• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2568-2571
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• 2002

A LCD backlight inverter control IC based on the piezoelectric transformer (PZT) for Cold Cathode Fluorescent Lamp (CCFL) lighting is proposed. It is indeed a variable frequency, variable duty (VFVD) controller having dual feedback control loops for achieving both the regulation of lamp current and the maximum efficiency. The PWM controller regulates the lamp current, while the PLL controller tunes the operating frequency to the frequency that the efficiency of the combined LC-PZT resonator becomes maximum. The mixed PLL/PWM control technique lets the backlight inverter operate at the maximum efficiency in spite of the variation of component and environment. The controller features include a protection for an open or broken lamps, and an open lamp regulation.

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.99-102
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• 2001

In this paper, the electronic ballast was developed to control 250W metal halide lamp. To avoid acoustic resonance phenomenon, we calculated the acoustic resonance band and determined the driving frequence to from 70kHz to 100kHz. Due to the switching loss of MOSFET, many problems are caused in the inverter circuit during lighting the lamp, so we have reduced the loss by connecting the capacitor to reduce inrush current In this paper, main research area is to find the methods to operate the Iamp on regulated constant output. After detecting the current I and voltage V of the lamp, we changed the driving frequency by changing the DC voltage level.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1304-1306
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• 1996

A regenerative signal amplifying gate driver of self-excited electronic ballast is presented. It can be used for high pressure sodium (HPS) lamp without auxiliary external ignitor. Since the HPS lamp requires very high ignition voltage at start up, the resonant frequency of the circuit must be increased to obtain high voltage oscillations in spite of relatively small resonant current. The presented gate driver amplifies the current of gate drive transformer and raises the gate-source voltage Quickly to turn on the MOSFET switches. Hence, the resonant frequency can be increased more than 100kHz. The HPS lamp used in the simulation and experiment has the rating of 400W input power at 220V input ac voltage source. The experiments show that the resonant frequency is above 150kHz at start up.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.56 no.3
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• pp.148-154
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• 2007

In this paper, characteristics of ignition voltage and current by wire length of HID(High Intensity Discharge) lamp circuit are analyzed. In the construction field, decision of the wire thickness for HID lamp circuit has the problems, and these are presented. Through transmit parameters, equivalent model of the ballast and HID lamp circuit was derived. The graph of voltage reduction about length between the ballast and the lamp is shown. The simulation of proposed model and experimental results are presented in order to validate the proposed method. The proposed model and graph can use to choose the proper length of wire between the ballast and the lamp in the field.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.1
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• pp.27-32
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• 2003

The thesis is used by PSpice circuit model to the characteristics of a fluorescent lamp modified form of he classical Cassie and Mayr equations in order to show the characteristics of HID(High-Intensity Discharge) Lamp. This is useful for applying high-frequency electric ballast for HID Lamp, and show that the result of experimentations and simulations, such as lamp rating, input voltage, high-frequency electric ballast which is using the ABM circuit model of the low pressure sodium lamp, come to the voltage and current wave.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.465-466
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• 2007

In electrode-less lamp, The key point in creating an efficient light source based on RF discharge is to minimize the RF power loss in the RF coupler which for Anderson's type of RF lamp is due to losses in the ferrite core. This loss depends on the particular ferrite material, its size, geometry, frequency in this kind of inductive lamp shows that the correct choice of discharge current has a crucial effect on the core loss. In this study, we measured Ferrite temperature in normal state, then analyzed electrical and optical characteristics according to ferrite shape. We were able to know that was ferrite of the antenna had relate closely with temperature and luminous of the lamp. Also we appraised temperature and electrical, optical properties during turn on the lamp.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.10
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• pp.384-388
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• 1985

In this paper, an attempt is made to derive the variation equatios of the discharge current and the luminous flux for flourescent lamp subjected to a transverse magnetic field. As the field increases, so do the electric field, the electron temperature, and the luminous flux, while the current decreases. The theory is in a reasonable agreement with the experimental results, taking account of many approximations and restrictions.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.4
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• pp.503-508
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• 2010

Common LED (Light Emitting Diode) lamp has many advantages to compare with fluorescent lamp, long life and no pollution matter like the mercury. The LED lamp is a good light source especially for shipboard lighting because of its compact structure which prevents explosion and shock. Also, low maintenance cost is expected due to its longer life time in comparison with conventional lamps. The LED lamp, however, need some estimates that change of voltage and frequency, vibration, moisture on board to definite accommodation of the LED lamp to shipboard. The purpose of this study is to compare physical properties of a fluorescent lamp with one of the common LED lamp so as to analyze accommodation of common LED lamp on board. This study was carried out in two stages. First, temperature, humidity of illumination, voltage, electric current, frequency and electric power were measured by using experimental equipments. Second, a comparative analysis of consumption electric power, annual oil charge, annual CO2 emission and lamp life time, etc of the fluorescent lamp and common LED one was made. As a result of the study, the consumption electric power of fluorescent lamp was 50% higher than one of the common LED lamp. As a result of measuring life time, it was found that life time of common LED lamp was more about 3.5 fold than one of the fluorescent lamp. Considering these results, it's thought that common LED lamp is verified that energy saving is possible and using is possible as substitute for fluorescent lamp on board.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.98-103
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• 2001

In case that electronic ballast employing a valley-fill passive power factor correction (PFC) circuit is used for feeding fluorescent lamps, a new method to reduce crest factor of the lamp current is studied in this paper. In order to reduce crest factor to lower value, a pulse frequency modulation technique based on the waveform of the dc-link voltage which is predetermined by the passive PFC circuit, is taken into the switching control action of the electronic ballast. An equation-based analysis between the crest factor of lamp current and the effect of varying the inverter switching frequency is comprehensively performed.

• Laser Solutions
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• v.10 no.1
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• pp.11-17
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• 2007

We presented the proper laser processing conditions for the capillary line marking, which could be applied for the fabrication of injection needles. With changing the parameters such as lamp current, duty cycle and beam amplification factor of beam expander, we evaluated the processing performance considering amount of dross, processing efficiency and processed linewidth in the sample. We could carry out the proper line marking at the condition of 70% lamp current, duty cycle of 7-10% and 6-times amplification of beam diameter. To perform efficient line processing, the utilization of duty cycle of 12% at 80% lamp current was also preferred.