YIG-tuned Oscillator Design on Printed Circuit Board using Surface Mount Technology

Author(s):  
Amir Effendy Muhammad Afifi
Manufacturing ◽  
2002 ◽  
Author(s):  
J. Cecil ◽  
A. Kanchanapiboon

This paper presents a framework for supporting virtual prototyping related activities in the domain of printed circuit board (PCB) assembly. The focus of discussion is restricted to Surface Mount Technology (SMT) based processes only. In general, Virtual Prototyping enables the conceptualization, evaluation and validation of proposed ideas, plans and solutions. Using a virtual prototyping framework, cross functional evaluation and analysis can be facilitated where designers, manufacturing engineers, testing and other life-cycle team members can communicate effectively as well as identify and eliminate problems, which may arise later in the downstream manufacturing and testing activities.


Author(s):  
Gerald Weis

Increasing efficiency in power electronic circuits requires innovative cooling concepts and a low impedance connection in the power path as well as low inductance driving circuits placed as close as possible to the main power switches. A direct comparison between state-of-the-art standard surface-mount build-ups and power switches embedded directly into the printed circuit board shows the high potential of integrated electronics. Measurements at defined operating point(s) verify improved thermal performance due to more heat spreading area, as well as higher achievable switching speed. For performance benchmarking two similar versions of half bridge circuits in DC-DC buck configuration were built to be compared in measurement. The first configuration uses standard, state-of-the-art SMD packages assembled onto the module. For the second half bridge module an embedded power path was used: The power transistors (GaN HEMT devices) are mounted inside the printed circuit board (PCB) and galvanically isolated from the heat sink pad on top of the package. Both versions use exactly the same schematic, layer stack-up and copper structure on the six layers used. A slightly different laser drill configuration was necessary because embedded parts are connected by copper filled laser drill holes. This measure was taken to optimize the modules according to their technology. Each module has an NTC thermistor mounted at the same distance to the half bridge transistors, and is used to indicate the temperature of the transistor dies during measurement. To cover a wide range of operational conditions the devices under test (DUTs) were stressed under hard switching operation (HSW) as well as triangular current mode (TCM). HSW causes more stress because the opposite transistor is switched before the whole energy of Coss has been discharged. In TCM the current through the inductor is becoming negative for a short time period and discharges the Coss capacitors of the power transistors. The test conditions were set as follows: 150V, 11A with 200kHz switching frequency in HSW mode. The switching behavior is similar, because both modules uses the same power transistors. Due to less parasitic impedance at the embedded module the turn-on behavior is slightly improved at the embedded module. Embedding as a new, innovative concept is compared to standard technologies. First measurements show that the embedded DUT stays 20K below the temperature of the standard module while running at the same load current. Additionally fewer disturbances were observed at the embedded module.


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