A System to Package Perspective on Transient Thermal Management of Electronics

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
H. Peter de Bock ◽  
David Huitink ◽  
Patrick Shamberger ◽  
James Spencer Lundh ◽  
Sukwon Choi ◽  
...  
Keyword(s):  
Steady State ◽  
Thermal Management ◽  
Thermal Design ◽  
System Level ◽  
Control Mechanisms ◽  
Thermal Loads ◽  
Chip Surface ◽  
Wide Range ◽  
Transient Thermal ◽  
The Way

Abstract There are many applications throughout the military and commercial industries whose thermal profiles are dominated by intermittent and/or periodic pulsed thermal loads. Typical thermal solutions for transient applications focus on providing sufficient continuous cooling to address the peak thermal loads as if operating under steady-state conditions. Such a conservative approach guarantees satisfying the thermal challenge but can result in significant cooling overdesign, thus increasing the size, weight, and cost of the system. Confluent trends of increasing system complexity, component miniaturization, and increasing power density demands are further exacerbating the divergence of the optimal transient and steady-state solutions. Therefore, there needs to be a fundamental shift in the way thermal and packaging engineers approach design to focus on time domain heat transfer design and solutions. Due to the application-dependent nature of transient thermal solutions, it is essential to use a codesign approach such that the thermal and packaging engineers collaborate during the design phase with application and/or electronics engineers to ensure the solution meets the requirements. This paper will provide an overview of the types of transients to consider—from the transients that occur during switching at the chip surface all the way to the system-level transients which transfer heat to air. The paper will cover numerous ways of managing transient heat including phase change materials (PCMs), heat exchangers, advanced controls, and capacitance-based packaging. Moreover, synergies exist between approaches to include application of PCMs to increase thermal capacitance or active control mechanisms that are adapted and optimized for the time constants and needs of the specific application. It is the intent of this transient thermal management review to describe a wide range of areas in which transient thermal management for electronics is a factor of significance and to illustrate which specific implementations of transient thermal solutions are being explored for each area. The paper focuses on the needs and benefits of fundamentally shifting away from a steady-state thermal design mentality to one focused on transient thermal design through application-specific, codesigned approaches.

A Simple Thermal Model of Bearings With Transient Effects

2010 ◽  
Author(s):  
Karleine M. Justice ◽  
Ian Halliwell ◽  
Jeffrey S. Dalton
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Thermal Management ◽  
Heat Load ◽  
Transient Behavior ◽  
Gas Turbine Engine ◽  
System Level ◽  
Lubrication System ◽  
Transient Effects ◽  
Turbine Engine

In thermal management, system-level models provide an understanding of interactions between components and integration constraints — issues which are exacerbated by tighter coupling in both real life and simulation. A simple model of the steady-state thermal characteristics of the bearings in a two-spool turbofan engine has been described in previous work [1], where it was compared with a more comprehensive tribology-based simulation. Since failure is more likely to occur during transient rather than steady-state operating conditions, it is important that transient behavior is also studied. Therefore, development of models capable of capturing transient system-level performance in air vehicles is critical. In the current paper, the former simple model is used for the generation of a method to replicate the transient effects of heat loads within the lubrication system of a gas turbine engine. The simple engine model that defined the lubrication system is representative of a twin-spool, mid-size, high bypass ratio turbofan used in commercial transport. In order to demonstrate the range and versatility of the parametric heat load model, the model is now applied to the transient operation of a low-thrust unmanned aerial vehicle (UAV) engine, similar to that found on the Global Hawk. There are five separate bearings in the oil loop model and four separate oil sump locations. Contributions to the heat load calculations are heat transfer through the bearing housings and friction caused by station temperatures and shaft speeds, respectively. The lubrication system has been simplified by applying general assumptions for a proof-of-concept of the new transient parametric model. The fuel flow rate for the fuel-cooled oil cooler (FCOC) is set via the full authority digital electronic control (FADEC) in the transient engine model which is coupled to the parametric heat load model. Initially, it is assumed that total heat transfer from the bearings to the oil correspond to oil temperature changes of 150–250°F (83–139°C). The results show that successful modeling of the transient behavior on the thermal effects in the bearings of a gas turbine engine using the MATLAB/Simulink environment have been achieved. This is a valuable addition to the previous steady-state simulation, and the combined tools may be used as part of a more sophisticated thermal management system. Because it is so simple and scalable, the tool enables thermal management issues to be addressed in the preliminary design phase of a gas turbine engine development program.

scholarly journals A Review On Transient Thermal Management of Electronic Devices

2021 ◽  
Author(s):  
John Mathew ◽  
Shankar Krishnan
Keyword(s):  
Thermal Management ◽  
Laser Diode ◽  
High Power ◽  
Electronic Devices ◽  
Thermal Response ◽  
Heat Pipes ◽  
Design Guidelines ◽  
Thermal Design ◽  
Laser Diode Arrays ◽  
Transient Thermal

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.

Challenges in Energy Efficient Thermal Management

2003 ◽  
Author(s):  
Kazuaki Yazawa
Keyword(s):  
Thermal Management ◽  
Energy Efficient ◽  
Minimum Energy ◽  
Thermal Design ◽  
System Level ◽  
Total System ◽  
Efficient Design ◽  
Transient Phenomena ◽  
The Impact ◽  
Extended Review

For a surveillance of energy efficient thermal management, an extended review of literatures has been done. Covered cooling technologies are intended for or supposed to relate to energy efficient design. Individual technologies are categorized with the discussion of advantage/disadvantages. In addition, the impact such as volume and mass of total system design is discussed. A universal criterion of metric to measure the effectiveness of optimization for minimum energy input is proposed. Extensive review of the supposed relevant technologies gives the idea that each model could be used for energy efficient thermal design. On the other hand, it has been found that the lack of system level modeling as well as the considerations of transient phenomena is not enough. Since these are essential, it should be the challenge toward the future of environmental friendly thermal designs.

System Level Transient Thermal Performance of High-Power Dynamic Microelectronics

2009 ◽  
Author(s):  
Victor Chiriac
Keyword(s):  
Steady State ◽  
High Power ◽  
Superposition Principle ◽  
Peak Temperature ◽  
System Level ◽  
Final Temperature ◽  
Thermal Budget ◽  
Power Dynamic ◽  
Current Limit ◽  
Transient Thermal

System-level thermal transient analysis of High-Power Dynamic Microelectronics System is performed using numerical simulations. The SmartMOS-type device is packaged in 20 lead SOIC module with exposed copper slug. The package is attached to 4-layer PCB with embedded thermal vias. The challenge resides in the transient thermal interaction between the dynamic heat sources (high/low side motors), activated simultaneously at different powering profiles. Several operating steps are simulated, and the transient thermal behavior for each source is analyzed then optimized during the process. The low side motor reaches a peak temperature of ∼126.1°C at 2.25s, while the final temperature reached by the motor after one cycle (2.565 s) is ∼75.9°C. The DC current limit study indicates that the current over 1A exceeds the thermal budget. The case with 0.5A current limit reaches 135°C after 4 cycles, satisfying the thermal budget. Additional studies for an equivalent system were performed with only the high side driver actively dissipating 120W for 2.56 ms. The peak temperature reached by the system during the first cycle (2.56 us) is ∼65°C. Analytical study was performed to evaluate the steady state (final) temperature after a large number of dynamic powering cycles, based on heating/cooling behavior and superposition principle. The peak temperature reached by the IC will not exceed 92°C (using the steady state value and the temperature fluctuations per transient cycle). A correlation to predict the peak temperatures reached by the dynamic system after a long number of powering cycles is provided.

A Model Predictive Framework for Thermal Management of Aircraft

2015 ◽  
Author(s):  
Timothy O. Deppen ◽  
Joel E. Hey ◽  
Andrew G. Alleyne ◽  
Timothy S. Fisher
Keyword(s):  
Thermal Management ◽  
High Performance ◽  
Heat Dissipation ◽  
Electrical Power ◽  
Electrical Equipment ◽  
Thermal Loads ◽  
Case Scenario ◽  
Worst Case ◽  
Order Of Magnitude ◽  
Transient Thermal

The challenge of managing heat dissipation and enforcing operational constraints on temperature within a high-performance tactical aircraft is considered. For these systems, power density of the electrical equipment and the associated thermal loads are quickly outpacing the means of conventional thermal management systems (TMS) to provide on-demand cooling and in order to prevent thermal run away. The next generation of tactical aircraft is projected to include an order of magnitude greater thermal and electrical power magnitudes, and the time scale over which thermal loads will change is expected to shrink. To meet this rapidly evolving challenge, designing a TMS for the “worst case” scenario based on a steady-state thermal analysis will be infeasible. Rather, a holistic systems perspective is needed with new control methodologies that capture and even exploit the transient thermal behavior. To this end, a model predictive control strategy is presented that utilizes preview of upcoming loads and disturbances to prevent violation of temperature constraints. A simulation case study demonstrates that the predictive thermal controller can dramatically reduce constraint violations while reducing the work required by the TMS when compared to a cascaded PI feedback controller.

scholarly journals Stochastic steady state gain in a gene expression process with mRNA degradation control

2012 ◽  
Vol 9 (72) ◽  
pp. 1589-1598 ◽  
Author(s):  
Hiroyuki Kuwahara ◽  
Russell Schwartz
Keyword(s):  
Gene Expression ◽  
Transcriptional Regulation ◽  
Steady State ◽  
Protein Level ◽  
Mrna Level ◽  
System Level ◽  
Wide Range ◽  
Molecular Reactions ◽  
Transcriptional Bursting ◽  
Regulation Model

Recent analyses with high-resolution single-molecule experimental methods have shown highly irregular and variable bursting of mRNA in a wide range of organisms. Noise in gene expression is thought to be beneficial in cell fate specifications, as it can lay a foundation for phenotypic diversification of isogenetic cells in the homogeneous environment. However, because the stability of proteins is, in many cases, higher than that of mRNAs, noise from transcriptional bursting can be considerably buffered at the protein level, limiting the effect of noisy mRNAs at a more global regulation level. This raises a question as to what constructive role noisy mRNAs can play in the system-level dynamics. In this study, we have addressed this question using the computational models that extend the conventional transcriptional bursting model with a post-transcriptional regulation step. Surprisingly, by comparing this stochastic model with the corresponding deterministic model, we find that intrinsic fluctuations can substantially increase the expected mRNA level. Because effects of a higher mRNA level can be transmitted to the protein level even with slow protein degradation rates, this finding suggests that an increase in the protein level is another potential effect of transcriptional bursting. Here, we show that this striking steady state increase is caused by the asynchronous nature of molecular reactions, which allows the transcriptional regulation model to create additional modes of qualitatively distinct dynamics. Our results illustrate non-intuitive effects of reaction asynchronicity on system dynamics that cannot be captured by the traditional deterministic framework. Because molecular reactions are intrinsically stochastic and asynchronous, these findings may have broad implications in modelling and understanding complex biological systems.

Transient Thermal Management of a Handset Using Phase Change Material (PCM)

2002 ◽  
Vol 124 (4) ◽  
pp. 419-426 ◽  
Author(s):  
Marc Hodes ◽  
Randy D. Weinstein ◽  
Stephen J. Pence ◽  
Jason M. Piccini ◽  
Lou Manzione ◽  
...  
Keyword(s):  
Steady State ◽  
Phase Change ◽  
Thermal Management ◽  
Phase Change Materials ◽  
Maximum Temperature ◽  
Ir Camera ◽  
Steady State Heat ◽  
Steady State Heat Transfer ◽  
Time Required ◽  
Transient Thermal

The power density of portable electronic devices continues to increase because packaging advances reduce their size even as features are added and enhanced. Designing thermal management systems to accommodate steady-state conditions as opposed to fixed duty cycles can substantially increase cost, size, and weight. The feasibility of transient thermal management of handsets using phase change materials (PCMs) was experimentally investigated using an ABS handset mock-up. At selected intervals of time, the nonuniform case temperature of the handset was measured using an infrared (IR) camera, while thermocouples measured the temperatures of the PCM and simulated power amplifier (heater). Transient and steady-state heat transfer rates by natural convective and radiation from the handset to the environment were numerically computed from the temperature data in the thermal images. The effects of PCM material, power supplied to the handset, and handset orientation on the time required for the handset case to reach a given (maximum) temperature and “recovery” time were examined.

Steady-State and Transient Thermal Performance Optimization of Power Automotive Modules

2009 ◽  
Author(s):  
Victor Chiriac
Keyword(s):  
Steady State ◽  
Thermal Performance ◽  
Numerical Study ◽  
Peak Temperature ◽  
System Level ◽  
Main Concern ◽  
Thermal Impact ◽  
Automotive Applications ◽  
Isothermal Boundary ◽  
Transient Thermal

An extensive 3-D conjugate numerical study is conducted to assess the thermal performance of power packages for automotive applications. The automotive industry deals on a daily basis with various package and module-level thermal issues when managing the routing of very high current. The study provides a better understanding of the strengths and weaknesses of IC incorporation into a system module, for present and future product development. Several packages are investigated, ranging from smaller die/flag size to larger ones, single or multiple heat sources, operating under various powering and boundary conditions. The steady state and transient thermal impact of the thicker lead frame and die attach material on the overall thermal behavior is evaluated. The main concern is exceeding the thermal budget at an external ambient temperature of 85°C, specific for the relatively extreme automotive operating environments. Under one steady state (1W) operating scenario, the PQFN package reaches a peak temperature of ∼106.3°C, while under 37W@40ms of transient powering, the peak temperature reached by the corner FET is ∼260.8°C. With an isothermal boundary (85°C) attached to the board backside, the junction temperature does not change, as the PCB has no significant thermal impact. When the isothermal boundary is attached to package bottom, peak temperature drops by 20% after 40 ms. Additional system level with multiple optimized packages placed on a custom PCB is evaluated numerically and experimentally, placing an emphasis on the superior thermal performance of this new class of power packages for automotive applications. The optimized numerical model approximates closely the empirical results (121–126°C vs. 127.5°C), within 1–2%.

Investigation of Steady State and Transient Thermal Management in Portable Telecommunication Product – Part 2

2005 ◽  
Vol 2 (2) ◽  
pp. 98-109
Author(s):  
Cheang Soon Yee ◽  
G.A. Quadir ◽  
Z.A. Zainal ◽  
K.N. Seetharamu
Keyword(s):  
Thermal Conductivity ◽  
Phase Change ◽  
Thermal Management ◽  
Recovery Period ◽  
System Level ◽  
Element Analysis ◽  
Simulation Methodology ◽  
Conductivity Enhancement ◽  
Enthalpy Changes ◽  
Transient Thermal

In Part 2 of this paper, transient thermal management in portable telecommunication product using phase change material (PCM) was numerically investigated. The thermal time-dependent simulation methodology using non-linear transient finite element analysis (FEA) on a solid conduction cellular phone model cooled by natural convection and radiation was verified experimentally. For the phase change problem itself, a pure conduction PCM model with enthalpy changes was utilized. The effect of convection heat transfer in liquid phase is enhanced thermal conductivity. The numerical methodology used by Hodes et al. [3] and Lamberg et al. [13] was verified with both package and system level experimental results. With the confidence gained from the verification work using this simulation methodology, further parametric study was carried out. In this paper, the effect of PCM volume, aspect ratio of the container and amount of heat dissipated are examined. The advantages gained from its recovery period and introduction of thermal conductivity enhancement are also discussed.

Investigation of Steady State and Transient Thermal Management in Portable Telecommunication Product – Part 1

2005 ◽  
Vol 2 (1) ◽  
pp. 40-54 ◽  
Author(s):  
Cheang Soon Yee ◽  
K.N. Seetharamu ◽  
G.A. Quadir ◽  
Z.A. Zainal
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Thermal Management ◽  
Three Dimensional ◽  
Cellular Phone ◽  
Simulation Method ◽  
Conduction Path ◽  
Element Analysis ◽  
Fea Simulation ◽  
Transient Thermal

Steady state and transient thermal management in a portable telecommunication product was investigated. The steady state analysis portion will be discussed in details in Part 1. The investigation was conducted using finite element analysis (FEA) simulation on a cellular phone model. The three-dimensional simulation is based on a solid conduction cellular phone model cooled by natural convection and radiation. The FEA simulation method was verified with experimental results. In this paper, simulation study was carried out to examine various thermal solution options to improve on the heat transfer from the package to the surrounding. As conduction is the predominant heat transfer within the cellular phone, the thermal resistance can be reduced by creating a solid conduction path between the heat dissipating packages with the housing wall and improving the housing wall conduction material.

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