• Journal of Power Electronics
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• 제16권3호
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• pp.840-848
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• 2016

A primary-side regulation AC-DC converter operating in the PFM (Pulse Frequency Modulation) mode with a high precision output current is designed, which applies a novel inductance compensation technique to improve the precision of the output current, which reduces the bad impact of the large tolerance of the transformer primary side inductance in the same batch. In this paper, the output current is regulated by the OSC charging current, which is controlled by a CC (constant current) controller. Meanwhile, for different primary inductors, the inductance compensation module adjusts the OSC charging current finely to improve the accuracy of the output current. The operation principle and design of the CC controller and the inductance compensation module are analyzed and illustrated herein. The control chip is implemented based on a TSMC 0.35μm 5V/40V BCD process, and a 12V/1.1A prototype has been built to verify the proposed control method. The deviation of the output current is within ±3% and the variation of the output current is less than 1% when the inductances of the primary windings vary by 10%.

• 한국전자파학회논문지
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• 제13권10호
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• pp.1025-1033
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• 2002

본 논문에서는 위성중계기용 Ku-대역 증폭기에 사용되어질 수 있는 온도보상회로에 대하여 기술하였다. 위성중계기용 증폭기에서 요구하는 온도 규격과 다양한 온도보상 방식의 장단점을 살펴본 후 위성중계기용 증폭기에 적합한 온도보상회로로서 능동 바이어스 회로, 감쇄기를 이용한 온도보상회로, ALC Loop를 이용한 온도 보상회로를 선정하여 각자의 회로를 설계하였다. 각각의 온도보상회로는 설계 결과와 일치하는 실험 결과를 얻을 수 있었다. 이러한 결과는 실제 Ku-대역 위성중계기용 능동부품인 채널증폭기, 저잡음 증폭기, 중간 주파수 증폭기 등에 사용되어졌으며, 설계 규격을 만족하는 결과를 얻을 수 있었다.

• Journal of Power Electronics
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• 제16권5호
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• pp.1661-1668
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• 2016

A fixed off-time controlled high power factor ac-dc LED driver is proposed in this paper, which employs a novel zero-crossing-compensation (ZCC) circuit based on a fixed off-time controlled scheme. Due to the parasitic parameters of the system, the practical waveforms have a dead region. By detecting the zero-crossing boundary, the proposed ZCC circuit compensates the control signal VCOMP within the dead region, and is invalid above this region. With further optimization of the parameters KR and Kτ of the ZCC circuit, the dead zone can be eliminated and lower THD is achieved. Finally, the chip is implemented in HHNEC 0.5μm 5V/40V HVCMOS process, and a prototype circuit, delivering 7~12W of power to several 3-W LED loads, is tested under AC input voltage ranging from 85V to 265V. The test results indicate that the average total harmonic distortion (THD) of the entire system is approximately 10%, with a minimum of 5.5%, and that the power factor is above 0.955, with a maximum of 0.999.

• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.141-145
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• 2021

The brightness of the Organic Light Emitting Diode (OLED) display is controlled by thin-film transistors (TFTs). Regardless of the materials and the structures of TFTs, an OLED suffers from the instable threshold voltage (V_th) of a TFT during operation. When designing an OLED pixel with circuit simulation tool such as SPICE, a designer needs to take V_th shift into account to improve the reliability of the circuit and various compensation methods have been proposed. In this paper, the effect of the compensation circuits from two typical OLED pixel circuits proposed in the literature are studied by the transient simulation with a SPICE tool in which the stretched-exponential time dependent V_th shift function is implemented. The simulation results show that the compensation circuits improve the reliability at the beginning of each frame, but V_th shifts from all TFTs in a pixel need to be considered to improve long-time reliability.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.850-853
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• 2009

Many well-known pixel compensation circuits have been applied to control TFT $V_{th}$ variations on small size AMOLED panels. For large (>30-inch) AMOLEDs, luminance and color uniformity are affected by TFT variations, but also by ELVDD IR drop and cavity non-uniformity which are not easily compensated by in-pixel circuits. AMOLED panels may also suffer from manufacturing-induced mura. An external compensation method based on optical measurements is proposed and applied to large AMOLED panels. It improves luminance uniformity by up to 95% at 200nits and color uniformity by up to 99% (${\Delta}$u'v' <0.004) on large AMOLED panels, and provides-increased margin against processinduced mura.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.376-378
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• 1995

A method is presented for the design and fabrication of the temperature compensation circuits on the Clark electrodes for measuring the dissolved oxygen(DO) concentration. The discussion includes a method of the sensor interface circuits for the DO sensor. Typical polarograms for the DO probes under test using this sensor circuits are presented. High accuracy over 99 % of the I to V conversion using the proposed circuit is verified. Temperature dependence for the test DO probe is well compensated automatically using the thermistor($2k\Omega,\;25^{\circ}C$) in series with correction resistor in the feedback loop of the op-amp circuit in the temperature range of the 0-50$^{\circ}C$.

• Journal of Information Processing Systems
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• 제7권1호
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• pp.93-102
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• 2011

In deeply scaled CMOS technologies, two major non-ideal factors are threatening the survival of the CMOS; i) PVT (process, voltage, and temperature) variations and ii) leakage power consumption. In this paper, we propose a novel post-silicon tuning methodology to scale optimum voltage and frequency "dynamically". The proposed design technique will use our PVT sensor circuits to monitor the variations and based on the monitored variation data, voltage and frequency will be compensated "automatically". During the compensation process, supply voltage is dynamically adjusted to guarantee the minimum total power consumption without violating the frequency requirement. The simulation results show that the proposed technique can reduce the total power by 85% and the static power by 53% on average for the selected ISCAS'85 benchmark circuits with 45 nm CMOS technology compared to the results of the traditional PVT compensation method.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.466-469
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• 2009

The life time of AMOLED displays has been dependent on OLED materials up to this point. In particular, image sticking (burn-in) has been one of the most critical issues for AMOLEDs. This paper proposes image sticking compensation AMOLED pixel circuits to address the problem without requiring process or material improvements to the OLED itself. We verified the performance of those circuits by simulation and actual panel implementation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.688-692
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• 1988

The active filter system for harmonic current compensation is presented in this paper. The active filter, composed of a three-phase voltage-type PWM inverter and the capacitor, compensates both the harmonic currents and the reactive power by injecting the PWM current to the ac line. This paper describes the principle of harmonic current compensation, the calculation circuits for the harmonic currents to be injected, the several compensation characteristics. Also the experimental results are shown to verify the theory proposed in this paper.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.355-358
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• 2003

Basically, the mis-convergence, which is inevitable in CRT Projection TV. is the degree of deviation of red and blue from green beam. The cause of mis-convergence is the change of magnetic field and electrical characteristic in deflection circuits and convergence amplification circuit. A new and easily implementable mis-convergence compensation algorithm is presented in this paper. The proposed algorithm does not needs any compensation devices. It uses only TV OSD and a remote controller and anyone who wants to compensate can easily correct the mismatch. Through real compensation experiments, it is found that the proposed algorithm is useful and effective one.