scholarly journals Transient Simulation for the Thermal Design Optimization of Pulse Operated AlGaN/GaN HEMTs

Micromachines ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 76
Author(s):  
Huaixin Guo ◽  
Tangsheng Chen ◽  
Shang Shi

The thermal management and channel temperature evaluation of GaN power amplifiers are indispensable issues in engineering field. The transient thermal characteristics of pulse operated AlGaN/GaN high electron mobility transistors (HEMT) used in high power amplifiers are systematically investigated by using three-dimensional simulation with the finite element method. To improve the calculation accuracy, the nonlinear thermal conductivities and near-junction region of GaN chip are considered and treated appropriately in our numerical analysis. The periodic transient pulses temperature and temperature distribution are analyzed to estimate thermal response when GaN amplifiers are operating in pulsed mode with kilowatt-level power, and the relationships between channel temperatures and pulse width, gate structures, and power density of GaN device are analyzed. Results indicate that the maximal channel temperature and thermal impedance of device are considerably influenced by pulse width and power density effects, but the changes of gate fingers and gate width have no effect on channel temperature when the total gate width and active area are kept constant. Finally, the transient thermal response of GaN amplifier is measured using IR thermal photogrammetry, and the correctness and validation of the simulation model is verified. The study of transient simulation is demonstrated necessary for optimal designs of pulse-operated AlGaN/GaN HEMTs.

Author(s):  
Julia C. Huang ◽  
Niyati Pise ◽  
Deepak Ganapathy ◽  
Shushanth Prabhu ◽  
Ethan J. Warner

The ever increasing power dissipation requirements of electronic components and the need to provide reliable, cost-effective thermal solutions requires the thermal engineer to accurately understand the component’s thermal design power (TDP). The TDP is impacted not only by the power-performance characteristics of the component architecture, but also by the inherent thermal characteristics of the cooling solution. A suitable TDP definition thus requires a clear understanding of the transient thermal response (resistance and capacitance) of the cooling solution. In this paper, a simple electrical analogy impedance network model that resembles the component with cooling solution is developed. Correlation models to predict the resistance and capacitance for this impedance network are built based on easily available parameters such as heat sink mass, surface area, specific heat etc. The accuracies of these models are validated experimentally with data collected on a PCB with several different thermal solutions. Development of these correlation models eliminates the need for complex time consuming transient experiments to characterize the system thermal characteristics like capacitance, which allows faster, more realistic TDP definitions and ability to analyze multiple thermal designs quickly and accurately.


Author(s):  
John Mathew ◽  
Shankar Krishnan

Abstract Much effort in the area of electronics thermal management has focused on developing cooling solutions that cater to steady-state operation. However, electronic devices are increasingly being used in applications involving time-varying workloads. These include microprocessors (particularly those used in portable devices), power electronic devices such as IGBTs, and high-power semiconductor laser diode arrays. Transient thermal management solutions become essential to ensure the performance and reliability of such devices. In this review, emerging transient thermal management requirements are identified, and cooling solutions reported in the literature for such applications are presented with a focus on time scales of thermal response. Transient cooling techniques employing actively controlled two-phase microchannel heat sinks, phase change materials (PCM), heat pipes/vapor chambers, combined PCM-heat pipes/vapor chambers, and flash boiling systems are examined in detail. They are compared in terms of their thermal response times to ascertain their suitability for the thermal management of pulsed workloads associated with microprocessor chips, IGBTs, and high-power laser diode arrays. Thermal design guidelines for the selection of appropriate package level thermal resistance and capacitance combinations are also recommended.


2006 ◽  
Vol 129 (7) ◽  
pp. 790-797 ◽  
Author(s):  
Rodrigo A. Escobar ◽  
Cristina H. Amon

Lattice Boltzmann method (LBM) simulations of phonon transport are performed in one-dimensional (1D) and 2D computational models of a silicon-on-insulator transistor, in order to investigate its transient thermal response under Joule heating conditions, which cause a nonequilibrium region of high temperature known as a hotspot. Predictions from Fourier diffusion are compared to those from a gray LBM based on the Debye assumption, and from a dispersion LBM which incorporates nonlinear dispersion for all phonon branches, including explicit treatment of optical phonons without simplifying assumptions. The simulations cover the effects of hotspot size and heat pulse duration, considering a frequency-dependent heat source term. Results indicate that, for both models, a transition from a Fourier diffusion regime to a ballistic phonon transport regime occurs as the hotspot size is decreased to tens of nanometers. The transition is characterized by the appearance of boundary effects, as well as by the propagation of thermal energy in the form of multiple, superimposed phonon waves. Additionally, hotspot peak temperature levels predicted by the dispersion LBM are found to be higher than those from Fourier diffusion predictions, displaying a nonlinear relation to hotspot size, for a given, fixed, domain size.


Author(s):  
Anwar Jarndal ◽  
Pouya Aflaki ◽  
Louay Degachi ◽  
Ahmed Birafane ◽  
Ammar Kouki ◽  
...  

2011 ◽  
Vol 17 (5) ◽  
pp. 369-379 ◽  
Author(s):  
David Schick ◽  
Sudarsanam Suresh Babu ◽  
Daniel R. Foster ◽  
Marcelo Dapino ◽  
Matt Short ◽  
...  

Author(s):  
Jiashen Li ◽  
◽  
Yun Pan ◽  

The improvement of chip integration leads to the increase of power density of system chips, which leads to the overheating of system chips. When dispatching the power density of system chips, some working modules are selectively closed to avoid all modules on the chip being turned on at the same time and to solve the problem of overheating. Taking 2D grid-on-chip network as the research object, an optimal scheduling algorithm of system-on-chip power density based on network-on-chip (NoC) is proposed. Under the constraints of thermal design power (TDP) and system, dynamic programming algorithm is used to solve the optimal application set throughput allocation from bottom to top by dynamic programming for the number and frequency level of each application configuration processor under the given application set of network-on-chip. On this basis, the simulated annealing algorithm is used to complete the application mapping aiming at heat dissipation effect and communication delay. The open and closed processor layout is determined. After obtaining the layout results, the TDP is adjusted. The maximum TDP constraint is iteratively searched according to the feedback loop of the system over-hot spots, and the power density scheduling performance of the system chip is maximized under this constraint, so as to ensure the system core. At the same time, chip throughput can effectively solve the problem of chip overheating. The experimental results show that the proposed algorithm increases the system chip throughput by about 11%, improves the system throughput loss, and achieves a balance between the system chip power consumption and scheduling time.


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