• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.389-390
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• 2007

배터리 기반 시스템(휴대폰, PDA, 노트북)에서 현재 배터리에 대한 정확한 잔량 표시는 중요하다. 사용자입장에서 언제 배터리를 충전시켜야 하는지 알아야 하기 때문이다. 그런데 지금까지의 배터리 잔량 측정 장치를 보게 되면, 배터리의 전압만을 측정[1]하여 잔량을 표시하는 방식으로서 여기에는 여러 가지 문제점이 있다. 가장 중요한 문제점으로는 순간적인 배터리 전압강하에 따른 실 시간적이고 정확한 보상체계가 갖춰져 있지 않다는 점이다. 물론 하드웨어적으로 Schmitt Trigger라는 회로[2]를 구성하여 이를 방지해 놓고 있기는 하지만 Hysteresis margin[3]을 벗어난 값에 대해서는 보상을 해주지 않는다. 이런 보상은 보통 소프트웨어적으로 각 이밴트별 룩업 테이블을 만들어서 compensation하고 있기는 하지만, 수많은 이벤트에 대한 보상 값들과 예상치 못한 동작상의 오류를 막을 수는 없다. 따라서 이에 대한 근본적인 대안으로서 본 논문에서는 load current를 측정하여 그에 따른 전압강하를 계산하고 실시간적으로 배터리 전압에 보상을 해줌으로서 보다 정확한 배터리 잔량 표시를 구현하고자 한다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.4
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• pp.195-199
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• 2014

A bridge resistance deviation-to-period (BRD-to-P) converter is presented for interfacing resistive biosensors. It consists of a linear operational transconductance amplifier (OTA) and a current-controlled oscillator (CCO) formed by a current-tunable Schmitt trigger and an integrator. The free running period of the converter is 1.824 ms when the bridge offset resistance is $1k{\Omega}$. The conversion sensitivity of the converter amounts to $3.814ms/{\Omega}$ over the resistance deviation range of $0-1.2{\Omega}$. The linearity error of the conversion characteristic is less than ${\pm}0.004%$.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.463-464
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• 2008

As the demands of LCD and PDP TV are increasing, the high performance HVICs(High Voltage Gate Driver ICs) technology is becoming more necessary. In this paper, we designed the HVIC that has enhanced noise immunity and high driving capability. It can operate at 500KHz switching frequency and permit 600V input voltage. High-side level shifter is designed with noise protection circuit and schmitt trigger. Therefore it has very high dv/dt immunity, the maximum being 50V/ns. The HVIC was designed using $1{\mu}m$ BCD 650V process and verified by Spectre and PSpice of Cadence inc. simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.582-586
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• 2005

This paper presents a new structure of Phase Locked Loop(PLL) which changes its loop bandwidth according to the locking status. The proposed PLL consists of a conventional PLL and, Locking Status Indicator(LSI). The LSI decides the operating bandwidth of loop filler. When the PLL becomes out of lock, the PLL increases the loop bandwidth and achieves fast locking. When the PLL becomes in-lock, this PLL decreases the loop bandwidth and minimizes phase noise output. The PLL can achieve fast locking and low phase noise output at the same time. Proposed PLL's locking time is less than $40{\mu}s$ and spur is 76.1dBc. It is simulated by HSPICE in a Hynix CMOS $0.35{\mu}m$ Process.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.2
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• pp.113-118
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• 2005

This paper shows a satellite battery cell voltage monitor system to make differential voltage measurements when one or both measurement points are beyond voltage range allowed by a conventional differential amplifier. This system is particularly useful for monitoring the individual cell voltage of series-connected cells that constitute a rechargeable satellite battery in which some cell voltages must be measured in the presence of high common mode voltage.

• Journal of the Korean Society of Marine Environment & Safety
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• v.11 no.1 s.22
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• pp.29-37
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• 2005

The design and development if Resonant-type Magnetometer(RM) using isotropic magnetic with high permeability is described in this paper. At first, the relationship between the inductance L if the coil winding on a magnetic material and the permeability u(H) appearing in the magnetic material with isotropic and high permeability is defined as a background theory. Then the circuit if RM, which is to obtain the values if L as the change qf frequency is implemented using simple Schmitt Trigger Circuit Through the swinging tests, which is to evaluate the measurement ability if RM, the measurement possibility for the component of earth field was confined.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.1
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• pp.40-44
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• 2014

A bridge resistance deviation-to-period (BRD-to-P) converter is presented for interfacing resistive biosensors. It consists of a linear operational transconductance amplifier (OTA) and a current-controlled oscillator (CCO) formed by a current-tunable Schmitt trigger and an integrator. The free running period of the converter is 1.824 ms when the bridge offset resistance is $1k{\Omega}$. The conversion sensitivity of the converter amounts to $3.814ms/{\Omega}$ over the resistance deviation range of $0-1.2{\Omega}$. The linearity error of the conversion characteristic is less than ${\pm}0.004%$.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.11
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• pp.83-91
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• 1990

VOC(coltage controlled oscillator) circuits are necessary in applications such at the demodul-ation of FM signals, frequency synthesizer, and for clock recovery from digital data. In this paper, we designed the VCO circuit based on a OTA(operational transconductance amplifier) and the OP amp which using a differential amplifier by BiCMOS circuit. It consists of a OTA, voltage contorolled integrator and a schmitt trigger. Conventional VCO circuits are designed using the CMOS circuit, but in this paper we designed newly BiCMOS VCO circuit which has a good drive avlity, As a result of SPICE simulation, output frequency is 141KHz at 105KHz, and sensitivity is 15KHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.7
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• pp.771-777
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• 2008

In this paper, a frequency doubler using modified time-delay technique is proposed. A voltage controlled delay line (VCDL) in the proposed frequency doubler compensates the group delay time mismatching between input and delayed signal. With the group delay time matching and waveform shaping using the adjustable Schmitt triggers, the unwanted fundamental component($f_0$) and the higher order harmonics such as third and fourth are diminished excellently. In result, only the doubled frequency component($2f_0$) appears dominantly at the output port. The frequency doubler is designed at 1.15 GHz of $f_0$ and fabricated with TSMC $0.18\;{\mu}m$ CMOS process. The measured output power at $2f_0$ is 2.67 dBm when the input power is 0 dBm. The obtained suppression ratio of $f_0,\;3f_0$, and $4f_0$ to $2f_0$ are 43.65, 38.65 and 35.59 dB, respectively.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.133-139
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• 2005

Resonant-Type Magnetometer(RM) using high permeability isotropic magnetic material is designed to implement Smart Digital Compass. Theoretically, the inductance L of a coil, winding on the magnetic core, is proportion to the change of permeability $\mu(H)$ and, the change values of L can be obtain as the change of frequency by simple Schmitt Trigger circuit. By the use of integrated circuit switch, the RM can be designed with simple circuit and it can provide overcoming the drift by temperature and the variation of operating points in $\mu(H)$ curve. The facts that Metglas 2705M is an optimum magnetic material and ship's permanent magnetism can be obtain from measured values of RM are also known in this study.