• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.980-981
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• 2015

A quasi-resonant flyback converter using a simple 8-bit microcontroller for a LED lighting is proposed in this paper. The proposed converter is easily and precisely controlled by the simple controller using a low-cost 8-bit microcontroller. Also, in order to operate the 8-bit microcontroller, the proposed converter system does not require any additional power supply for the controller. A prototype power supply is developed to supply a 270[W] LED lighting with the wide input voltage ranges ($175[V_{ac}]-265[V_{ac}]$). Experimental results will be show the practicality and validity of the proposed circuit.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1008-1009
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• 2015

An emergency diesel generator system is an independent source of power that supports important electrical systems on loss of normal power supply. AVR(Automatic Voltage Regulator) is a regulator which regulates the output voltage at a nominal constant voltage level. Specially, a power supply for the AVR must be operated at the very wide input range. In this paper, a flyback power supply with very wide input voltage range is proposed.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.374-377
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• 2002

This paper presents dynamic analyses and control design of the current-mode controlled active-clamp forward-flyback converter. The circuit averaging technique is used to extract the small-signal circuit model for the power stage From the small-signal circuit model of the power stage, the open-loop transfer functions are derived and used for the compensation design. The analysis results are verified using an experimental converter that delivers a 3.3V/10A output from a $40\~60V$ input source.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.498-501
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• 2002

In the conventional PWM converter, high-frequency switching techniques was used for high-density of energy, but occurred a lot of problems such as switching losses, switching voltage/current stresses, EMI(Electromgnetic Interference) and so on. To overcome these problems, various soft switching techniques have been presented. However these techniques are focused on reducing switching losses and voltage/current stresses . The simulation and experimental results are shown that the active clamp ZVS flyback converter with the proposed RPWM(Random Pulse Width Modulation) technique reduces the conducted noise.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.9-10
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• 2010

The lighting control power circuits should be designed in stable region according to the environment. A stable circuit is analyzed using ac equivalent circuits. The flyback converter with wide input voltage ranges is suitable for lighting control system. It is designed optimally for stability. The specifications are that the input voltage is 90V-230V, the output power is 12V/2.5A. The stability analysis is established using PSM(Phase Sensitive Multimeter) in experiment. As a result, it is confirmed that the gain margin and the phase margin are in stable area. The validity of the experimental measurement is verified.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.384-388
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• 1999

This paper presents auto-tuning to compensate the integrator windup of the current and the speed PID controller of DC motor, which suppress the overshoot of transient response without delay of rising time. The simulation results using Matlab show the validity of auto-tuning methods.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1065-1066
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• 2006

The multi-resonant converter minimizes the parasitic oscillations using the resonant tank circuit absorbed parasitic reactances in a converter. So the converter can be operated at a high frequency and it provides a high efficiency because the switching power losses are reduced effectively. However, the high resonant voltage stress of semiconductors leads to the conduction loss. In this paper, it is proposed the novel flyback multi-resonant converter. The converter input is divided by two series input capacitors. And also the resonant stress is reduced to 2-3 times input voltage without any complexity and it provides the various circuit schemes in lots of applications. The proposed converters are verified through simulation and experiment.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.1
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• pp.59-65
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• 2018

A new single-stage flyback power converter with PFC for electrolytic capacitor-less LED driver is proposed in this study. This method minimizes the peak-to-average ratio of the LED driving pulsating current by adding the LED driving current near the LED current valley area, as well as the third harmonic component injection into the input current. The reduced peak current value of the LED drive current minimizes the thermal stress of the LED itself, thereby increasing the reliability of the LED, as well as achieving a long lifetime. Simulation and experimental results show the usefulness of the proposed topology.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.332-333
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• 2018

This paper presents an advanced abnormal over-current protection with $SuperFET^{(R)}$ 800V MOSFET in Flyback converter. In advanced abnormal over-current protection, digital pattern generator is proposed to detect a steep di/dt current condition when secondary rectifier diode or the transformer is shorted. If current sensing signal is larger than current limit during consecutive switching cycle, Gate signal will be stopped for 7 internal switching periods. If the abnormal over-current maintains pattern, the controller goes into protection mode. The Advanced over-current protection has been implemented in a 0.35um BCDMOS process (ON Semiconductor process).

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.137-139
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• 2005

본 논문에서는 30W급 스위칭형 직류전원장치 (Switching Mode Power Supply : SMPS)에 준공진형 프라이 백 스위칭 레귤레이터(quasi-resonant flyback switching regulator)를 적용하여 방사노이즈(radiation-noise)를 억제한 사례에 대하여 설명하고 있다. 기존의 PI사(社)의 TOP IC 시리즈$^{[1]}$와 같이 보편적으로 사용되고 있는 일명, 하드 스위칭(hard-switching)형 레귤레이터를 사용할 경우, 고속 스위칭시에 스위칭 손실(switching loss)과 스위칭 노이즈(switching noise)가 발생한다. 이로 인하여 SMPS의 발열에 따른 효율저화와 방사 노이즈에 의한 전파방해 등이 문제점이 된다. 본 논문에서는 일본의 Sanken사(社)에서 개발/시판중인 준공진형 스위칭 레귤레이터인 STR-F6000 IC 시리즈$^{[2]}$를 이용하여 프라이백 SMPS를 구성하여 방사노이즈를 저감하였다.