• Journal of the Microelectronics and Packaging Society
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• v.15 no.1
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• pp.39-44
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• 2008

In this paper, fully embedded 2.4GHz WLAN band pass filter (BPF) was investigated into a multi-layered organic packaging substrate using high Q spiral stacked inductors and high Dk MIM capacitors for low cost RF System on Package (SOP) applications. The proposed 2.4GHz WLAN BPF was designed by modifying chebyshev second order filter circuit topology. It was comprised of two parallel LC resonators for obtaining two transmission zeros. It was designed by using 2D circuit and 3D EM simulators for finding out optimal geometries and verifying their applicability. It exhibited an insertion loss of max -1.7dB and return loss of min -l7dB. The two transmission zeros were observed at 1.85 and 6.7GHz, respectively. In the low frequency band of $1.8GHz{\sim}1.9GHz$, the stop band suppression of min -23dB was achieved. In the high frequency band of $4.1GHz{\sim}5.4GHz$, the stop band suppression of min -l8dB was obtained. It was the first embedded and the smallest one of the filters formed into the organic packaging substrate. It has a size of $2.2{\times}1.8{\times}0.77mm^3$.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.7
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• pp.343-351
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• 2003

In this paper, interleaved boost converter is applied as a first-stage converter in switch mode power supply. The first-stage converter plays a role to improve power factor. Interleaved Boost Power Factor Corrector(IBPFC) can reduce input current ripple as a single voltage control loop only without inner current loop, because input current is divided each 50% by two switching devices. Each converter cell is also operated in discontinuous current mode and inductor current of each converter is discontinuous. Total input current which is composed by each converter cell is continuous current. Thus, IBPFC is able to improve input current ripple. IBPFC operating in discontinuous current mode can be classified as six modes from switching state and be carried out state space averaging small signal modeling. A control transfer function is obtained according to the modeling. Not only steady-state characteristics but also dynamic characteristics is considered. Single voltage control loop is also constructed by the control transfer function. From experimental result, improvement of power factor and input current ripple are verified.

• ETRI Journal
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• v.35 no.3
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• pp.554-557
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• 2013

This letter presents a power amplifier (PA) with an on-chip power detector for 2.4-GHz wireless local area network application. The power detector consists of a clamp circuit, a diode detector, and a coupled line directional coupler. A series inductor for an output matching network in the PA is combined with a through line of the coupler, which reduces the coupling level. Therefore, the coupler employs a metamaterial-based transformer configuration to increase coupling. The amount of coupling is increased by 2.5 dB in the 1:1 symmetric transformer structure and by 4.5 dB from two metamaterial units along the coupled line.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.75-76
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• 2016

This paper proposes a power factor correction circuit with a high efficiency over a wide load range characteristics for a communication power supply. And the characteristic verification is applied to produce a design of prototype. Power factor correction circuit can reduce conduction losses by applying Bridgeless Boost Converter for efficiency. Over a wide load range to maintain the efficient, the control method of a PWM controller is divided by two sections according to the load area. In the low-load region, it was reduced switching losses by applying the critical conduction mode control method. On the other hand, in the heavy-load area, the hysteresis current control method is used to maintain the high efficiency over a wide load range by limiting the peak noise of the inductor.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.156-159
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• 1991

At LCCSI system, output capacitor of inverter and inductor of load motor raise mutuality operation. This parallel resonant increase equivalent impedance of inverter load and give wrong effect at LCCSI system. This paper carried out resonant analysis of LCCSI system. The result of analysis, particular resonant point of two was discovered that a resonant of S=0 vicinity and $\beta$ resonant of S=1 vicinity. In addition to, the case of harmonics resonant not come from $\alpha$ resonant but come from $\beta$ resonant. A moment of working of LCCSI system, resonant line must not suddenly variation. Accordingly, resonant line is a necessity for doing $f{\alpha}$ vicinity by properly capacitor value selection.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2020-2022
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• 1997

An active clamp forward converter is proper for minimization and basically makes high efficiency of the system because of soft switching type. Especially, when applied to forward converter, it widens the control range of duty ratio and is suitable for high input voltage. In other hand, the current doubler has high utility efficiency of transformer and reduces output current ripple because it always transfers the power through the transformer and has two inductor with opposite slope. So, this paper explained the conduction mode of an active clamp forward converter with the current doubler rectifier.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.423-426
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• 2007

An active Balun is designed for RFID reader at 2.45GHz. The Balun is integrated inside the receiver, then the LNA and mixer can be connected. The unbalanced LNA output signal is transformed to a balanced signal at the input mixer The RF mixer and LO mixer, by using this balun. The Balun provided a balanced signal with two output stage, gain mismatch is 0.116dB. The phase show a good behavior with $163.918^{\circ}$,$-16.609^{\circ}$. The phase mismatch is about $0.527^{\circ}$. The tight difference between the gain and phase on each brancd, is because of the used capacitor and integrated inductor and the other parasitic element inside the balun.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.155-157
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• 2009

This paper proposed a soft switching boost converter with an auxiliary circuit, and a modified control method for reduction of switch stress. The proposed converter applies an auxiliary circuit, which is added to the conventional boost converter and used to achieve soft switching for both a main switch and an auxiliary switch. The auxiliary circuit consist of a resonant inductor and two capacitors, an auxiliary switch. The main switch is operated ZVS turn-on, turn-off also auxiliary switch is operated ZCS turn-on, ZVS turn-off. The proposed soft switching boost converter has lower switch loss and higher efficiency than conventional soft switching boost converter.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.963_964
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• 2009

This paper presents an output ripple reduction of Active-Clamp Forward Converter, which is mainly composed of interleaving two active-clamping forward converters. By interleaving, Output ripple is reduced. The leakage inductance of the transformer or an additional resonant inductance is employed to achieve ZVS during the dead times. The duty cycles are not limited to be equal and within 50%. The complementary switching and the resulted interleaved output inductor currents diminish the current ripple in output capacitors. Accordingly, the smaller output chokes and capacitors lower the converter volume and increase the power density. Detailed analysis of this ouput reduction of Active-Clamp Forward Converter is described.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.961_962
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• 2009

A novel, two-inductor, interleaved power-factor-corrected (PFC) boost converter that exhibits voltage-doubler characteristic when it operates with a duty cycle greater than 0.5 is introduced. The voltage-doubler characteristic of the proposed converter makes it quite suitable for universal-line (90~265VRMS) PFC applications. Because the proposed PFC boost rectifier operates as a voltage doubler at low line, its low-line range efficiency is greatly improved compared to that of its conventional counterpart. The performance of the proposed PFC rectifier was evaluated on an experimental 300W PFC prototype.