• International journal of advanced smart convergence
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• 제8권4호
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• pp.138-146
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• 2019

In this paper, we proposed a soft-switched synchronous buck converter, which can perform charging the battery. The proposed converter has low switching loss even at high frequency operation due to its soft switching characteristics. The converter operates in synchronous mode to minimize conduction loss, resulting in small conduction loss, also. In this reason, the efficiency of the converter can be greatly improved even in high frequency. The size and weight of the converter can be reduced by high frequency operation of the converter. In this paper, we designed a battery charger with a switching frequency of 100 kHz. The designed converter also simulated to prove the converter's characteristics of synchronous operation as well as soft switching operation. The simulation shows that the proposed converter always meets the soft switching conditions of turning on and off switching in the zero voltage and zero current states. Therefore, simulation results have confirmed that the proposed battery charger had soft switching characteristics. The simulation results for transient response to charge current for the designed converter show that the converter responds to charge current commands quickly within 0.05 ms.

• 전력전자학회논문지
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• 제13권4호
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• pp.311-318
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• 2008

본 논문은 소프트 스위칭 기법을 적용한 싱크로너스 양방향 DC-DC 컨버터를 제안한다. 제안된 컨버터는 싱크로너스 벅 컨버터를 병렬구성을 하여 인터리브드 기법을 통해 도통 손실을 줄이고, 하나의 공진인덕터를 사용한 ZVT-Cell을 적용함으로써 스위칭 손실을 최소화 하였다. 전 부하 범위에서 CCM(Continuous Conduction Mode) 으로 동작하고 ZVS가 성립되도록 하였으며, 전류주입 기법을 통해 넓은 출력전압 범위에서도 ZVS 조건을 만족하였다. 또한, 기존 싱크로너스 벅 컨버터의 데드타임(dead time)동안 발생하는 역병렬 다이오드의 도통손실 및 dv/dt, di/dt 발생을 저감하는 효과를 얻을 수 있다. 제안된 컨버터의 유효성은 실험을 통해서 검증하였다.

• 전자공학회논문지SC
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• 제43권5호
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• pp.28-35
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• 2006

본 논문은 회로 구성 블록으로 CMOS 연산 트랜스컨덕턴스 증폭기(OTA)를 사용한 새로운 3.3-1 V 동기식 buck DC/DC 컨버터를 제안한다. PWM 회로의 오차 증폭기 OTA는 온도 안정성 향상을 위해 보상되었다. 보상된 OTA 트랜스컨덕턴스 이득의 온도 계수는 $0-100^{\circ}C$ 범위에서 $150\;ppm/^{\circ}C$ 이하이다. $0.35{\mu}m$ 표준 CMOS 공정으로 HSPICE 시뮬레이션을 수행한 결과는 40-125 mA의 부하 전류 범위에서 제안된 컨버터의 효율이 80% 이상임을 보여준다. 이러한 결과는 제안된 컨버터가 전지로 동작되는 시스템에 이용하기에 적당함을 보여준다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.122-122
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• 2009

최근 PC의 성능이 향상되면서, 고성능의 전원공급 장치가 요구되고 있다. 특히 CPU에 대전력을 공급하는 싱크로너스 벅 컨버터는 파워 MOSFET을 구동하기 위해 별도의 구동 IC가 필요하다. 본 논문은 adaptive 지연을 이용하여 파워 MOSFET을 구동하는 싱크로너스 벅 구동 IC를 설계하였다. 고정밀도의 밴드캡 기준회로와 비교기를 이용하여 30 ns의 adaptive 지연을 생성하며, 전력소모를 줄이기 위해 저전압에서 동작하는 UVLO(under voltage lock out)를 설계하였다. 또한 상단 파워 MOSFET을 구동하기 위하여 부트스트랩 방식을 이용하며, 부트스트랩 다이오드를 IC 내부에 내장하여 컨버터의 설계비용을 줄였다. 설계한 구동 IC의 동작 전압 범위는 8 V - 15 V이며, 출력 전류는 최대 2A이다. 싱크로너스 벅 구동 IC는 $0.5\;{\mu}m$ BiCMOS(Bipolar-CMOS) 공정 파라미터를 사용하여 설계되었으며, 시뮬레이션은 Cadence사의 Spectre를 이용하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 추계학술대회 논문집
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• pp.28-30
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• 2007

For the design of the voltage regulation module(VRM) having a high performance, current sensing is one of the most important functions. In this paper, three different methods for sensing the current in the multi-phase synchronous buck converter are analyzed considering the efficiency, accuracy and cost. The experiments are performed for the three current sensing methods to verify the theoretic analysis.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.31-33
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• 2008

A novel lossless current sensing technique for a synchronous buck converter is presented. The inductor DCR method is generally used as a low cost and lossless current sensing technique of DC/DC converters. It is however difficult to obtain the accurate current value for the conventional DCR method because the inductor resistance varies depending on the operating frequency. In order to overcome this problem, an improved current sensing technique is proposed, which has the separated DC and AC sensing circuits. The concept and operation of the proposed method are explained and the experimental results are provided to show its effectiveness.

• Journal of Power Electronics
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• 제14권4호
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• pp.796-805
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• 2014

A digital controller with a low-power approach for point-of-load synchronous buck converters is discussed and compared with its analog counterpart to confirm its feasibility for system integration. The tri-mode digital controller IC in $0.35{\mu}m$ CMOS process is presented to demonstrate solutions that include a PID, quarter PID, and robust RST compensators. These compensators address the steady-state, stand-by, and transient modes according to the system operating point. An idle-tone free condition for ${\Sigma}-{\Delta}$ DPWM reduces the inherent tone noise under DC-excitation. Compared with that of the traditional approach, this condition generates a quasi-pure modulation signal. Experimental results verify the closed-loop performances and confirm the power-saving mechanism of the proposed controller.

• 전력전자학회논문지
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• 제28권1호
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• pp.30-38
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• 2023

In this paper, a constant current(CC) and constant voltage(CV) control method using a primary-side regulated(PSR) fly-buck converter is proposed. Because the primary-side structure of the fly-buck converter is the same as that of the synchronous buck converter, it always operates in continuous conduction mode(CCM). Therefore, in the proposed method, the load information on the secondary side can always be easily estimated by measuring the primary inductor current at the midpoint of the switch-on period. An accurate CC/CV control can be achieved through simple calculations based on this estimated information. Consequently, the proposed method is advantageous for optimizing the control performance of the PSR converter. The validity of the proposed control was verified using a 5 W prototype of a PSR fly-buck converter. The experimental results confirmed that the current reference of 500 mA was followed within the error range of 1.2%, and that the voltage reference of 12 V was followed within the error range of 1.8% despite the indirect control of the load current and output voltage from the primary side.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2002년도 학술대회논문집
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• pp.151-156
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• 2002

The output voltage of Synchronous Generator is regulated constantly by field current control in excitation system. A synchronous generator is equipped with an automatic voltage regulator(AVR), which is responsible for keeping the constant output voltage under normal operating conditions about various levels. High frequency PWM converter (Current Mode Control Buck converter) type excitation system for synchronous generator is able to sustain output voltage level properly when the fault condition happened. This paper deals with the design and evaluation of the excitation system controller for a synchronous generator to improve the steady state and transient stability. The simulation and experimental results show that the proposed excitation system is improve the respons time by the AVR(automatic voltage regulator) of 50kW synchronous generator that is applied the current mode control excitation system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 추계학술대회 논문집
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• pp.71-75
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• 2004

In this paper, in order to develop a simple and high efficient ballast without an external igniter, a half-bridge type ballast with a coupled inductor and a frequency controlled synchronous rectifier is proposed. The internal LC resonance of the buck converter is used In generate a high voltage pulse for the ignition, and the coupled inductor filter is used for steady state ripple cancellation. Also, a synchronous buck converter is applied for the DC/DC converter stage. In order to improve the efficiency of the ballast, a frequency control method is proposed. This scheme reduces a circulation current and turn off loss of the MOSFET switch on the constant power operation, which results in increase of the efficiency of the ballast system about $4\%$, compared to a fixed frequency control. It consists a 2-stage version ballast with a PFC circuit. The results are verified with hardware experiments.