• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.9
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• pp.576-583
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• 2004

This paper presents a buck circuit topology of high-frequency with a single switching device. It solved the problem which arised from hard-switching in high-frequency using a resonant snubber and operating under the principle of ZCS turn-on and ZVS turn-off commutation schemes. In the existing circuit, it has the voltage stress that is almost twice of input voltage in a free-wheeling diode. In the proposed circuit, it has the voltage stress that is lower than input voltage with modifing a location of free -wheeling diode. In this paper, it expained the circuit operation of each mode and analyzed feedback-loop stabilization. Also it confirmed the waveform of each mode with simulation result. The experiment result verified the simulation waveform and compared the voltage stress of a free -wheeling diode in the exsiting circuit with the voltage stress of that in the proposed circuit. Moreover, it compares and analyzes the proposed circuit's efficiency with the hard-switching circuit's efficiency according to the change of load current.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.669-679
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• 2003

Through AIS(Automatic Identification System), ITU-R suggested the navigational data communication between ships and between ships and shore stations for the better safety of navigation, and it requires two different the transmitting output power level depending on its operating mode. According to ITU's recommendation, these levels should reach within 20% of its final value in 1ms. In this paper, an adequate feedback control circuit for power amplifier module is designed and implemented.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.642-647
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• 1998

A new small-signal model for the controlled on-time boost power factor correction (PFC) circuit is presented. The proposed small-signal model is valid up to high frequencies over lKHz. The model can be used in designing the voltage feedback compensation of PFC circuits, the control bandwidth of which is maximized with auxiliary means of removing the low-frequency ripple from the output. The accuracy of the model is confirmed by a 200W experimental hardware

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.253-256
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• 2002

A programmable CMOS negative resistor has been designed and fabricated in a 0.5um double poly double metal technology. The proposed CMOS negative resistor consists of a positive feedback OTA and a bump circuit with Gaussian-like I-V curve. Measurements of the fabricated chip confirm that the proposed CMOS resistor shows various negative resistance according to control voltage.

• Journal of KSNVE
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• v.5 no.1
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• pp.49-57
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• 1995

An electronic circuit device is developed such that the displacement between an electromagnet and a moving target can be estimated from the coil current measurement, and then applied to an active magnetic bearing system. In order to levitate the shaft without using displacement sensor the stable control gains are obtained from the linearized model which includes the gap estimation circuit. Experimental results show that the shaft, by the estimated gap feedback, can be levitated within $\pm$6 ${\mu}m$ positioning error.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.11
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• pp.66-73
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• 1993

This paper presents an analog circuit implementation and experimental resuls of the Hopfield type neural network. The proposed architecture enables the reconfiguration betwewn feedback and feedforward networks and employs new circuit designs for the weight supply and storage, analog multilier, nd current-voltage converter, in order to achieve area efficiency as well as function al versatility. The layout design of the eight-neuron neural network is tested as an associative memory to verify its applicability to real world.

• Journal of IKEEE
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• v.18 no.2
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• pp.220-227
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• 2014

This paper presents a control method of Single-Inductor Dual-Output DC-DC Converter using Common mode feedback and differential feedback loops. To generate duty used for differential mode feedback loop, this paper propose relative sawtooth circuit using current divider circuit which makes ramp signal with variable dead-time. Two outputs of the Single-Inductor Dual-Output DC-DC Converter are specified for 2.8 V and 4.2 V with input voltage 2.5 V. The maximum conversion efficiency of designed SIDO DC-DC Converter is 95% at total output power of 539mW. Cross regulations of Boost1 and Boost2 are 3.57% and 4% each, when increasing twice times output current.

• The Transactions of the Korea Information Processing Society
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• v.1 no.2
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• pp.272-278
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• 1994

The paper proposes a test pattern generator and a signature analyzer for pseudoexhaustive testing of the combinational circuit part within a sequential circuit when performing built-in self test of the circuit. The test pattern generator can scan in the seed test pattern and generate exhaustive test patterns. The signature analyzer can perform the analysis of the circuit response and scan out the result. Such test pattern generator and signature analyzer have been developed using SRL(shift register latch) and LFSR(linear feedback shift register).

• Journal of information and communication convergence engineering
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• v.18 no.3
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• pp.201-206
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• 2020

This paper presents a new method for controlling the current of lighting LEDs without current sensors. This method can be used as backup against LED current sensor faults. LED lighting requires a circuit with a constant current in order to maintain the same brightness when the ambient temperature changes. Therefore, we propose a new current estimation method to provide backup in case of current sensor faults based on the calculation of the inductor current. In the fabricated circuit, the average current changes from 144.03 mA to 155.97 mA when the ambient temperature changes from 0℃ to 60℃. The application of this study can enable the fabrication of a driving IC for LEDs in the form of a single chip without sensing resistors. This is expected to reduce the complexity of the peripheral circuit and enable precise feedback control.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.6
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• pp.455-462
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• 2004

This paper is concerned with the implementation of the active vibration suppression controller using analog circuit and microprocessor. The target active vibration controller is the positive position feedback(PPF) controller since it provides a simple algorithm suitable for both analog circuit and digital controllers. In this study, the analog PPF controller is realized using an operational amplifier and the digital PPF controller is realized using a low-cost micro-controller. The circuit diagrams are explained in detail. We then discuss the advantages and disadvantages of both methods from the view of practical implementation. Experimental results show that both implementation methods can be effectively used for the active vibration control but need to be chosen based on the mission objective.