Design Methodology of Small Signal Power Amplifier using Linear S-parameter Model

This paper illustrates the linear design procedure and simulation of small signal power amplifier at frequency of 900 MHz based on an RF MOSFET device of type RD45HMF1 [15] fromMISTUSHIBUSHI. The linear S-Parameter model of this device is used in Agilent ADS to design the power stage includingthe stability analysis,complex conjugate matching and design of source and load matching networks. The linear model is specifically required to achieve the desired gain with better input and output return losses.The matching network is then designed to achieve specified performance figures.It is hoped that the understanding gained through the work will be useful in futureSSPA developments

Radiation and Temperature Hard Multi-Pixel Avalanche Photodiodes

The structure and method of fabricating a radiation and temperature hard avalanche photodiode with integrated radiation and temperature hard readout circuit, comprising a substrate, an avalanche region, an absorption region, and a plurality of Ohmic contacts are presented. The present disclosure provides for tuning of spectral sensitivity and high device efficiency, resulting in photon counting capability with decreased crosstalk and reduced dark current

Design and construction of a half-bridge using wide-bandgap transistors

A continuously increasing demand of electric power makes energy efficiency imperative in modern technology. The transistor is considered as the fundamental element of modern electronic products

Electro-Thermal Effects of Power Transistors on Converter Performance

In this work, a comparative study of the electrical and thermal performance of a silicon carbide (SiC) MOSFET and a silicon (Si) IGBT power transistor, operating in a DC/DC boost converter, is presented. Behavioral models of Powerex Inc. switching transistors were developed in Synopsys SaberRD and used to predict the converter electrical efficiency; ANSYS Icepak modeling software was used for thermal simulations to identify potential hot spots. This work provides an overall, electro-thermal analysis of both transistor types with respect to switching frequency in the boost converter circuit. Optimal switching frequencies for each device at a given current are observed, and thermal performance of the SiC MOSFET is quantified with comparable or greater electrical efficiency to the Si IGBT. Our SiC MOSFET temperature measurements further validated published mathematical expressions, which help, in this study, to identify the best operating frequency with respect to electrical and thermal performance. Performance analysis and design considerations from the DC/DC converter were then applied to design a 2kW, high power density, gallium nitride (GaN) based, modular multilevel converter (M2C). Half-bridge submodules for a single-phase, low voltage, high power density inverter (450 VDC, 2 kW, < 40in3 volume) were designed, constructed, and analyzed. This power density is predicted through the utilization of the EPC2014C gallium nitride (GaN) transistor into the half-bridge submodules of the M2C. These submodules are configured in series and parallel, with a switching frequency of 24 kHz, to achieve the voltage and current requirements. Each arm of the M2C was designed onto a double-sided, 6-layer, printed circuit board (PCB). The design and fabrications for these power boards are discussed as well. The design, fabrication, and analysis of all three power conversion circuits presented here also include similar analysis for their gate drive circuits

High Density Power Conversion Electronics Enabled by GaN-Based Modular Topologies

This dissertation explores the use of modular multilevel converter (MMC) architectures, coupled with wide-bandgap semiconductors, to achieve high power-density in power electronics converters. At the converter level, the capabilities of the modular multilevel converter are investigated for their use in low voltage, low power, DC-DC and DC-AC applications. This investigation shows that the use of modular multilevel architectures enables low voltage Gallium Nitride high electron mobility transistors (GaN HEMTs) to be used in applications for which their voltage thresholds are not typically suited. This results in lightweight, compact, conversion systems. GaN HEMTs have been shown to provide a low loss, low volume alternative to Silicon transistors for power conversion, but require several enabling technologies to make them ideally suited to high-density converters. This work therefore presents two enabling technologies for GaN-based conversion circuits. First, a technique is developed that optimizes the gate resistance for driving GaN HEMTs in order to ensure safe, rapid device turn on. Next, the development of planar magnetic transformers is discussed, with a focus on high-frequency converter operation. For each of these technologies mathematical analysis, circuit simulation, and hardware development are performed and compared to ensure proper functionality. Taking advantage of those two enabling technologies, two converter architectures based on the MMC structure are developed. First, a DC-AC MMC is presented, taking advantage of GaN HEMTs and minimal filtering requirements to achieve high power density in low voltage systems. Next, that topology is extended and a novel DC-DC converter based on two coupled DC-AC MMCs is presented. Both systems are described mathematically, simulated, and developed as hardware prototypes to prove functionality. While both converter systems are relevant for applications in DC microgrids, the DC-AC converter will be specifically investigated for its application as a variable speed drive in naval power systems. Likewise, the DC-DC MMC will be shown to provide new solutions for high voltage spacecraft power systems. Based on the work presented in this dissertation, engineers will be presented with alternatives to traditional methods of achieving high density in power conversion systems. By coupling the low filtering requirements and low losses of the modular multilevel converter with low voltage, highly efficient GaN HEMTs, the presented converter systems achieve high power density and efficiency with minimal filtering requirements. The result of this work is two novel converter systems that will enable further research into lightweight, low volume, power conversion