• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1009-1010
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• 2008

This paper presents a real-time aging measurement and feasible compensation system for the prolonged lifetime of OLED panel. The proposed system is composed of four parts, a PC with a man-machine interface, a measurement block, an adaptive amplifier block, and a compensation block. We apply a tree algorithm for less complexity and convenience of measurement on the degree of aging. An adaptive multi-stage differential amplifier is also implemented to deal with a various range of input voltages at the same spot.

• Journal of the Korean Institute of Telematics and Electronics
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• v.4 no.4
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• pp.2-12
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• 1967

A pair of insulated-gate metal-oxide-semiconductor field-effect transistor has been used to measure the direct current produced from the ionization chamber in the range of to A. An analisis of direct-current differential amplifier giving the expressions of the common-mode rejection ratio and the rralization of the constant-current generator to give very large effective source resistance has been presented. Voltage gain is 6.6, drift at the room temperature is 1.5mv per day. The common-mode rejection ratio is obtained maximum 84db. These facts give the feasibility of small direct-current measurements by utilizing this type transistors.

• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.1
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• pp.14-19
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• 1982

A differential amplifier has been designed and fabricated using aluminum-gate PMOS technology, Only enhaneement-mode MOSFET's are used in the circuit and the dimensions of transistors have been determined using simulation program MSINC. The fabricated integrated circuit with +15V and -l5V power supplies shows an open-loop DC voltage gain of 42 dB, a common mode rejection ratio (CMRR) of 50 dB, and a Power consumption of 20mW.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.479-482
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• 1993

A fully balanced differential amplifier can achieve high-gain wide-bandwidth characteristics. And also, Offset PSRR, CMRR and Noise performance of that are excellent, but these merits can be achieved only when the architecture holds fully balanced. Commonly, the fully balanced differential amplifier has a common mode feedback(CMFB) circuit in order to maintain the balance. This paper presents improved characteristics of the CMFB circuit and designs the wide-bandwidth CMOS Op-amp. The unity gain bandwidth of this Op-amp is 50MHz with the load capacitor 2pF, and the value of phase margin is $85^{\circ}$.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.667-670
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• 1998

Novel bipolar transresistance amplifier(TRA) for high-accuracy current-mode signal processing is described. The TRA consists of two current follower for the current inputs, a current summer for curent-differential, and a voltage follower for the voltage output. The simulation results show that the impedence of the current input and the voltage output is 0.5 $\Omega$ and the 3-dB cutoff frequency when used as a current to voltage converter extends beyond 40 MHz.

• Transactions on Semiconductor Engineering
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• v.2 no.3
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• pp.6-12
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• 2024

This paper presents a study on a 2.4GHz differential cascode power amplifier(PA) fabricated using a 130nm CMOS process. This PA is designed for wireless power transmission applications and consists of two differential stages with custom-designed balun transformers for single-ended output. Balun transformers are utilized not only for the output stage but also for power match-ing between each stage. Additionally, a bias circuit with temperature compensation capability is added to maintain stable bias voltage in the 2.4GHz frequency band. As a result, it achieves an output power of 21.75 dBm with a power-added efficiency(PAE) of 40.9% at TT/40℃.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.10
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• pp.941-944
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• 2016

This paper proposes 24 GHz power amplifier for automotive collision avoidance and surveillance short range radar using Samsung 65-nm CMOS process. The proposed circuit has a 2-stage differential power amplifier which includes common source structure and transformer for single to differential conversion, impedance matching, and power combining. The measurement results show 15.5 dB maximum voltage gain and 3.6 GHz 3 dB bandwidth. The measured maximum output power is 13.1 dBm, input $P1_{dB}$ is -4.72 dBm, output $P1_{dB}$ is 9.78 dBm, and maximum power efficiency is 17.7 %. The power amplifier consumes 74 mW DC power from 1.2 V supply voltage.

• Journal of IKEEE
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• v.27 no.1
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• pp.53-58
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• 2023

In this paper, a Radio Frequency (RF) transformer (TF) based on LTCC (Low Temperature Co-fired Ceramic) for the output stage of differential power amplifiers is presented. Instead of using an usual L-C matching circuit, a small-sized transformer was implemented on the LTCC board and the results were verified through simulation. For reduced size and better performance, a TF using more metal layers was implemented and compared with the existing TF through simulation. As a result of comparison, the proposed TF has an area reduced by 55% and a coupling coefficient increased by 25%, and insertion loss improvement of about 0.4dB at 5GHz was confirmed.

• Journal of the Korean Institute of Telematics and Electronics
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• v.4 no.3
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• pp.28-33
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• 1967

The analysis of differential amplifier is simplified by the extention of bisection theorem. In order to reduce the thermal and porwor drifts, a self compensating circuit is employed. The optimum conditions of the self compensating circuit are: the base-emitter voltage of one transistor should be equal to the other's base-emitter voltage for basic self compensating circuit, the tempereature coefficients of base-emitter voltage of one transistor equal to the others for thermal compensation. By regarding the thermal and power drifts the experiments were performed were performed and the numerical results were consistent with the measured values.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.11
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• pp.836-845
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• 2001

A Novel fully-differential bipolar current subtracter(FCS) and its application to current controlled current amplifier(CCCA) for high-accuracy current-mode signal processing were designed. To obtain full-differential current output, the FCS was symmetrically composed of two current follower with low current-input impedance. The CCCA to control output current by the bias current was consisted of the subtracter and a current gain amplifier(CGA) with single-ended current output.. The simulation result shows that the FCS has current-input impedance of 5 Ω and a good linearity. The CCCA has 3-dB cutoff frequency of 20 MHz for the range over bias current 100 $\mu$A to 20 mA. The power dissipation of the FCS and CCCA are 1.8 mW and 3 mW, respectively.