scholarly journals A Survey on Microtransformers

2021 ◽  
Vol 16 (2) ◽  
pp. 1-12
Author(s):  
Fellype Nascimento ◽  
Antonio Carlos da Costa Telles ◽  
Ednan Joanni ◽  
Ricardo Cotrin Teixeira

The miniaturization of magnetic devices is a subject of enduring interest, since inductors and transformers of very small dimensions are constantly being required for integration into microchips and electrical circuit boards. The main objective of this survey is to supply a compilation of the published research on microtransformers, and to work as a support material, helping in the choice of the most appropriate technology and device configuration for a particular application. The text describes the historical development of microtransformers, the structures in which these devices might be assembled, the various proposed geometries, the fabrication processes, and the type of core used. A brief discussion of equivalent circuit modeling is presented. The current state of the technology in relation to commercial devices is then examined, pointing out some unsolved problems that warrant further studies.

Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 63
Author(s):  
Saima Hasan ◽  
Abbas Z. Kouzani ◽  
M A Parvez Mahmud

This paper presents a simple and comprehensive model of a dual-gate graphene field effect transistor (FET). The quantum capacitance and surface potential dependence on the top-gate-to-source voltage were studied for monolayer and bilayer graphene channel by using equivalent circuit modeling. Additionally, the closed-form analytical equations for the drain current and drain-to-source voltage dependence on the drain current were investigated. The distribution of drain current with voltages in three regions (triode, unipolar saturation, and ambipolar) was plotted. The modeling results exhibited better output characteristics, transfer function, and transconductance behavior for GFET compared to FETs. The transconductance estimation as a function of gate voltage for different drain-to-source voltages depicted a proportional relationship; however, with the increase of gate voltage this value tended to decline. In the case of transit frequency response, a decrease in channel length resulted in an increase in transit frequency. The threshold voltage dependence on back-gate-source voltage for different dielectrics demonstrated an inverse relationship between the two. The analytical expressions and their implementation through graphical representation for a bilayer graphene channel will be extended to a multilayer channel in the future to improve the device performance.


Author(s):  
Yilin Shang ◽  
Leipo Liu ◽  
Yifan Di ◽  
Zhumu Fu ◽  
Bo Fan

This paper considers the problem of guaranteed cost and finite-time event-triggered control of fractional-order switched systems. Firstly, an event-triggered scheme including both the information of current state and an exponential decay function is proposed, and a novel cost function that adopts the characteristics of fractional-order integration is presented. Secondly, some sufficient conditions are derived to guarantee that the corresponding closed-loop system is finite-time stable with a certain cost upper bound, using multiple Lyapunov functions and average dwell time approach. Meanwhile, the event-triggered parameters and state feedback gains are simultaneously obtained via solving linear matrix inequalities. Moreover, Zeno behavior does not exist by finding a positive lower bound of the triggered interval. Finally, an example about fractional-order switched electrical circuit is provided to show the effectiveness of the proposed method.


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