• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.133-136
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• 2000

A new Op-Amp output buffer is presented for driving large-size LCD panels. The proposed Op-Amp is designed by combining a common source and a common drain amplifier to have a high slew rate and to minimize the quiescent current. The proposed circuits are simulated in a high-voltage 0.6${\mu}{\textrm}{m}$ CMOS process, dissipates only 20${\mu}{\textrm}{m}$ static current, and have 83dB open-loop DC gain and 60$^{\circ}$phase margin.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.4
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• pp.461-466
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• 1999

A CMOS op amp with rail-to-rail input and output ranges is designed in a one-volt supply. The output stage of the op amp is used in a common source amplifier that operates in sub-threshold region to design a low voltage op amp with rail-to-tail output range. To drive heavy resistor and capacitor loads with rail-to-rail output ranges, a common source amplifier which has a low output resistance is utilized. A bulk-driven differential pair and a bulk-driven folded cascode amplifier are used in the designed op amp to increase input range and achieve 1 V operation. Post layout simulation results show that low frequency gain is about 58 ㏈ and gain bandwidth I MHz. The designed op amp has been fabricated in a 0.8${\mu}{\textrm}{m}$ standard CMOS process. The measured results show that this op amp provides rail-to-rail output range, 56㏈ dc gain with 1 MΩ load and has 0.4 MHz gain-bandwidth with 130 ㎊ and 1 kΩ loads.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.585-586
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• 2008

In this paper, a novel beta-multiplier reference current source circuit for the 800mV power-supply voltage is presented. In order to cope with the narrow input common-mode range of the OpAmp in the reference circuit, shunt resistive voltage divider branches were deployed. High gain OpAmp was designed to compensate intrinsic low output resistance of the MOS transistors. The proposed reference circuit was designed in a standard 0.18um CMOS process with nominal Vth of 420mV and -450mV for nMOS and pMOS transistor respectively. The total power consumption including OpAmp is less than 50uW.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.172-178
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• 2014

This paper presents a new model of the Miller effect. The new Miller effect model is obtained from the accurate AC gain which includes the effect of the output capacitance of the common-source (CS) amplifier. The new Miller effect model consists of the series connection of a capacitance and a parallel RC circuit, one at the input and the other at the output. The frequency response obtained by the new Miller effect model is equal to that obtained from the original circuit. Even though the new model is complicated, the 3-dB frequency can be easily estimated by using the open-circuit time constants method without the node analysis.

• Journal of Energy Engineering
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• v.22 no.4
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• pp.394-398
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• 2013

At present, using of electromagnetic control valve (ECV) in external variable displacement swash plate type compressor is a common issue. Solenoid operated ECV controls vehicle air conditioning system through a pulse width modulation (PWM) input signal that supplied from an external source. Different port pressure controls the swash plate movement inside the compressor at certain angles that finally determines the refrigerant flow rate to the vehicle compartment for passengers comfort. In this paper, crankcase pressure flow (Pc flow) is calculated with some ECV samples with corresponding to amount of variable supply of current ranges from 0.20Amp to 0.95Amp.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.1
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• pp.85-93
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• 2007

This paper presents new LVDS I/O circuits with a high noise margin for use in highly parallel I/O environments. The proposed LVDS I/O includes transmitter and receiver parts. The transmitter circuits consist of a differential phase splitter and a output stage with common mode feedback(CMFB). The differential phase splitter generates a pair of differential signals which have a balanced duty cycle and $180^{\circ}$ phase difference over a wide supply voltage variation due to SSO(simultaneous switching output) noises. The CMFB output stage produces the required constant output current and maintains the required VCM(common mode voltage) within ${\pm}$0.1V tolerance without external circuits in a SSO environment. The proposed receiver circuits in this paper utilizes a three-stage structure(single-ended differential amp., common source amp., output stage) to accurately receive high-speed signals. The receiver part employs a very wide common mode input range differential amplifier(VCDA). As a result, the receiver improves the immunities for the common mode noise and for the supply voltage difference, represented by Vgdp, between the transmitter and receiver sides. Also, the receiver produces a rail-to-rail, full swing output voltage with a balanced duty cycle(50% ${\pm}$ 3%) without external circuits in a SSO environment, which enables correct data recovery. The proposed LVDS I/O circuits have been designed and simulated with 0.18um TSMC library using H-SPICE.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.2
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• pp.99-107
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• 2006

Magnetic nondestructive testing is very useful far detecting a crack on the surface or near of the surface of the ferromagnetic materials. The distribution of the magnetic flux leakage (DMFL) on a specimen has to be obtained quantitatively to evaluate the crack. The magnetic camera is proposed to obtain the DMFL at the large lift-off. The magnetic camera consists of a magnetic source, magnetic lens, analog to digital converters (ADCs), interface, and computer. The magnetic leakage fields or the distorted magnetic fields from the object, which are concentrated on the magnetic lens, are converted to analog electrical signals tv arrayed small magnetic sensors. These analog signals are converted to digital signals by the ADCs, and are stored, imaged, and processed by the interface and computer. However the magnetic camera has limitations with respect to converting and switching speed, full range and resolution, direct memory access (DMA), temporary storage speed and volume because common ADCs were used. Improved techniques, such as those that introduce the operational amplifier (OP-Amp), amplify the signal, reduce the connection line, and use the low pass filter (LPF) to increase the signal to noise ratio are necessary. This paper proposes the exclusive embedded ADC including OP-Amp, LPF, microprocessor and DMA circuit for the magnetic camera to satisfy the conditions mentioned above.