• 반도체디스플레이기술학회지
• /
• 제17권3호
• /
• pp.21-26
• /
• 2018

In this paper, the switching characteristics of the active clamp type flyback converter, which is deemed suitable for the miniaturization of the external power supply for home appliance, were analyzed and the process of reducing the switching loss was explained. The active clamp type flyback converter operating in the DCM has confirmed that the surge voltage of the main switch does not occur and the turn-off / on loss of the switch do not occur in principle. Also, in the case of the switch for synchronous rectifier, it was showed that the switch current showed half-wave rectified sinusoidal characteristic, and the switching loss was reduced. The switching characteristics of the experimental results gathered from 120 W class prototype were compared with the theoretical waveform in the steady-state and it was confirmed that the power conversion efficiency of the active clamp type flyback converter was maintained high due to the reduction of the switching loss.

• 반도체디스플레이기술학회지
• /
• 제16권2호
• /
• pp.49-54
• /
• 2017

In this paper, recent researches on new and renewable energy have been conducted due to problems such as energy exhaustion and environmental pollution, and new researches on high efficiency and high speed switching are needed. Therefore, we compared the efficiency by using high speed switching devices instead of IGBT which can't be used in high speed switching. The experiment was performed theoretically by applying the same parameters of the high speed switching devices which are the Cool MOS of Infineon Co., SiC C3M of Cree, and GaN FET device of Transform, by implementing the DC-DC boost converter and measuring the actual efficiency for output power and frequency. As a result, the GaN FET showed good efficiency at all switching frequency and output power.

• 반도체디스플레이기술학회지
• /
• 제20권3호
• /
• pp.157-160
• /
• 2021

In this paper, a 20W class multi-output QR flyback converter for auxiliary power supply was designed to stabilize 4 output voltages, and the efficiency and load characteristics were compared and analyzed. It was checked if each output affects other output characteristics through experiment. As a result, the experimental circuit reached a high efficiency of 82.5% or more at a load power of over 20W, and the maximum power loss was 2.6W. Consequently, it was confirmed that all of 4 output voltages of the multi-output QR flyback converter constructed in this paper were stabilized within 0.5% in full-load range, and each output was independently controlled in an electrically isolated state.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2013년도 추계학술대회 논문집
• /
• pp.5-6
• /
• 2013

본 논문에서는 모바일 기기 등에 사용되는 소형 디스플레이를 위한 고효율 경계모드 탭인덕터 부스트 LED 구동회로를 분석하여 장점을 밝히고 최적의 설계기준을 제시한다.

• 전력전자학회논문지
• /
• 제10권3호
• /
• pp.226-232
• /
• 2005

최근 많은 나라들이 상용전원의 왜곡을 방지하기 위해 AC 라인에 직접 연결하는 제품에 IEC 61000-3-2 나 IEEE 59 와 같은 고조파 규제를 가하고 있다. 따라서 최근 차세대 디스플레이 소자로 각광을 받고 있는 PDP(플라즈마 디스플레이 패널) 역시 이런 규제치를 만족하기 위해 역률개선회로를 부착하고 있다. 기존의 PDP 파워 모듈에서는 일반적으로 잘 알려진 부스트 컨버터를 이용해 역률개선회로를 구성하여 사용하였다. 그러나 PDP 자체의 열과 브리지 다이오드의 과도한 발열 때문에 시스템의 안전성을 보장할 수가 없었다. 본 논문에서는 PDP 파워 모듈용 역률개선회로로 브리지 없는 부스트 컨버터를 이용함으로써 효율, 소자 수, 발열상태 등 여러 가지 측면에서 기존회로와 비교 분석을 하고 그것의 제품 적용 가능성을 살펴보고자 한다.

• 한국전자통신학회논문지
• /
• 제18권4호
• /
• pp.617-624
• /
• 2023

최근, 전자 제품의 소형화와 저소비전력화 및 향상된 효율과 역률개선이 큰 관심 사항이 되고 있다. 본 논문에서는 PWM 제어기반의 AC-DC 컨버터를 설계, 제작하였다. AC-DC 컨버터는 하나의 정류회로와 하나의 출력전압 제어 회로가 직렬로 연결되는 구조로 설계하였으며, 정류회로는 다이오드 기반 단상 전파전류 회로, 출력전압 제어 회로는 PWM 제어기반의 DC-DC 변환 회로를 적용하였다. PWM 제어를 위한 주 제어장치로 아두이노를 이용하였으며, LCD를 출력 단에 구성하여 제어 결과를 확인할 수 있도록 하였다. 시험회로를 통한 반복 실험들을 통해서 오실로스코프와 LCD에 디스플레이 되는 출력전압과 목표 출력전압의 오차를 확인하였으며, 오실로스코프 측정값을 기준으로 약 5%의 오차율을 보임으로써 제안된 설계 방법론의 유효성을 확인할 수 있었다.

• 반도체디스플레이기술학회지
• /
• 제7권2호
• /
• pp.23-27
• /
• 2008

Recently, regulation for THD (Total Harmonic Distortion) such as IEC 61000-3-2, IEEE 519 is being reinforced about a product which directly connects to AC line in order to prevent distortion of common power source in electronic equipment and electrical machinery. In order to satisfy these regulations, conventional circuits were used two-stage structure attached power factor correction circuit at ahead of converter but this method complicate the circuit and then a number of element increases thereupon the cost of production rises. in this paper, we propose a high efficiency single-stage 300W PFC fly-back converter that improved power factor and efficiency than conventional two-stage power module.

• 반도체디스플레이기술학회지
• /
• 제19권4호
• /
• pp.99-104
• /
• 2020

In this paper, efficiency and loss characteristics of GaN FET were reported by applying it into the QR flyback converter. In particular, for the comparison of efficiency characteristics, QR flyback converter experimental circuits with Si FET and with GaN FET were separately produced in 12W class. As a result of the experiment, the experimental circuit of the QR flyback converter using GaN FET reached a high efficiency of 90% or more when the load power was 2W or more, and the maximum efficiency was observed to be about 92%, and the maximum loss power was about 1.1W. Meanwhile, the efficiency of the experimental circuit with Si FET increased as the input voltage increased, and the maximum efficiency was observed to be about 82% when the load power was 9W or higher, and the maximum loss power was about 2.8W. From the results, it is estimated that that in the case of the experimental circuit applying the GaN FET switch, the power conversion efficiency was improved as the switching loss and conduction loss due to on-resistance were reduced, and the internal loss due to the synchronous rectifier was minimized. Consequently, it is concluded that the GaN FET is suitable for under 20W class power supply unit as a high efficiency power switch.

• 반도체디스플레이기술학회지
• /
• 제21권2호
• /
• pp.95-100
• /
• 2022

In this paper, a power loss analysis technique of a high-frequency transformer of a bidirectional DAB (Dual Active Bridge) converter is reported. To miniaturize the transformer of the dual active bridge converter, a resonant inductor was designed with an air gap included low-coupled rate state core to combine leakage inductor with the resonant inductor which is required for soft-switching. In this paper, leakage inductance and magnetizing inductance, core material, type of winding and winding method are included in the dual active bridge transformer loss analysis process to enable optimal design at the initial design stage. Transformer loss analysis for dual active bridge with a switching frequency of 200 kHz and maximum output of 5 kW was executed, and elements necessary for design based on the number of turns on the primary side were graphed while maintaining the transformer turns ratio and window area. In particular, it was possible to determine the optimal number of turns and thickness of the transformer, and ultimately, the total loss of the transformer could be estimated.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
• /
• pp.139-142
• /
• 2004

Recently the PDP is the most remarkable media for a next generation display device. In this paper, we proposed the PDP dedicated AC-DC converter using quasi resonant method because the PDP has a lot of power dissipation so we need to develope. The proposed converter using one transformer has soft switching and a advantage to lower voltage stress in switch and also is predicted to have high power efficiency, we proposed the principles and theory using the zero voltage switching and verified the validity through a experiment.