• Transactions on Electrical and Electronic Materials
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• 제2권4호
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• pp.1-6
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• 2001

In this paper, a 1.5 V high-gain high-frequency CMOS complementary operational amplifier is presented. The input stage of op-amp is designed for supporting the constant transconductance on the Input stage by consisting of the parallel-connected rail-to-rail complementary differential pairs. And consisting of the class-AB rail-to-rail output stage using the concept of elementary shunt stage and the grounded-gate cascode compensation technique for improving the low PSRR which was a disadvantage in the general CMOS complementary input stage, the load dependence of open loop gain and the stability of op- amp on the output load are improved, and the high-gain high-frequency operation can be achieved. The designed op-amp operates perfectly on the complementary mode with the 180° phase conversion for a 1.5 V supply voltage, and shows the DC open loop gain of 84 dB, the phase margin of 65°, and the unity gain frequency of 20 MHz. In addition, the amplifier shows the 0.1 % settling time of .179 ㎲ for the positive step and 0.154 ㎲ for the negative step on the 100 mV small-signal step, respectively, and shows the total power dissipation of 8.93 mW.

• 센서학회지
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• 제31권2호
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• pp.120-124
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• 2022

With advancements in underwater stealth technology for naval vessels, new sensor configurations for detecting targets have been attracting increased attention. Latest underwater mines adopt multiple sensor configurations that include electric field sensors to detect targets and to help acquire accurate ignition time. An underwater electric field sensor consists of a pair of electrodes, signal processing unit, and preamplifier. For detecting underwater electric fields, the preamplifier requires low-noise amplification at ultra-low frequency bands. In this paper, the specific requirements for low-noise preamplifiers are discussed along with the experimental results of various setups of matched transistors and chopper stabilized operational amplifiers. The results showed that noise characteristics at ultra-low frequency bands were affected significantly by the voltage noise density of the chopper amplifier and the number of matched transistors used for differential amplification. The fabricated preamplifier was operated within normal design parameters, which was verified by testing its gain, phase, and linearity.

• 스마트미디어저널
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• 제4권2호
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• pp.55-61
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• 2015

A bandwidth-enhanced ultra-wide band (UWB) CMOS balun-LNA is implemented as a part of a software defined radio (SDR) receiver which supports multi-band and multi-standard. The proposed balun-LNA is composed of a single-to-differential converter, a differential-to-single voltage summer with inductive shunt peaking, a negative feedback network, and a differential output buffer with composite common-drain (CD) and common-source (CS) amplifiers. By feeding the single-ended output of the voltage summer to the input of the LNA through a feedback network, a wideband balun-LNA exploiting negative feedback is implemented. By adopting a source follower-based inductive shunt peaking, the proposed balun-LNA achieves a wider gain bandwidth. Two LNA design examples are presented to demonstrate the usefulness of the proposed approach. The LNA I adopts the CS amplifier with a common gate common source (CGCS) balun load as the S-to-D converter for high gain and low noise figure (NF) and the LNA II uses the differential amplifier with the ac-grounded second input terminal as the S-to-D converter for high second-order input-referred intercept point (IIP2). The 3 dB gain bandwidth of the proposed balun-LNA (LNA I) is above 5 GHz and the NF is below 4 dB from 100 MHz to 5 GHz. An average power gain of 18 dB and an IIP3 of -8 ~ -2 dBm are obtained. In simulation, IIP2 of the LNA II is at least 5 dB higher than that of the LNA I with same power consumption.

• 대한전자공학회논문지
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• 제3권2호
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• pp.10-17
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• 1966

어떤 R-C 분포회로의 징분방정식의 해가 기지일 때 이것을 이용하여 다수의 다른 분포회로의 징분방정식의 해를 구하는 방법이 얻어졌다. 임의의 R-C 분포회로를 제작의 편의상 R(x)C(x)=일정인 회로로 등가변환하는 도해적방법이 얻어졌으며 해석적증명도 가능하다. 또 이론적 취급의 통일과 간단을 위하여 임의의 R-C분포회로를 R(x), C(x) 어느 한쪽이 일정한 분포회로로 등가변환하는 방법이 얻어졌다. 이 후자의 회로와 근사적인 집중정수회로를 생각하므로서 분포회로의 근사적인 해석, 합성이 비교적 간단하게 이루어 질 수 있다. 6x A method by which solutions of the differential equations of any other distributed circuits can be obtained is described when the solution of the differential equation of an R-C distributed amplifier is known. A graphical method of transforming any R-C ditributed circuit into an equivalent circuit which has a constant R(x)-C(x) was also obtained. The theoretical verification of this method is possible. For simplicity, any R-C distributed circuit can be transformed into an equivalent circuit which is a distributed circuit of either constant R(x) or C(x). Using this equivalent circuit and considering a lumped circuit, an approximate analysis and synthesis can be made simply.

• 조명전기설비학회논문지
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• 제28권10호
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• pp.63-68
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• 2014

This paper deals with a methodology that applies the time-varying magnetic fields produced by the cloud discharges to find the direction of thunderstorm movement. We investigated the basic performance of the magnetic field measurement system composed of multi-turn loop-type sensors, the differential amplifier and active integrator. As a result, the response characteristics of the magnetic field sensor system to sinusoidal signals was excellent. The frequency bandwidth ranges from about 1 kHz to 500 kHz, the response sensitivity was 0.16mV/nT. In addition, we proposed the algorithm that determines the direction of lightning discharges using the comparison of the output signals of right-angled loop-type magnetic field sensors. The accuracy of the direction finding of lightning discharges is fairly well within the measurement error of less than $5^{\circ}$. The magnetic field measurement system proposed in this work can be used to track the direction of thunderstorm movement.

• 전자공학회논문지C
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• 제35C권12호
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• pp.59-65
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• 1998

본 논문에서는 트랜스컨덕턴스 특성을 개선한 새로운 CMOS Rail-to-Rail 입력단 회로를 설계하였다. 회로 모의 실험기 HSPICE를 통해서 새로운 입력단 회로의 동상 입력 전압 범위에 대한 새로운 회로의 성능을 검증하였다. 새로운 입력단 회로는 기존의 Rail-to-Rail 입력단 회로에 동상 입력 전압에 따라서 동작조건이 변하는 4개의 입력 트랜지스터와 4개의 전류원/싱크를 추가함으로써 구성된다. 새로운 입력단 회로는 두 차동 회로 중에서 어느 한 회로만이 동작하는 영역에서는 신호증폭에 기여하는 트랜지스터의 DC 전류양에는 영향을 미치지 않는 반면, 두 차동 회로가 모두 동작하는 영역에서는 신호증폭에 기여하는 트랜지스터의 DC 전류양을 1/4로 감소시킨다. 그 결과 새로운 입력단 회로는 강반전 영역에서 전 동상 입력 전압 범위에 걸쳐 거의 일정한 트랜스컨덕턴스 특성과 단일 이득 주파수 특성을 보이며 전 동상 입력 전압 범위에 대해서 최적의 주파수 보상을 가능하게 한다.

• International Journal of Control, Automation, and Systems
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• 제5권1호
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• pp.35-42
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• 2007

This paper presents an INS(Inertial Navigation System) grade, surface micro-machined differential resonant accelerometer(DRXL) manufactured by an epitaxially grown thick poly silicon process. The proposed DRXL system generates a differential digital output upon an applied acceleration, in which frequency transition is measured due to gap dependent electrical stiffness change. To facilitate the resonance dynamics of the electromechanical system, the micromachined DRXL device is packaged by using the wafer level vacuum sealing process. To test the DRXL performance, a nonlinear self-oscillation loop is designed based on the extended describing function technique. The oscillation loop is implemented using discrete electronic elements including precision charge amplifier and hard feedback nonlinearity. The performance test of the DRXL system shows that the sensitivity of the accelerometer is 24 Hz/g and its long term bias stability is about 2 mg($1{\sigma}$) with dynamic range of ${\sigma}70g$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.388-390
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• 1997

We describe the characteristic of LVI(Low-voltage Impulse) test system and methods to detect the deformation of windings in the power transformers. Any winding deformation will result in a change of capacitance between winding parts and possibly some change in the winding inductance. These changes will then result in a change in the responce to the applied pulse in both the magnitude and period of the resulting oscillations. A results of measured differential method in stead of typical method, the sensitivity is greatly improved by the use of differential methods where the pulse is applied to two identical windings and the response measured with a differential amplifier.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권6호
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• pp.768-776
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• 2014

Using a simplified high-frequency small-signal equivalent circuit model for BSIM3 MOSFET, the fully differential two-stage folded-cascode CMOS operational amplifier is analyzed to obtain its small-signal voltage transfer function. As a result, the expressions for dc gain, five zero frequencies, five pole frequencies, unity-gain frequency, and phase margin are derived for op amp design using design equations. Then the analysis result is verified through the comparison with Spice simulations of both a high speed op amp and a low power op amp designed for the $0.13{\mu}m$ CMOS process.

• 전기전자학회논문지
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• 제21권4호
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• pp.375-380
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• 2017

A differential current-to-time interval converter is presented for current mode sensors. It consists of a ramp voltage generator, a current mode sensor, a reference current source, two current-tunable Schmitt triggers, a one-shot multivibrator, and two logic gates. The design principle is to apply a ramp voltage to each input of the two current-tunable Schmitt triggers whose threshold voltages are proportional to the drain current values of the current mode sensors. A proposed circuit converts a current change in the ISFET biosensor into its equivalent pulse width change. A prototype circuit built using TSMC 0.18 nm CMOS process exhibit a conversion sensitivity amounting to $726.9{\mu}s/pH$ over pH variation range of 2-12 and a linearity error less than ${\pm}0.05%$.