five (455) 7^th to 9^th grade students in Korea participated in this research. To assess students' smart device competency, Smart Media Literacy Quotient (SMLQ) which consisted of 18 items regarding the operation ability of smart media and its application (14 items) and positive beliefs of smart media (4 items) was administered to each student. The findings of this study first showed that students' smart media literacy varied according to their characteristics such as gender, grade, class (subject), and socio-economic status. Female students' scores were higher in overall smart media literacy operation and learning ability of smart media than male students. 7^th grade middle school students represented lower smart media literacy scores, compared to 8^th and 9^th graders. Also, minority students were significantly lower in smart media literacy, operation and learning ability of smart media, and positive belief of smart media than the non-minority students. Second, overall smart media literacy and operation and learning ability of smart media varied among high, medium, and low score achievers in inquiry tasks. Low scored students in inquiry tasks were significantly lower in overall smart media literacy and operation and learning ability of smart media than medium scored students. Lastly, smart media literacy also varied by students' dropout/completion. Students who dropped out reported significantly lower scores in overall smart media literacy, operation and learning ability of smart media, and positive belief of smart media.