• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.529-533
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• 2000

This paper present a new sort of multilayer piezoelectric ceramic transformer for AC-adapt. This piezoelectric transformer operates n the second thickness extensional vibration mode. The output voltage of the multilayer piezoelectric transformer was simulated using ANSYS. As results, the maximum stress appeared at the two points where one is the middle of input and the other is middle of output side in Second thickness extensional vibration mode. And output voltage was inversely decreased by increasing number of output layers.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.226-229
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• 2005

In this study, a step-down piezoelectric transformer was fabricated to utilize as an adapter for charging batteries of mobile electronic appliances. The ceramic part of the transformer is $Pb[(Mn_{1/3}Sb_{2/3})_{0.05}Zr_{0.475}Ti_{0.475}]O_3$ with mechanical quality factor of 1600, electromechanical coupling coefficient 59 %, and piezoelectric constant d33 1300, which can be utilized as a piezoelectric transformer. A simply fabricated disk-typed test pattern of diameter 28 mm and thickness 2 mm was used to characterize resonant frequency, Qm, kp according to the different input/output electrode area. efficiency and power as a function of load resistance was also investigated. The sample APT showed some spurious mode and BPT showed better frequency property. Taking all properties which are admittance, effective electromechanical coupling coefficient and mechanical quality factor most suitable for piezoelectric transformer is BPT which has 12 mm diameter electrode and the condition of 15 Vrms, 30 $\Omega$ made the maximum efficiency of 93.7 % and maximum power is 6W with 50 Vrms.

• 조명전기설비학회논문지
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• 제17권2호
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• pp.28-33
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• 2003

기계적인 에너지를 전기적인 에너지로 변환시키는 장치인 압전변압기는 고전압\ulcorner고효율의 소형변압기이다. 압전변압기는 노트북용 LCD backlight 구동장치로 적합하며, 공진주파수에서 동작시 거의 정현파에 가까운 교류파형을 출력하는 장치이다. 본 논문에서는 입력 DC 전압으로부터 FET를 구동시키는 게이트 신호로 변환시킨 다음 LC공진을 통하여 정현파를 생성시켜 압전변압기를 구동시키는 인버터에 대하여 논의하였다. 실험결과 압전변압기의 전압 이득과 공진주파수는 부하에 비례하며, 전압 이득은 입력전압의 변화에는 무관하게 나타났다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.255-258
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• 1998

In this paper. we designed and simmulated a ring-dot type piezoelectric transformer. As the result, piezoelectric transformer of 25${\times}25{\times}3.5mm$ size (Dot electrode diameter of Ilmm) show the maximum displacement, stress and output power. When the Input voltage of piezoelectric transformer was 155V. Output voltage show 30V and output power 9W at the load resistance of $100\Omega$

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.196-197
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• 2006

In this study, low temperature sintering multilayer piezoelectric transformer for DC-DC converter were manufactured using (PbCaSr)Ti(MnSb)$O_3$ ceramics and thin their electrical properties were investigated according to the vanation of frequency and load resistance. The voltage step-up ratio of multilayer piezoelectric transformer showed the maximum value m the vicinity of 1.3MHz and increased according to the increase of load resistance. When the output impedance coincided with the load resistance, the piezoelectric transformer showed the temperature rise of about $21^{\circ}C$ under the output power of 6W.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.70-73
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• 2000

This paper present a new sort of multilayer piezoelectric ceramic transformer for AC-adapter. This piezoelectric transformer operates in the second longitudinal vibration mode. The output voltage of the multilayer piezoelectric transformer was simulated using ANSYS, that is one of the FEM analysis program. As results, the minimum displacement was occurred at the two paints where one is the middle of input and the other is middle of output side in second thickness extensional vibration mode. And output voltage was inversely decreased by increasing number of output layers. 缀Ѐ㘰〻ሀ䝥湥牡氠瑥捨湯汯杹

• 한국산학기술학회논문지
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• 제11권1호
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• pp.113-118
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• 2010

압전 변압기와 CCFL, 형광등의 전기적 등가회로에 의한 PSPICE 모델을 제시하였고, 차세대 35W급 초절전형 삼파장 T5 형광램프용 고효율 형광등 안정기를 개발하였다. 이 안정기는 역률개선회로와 인버터에 압전 변압기를 채용하여 T5 형광램프의 점등실험을 하였으며, 압전 변압기의 효율적인 구동과 정확한 주파수 공급을 위하여 PLL방식을 사용하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.234-235
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• 2005

This paper present a new disk-type piezoelectric transformer. The input side of the transformer has a crescent-shaped electrode and the output side has a focused poling direction. The piezoelectric transformers operated in each transformer's resonance vibration mode. The electrodes and poling directions on commercially available piezoelectric ceramic disks were designed so that the planar or shear mode coupling factor ($k_p,\;k_{15}$) becomes effective rather than the transverse mode coupling factor ($k_{31}$).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.273-277
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• 1999

A cold cathode flourescent lamp for the backlight in the notebook computer requires high input voltage about 1300(V) when it turns on. But once a discharge starts, the input voltage can be dropped by about one-third for continued output. The equivalent impedance also varies from open to several dozens of kilo-ohms. The piezoelectric transformer converts electrical energy into mechanical energy and then converts it back to electrical energy at a high voltage. Its high output voltage, high efficiency and small size are suitable for driving the LCD backlight in the notebook computer. The piezoelectric transformer operates near the resonance frequency and the output waveform is close to sine wave with very little noise. This paper suggests an inverter for LCD backlight of notebook computer using piezoelectric transformer that includes voltage to frequency converter for gate signal which is useful for tracking of variable resonance frequency depending on load impedance.

• 한국전기전자재료학회논문지
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• 제15권6호
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• pp.499-503
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• 2002

In this study, to develop the high power piezoelectric transformer for adaptor, PSN-PNN-PZT system ceramics were formulated as a function of $MnO_2$ addition and its dielectric and piezoelectric characteristics were investigated. Multi-layer piezoelectric transformer using an excellent composition was also fabricated and its electrical properties evaluated. The composition ceramics added to 0.5wt%$MnO_2$ showed the maximum value of $k_p=0.61$ and $Q_m=1.321$. As the output power of piezoelectric transformer is increased, its temperature rise increased. At the fixed 18W output power, the transformer was stably operated.