scholarly journals A Unified Switch Loss Model and Design Consideration for Multilevel Boost PFC With GaN Devices

2021 ◽  
Vol 6 (4) ◽  
pp. 349-358
Author(s):  
Jiawen Wu ◽  

Recently, multilevel converters with gallium nitride (GaN) devices have shown marvelous advantages for power factor correction (PFC) conversion to meet the increasingly higher efficiency and power density requirements. In the traditional design process for the multilevel PFC converter, it is necessary to separately optimize the devices of the corresponding breakdown voltage under different level number, which causes difficulty to the overall optimization of the entire system. In this paper, a unified minimum loss model for GaN switches regardless of voltage levels is proposed to optimize the efficiency based on device’s new figure-of-merit (NFoM) (NFoM = COSS(ER) RDS(on)). With the help of this unified minimum loss model, it simplifies the efficiency optimizing methodology according to the NFoMs of GaN devices for multilevel PFC converter. According to the methodology, a 2 kW cascaded H-bridge (CHB) PFC prototype is constructed to verify the design methodology, achieving over 99% efficiency with power density over 1000 W/in3 .

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4955
Author(s):  
Mohamed Y. Elsayed ◽  
Sherif M. Sherif ◽  
Amina S. Aljaber ◽  
Mohamed A. Swillam

Waveguides with sub-100 nm thickness offer a promising platform for sensors. We designed and analyzed multimode interference (MMI) devices using these ultrathin platforms for use as biosensors. To verify our design methodology, we compared the measured and simulated spectra of fabricated 220-nm-thick MMI devices. Designs of the MMI biosensors based on the sub-100 nm platforms have been optimized using finite difference time domain simulations. At a length of 4 mm, the 50-nm-thick MMI sensor provides a sensitivity of roughly 420 nm/RIU and with a figure of merit (FOM) definition of sensitivity/full-width-at-half-maximum, the FOM is 133. On the other hand, using a thickness of 70 nm results in a more compact design—only 2.4 mm length was required to achieve a similar FOM, 134, with a sensitivity of 330 nm/RIU. The limits of detection (LOD) were calculated to be 7.1 × 10−6 RIU and 8.6 × 10−6 RIU for the 50 nm and the 70-nm-thick sensor, respectively. The LOD for glucose sensing was calculated to be less than 10 mg dL−1 making it useful for detecting glucose in the diabetic range. The biosensor is also predicted to be able to detect layers of protein, such as biotin-streptavidin as thin as 1 nm. The ultrathin SOI waveguide platform is promising in biosensing applications using this simple MMI structure.


Circuit World ◽  
2019 ◽  
Vol 45 (3) ◽  
pp. 156-168 ◽  
Author(s):  
Yavar Safaei Mehrabani ◽  
Mehdi Bagherizadeh ◽  
Mohammad Hossein Shafiabadi ◽  
Abolghasem Ghasempour

Purpose This paper aims to present an inexact 4:2 compressor cell using carbon nanotube filed effect transistors (CNFETs). Design/methodology/approach To design this cell, the capacitive threshold logic (CTL) has been used. Findings To evaluate the proposed cell, comprehensive simulations are carried out at two levels of the circuit and image processing. At the circuit level, the HSPICE software has been used and the power consumption, delay, and power-delay product are calculated. Also, the power-delaytransistor count product (PDAP) is used to make a compromise between all metrics. On the other hand, the Monte Carlo analysis has been used to scrutinize the robustness of the proposed cell against the variations in the manufacturing process. The results of simulations at this level of abstraction indicate the superiority of the proposed cell to other circuits. At the application level, the MATLAB software is also used to evaluate the peak signal-to-noise ratio (PSNR) figure of merit. At this level, the two primary images are multiplied by a multiplier circuit consisting of 4:2 compressors. The results of this simulation also show the superiority of the proposed cell to others. Originality/value This cell significantly reduces the number of transistors and only consists of NOT gates.


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