• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.13 no.3
• /
• pp.25-33
• /
• 1999

In this paper, the method of reducing hanmnics and correcting of power factor in single PWM converter associated with diode rectifier and boost converter is studied. In the general diode rectifier there are sorre problems that discontinuous current of reducing power factor and including distortion of hanmnics at the input current affects other sources. To solve the problems of performance degradation due to pulse wavefonn in the input current, the ac-dc converter in which the hanmnic distortion in the input current is reduced using a third-hanmnic-injected PWM is proposed. A lower power loss of switching and easy configuration of circuit are obtained by adopting discontinuous current mode. Simulation and experimental results of ac-dc converter with 5[kHz] switching frequency are presented and correction of power factor and reduction of total hanmnic distortion was established.lished.

• Journal of IKEEE
• /
• v.11 no.1 s.20
• /
• pp.54-60
• /
• 2007

In this study novel ESD protection device, namely, N/P-type Low Voltage Triggered SCR, has been proposed, for high speed I/O interface. Proposed device could lower high trigger voltage($\sim$20V) of conventional SCR and reduce latch-up phenomenon of protection device during the normal condition. In this Study, the proposed NPLVTSCR has been simulated using TMA MEDICI device simulator for electrical characteristic. Also the proposed device's test pattern was fabricated using 90nm TSMC's CMOS process and was measured electrical characteristic and robustness. In the result, NPLVTSCR has 3.2V $\sim$ 7.5V trigger voltage and 2.3V $\sim$ 3.2V holding voltage by changing PMOS gate length and it has about 2kV, 7.5A HBM ESD robustness(IEC61000-4-2).

• Journal of IKEEE
• /
• v.24 no.3
• /
• pp.803-813
• /
• 2020

This paper presents a high efficiency resonant flyback converter using a single-chip microcontroller. The proposed converter primary performs the resonant switching by applying the asymmetrical pulse-width modulation (APWM) to the half-bridge power topology. And the converter secondary uses the diode flyback rectifier as its power topology and operates with the zero current switching (ZCS). Thus the proposed converter achieves high efficiency. The total structure of proposed converter is very simple because it uses a single-chip microcontroller and bootstrap circuit for its control and drive, respectively. First, this paper describes the converter operation according to each operation mode and shows its steady-state analysis. And the software control algorithm and drive circuits operating the proposed converter are explained. Then, the operation characteristics of proposed converter are shown through the experimental results of an implemented prototype based on each explanation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.27 no.1
• /
• pp.84-87
• /
• 2016

In this paper, a receiver for wireless power transfer is proposed. The receiver consists of a 100 W rectifier in 1.8 MHz frequency band, and a constant current charger. In particular, two kinds of protection circuits are installed in the rectifier. They are a over-voltage protection circuit which block the input voltages greater than 30 V and a active-dummy load which maintains the receiver input impedance by automatically consuming the remaining input power. The constant current charger is designed to charge the battery with a charging current of up to 1 A. A wireless charging system is fabricated using the proposed receiver. The system is composed of a 130 W transmitter, two magnetic resonator, and proposed receiver for charging a 48 V Li-Ion battery using the coupled magnetic resonance method. By the measurement result, the system efficiency is about 54 %.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.4
• /
• pp.356-362
• /
• 2005

In this paper, in order to develop a simple and high efficient ballast without an external ignitor, 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 to 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 trun 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 nth hardware experiments.

• Journal of Advanced Navigation Technology
• /
• v.24 no.6
• /
• pp.566-572
• /
• 2020

In a wireless power transmitter, the characteristics and effects of wireless power transmission between two induction coils are investigated, and a power converter circuit and a battery charger/discharger circuit using wireless power transmission technology are proposed. The advantage of wireless power transmitters and wireless chargers is that, instead of the existing plug-in-mounted wired charger (OBC; on-board charger), the user can wirelessly charge the battery without connecting the power source when charging power to the battery. There is. In addition, the advantage of wireless charging can bring about an energy efficiency improvement effect by using the secondary side rectifier circuit and the receiving coil, but the large-capacity long-distance wireless charging method has a limitation on the transmission distance, so many studies are currently being conducted. The purpose of the study is to study the transmitter circuit and receiver circuit of a wireless power transmission device using a primary coil, a secondary coil, and a half bridge series resonance converter, which can transmit power of a non-contact type power transmitter. As a result, a new topology was applied to improve the power transmission distance of the wireless charging system, and through an experiment according to each distance, the maximum efficiency (95.8%) was confirmed at an output of 3 kW at an 8 cm transmission distance.

• Journal of IKEEE
• /
• v.20 no.1
• /
• pp.45-53
• /
• 2016

This paper presents a CMOS interface circuit for vibration energy harvesting with MPPT (Maximum Power Point Tracking). In the proposed system a PMU (Power Management Unit) is employed at the output of a DC-DC boost converter to provide a regulated output with low-cost and simple architecture. In addition an MPPT controller using FOC (Fractional Open Circuit) technique is designed to harvest maximum power from vibration devices and increase efficiency of overall system. The AC signal from vibration devices is converted into a DC signal by an AC-DC converter, and then boosted through the DC-DC boost converter. The boosted signal is converted into a duty-cycled and regulated signal and delivered to loads by the PMU. A full-wave rectifier using active diodes is used as the AC-DC converter for high efficiency, and a DC-DC boost converter architecture using a schottky diode is employed for a simple control circuitry. The proposed circuit has been designed in a 0.35um CMOS process, and the designed chip occupies $915{\mu}m{\times}895{\mu}m$. Simulation results shows that the maximum power efficiency of the entire system is 83.4%.

• Journal of the Microelectronics and Packaging Society
• /
• v.13 no.1 s.38
• /
• pp.31-35
• /
• 2006

This paper is studied on a protective control system for electrical fire used electrical characteristics of SCR and multilayer-type PTC thermistor. The PTC thermistor has characteristic or positive resistivity temperature coefficient according to the temperature variation, which is construction of a regular square and cube demarcation with $BaTiO_{3_}$Ceramics of positive temperature coefficient. Also PTC shows the phenomenon which is rapidly increased in the resistivity if the temperature is increased over Curie temperature point. This paper is proposed on a protective control system used multilayer-type PTC which is protected from electrical fire due to electric short circuit faults or overload faults. Some experimental results of the proposed apparatus is confirmed to the validity of the analytical results.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.5
• /
• pp.1052-1058
• /
• 2005

This paper dealt with the design and fabrication of a low frequency electronic ballast for ruh attracting lamps. The proposed electronic ballast was composed of a full-wave rectifier, a step don converter operated as a constant power controled current source, an inverter operated by 130 Hz square wave, and an ignition circuit. An acoustic resonance phenomenon of discharge lamps could be eliminated by application of 130 Hz square wave. Also, a circuit of high voltage pulse generation for lamp ignition was added to the ballast. From the experimental results, voltage and current of the lamp operated by the electronic ballast were estimated 132.5 V and 7.6 A, respectively. and the power consumption was about 1,000 W. The weight of the ballast, which is one of important advantages, was reduced to one-fifth of conventional magnetic ballasts.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.14 no.2
• /
• pp.89-96
• /
• 2000

This paper describes the forward type pulse power supply which is the simple circuit configuration and easy to be managed using a power semiconductor switching device(Power-MOSFET) in the view of commercialization. The maximum value of output pulse voltage of the proposed pulse power supply system can be realized by the variation of phase angle($\phi$) of bridge rectifier circuit and also its pulse period is determined by the duty ratio of Power-MOSFET. The principle of basic operating and the operating characteristics of the forward type pulse power supply are estimated by the switching frequency, the variation of phase angle($\phi$)It is shown that theoretical and experimental results are in good agreement by comparing simulation and experimental results of proposed pulse power supply when a lamp type ozonizer can be used as a load. This proposed pulse power system shows that it can be practically used in the future as a power source system in various fields.