• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.6 s.336
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• pp.1-8
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• 2005

In this paper, CMOS A/D converter with 6bit 2GSPS Nyquist input at 1.8V is designed. In order to obtain the resolution of 6bit and the character of high-speed operation, we present an Interpolation type architecture. In order to overcome the problems of high speed operation, a novel One-zero Detecting Encoder, a circuit to reduce the Reference Fluctuation, an Averaging Resistor and a Track & Hold, a novel Buffered Reference for the improved SNR are proposed. The proposed ADC is based on 0.18um 1-poly 3-metal N-well CMOS technology, and it consumes 145mW at 1.8V power supply and occupies chip area of 977um $\times$ 1040um. Experimental result show that SNDR is 36.25 dB when sampling frequency is 2GHz and INL/DNL is $\pm$0.5LSB at static performance.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.151-160
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• 2017

This paper presents a new technique of reference current generator based on Kalman filter (KF) estimator for three-phase shunt active power filter (APF). The stationary reference frame (d-q algorithm) is used to transform the load currents into DC component. The harmonics of load currents are extracted and the three-phase reference currents are generated using KF estimator. The work is simulated using Matlab/Simulink platform. To validate the simulation results, an experimental test-rig have been perform using real-time control dSPACE DS1104. In addition, hysteresis current control was used to generate the switching signal for the correction of the harmonics in the system. The non-linear load were constructed with three-phase rectifier which connected in series with inductor and parallel with resistor and capacitor. The results shows that the new technique of shunt APF embedded with KF is proven to eliminate the harmonics created by the non-linear load with some improvement on the total harmonics distortion (THD).

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.557-560
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• 2004

In this study, we design the one-chip PWM IC for SMPS (Switching Mode Power Supply) application. We determine the IC spec. and simulated each block of PWM IC (Reference, Error amp., Comparator, Oscillator) with Smart Spice (SILVACO Circuit Simulation Tool). Reference circuits generate constant voltage(5V) in the various of power supply and temperature condition. Error amp. is designed with large DC gain (${\simeq}65dB$), unity frequency (${\simeq}190kHz$) and large PM($75^{\circ}$).Saw tooth generators operate with 20K oscillation frequency (external resistor, capacitor).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.699-702
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• 2002

A DC current sensor is disclosed in which two pairs of saturable cores are provided so as enclose a conductor carrying a direct current to be measured. On each of the saturable cores, a bias winding, a feedback winding and an output winding are wound. Circuit for detection of an asymmetry in the magnetization current, generated by a reference alternating voltage, in a signal-conditioner. The reference alternating voltage is fed to the respective series circuits such that no resultant induction current is induced in the modulating current. The voltages over the resistor form input signals for two peak value detectors, the strength of the output signal of which represents the degree of asymmetry of magnetization current. This paper describes the development a DC current sensor and its signal-conditioner.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.6
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• pp.699-706
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• 2015

A previous adapter have a single-ouput, however, a demand of a multi-output adapter increase in the recent industrial site. In order to satisfy the demand, in this research, we implement a programmable high efficiency multi-output adapter. The basic structure of the adapter introduced in this paper is a sort of flyback. The way for producing the reference voltage of the adapter proposed is similar to the way in the general flyback implemented with TL431. In addition to the basic concept of the design, however, we introduce a digital variable resistor, AD5246BKSZ10-RL7 and a microcontroller for changing a programmable multi-output. It makes output be variable that the digital variable resistor change the reference voltage of the adapter by order of the microcontroller. The adapter output voltage is controllable in the range of 20V by the user, and the power efficiency is proven to be 85%.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.9
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• pp.49-56
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• 1998

In this paper, a design of bias circuit in temperature independent voltage detect circuit is proposed. In order to realize this intention, we are used the differences in temperature coefficient of thermal voltage, resistor and transistor forward voltage(V$\sub$BE/) which is consisted in comparator. That is, It is realized by compensating the difference of temperature coefficient due to using components with each different temperature coefficient. As well, reference voltage of the circuit is accomplished by the difference of transistor forward voltage($\Delta$V$\sub$BE/) in comparator. In using reference voltage, resistor and V$\sub$BE/ Multiplier, we can design detect voltage of the circuit. In order to test operation of proposing circuit, we manufactured IC. Then, we measured operating characteristics and capability of the circuit by using HP4145B and temperature chamber. The result, we could obtain the good variation of temperature from -0.01 %/$^{\circ}C$ to -0.025 %/$^{\circ}C$.

• Transactions on Electrical and Electronic Materials
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• v.17 no.5
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• pp.289-292
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• 2016

This paper dealt with the optimal design of a follow current disconnector for DC arresters used in electric traction vehicles. The disconnector separates the ground lead from an arrester to prevent a line-to-ground fault of an aged arrester and should not affect the operation and function such as the reference and the clamping voltage of the connected arrester. The designed disconnector is composed of a resistor, a spark gap, and a cartridge. The results showed that the sparkover voltage increased with the gap distance whereas the reference voltage was almost the same as that without the disconnector. The sparkover voltage was 3.95 kV when the gap distance was 0.5 mm. Regardless of the gap distance, the reference and the clamping voltage of the assembled disconnector with an arrester were measured to be the same as those of the arrester alone.

• Progress in Superconductivity
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• v.3 no.2
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• pp.151-158
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• 2002

We developed a useful SQUID magnetometer for biomagnetic applications, magnetoencepha-logram(MEG) and magnetocardiogram(MCG), etc. The SQUIDs are based on Double Relaxation Oscillation SQUID(DROS). DROS consists of two SQUIDs(signal SQUID and reference SQUID) in series, and a relaxation circuit of an inductor and a resistor. Specially we used single reference junction instead of the reference SQUID. The SQUIDs are based on hysteretic $Nb/AlO_{x}$Nb junctions, fabricated by using a simple four level process. Because DROS magnetometer has large flux-to-voltage transfer coefficient, we can use simple flux-locked loop electronics fur SQUID operation. When the DROS magnetometer was operated inside a magnetically shielded room, its average magnetic field noise was about 3 (equation omitted) at 100 Hz. This noise level is low enough to measure biomagnetic fields. In this paper, we describe noise characteristics of DROS magnetometer, depending on the operation condition . .

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.39 no.4
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• pp.25-35
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• 2002

This work describes an 8b 200MHz time-interleaved subranging analog-to-digital converter (ADC) based on a single-poly digital CMOS process. Two fine ADCs for lower digital bits of the proposed ADC employ a time-sharing double-channel architecture to increase system speed and a new reference voltage switching scheme to reduce settling time of the reference voltages and chip area. The proposed intermeshed resistor string, which generates reference voltages for fine ADCs, improves linearity and settling time of the reference voltages simultaneously. The proposed sample- and-hold amplifier(SHA) is based on a highly linear common-drain amplifier and passive differential circuits to minimize power consumption and chip area with 8b accuracy and employs input dynamic common mode feedback circuits for high dynamic performance at a 200MHz sampling rate. A new encoding circuit in a coarse ADC simplifies the signal processing between the coarse ADC and two successive fine ADCs.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.1803-1804
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• 2006

The purpose of this paper is to implement a Labview based TFDR Real Time system through the instruments of Pci eXtensions for Instrumentation(PXI). The proposed load impedance measurement algorithm was verified by experiments via the implemented real time system. The TFDR real time system consisted of the reference signal design, signal generation, signal acquisition, algorithm execution and results display parts. To implement real time system, all of the parts wore programmed by the Labview which is one of graphical programming languages. In the application software implemented by the Labview we were able to design a suitable reference signal according to the length and frequency attenuation characteristics of the target cable and controled the arbitrary waveform generator(ZT500PXI) of the signal generation part and the digital storage oscilloscope(ZT430PXI) of the signal acquisition part. By using the TFDR real time system with the terminal resistor on the target cable, we applied to the load impedance measurements. In the proposed load impedance algorithm a normalized time-frequency cross correlation function and a cross time-frequency distribution function was employed to calculate the reflection coefficient and phase difference between the input and the reflected signals.