Analysis of the noise and efficiency characteristics in a quasi-resonant converter
A quasi-resonant converter using flyback topology can realize soft switching with relatively simple circuit. However, a switching device with high withstand voltage is necessary to achieve complete zero voltage switching when the input voltage is high and it causes decrease of efficiency because a switching device with high withstand voltage has relatively high on voltage. Therefore, we analyzed efficiency and noise of a quasi-resonant converter with a low breakdown voltage and low on voltage switching device under the condition of non-zero voltage switching. As a result of the analysis, it is found that high efficiency and low noise are achieved with non-zero voltage switching.
Analysis of the Radiation Noise and Efficiency Characteristics in a Quasi-resonant Converter
In this paper, the radiation noise and efficiency of the quasi-resonant converter are analyzed. A quasiresonant converter using the flyback topology can realize the soft switching with simpler circuit. However, switching devices with the high withstand voltage is necessary to achieve the complete ZVS and it causes the low power efficiency because a switching device with the high withstand voltage has the high on-voltage. On the other hand, the swithching device with the low withstand voltage and then the low on-resistance can be used with the non-ZVS. Therefore the performance characteristics such as the efficiency and radiation noise are analyzed on the quasiresonant converter with the ZVS and the non-ZVS. As a result, it is clarified that the low radiation noise and high power efficiency are achieved with the non-ZVS.
Selective etching of InP in NaF solution
Abstract The crossing porous structure of InP has been obtained by electrochemical etching in NaF solutions. The behavior of the periodic oscillation occurs at different potential ranges for the different concentrations of solutions, and it will disappear with the concentration of the solution decreased. The scanning electron microscope (SEM) image shows that the pores have two directions on the surface and are perpendicular to each other. The two directions are assigned to [0 1 1] and [ 0 1 ¯ 1 ], respectively. The SEM image of the cross-section also shows that the two directions are assigned to [1 1 1]B and [ 1 1 ¯ 1 ¯ ]B. Both are due to the selective etching of F− ions. The crossing porous structure of InP is a very promising feature for the three-dimensional structure of III–V compound semiconductors for photonic band gap materials.