• Journal of IKEEE
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• v.14 no.3
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• pp.250-255
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• 2010

The interleaved power management IC(PMIC) with DTMOS(Dynamic Threshold voltage MOSFET) switching device is proposed in this paper. The buck-boost converter used to provide the high output voltage and low output voltage for portable applications. Also we used the PWM(Pulse Width Modulation) control method for high power efficiency at high current level. DTMOS with low on-resistance is designed to decrease conduction loss. The interleaved PMIC to reduce output ripple. And step-down DC-DC converter in stand-by mode below 1mA is designed with LDO in order to achive high efficiency.

• Journal of IKEEE
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• v.23 no.1
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• pp.99-106
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• 2019

This paper propose a new form of UPQC (Unified Power Quality Compensator) to compensate the current and voltage quality problems of nonlinear loads. The conventional UPQC system consists of a series inverter, a parallel inverter, and a common DC link. A new type of UPQC proposed is a parallel compensator with SVC (Static Var Compensator) added to compensate for the wide compensation range and low DC link voltage. The parallel inverter compensates the reactive power generated by the nonlinear load, and the series inverter compensates the sag and swell generated at the power supply side.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.317-320
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• 2000

This paper proposes a voltage compensation method to improve the control performance of B4 inverter which is studied for low-cost drive systems. The B4 inverter employs only four switches and it has a center-tapped connection in the split dc-link capacitors to one phase of a three-phase motor. In the B4 topology unbalan-cd three-phase voltages will be generated by the dc link voltage ripple. To solve this problem we present a voltage compensation method which adjusts switching times considering dc link voltage ripple. The proposed method is verified by simulation results,

• Journal of IKEEE
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• v.23 no.3
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• pp.1054-1060
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• 2019

A extension of the high boost voltage-lift DC-DC converter with large conversion ratio has been proposed in this paper. The proposed extension is combined the switched-inductor cell (SL-cell) and modular voltage cell (MV-cell). The proposed structure can achieve the large voltage conversion without high duty-cycle and the low voltage of the components. Moreover, the PID controller for novel SL-MV voltage-lift DC-DC converter also introduces. This technique a good-performance output voltage can kept constant with an good transient performance when the output load is suddenly changed. In order to prove the theoretical analysis, the experimental setup has been built for the DC load of $150[{\Omega}]$ and $300[{\Omega}]$. In addition, the transient of output voltage has been tested to determine the controller. Experimental results validate the effectiveness of the theoretical analysis proving the satisfactory converter performance.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.2
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• pp.95-103
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• 2007

Dynamic voltage scaling (DVS) is a well-known and effective power management technique. While there has been research on slack distribution, voltage allocation and other aspects of DVS, its effects on non-voltage-scalable devices has hardly been considered. A DC-DC converter plays an important role in voltage generation and regulation in most embedded systems, and is an essential component in DVS-enabled systems that scale supply voltage dynamically. We introduce a power consumption model of DC-DC converters and analyze the energy consumption of the system including the DC-DC converter. We propose an energy-optimal off-line DVS scheduling algorithm for systems with DC-DC converters, and show experimentally that our algorithm outperforms existing DVS algorithms in terms of energy consumption.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2729-2734
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• 2011

In this paper, an active replica Low-dropout(LDO) regulator with DC voltage matching circuit is presented. In order to match the voltage between replica and output of regulator, DC voltage matching circuit is designed. The active replica low dropout regulator has higher Power Supply Rejection(PSR) than that of conventional regulator. The designed DC voltage matching circuit can reduce the drawback that may be occurred in replica regulator. And using fully active element in regulator can reduce the chip area and heat noise with resistor. As results of HSPICE simulation with 0.35um CMOS parameter, the designed active replica LDO regulator achieves Power Supply Rejection, -28@10Hz better than -17@10Hz of conventional replica regulator without DC matching circuit. And the output voltage is 3V.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.4
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• pp.57-66
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• 2012

When typical Z-source DC/AC inverter(ZSI) is operated in high voltage gain area, because of its high duty ratio, voltage and current stress in Z-network of typical ZSI are increased. This paper proposes a new switched trans ZSI(STZSI) with two switched trans cells which consist of one trans and two diodes. To confirm the operation performance of the proposed system, the PSIM simulation is performed for typical ZSI, switched inductor ZSI and the proposed STZSI. Voltage / current stress and transient state characteristics of each method are compared under the condition of DC input voltage 100[V] and output phase voltage 66[Vrms]. As a result, we confirmed that transient state of the proposed STZSI is short compared with the conventional ZSI because the high voltage gain is obtained using the same duty ratio, also a low duty ratio is required for the same output voltage. Finally, we could know the proposed system have low voltage and current stress in Z-network compared with the conventional ZSI.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.6
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• pp.507-515
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• 2012

DC-DC converter which composed of LLC resonant converter, operated by fixed switching frequency with fixed duty cycle (50%), and flyback converter to provide constant output voltage($400V_{DC}$) with variation of input voltage($30-60V_{DC}$) is proposed in this paper. To obtain constant output voltage($400V_{DC}$), flyback converter is not operated in case of above the maximum input voltage($60V_{DC}$) and operated as the input voltage decreases to below 60VDC. Therefore, flyback converter can be designed to the 50% power rating of the maximum power in the proposed DC-DC converter. Operation modes and voltage gain characteristics were analyzed and a 360W prototype converter was tested to verify the proposed converter.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.4
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• pp.123-129
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• 2003

We propose a high voltage dc-dc converter for a CW (continuous wave) $CO_2$ laser system using a current resonant half-bridge inverter and a Cockcroft-Walton circuit. This high voltage power supply includes a 2-stage voltage multiplier driven by a regulated half-bridge series resonant inverter. The inverter drives a step-up transformer and the secondary transformer is applied to the voltage multiplier. It is highly efficient because of the reduced amount of switching losses by virtue of the current resonant half-bridge inverter, and also due to the small size, low parasitic capacitance in the transformer stage owing to the low number of winding turns of the step up secondary transformer combined with the Cockroft-Walton circuit. We obtained a maximum laser output power of 44 W and a maximum system efficiency of over 16%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6258-6263
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• 2014

The LDC (Low Voltage DC-DC Converter) used for hybrid vehicles and electric vehicles was utilized to supply the electric apparatus load with a voltage and to charge the auxiliary batteries by receiving a high DC voltage from the high voltage battery. The LDC has a long-time load test during the manufacturing process. On the other hand, it has the disadvantage of considerable energy consumption because it has the structure to release the power as 100% heat during a load test. Therefore, in this paper, a recycling load test method was proposed and 75~90% energy saving was realized.