• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.11
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• pp.83-91
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• 1990

VOC(coltage controlled oscillator) circuits are necessary in applications such at the demodul-ation of FM signals, frequency synthesizer, and for clock recovery from digital data. In this paper, we designed the VCO circuit based on a OTA(operational transconductance amplifier) and the OP amp which using a differential amplifier by BiCMOS circuit. It consists of a OTA, voltage contorolled integrator and a schmitt trigger. Conventional VCO circuits are designed using the CMOS circuit, but in this paper we designed newly BiCMOS VCO circuit which has a good drive avlity, As a result of SPICE simulation, output frequency is 141KHz at 105KHz, and sensitivity is 15KHz.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.6
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• pp.554-560
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• 1999

In this paper, a vibration suppression method using an energy stored in winding inductance and an induced v voltage of the Linear Stepping Motor(LSM) is shown, and it is applied to a new one-phase excitation method A And a magnetic equivalent circuit is based on the structure of the LSM, and then the electric equivalent circuit of the LSM is derived by solving equations for the magnetic equivalent circuit. Several dynamic characteristics of the LSM are analyzed by the ACSL with the voltage equations, the force equations and the kinetic equation, a and are measured by experimental system.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.876-879
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• 2002

A novel driving technology of PDP, which enables to decrease the sustain voltage of conventional technology by half without lowering the gas discharging voltage. This technology, realizable without much increased cost of the semiconductor devices, gives a significant improvement in the power efficiency, essential for the design of a drive circuit for PDP. A comparative analysis and experimental results are presented to show the validity of the proposed driving technology.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.442-445
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• 2001

The sustaining driver for color ac plasma display panel should provide alternating high voltage pulses and recover the energy discharged from the intrinsic capacitance between the scanning and sustaining electrodes inside the panel. In this paper, a novel efficient energy recovery circuit employing boost-up function is proposed to achieve a faster rise-time and in order to obtain a stable sustain voltage. The principle of operation, features, and simulated results are illustrated and verified on an equivalent capacitance, which is equals In that of 40-inch-panel, 200 (kHz).

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1153-1155
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• 2005

This paper deals with dynamic characteristics of LSRM according to drive condition. First, in experiment of LSRM, position of LSRM detected approximation sensor. Position choose mover of LSRM and inductance. When approved current in each phase by decided position, we made sure current and voltage according to turn-on, turn-off. Second, in dynamic characteristic of LSRM, through an experiment, we decided turn-on position of inductance profile. Also, we presented dynamic characteristic analysis model which is consisted at motor and sensor signal part, etc., and substitute circuit constant that get using magnetic equivalent circuit method, we confirmed current and voltage waveform.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.464-466
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• 1996

IGBT devices have the best features of both power MOSFETs and power bipolar transistors, i.e., efficient voltage gate drive requirements and high current density capability. When designing circuit and systems that utilize IGSTs or other power semiconductor devices, circuit simulations are needed to examine how the devices affect the behavior of the circuit. The IGBT model in this paper is verified by comparing the results of the model with experimented results for various circuit operating conditions. The model performs well and describes experimented results accurately for the range of static and dynamic condition in which the device is intended to be operated.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.562-564
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• 1994

IGBT devices have the best features of both power MOSFETs and power bipolar transistors, i. e., efficient voltage gate drive requirements and high current density capability. The interaction of the IGBT with the load circuit can be described using the device model and the state equation of the load circuit. The protection circuit requirements are unique for the IGBT and can be examined using the model.

• Journal of Power Electronics
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• v.12 no.6
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• pp.954-959
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• 2012

A hybrid switch that uses a microelectromechanical system (MEMS) switch as a gate driver of a MOSFET is applied to an energy harvesting system. The power management circuit adopting the hybrid switch provides ultralow leakage, self-referencing, and high current handling capability. Measurements show that solar energy harvester circuit utilizing the MEMS-MOSFET hybrid switch accumulates energy and charges a battery or drive a resistive load without any constant power supply and reference voltage. The leakage current during energy accumulation is less than 10 pA. The power management circuit adopting the proposed hybrid switch is believed to be an ideal solution to self-powered wireless sensor nodes in smart grid systems.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.833-836
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• 1993

A flyback type power converter circuit for switched reluctance motor drives is presented. In this converter circuit, the energy extracted from an off going phase is stored in an additional capacitor. The energy stored is used to either be returned to the source frequently or energize the conducting phase during the conduction interval through the transformer. The additional switch to pass the energy stored in the capacitor to the source or the conducting phase is switched under a relatively low voltage condition. Its switching frequency is relatively high so that the size of the transformer can be reduced. The design guideline for the capacitor and the transformer is described. The effectiveness of the presented converter circuit is compared to other circuits through the analysis and experiment.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.473-477
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• 2007

The development of advanced Insulated Gate Bipolar Transistor(IGBT)has enabled high-frequency switching operation and has improved the performance of PWM inverters for motor drive. However, the high rate of dv/dt of IGBT has adverse effects on motor insulation stress. In many motor drive applications, the inverter and motor are separated and it requires long motor feds. The long cable contributes high frequency ringing at the motor terminal and it results in hight surge voltage which stresses the motor insulation. The inverter output filter and RDC snubber are conventional method which can reduce the surge voltage. In this paper, we propose the new low loss snubber to reduce the motor terminal surge voltage. The snubber consists of the series connection of charging/discharging capacitor and the voltage-clamped capacitor. At IGBT turn-off, the snubber starts to operate when the IGBT voltage reaches the voltage-clamped level. Since dv/dt is decreased by snubber operating, the peak level of the surge voltage can be reduced. Also the snubber operates at the IGBT voltage above the voltage-clamped level, the snubber loss is largely reduced comparing with RDC snubber. The proposed snubber enables to reduce the motor terminal surge voltage with low loss.