• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
• /
• pp.1642-1645
• /
• 2007

The brightness of LED changes according to the current flowing through LEDs. The current mirror was used to drive LEDs effectively. The reference current of the current mirror was usually controlled by the resistor but the size of this resistor is very large and this resistor consumes too much power for high power LED backlight driving. The reference current of the current mirror LED driver was controlled by using flyback converter at small size with low power consumption in this paper. The concept of active current source was presented.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
• /
• pp.395-398
• /
• 2004

High-linearity voltage-controlled current sources (VCCSs) circuits for wide voltage-controlled oscillator and automatic gun control were proposed. The VCCS consists of emitter follower for voltage input, two common-base amplifier which their emitter connected for current output, and current mirror which connected the two amplifier for large output current. The VCCS used only five transistors and a resistor without an extra bias circuit. Simulation results show that the VCCS has current output range from 0mA to 300mA over the control voltage range from 1V to 4.8V at supply voltage 5V. The linearity error of output current has less than $1.4\%$ over the current range from 0A to 300mA.

• 한국통신학회논문지
• /
• 제5권1호
• /
• pp.70-75
• /
• 1980

本 論文은 2個의 電流미러(Current mirror)로 構成한 電壓制御負抵抗回路를 새롭게 提示하였고, 이 構成된 回路의 動作을 推定하고, 解析하였다. 그리고 回路에서 R과 直列로 Zener Diode를 入하여 Vp를 높이고 外部抵抗을 可變시켜 負抵抗特性을 보았는데 實驗을 通하여, 推定되는 回路動作의 實現과 解析結果에서 얻은 負抵抗測와 實驗値가 大體로 一致함을 確認하였다.

• 대한전자공학회논문지SD
• /
• 제41권7호
• /
• pp.89-96
• /
• 2004

넓은 범위의 전압-제어 발진기 및 자동 이득 조절기의 실현을 위한 고선형 전압-제어 전류원(VCCS) 회로를 제안하였다. 제안한 VCCS는 전압 입력을 위해 이미터 폴로워, 전류 출력을 위해 이미터가 결합된 두 개의 공통-베이스 증폭기, 그리고 넓은 범위의 전류 출력과 높은 선형성을 얻기 위해 두 증폭기를 결합한 전류 미러로 구성된다. VCCS의 회로는 별도의 바이어스회로가 없이 단지 5개의 트랜지스터와 1개의 저항기만 사용하였다. 시뮬레이션 결과 제안한 VCCS는 5V의 공급전압에서 1V에서 4.8V까지의 제어-전압에 대하여 최대 0A에서 300㎃까지의 전류를 출력할 수 있다. 0㎃에서 300㎃의 출력 전류의 최대 선형 오차는 1.4 %이였다.

• 한국전자파학회논문지
• /
• 제27권2호
• /
• pp.212-215
• /
• 2016

본 논문에서는 $0.18{\mu}m$ CMOS 공정을 사용하여 5.08 GHz에서 동작하는 링 전압 제어 발진기(Ring Voltage Controlled Oscillator, Ring VCO)를 제작하였다. Ring VCO는 3단 구조로 각 단의 트랜지스터 크기 비율을 다르게 하여 전류 변화에 따른 소모 전력이 달라짐을 확인하였다. Core의 양단 위, 아래에는 Current Mirror로 전류를 제어하도록 구성하였고, 주파수 조절을 위해 제어 전압을 추가하였다. Ring VCO 측정 결과, 주파수 범위는 65.5 %(1.88~5.45 GHz), 출력 전력 -0.30 dBm, 5.08 GHz 중심주파수에서 -87.50 dBc/Hz @1 MHz의 위상잡음을 갖는다. 또한, 2.4 V 전원에서 31.2 mW 소모 전력을 확인하였다.

• Transactions on Electrical and Electronic Materials
• /
• 제14권5호
• /
• pp.235-241
• /
• 2013

A low power CMOS control circuit is applied in an integrated DC-DC buck converter. The integrated converter is composed of a feedback control circuit and power block with 0.35 ${\mu}m$ CMOS process. A current-sensing circuit is integrated with the sense-FET method in the control circuit. In the current-sensing circuit, a current-mirror is used for a voltage follower in order to reduce power consumption with a smaller chip-size. The N-channel MOS acts as a switching device in the current-sensing circuit where the sensing FET is in parallel with the power MOSFET. The amplifier and comparator are designed to obtain a high gain and a fast transient time. The converter offers well-controlled output and accurately sensed inductor current. Simulation work shows that the current-sensing circuit is operated with an accuracy of higher than 90% and the transient time of the error amplifier is controlled within $75{\mu}sec$. The sensing current is in the range of a few hundred ${\mu}A$ at a frequency of 0.6~2 MHz and an input voltage of 3~5 V. The output voltage is obtained as expected with the ripple ratio within 1%.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제4권4호
• /
• pp.269-274
• /
• 2004

Current delivery system, in which the analog current produced by a unique DAC circuit is stored into a current-memory circuit and delivered in a time-divided sequence, shows variation of output current as low as 4% in a current source data-driver IC for AM-OLED driven by a current-programmed method without any fuse repairing after fabrication. This driver IC has 54 outputs and can sink constant current as low as 3 ${\mu}A$ with 6-bit analog levels. Such a low current level without variation can hardly be obtained by an ordinary MOS transistor because the current level is in the sub-threshold region and changes exponentially with threshold voltage variation. Thus we adopted a current mirror circuit composed of bipolar transistors to supply well-controlled current within a nano-ampere range.

• Journal of the Optical Society of Korea
• /
• 제16권3호
• /
• pp.313-317
• /
• 2012

We have evaluated a 1.3 ${\mu}m$ vertical-cavity surface-emitting laser (VCSEL), whose bottom mirror and central active layer were grown by metal organic chemical vapor deposition (MOCVD) and whose top mirror was covered with a dielectric coating, for 10 Gb/s data transmission over single-mode fibers (SMFs). Successful demonstration of error-free transmission of the directly modulated VCSEL signals at data rate of 10 Gb/s over a 10 km-long SMF was achieved for operating temperatures from $20^{\circ}C$ to $60^{\circ}C$ up to bit-error-rate (BER) of $10^{-12}$. The DC bias current and modulation currents are only 7 mA and 6 mA, respectively. The results indicate that the VCSEL is a good low-power consuming optical signal source for 10 GBASE Ethernet applications under controlled environments.

• Current Optics and Photonics
• /
• 제6권4호
• /
• pp.420-429
• /
• 2022

In this paper, the details and design process of an optical system for space target detection cameras are introduced. The whole system is divided into three structures. The first structure is a short-focus visible light system for rough detection in a large field of view. The field of view is 2°, the effective focal length is 1,125 mm, and the F-number is 3.83. The second structure is a telephoto visible light system for precise detection in a small field of view. The field of view is 1°, the effective focal length is 2,300 mm, and the F-number is 7.67. The third structure is an infrared light detection system. The field of view is 2°, the effective focal length is 390 mm, and the F-number is 1.3. The visible long-focus narrow field of view and visible short-focus wide field of view are switched through a turning mirror. Design results show that the modulation transfer functions of the three structures of the system are close to the diffraction limit. It can further be seen that the short-focus wide-field-of-view distortion is controlled within 0.1%, the long-focus narrow-field-of-view distortion within 0.5%, and the infrared subsystem distortion within 0.2%. The imaging effect is good and the purpose of the design is achieved.

• 센서학회지
• /
• 제18권2호
• /
• pp.128-134
• /
• 2009

Integrated circuit of a new neuron chain with a synapse function for Hodgkin-Huxley model which is a good electrical model about a real biological neuron is implemented in a $0.5{\mu}m$ 1 poly 2 metal CMOS technology. Pulse type neuron chain consist of series connected current controlled single neurons through synapses. For the realization of the single neuron, a pair of voltage mode oscillators using operational transconductance amplifiers and capacitors is used. The synapse block which is a connection element between neurons consist of a voltage-current conversion circuit using current mirror. SPICE simulation results of the proposed circuit show 160 mV amplitude pulse output and propagation of the signal through synapses. Measurements of the fabricated pulse type neuron chip in condition of ${\pm}2.5\;V$ power supply are shown and compared with the simulated results.