• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.4
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• pp.1229-1232
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• 2010

In this study, in order to develop multilayer piezoelectric transformer for high electromechanical coupling factor and mechanical quality factor. and to show the general approach to the design of inverters utilizing PT as a circuit element. The description of the piezoelectric effect is not present here and can be easily found in numerous publications as well as complex equations and formulae. What is the most important to understand is that "they are different" -one cannot just change an electromagnetic transformer (EMT) for a piezoelectric one. Several examples of PT-based circuitry will help to start and use multilayer piezoelectric transformer advantages most effectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.10
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• pp.815-820
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• 2001

The piezoelectric properties of the PT-PZ-PNN system ceramics were investigated depending on the variati on of the grain size. The grain size was varied by sintering temperature, and additive. The effect of the grain size on the electrical, dielectric, and piezoelectric properties was studied with respect to the feasibility of the application for the piezoelectric transformer. Grain size increased as the PMW contents increased. The smaller the particle size used, the smaller the grain size obtained. Specimens are densily sintered. Dielectric and piezoelectric properties are not always improved in proportion to the grain sizes. When he particle size are fine and the grain size are increased properly with the optimum additives, the piezoelectric preperties have good values. the specimen sintered at 1200$\^{C}$ with PMW 2 mol% and MnO$\_$2/ 0.5wt% contents exhibited good piezoelectric properties for a piezoelectric transformer.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.7
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• pp.376-383
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• 1999

The piezoelectric transformer (PT) is an electro-mechanical device that transfers electrical energy through a mechanical vibration. In this paper, a PT operating in the contour vibration mode is introduced for an application of fluorescent lamp ballast. Utilizing its inherent characteristics of the LC resonator and a high voltage gain to ignite the lamp in light load condition, an investigation of a power piezoelectric transformer as a potential component for a fluorescent lamp ballast is discussed. PT is easy to be produced in mass and reduces the cost of the ballast. The modified equivalent circuit model of the PT considering the operating current level is derived to design the fluorescent lamp ballast. This model describes the voltage gain of the PT in wide load variations and various input current levels. The experimental and simulation results are provided to verify theoretical analysis. The power capacity of the currently developed PT is relatively low (15W), but it can be increased by adopting a multi-layer structure and is currently under investigation. It is also possible to parallel the PT for higher power processing.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.78-81
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• 2000

The backlight inverter used in a laptop computer is investigated in this paper. It has been difficult for the electromagnetic transformer in the inverter to have a high efficiency and compact profile. In this study the piezoelectric transformer(PT) is used to reduce the loss and volume compared to the standard electromagnetic transformer. Comparison with the experimental inverter with the PT has been shown to validated the simulation program using the equivalent circuit model of the PT. A simple dimming control circuit was experimentally demonstrated and shown to have broad control.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.4
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• pp.175-182
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• 2000

The back-light inverter used in the laptop computer is designed in this paper. It has been difficult for electromagnetic transformer to enhance the efficiency and compact profile of the inverter. In this paper, (1) the piezoelectric transformer (PT) is used for reducing the loss; (2) the volumes of core and winding coil are used in electromagnetic transformer, and (3) the half-bridge series parallel resonant circuit is used in the driver of the inverter. The modified PT for this paper and the equivalent circuit are supported by the simulation program. The result of the experiment shows more than 91% improvement in terms of the efficiency.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.719-720
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• 2009

We suggest a new approach to lower the operating voltage of plasma display devices using a piezoelectric transformer (PT). $Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$ (PMNT) was used as a piezoelectric material. The Rosen-type PT, with a compact size of 10 mm ${\times}$ 20 mm ${\times}$ 0.3 mm, was fabricated on a glass substrate. The fabricated PT was operated as a half-wave vibration mode at around 80~90 kHz. The maximum voltage step-up ratio was 3 at 87.8 kHz when the input voltage was 10.32 V (peak-to-peak).

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.32-33
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• 2006

Processing and properties of high power piezoelectric transformer (PT) fabricated by PIM with nano-sized piezoelectric powders are demonstrated. The high power characteristics of a PMed dome-shaped PT were examined by the lighting test for a 55watt PL lamp. The 55watt PL lamp was successfully driven by the PIMed PT with sustaining efficiency higher than 98%. The transformer with ring/dot area ratio of 2.1 exhibited the maximum properties in terms of output power, efficiency and temperature stability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2660-2664
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• 2009

In this paper, it is reviewed is to acquaint a circuit design with features of piezoelectric ceramic transformers(PT) and to show the general approach to the design of inverters utilizing PT as a circuit element. The description of the piezoelectric effect is not present here and can be easily found in numerous publications as well as complex equations and formulae. What is the most important to understand is that "they are different" -one cannot just change an electromagnetic transformer (EMT) for a piezoelectric one. Several examples of PT-based circuitry will help to start and use PT's advantages most effectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.135-139
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• 2001

Contour vibration mode piezoelectric transformers were designed and fabricated to the square plate with size of $27.5{\times}27.5{\times}2.5(2.6,\;3.0)mm^3$ using PNW-PMN-PZT ceramics. Electrical characteristics of the piezoelectric transformer were investigated for fluorescent lamp ballast application. The electrical properties and characteristic temperature rise were measured using oscilloscope and infrared temperature sensor. A 28W fluorescent lamp was successfully driven by the fabricated transformers. After driving the lamp using Power Amplifier for 24 min, the output power, efficiency and characteristic temperature rise of PT2 piezoelectric transformer showed the appropriate values of 28.01 W, 99.43% and $11^{\circ}C$, respectively. The electronic ballast using PT2 piezoelectric transformer showed an excellent output power of 28.85 W and efficiency of 86.3%, respetively.

• Electrical & Electronic Materials
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• v.10 no.7
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• pp.732-736
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• 1997