• Journal of Sensor Science and Technology
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• v.8 no.1
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• pp.38-44
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• 1999

In this paper, we have constructed a self-diagnostic circuit which could detect erroneous signals in most cases that a eight-beam piezoresistive accelerometer were destroyed more than its one beam. To confirm the function of the circuit, PSPICE simulation was carried out. An IC chip was fabricated with a layout of KA 324 amplifier using a bipolar standard processing. After a package of the chip was sealed using a plastic package with 24 pins, the self-diagnostic characteristics were investigated. Then, the measured self-diagnostic characteristics of the circuit were compared with the PSPICE simulated result.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.1
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• pp.166-172
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• 2001

A RF wideband receiver for INMARSAT-B satellite communications system was composed of low noise amplifier and high gain amplifier, The low noise amplifier used to the resistive decoupling circuit for input impedance matching and self-bias circuits for low noise. The high gain amplifier consists of matched amplifier type to improve receiver gain. The active bias circuit can be used to provide temperature stability without requiring the large voltage drop or relatively high-dissipated power needed with a bias stabilization resistor. The bandpass filter was used to reduce a spurious level. As a result, the characteristics of the receiver implemented here show more than 60 dB in gain and less than 1.8:1 in input and output voltage standing wave ratio(VSWR), especially the carrier to noise ratio which is input signal level -126.7 dB m at 1537.5 MHz is a 45.23 dB /Hz at a 1.02 kHz.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.6
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• pp.91-98
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• 2004

This paper proposes a PCB plane model for generic SPICE circuit simulators. The proposed model reflects two frequency-dependent losses, namely skin and dielectric losses. After power/ground plane pair is divided into arrays of unit-cells, each unit-cell is modeled using a transmission line and two loss models. The loss model is composed of a resistor for DC loss, series HL ladder circuit for skin loss and series RC ladder circuit for dielectric loss. To verify the validity of the proposed model, it is compared with SPICE ac analysis using frequency-dependent resistors. Also, we show that the estimation results using the proposed model have a good correlation with that of VNA measurement for the typical PCB stack-up structure of general desktop PCs. With the proposed model, not only ac analysis but also transient analysis can be easily done for circuits including various non-linear/linear devices since the model consists of passive elements onl.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.10
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• pp.133-137
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• 2016

Use of UV gel for nail management have been increasing gradually. In order to develop an UV lamp necessary to UV gel, in this study, we was designed circuits of the UV-LED lamp. Power supply part that supplies constant power to the several UV-LEDs, was designed the circuit with the method of DC-DC converter. Taking into account the direction of the thumb nail and the position of the little finger nail, it was placed UV-LEDs. Input power of the power supply part was used as a battery voltage of 3.8[V]. The output voltage of the power supply part was appeared in approximately 3.1[V]. And in order to examine the state of change of the output voltage according to the amount of current consumption of UV-LEDs, after inserting of load resister, the output voltage was more than about 3.0[V] in the simulation results of the power supply part while changing the resistance value.

• Journal of IKEEE
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• v.18 no.4
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• pp.586-592
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• 2014

In this paper, high efficiency power management IC(PMIC) with DT-CMOS(Dynamic threshold voltage Complementary MOSFET) switching device is presented. PMIC is controlled PWM control method in order to have high power efficiency at high current level. The DT-CMOS switch with low on-resistance is designed to decrease conduction loss. The control parts in Buck converter, that is, PWM control circuit consist of a saw-tooth generator, a band-gap reference(BGR) circuit, an error amplifier, comparator circuit, compensation circuit, and control block. The saw-tooth generator is made to have 1.2MHz oscillation frequency and full range of output swing from supply voltage(3.3V) to ground. The comparator is designed with two stage OP amplifier. And the error amplifier has 70dB DC gain and $64^{\circ}$ phase margin. DC-DC converter, based on current mode PWM control circuits and low on-resistance switching device, achieved the high efficiency nearly 96% at 100mA output current. And Buck converter is designed along LDO in standby mode which fewer than 1mA for high efficiency. Also, this paper proposes two protection circuit in order to ensure the reliability.

• Journal of the Korean Vacuum Society
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• v.6 no.1
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• pp.20-27
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• 1997

We have investigated the formation techniques of copper thin films which would be useful for sub-quarter-micron integrated circuits. A chemical vapor deposition technology has been tried for the better side wall formation of the thin films, and a metal organic compound, named (hface)Cu(VTMS) (hexafluoroacetylacetonate vinyltrimethylsilane copper(I)) was used as the precursors. We have deposited the copper thin films on TiN and $SiO_2$substrates. The film resistivity and deposition selectivity have been measured as functions of substrate temperature and chamber pressure. Best electrical properties were obtained at $180^{\circ}C$ of substrate temperature and 0.6 Torr of chamber pressure. Under the optimum deposition conditions, polycrystalline copper structures were observed to be grown, and the deposition rate of 120 nm/min was measured. The electrical resistivity as low as 0.25$mu \Omega$.cm, and the surface roughness of 15.5 nm were also measured. These are the suitable electrical and material properties required in the sub-quarter-micron device fabrication. Also, in the substrate temperature range of 140-$250^{\circ}C$, high deposition selectivity was observed between TiN and $SiO_2$.

• Journal of IKEEE
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• v.14 no.2
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• pp.90-97
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• 2010

The high efficiency power management IC(PMIC) with DTMOS(Dynamic Threshold voltage MOSFET) switching device and DTMOS Error Amplifier is presented in this paper. PMIC is controlled with PWM control method in order to have high power efficiency at high current level. Dynamic Threshold voltage CMOS(DT-CMOS) with low on-resistance is designed to decrease conduction loss. The control parts in Buck converter, that is, PWM control circuits consist of a saw-tooth generator, a band-gap reference circuit, an DT-CMOS error amplifier and a comparator circuit as a block. the proposed DT-CMOS Error Amplifier has 72dB DC gain and 83.5deg phase margin. also Error Amplifier that use DTMOS more than CMOS showed power consumption decrease of about 30%. DC-DC converter, based on Voltage-mode PWM control circuits and low on-resistance switching device is achieved the high efficiency near 96% at 100mA output current. And DC-DC converter is designed with Low Drop Out regulator(LDO regulator) in stand-by mode which fewer than 1mA for high efficiency.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.5
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• pp.143-152
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• 2004

A novel low-power wideband bipolar second-generation current conveyors(CCIIs) and its application to universal instrumentation amplifier(UIA) were proposed. The CCII for accuracy voltage or current transfer characteristics and low current input impedance adopted adaptive current bias circuit into conventional class Ab CCII. The UIA consists of only two CCIIs and four resistors. Three instrumentation function of the UIA can be realized by selection of input signals and resistors. The simulation results show that the CCII has input impedance of 2.0$\Omega$ and the voltage gain of 60㏈ for frequency range from 0 to 50KHz when used as a voltage amplifier. The CCII has also good characteristics of current follower for current range from -100㎃ to ＋100㎃. The simulation results show that the UIA has three instrumentation amplifier functions without resistor matching. The UIA has the voltage gain of 40㏈ for frequency range from 0 to 100KHz when used as a fully-differential instrumentation amplifier. The power dissipations of the CCII and the UIA are 0.75㎽ and 1.5㎽ at supply voltage of $\pm$2.5V, respectively.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.1 no.2
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• pp.49-56
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• 1987

To save energy consumption, it is proposed to operate a discharge lamp with high frequency power. When designing a high frequency operating circuit containing a discharge lamp, the character of a lamp may be needed. And there are various methods to get and models for this. In this study, to present the volt-ampere character of a fluorescent lamp which gives a good saving effect, the nonlinear resistance model is suggested. And the validity of the model is verified by applying the model for the circuits with inductor ballast and capacifor ballast. This model, in contrast with the others, can be easily obtainable. And for comparison, the model using a modified Francis equation is examined. The method used in this study can be basically applied to the other discharge lamps. As a result, 1) Approximated 3rd order polynomial of nonlinear resistance model gives a good simulation result. 2) When operating in high frequency, the model using a modified Francis equation with constant coefficients can't be applied.

• Journal of Sensor Science and Technology
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• v.7 no.5
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• pp.300-305
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• 1998

In this paper, integrated pressure sensor with calibration of offset voltage and full scale output and temperature compensation of offset voltage and full scale output were designed. The signal conditioning circuitry are designed that calibrate the offset voltage and full scale output to desired values and minimize the temperature drift of offset voltage and full scale output. Designed circuits are simulated using SPICE in a bipolar technology. The ion implanted resistor of different temperature coefficient were used to trimming the desired values. As a results, offset voltage was calibrated to 0.133V and the temperature drift of offset voltage was reduced to $42\;ppm/^{\circ}C$. Also, the full scale output was calibrated to 4.65V and the temperature coefficient of full scale output was reduced to $40ppm/^{\circ}C$ after temperature compensation.