• Proceedings of the IEEK Conference
• /
• 2000.11b
• /
• pp.241-244
• /
• 2000

To investigate the compact effect of the different area of an active layer and the different type of heatsink on the junction to ambient transient thermal impedance, we have characterized the thermal behavior of power MOSFETs that have three different areas of an active layer and two types of heatsink. To do so, the "cooling curve method" has been used in order to measure the junction-to-ambient transient thermal impedance Zthja that represents the thermal behavior of the devices. The measured data depiets that the larger area of an active layer gives the better-in other words. smaller-thermal impedance, and that the larger size of a heatsink improves the thermal impedance.

• Journal of Power Electronics
• /
• v.16 no.1
• /
• pp.374-387
• /
• 2016

This paper derives an improved analytical model to estimate switching loss and analyze the effects of parasitic elements on the switching performance of SiC MOSFETs. The proposed analytical model considers the parasitic inductances, the nonlinearity of the junction capacitances and the nonlinearity of the trans-conductance. The turn-on process and the turn-off process are illustrated in detail, and equivalent circuits are derived and solved for each switching transition. The proposed analytical model is more accurate and matches better with experimental results than other analytical models. Note that switching losses calculated based on experiments are imprecise, because the energy of the junction capacitances is not properly disposed. Finally, the proposed analytical model is utilized to account for the effects of parasitic elements on the switching performance of a SiC MOSFET, and the circuit design rules for high frequency circuits are given.

• Journal of Electrical Engineering and Technology
• /
• v.11 no.5
• /
• pp.1179-1189
• /
• 2016

• Proceedings of the KIPE Conference
• /
• 2006.06a
• /
• pp.71-74
• /
• 2006

A new multi-output LLC resonant converter is proposed for high efficiency and low cost plasma display panel (PDP) power module. In the proposed converter, zero-voltage (ZV) turn-on of the primary MOSFETs and zero-voltage (ZC) turn-on and turn-off of the secondary diodes are guaranteed in the overall input voltage and output load ranges. In addition, the primary MOSFETs and the secondary diodes have the low voltage stresses clamped to input and the output voltages, respectively. Therefore, the proposed converter shows the high efficiency due to the minimized switching and conduction losses. Moreover, by employing the transformer with multiple secondary windings, the proposed converter can have multiple outputs, which show the great crossregulation characteristics. Therefore, the proposed converter is suitable for high efficiency and low cost PDP power module.

• Proceedings of the KIEE Conference
• /
• 1999.07e
• /
• pp.2035-2037
• /
• 1999

This paper describes an ASM(All Solid-state Modulator) pulsed power generator for non-thermal plasma applications. The proposed generator can produce 20kV, 500A, 100ns pulses at repetition rates up to 10kHz, and it is composed of 30 series connections of power circuit card assembly which contains paralleled MOSFETs, MOSFET drivers, energy storage capacitors and specially designed 1:1 pulse transformer. Higher pulse voltages and currents can easily be obtained by increasing the numbers of series and parallel connections of power circuit card and MOSFETs, respectively. Component layouts are optimized to minimize the leakage inductance and the voltage spikes across switching devices. Especially it put emphasis on the over-current protection (including short circuit) for the reliable operation in real situations. Experimental results show that the proposed pulser is very efficient in air pollution control application and could be useful for other applications such as synthesis of nanosize powders and non-thermal food processing.

• Journal of Electrical Engineering and information Science
• /
• v.3 no.3
• /
• pp.366-372
• /
• 1998

A high efficiency interleaved active clamp forward converter with self driven synchronous rectifiers for a modular power processor is presented. To simplify the gate drive circuits, N-P MOSFETs coupled active clamp method is used. An efficiency about 90% for the load range of 50-100% is achieved. The details of design for the power stage and current mode control circuit are provided, and also some experimental results are given.

• Proceedings of the KIPE Conference
• /
• 2014.11a
• /
• pp.193-194
• /
• 2014

This paper compares physical characteristic of MOSFET based on Si and SiC to achieve high efficiency in converters using MOSFETs which are typical switching elements. Also, it compares a result to compare operating efficiency when DC/DC converter is switching with each element.

• Journal of Power Electronics
• /
• v.16 no.1
• /
• pp.84-92
• /
• 2016

Compared with Si MOSFETs, the GaN FET has many advantages in a wide band gap, high saturation drift velocity, high critical breakdown field, etc. This paper compares the electrical properties of GaN FETs and Si MOSFETs. The soft-switching condition and power loss analysis in a flyback-forward high gain DC/DC converter with a GaN FET is presented in detail. In addition, a comparison between GaN diodes and Si diodes is made. Finally, a 200W GaN FET based flyback-forward high gain DC/DC converter is established, and experimental results verify that the GaN FET is superior to the Si MOSFET in terms of switching characteristics and efficiency. They also show that the GaN diode is better than the Si diode when it comes to reverse recovery characteristics.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.150-151
• /
• 2006

$Si_{0.88}Ge_{0.12}$/Si heterostructure channels grown by RPCVD were employed to n-type metal oxide semiconductor field effect transistors(MOSFETs), and their electrical properties were investigated. SiGe nMOSFETs presented very high transconductance compared to conventional Si-bulk MOSFETs, regardless substantial drawbacks remaining in subthreshold-slope, $I_{off}$, and leakage current level. It looks worthwhile to utilize excellent transconductance properties into rf applications requesting high speed and amplification capability, although optimization works on both device structure and unit processes are necessary for enhanced isolation and reduced power dissipation.

• Journal of the Korean Vacuum Society
• /
• v.17 no.3
• /
• pp.199-203
• /
• 2008

The effects of surface treatment by $O_2$ plasma on the Bio-FETs were investigated by using the pseudo-MOSFETs on the SOI substrates. After a surface treatment by $O_2$ plasma with different RF powers, the current-voltage and field effect mobility of pseudo-MOSFETs were measured by applying back gate bias. The subthreshold characteristics of pseudo-MOSFETs were significantly degraded with increase of RF power. Additionally, a forming gas anneal process in 2 % diluted $H_2/N_2$ ambient was developed to recover the plasma process induced surface damages. A considerable improvement of the subthreshold characteristics was achieved by the forming gas anneal. Therefore, it is concluded that the pseudo-MOSFETs are a powerful tool for monitoring the surface treatment of Bio-FETs and the forming gas anneal process is effective for improving the electrical characteristics of Bio-FETs.