• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.435-438
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• 1999

Nowadays, the inverter for CCFL(Cold-Cathode Fluorescent Lamp) driver is needed as form of compact size, low loss and high efficiency. This paper deals with comparison of characteristics of the electromagnetic push-pull type inverter and the piezoelectric half-bridge inverter for a CCFL driver. From the experimental results, the piezoelectric inverter is proven as more efficient than conventional electromagnetic inverter.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.1
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• pp.39-43
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• 2009

In order to develop piezoelectric inverter module for CCFL driving, Rosen-type multilayer piezoelectric transformer was fabricated. The output power and efficiency of mutilayer piezoelectric transformer according to the variation inner electrode layer were investigated. Mutilayer piezoelectric transformer was fabricated conventional mutilayer ceramic method using PZT base ceramics. Also, piezoelectric inverter module was adopted driving circuit with half-bridge type. The piezoelectric inverter module was set up with input voltage 12.5 V, switching frequency 104.3 KHz. The results showed the value of step-up ratio 100, efficiency 87% at load resistance of $100k{\Omega}$.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.3
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• pp.199-204
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• 2007

In this paper, EEFL, which is advantageous for driving multi-lamp and is able to reduce number of inverter, is used and Piezoelectric Transformer, which is able to reduce self loss, miniaturize and has high boosting transfer rate, and parallel connected to drive multi-lamp. For optimized EEFL driver circuit configuration, a Push-Pull type Piezoelectric inverter was designed and a simulation analysis was performed on the inverter circuit, and by applying multiple different type of driving methode, it is proved that a piezoelectric transformer can be used to manufacture a big screen multi-lamp driving inverter.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.9
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• pp.843-848
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• 2006

This paper explains the design and fabrication of an inverter for LCD backlight using a multilayer piezoelectric transformer. That inverter is operated by the burst dimming method whose dimming signal is controlled by the duty ratio of rectangular switching signal to a PWM controller. The brightness of CCFL's are investigated according to the various dimming signals, and when those CCFL's are turned on, the temperature distributions on the piezoelectric transformer and circuit components of the inverter are also investigated by a thermo-camera.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.48-54
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• 2017

In this paper, hysteresis voltage control method is proposed to an unidirectional inverter control for piezoelectric load. Piezoelectric load has electrically RC characteristic, and is driven by the inverter to control the output voltage waveform. When controling the output waveform by PI control, appropriate gains need to be selected. However, hysteresis control may minimize the output distortion because it has maximum proportional gain. In addition, Hysteresis control algorithm has simple structure to realize and the response is fast. Although the switching frequency of the inverter by hysteresis control varies, the switching frequency for the piezoelectric load is lower than that by PI control for equivalent performance. In particular, on implementing the algorithm using FPGA, the algorithm can be implemented in fewer pabrics and the processing time can be reduced. The superiority of the proposed hysteresis voltage control was proved for piezoelectric load through simulation and experiment.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.1
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• pp.33-38
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• 2003

This paper describes control principles of the piezoelectric ultrasonic motor which is operated by the ultrasonic vibration generated by the piezoelectric element. The piezoelectric ultrasonic motor has excellent characteristics such as compact size, noiseless motion, low speed, high torque and controllability, and has been recently applied for the practical utilization in industrial, consumer, medical and automotive fields. In this paper, the design of two-phase push-pull inverter for driving the piezoelectric ultrasonic motor is described, and a new control method of automatic resonant frequency tracking using PLL(Phase-Locked Loop) technique is mainly presented. the experimental results by this inverter system for driving the piezoelectric ultrasonic motor are illustrated herein. The inverter system with PLL technique improved the speed stability of the piezoelectric ultrasonic motor.

• 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.

• 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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.2320-2323
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• 2014

Piezoelectric inverter for driving CCFL is designed in this study. Of them, CCFL is generally used because it has advantages such as small size, high efficiency and good brightness characteristics. 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. The simulation program supports the modeled piezoelectric inverter for this paper and the equivalent circuit. The result of the experiment shows more than 90% improvement in terms of the efficiency.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.2
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• pp.130-137
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• 2005

LCD needs a backlight that is a light source as a photodetector that has a light modulation function and CCFL is used usually. Inverter that composes using existent winding transformer operates multi lamps, however, this efficiency falls by losses of core or winding and volume or weight increases or there is danger of fire by overheating. In order to solve these problems, a multi lamp driving Inverter using PT is composed according to the design guideline in this paper. We conformed whether the multi lamp drive method using EEFL that a current burden is less in applicable to piezoelectric inverter, and used the method that connect two piezoelectric transformers by parallel to an inverter.