Current Issue : October - December Volume : 2014 Issue Number : 4 Articles : 4 Articles
Capacitive leakage current is one of the most important issues for transformerless photovoltaic systems. In order to deal with\nthe capacitive leakage current, a new power electronic inverter circuit is proposed in this paper. The inverter circuit consists of\nsix switches and operates with constant common mode voltage. Theoretical analysis is conducted to clarify the circuit operation\nprinciple and the common mode characteristic. The performance evaluation test is carried out, and test results demonstrate that\nthe capacitive leakage current can be significantly minimized with the proposed power electronic inverter circuit....
In wireless energy transfer systems, the energy is transferred from a power source to an electrical load without the need of physical\nconnections. In this scope, inductive links have been widely studied as a way of implementing these systems. Although high\nefficiency can be achieved when the system is operating in a static state, it can drastically decrease if changes in the relative position\nand in the coupling coefficient between the coils occur. In this paper, we analyze the coupling coefficient as a function of the distance\nbetween two planar and coaxial coils in wireless energy transfer systems. A simple equation is derived from Neumann�s equation\nfor mutual inductance, which is then used to calculate the coupling coefficient. The coupling coefficient is computed using CST\nMicrowave Studio and compared to calculation and experimental results for two coils with an excitation signal of up to 10MHz.\nThe results showed that the equation presents good accuracy for geometric parameters that do not lead the solution of the elliptic\nintegral of the first kind to infinity....
A broadband linear-in-dB variable-gain amplifier (VGA) circuit is implemented in 0.18 ????m SiGe BiCMOS process. The VGA\ncomprises two cascaded variable-gain core, in which a hybrid current-steering current gain cell is inserted in the Cherry-Hooper\namplifier to maintain a broad bandwidth while covering a wide gain range. Postlayout simulation results confirmthat the proposed\ncircuit achieves a 2GHz 3-dB bandwidth with wide linear-in-dB gain tuning range from ?19 dB up to 61 dB.The amplifier offers a\ncompetitive gain bandwidth product of 2805GHz at the maximum gain for a 110-GHz f???? BiCMOS technology. The amplifier core\nconsumes 31mWfrom a 3.3V supply and occupies active area of 280 ????m by 140????m....
The respective transfer characteristics of the ultrathin body (UTB) and gate recessed channel (GRC) device, sharing same W/L\nratio but having a channel thickness of 46 nm, and 2.2nm respectively, were measured at 300K and at 77K. By decreasing the\ntemperature we found that the electrical behaviors of these devices were radically opposite: if for UTB device, the conductivity was\nincreased, the opposite effect was observed for GRC. The low field electron mobility and series resistance RSD values were extracted\nusing a method based on Y-function for both the temperatures. If RSD low values were found for UTB, very high values (>1M?)\nwere extracted for GRC. Surprisingly, for the last device, the effective field mobility is found very low (<1 cm2/Vs) and is decreasing\nby lowering the temperature. After having discussed the limits of this analysis.This case study illustrates the advantage of the Yanalysis\nin discriminating a parameter of great relevance for nanoscale devices and gives a coherent interpretation of an anomalous\nelectrical behavior....
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