Heat in Computers: Applied Heat Transfer in Information Technology

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Wataru Nakayama
Keyword(s):  
Heat Transfer ◽  
Integrated Circuits ◽  
Printed Circuit Board ◽  
Cfd Simulation ◽  
Coolant Flow ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Circuit Board ◽  
Evolutionary Trend ◽  
Simulation Code

Since the advent of modern electronics technology, heat transfer science and engineering has served in the development of computer technology. The computer as an object of heat transfer research has a unique aspect; it undergoes morphological transitions and diversifications in step with the progress of microelectronics technology. Evolution of computer's hardware manifests itself in increasing packing density of electronic circuits, modularization of circuit assemblies, and increasing hierarchical levels of system internal structures. These features are produced by the confluence of various factors; the primary factors are the pursuit of ever higher processing performance, less spatial occupancy, and higher energy utilization efficiency. The cost constraint on manufacturing also plays a crucial role in the evolution of computer's hardware. Besides, the drive to make computers ubiquitous parts of our society generates diverse computational devices. Concomitant developments in heat generation density and heat transfer paths pose fresh challenges to thermal management. In an introductory part of the paper, I recollect our experiences in the mainframe computers of the 1980s, where the system's morphological transition allowed the adoption of water cooling. Then, generic interpretations of the hardware evolution are attempted, which include recapturing the past experience. Projection of the evolutionary trend points to shrinking space for coolant flow, the process commonly in progress in all classes of computers today. The demand for compact packaging will rise to an extreme level in supercomputers, and present the need to refocus our research on microchannel cooling. Increasing complexity of coolant flow paths in small equipment poses a challenge to a user of computational fluid dynamics (CFD) simulation code. In highly integrated circuits the paths of electric current and heat become coupled, and coupled paths make the electrical/thermal codesign an extremely challenging task. These issues are illustrated using the examples of a consumer product, a printed circuit board (PCB), and a many-core processor chip.

Confirming the Signal Integrity in Transmission of Digital Signals on Microstrip Straight Circuits via the Eye Diagrams

2014 ◽  
Vol 5 (1) ◽  
pp. 737-741
Author(s):  
Alejandro Dueñas Jiménez ◽  
Francisco Jiménez Hernández
Keyword(s):  
Integrated Circuits ◽  
Printed Circuit Board ◽  
Signal Integrity ◽  
High Volume ◽  
Information Storage ◽  
Circuit Board ◽  
Electromagnetic Simulation ◽  
Electronic Systems ◽  
Digital Signals ◽  
Printed Circuit

Because of the high volume of processing, transmission, and information storage, electronic systems presently requires faster clock speeds tosynchronizethe integrated circuits. Presently the “speeds” on the connections of a printed circuit board (PCB) are in the order of the GHz. At these frequencies the behavior of the interconnects are more like that of a transmission line, and hence distortion, delay, and phase shift- effects caused by phenomena like cross talk, ringing and over shot are present and may be undesirable for the performance of a circuit or system.Some of these phrases were extracted from the chapter eight of book “2-D Electromagnetic Simulation of Passive Microstrip Circuits” from the corresponding author of this paper.

scholarly journals Compact Modelling of Electrical, Optical and Thermal Properties of Multi-Colour Power LEDs Operating on a Common PCB

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1286
Author(s):  
Krzysztof Górecki ◽  
Przemysław Ptak
Keyword(s):  
Integrated Circuits ◽  
Optical Model ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Junction Temperature ◽  
Optical Parameters ◽  
Spice Simulation ◽  
Light Emitting ◽  
Proposed Model ◽  
Good Agreement

This paper concerns the problem of modelling electrical, thermal and optical properties of multi-colour power light-emitting diodes (LEDs) situated on a common PCB (Printed Circuit Board). A new form of electro-thermo-optical model of such power LEDs is proposed in the form of a subcircuit for SPICE (Simulation Program with Integrated Circuits Emphasis). With the use of this model, the currents and voltages of the considered devices, their junction temperature and selected radiometric parameters can be calculated, taking into account self-heating phenomena in each LED and mutual thermal couplings between each pair of the considered devices. The form of the formulated model is described, and a manner of parameter estimation is also proposed. The correctness and usefulness of the proposed model are verified experimentally for six power LEDs emitting light of different colours and mounted on an experimental PCB prepared by the producer of the investigated devices. Verification was performed for the investigated diodes operating alone and together. Good agreement between the results of measurements and computations was obtained. It was also proved that the main thermal and optical parameters of the investigated LEDs depend on a dominant wavelength of the emitted light.

scholarly journals Estimating Recycling Return of Integrated Circuits Using Computer Vision on Printed Circuit Boards

2021 ◽  
Vol 11 (6) ◽  
pp. 2808
Author(s):  
Leandro H. de S. Silva ◽  
Agostinho A. F. Júnior ◽  
George O. A. Azevedo ◽  
Sergio C. Oliveira ◽  
Bruno J. T. Fernandes
Keyword(s):  
Integrated Circuits ◽  
Printed Circuit Boards ◽  
Printed Circuit Board ◽  
Electronic Waste ◽  
Decision Criterion ◽  
Economic Feasibility ◽  
Electronic Equipment ◽  
Circuit Board ◽  
Mechanical Recycling ◽  
Printed Circuit

The technological growth of the last decades has brought many improvements in daily life, but also concerns on how to deal with electronic waste. Electrical and electronic equipment waste is the fastest-growing rate in the industrialized world. One of the elements of electronic equipment is the printed circuit board (PCB) and almost every electronic equipment has a PCB inside it. While waste PCB (WPCB) recycling may result in the recovery of potentially precious materials and the reuse of some components, it is a challenging task because its composition diversity requires a cautious pre-processing stage to achieve optimal recycling outcomes. Our research focused on proposing a method to evaluate the economic feasibility of recycling integrated circuits (ICs) from WPCB. The proposed method can help decide whether to dismantle a separate WPCB before the physical or mechanical recycling process and consists of estimating the IC area from a WPCB, calculating the IC’s weight using surface density, and estimating how much metal can be recovered by recycling those ICs. To estimate the IC area in a WPCB, we used a state-of-the-art object detection deep learning model (YOLO) and the PCB DSLR image dataset to detect the WPCB’s ICs. Regarding IC detection, the best result was obtained with the partitioned analysis of each image through a sliding window, thus creating new images of smaller dimensions, reaching 86.77% mAP. As a final result, we estimate that the Deep PCB Dataset has a total of 1079.18 g of ICs, from which it would be possible to recover at least 909.94 g of metals and silicon elements from all WPCBs’ ICs. Since there is a high variability in the compositions of WPCBs, it is possible to calculate the gross income for each WPCB and use it as a decision criterion for the type of pre-processing.

scholarly journals A Self-Powered Nanogenerator for the Electrical Protection of Integrated Circuits from Trace Amounts of Liquid

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhuang Hui ◽  
Ming Xiao ◽  
Daozhi Shen ◽  
Jiayun Feng ◽  
Peng Peng ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
High Performance ◽  
Printed Circuit Board ◽  
Short Circuit ◽  
High Sensitivity ◽  
Short Circuit Current ◽  
Fast Response ◽  
Open Circuit ◽  
Circuit Board ◽  
Self Powered

Abstract With the increase in the use of electronic devices in many different environments, a need has arisen for an easily implemented method for the rapid, sensitive detection of liquids in the vicinity of electronic components. In this work, a high-performance power generator that combines carbon nanoparticles and TiO2 nanowires has been fabricated by sequential electrophoretic deposition (EPD). The open-circuit voltage and short-circuit current of a single generator are found to exceed 0.7 V and 100 μA when 6 μL of water was applied. The generator is also found to have a stable and reproducible response to other liquids. An output voltage of 0.3 V was obtained after 244, 876, 931, and 184 μs, on exposure of the generator to 6 μL of water, ethanol, acetone, and methanol, respectively. The fast response time and high sensitivity to liquids show that the device has great potential for the detection of small quantities of liquid. In addition, the simple easily implemented sequential EPD method ensures the high mechanical strength of the device. This compact, reliable device provides a new method for the sensitive, rapid detection of extraneous liquids before they can impact the performance of electronic circuits, particularly those on printed circuit board.

Integration of a K-Band Receiver Front-End Using a Copper Core Printed Circuit Board

2018 ◽  
Vol 2018 (1) ◽  
pp. 000384-000388
Author(s):  
Brian Curran ◽  
Jacob Reyes ◽  
Christian Tschoban ◽  
Ivan Ndip ◽  
Klaus-Dieter Lang ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Antenna Arrays ◽  
High Frequency ◽  
Printed Circuit Board ◽  
Cost Effective ◽  
Circuit Board ◽  
Front End ◽  
High Bandwidth ◽  
Increasing Demand ◽  
K Band

Abstract Increasing demand for high bandwidth wireless satellite connections and telecommunications has resulted in interest in steerable antenna arrays in the GHz frequency range. These applications require cost-effective integration technologies for high frequency and high power integrated circuits (ICs) using GaAs, for example. In this paper, an integration platform is proposed, that enables GaAs ICs to be directly placed on a copper core inside cavities of a high frequency laminate for optimal cooling purposes. The platform is used to integrate a K-Band receiver front-end, composed of four GaAs ICs, with linear IF output power for input powers above −40dBm and a temperature of 42°C during operation.

Separation of Natural Convection and Radiation by Changing Rotational Acceleration

Volume 1 ◽  
2004 ◽  
Author(s):  
Arnout Willockx ◽  
Gilbert De Mey ◽  
Michel De Paepe ◽  
Boguslaw Wiecek ◽  
Mariusz Felczak ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Centripetal Force ◽  
Rotational Acceleration ◽  
Governing Equations ◽  
Total Heat Transfer ◽  
Closed Cavity ◽  
Printed Circuit

The objective is to separate natural convection and radiation experimentally. Therefore a heat source is placed inside a closed cavity and the acceleration inside the cavity can be changed. A centrifuge is used to change the acceleration. A flat resistor etched on a printed circuit board of 10mm × 48mm, is placed in a hermetically sealed cylinder, which hangs under the arm of the centrifuge. The resistor is powered by a battery, dissipates 0,35W and has a surface temperature of 60°C at 1g. Natural convection is maintained inside the cylinder. Conduction is reduced to a negligible amount by construction of the experiment, thus convection and radiation are the main modes of heat transfer. The rotational speed of the centrifuge determines the centrifugal force in the cylinder. When the centripetal force increases, the temperature of the resistor decreases due to the increase of natural convection. The amount of radiation and total heat transfer can be determined from the experiment, so the amount of natural convection can also be determined. The experimental results are compared with the governing equations to validate the experiment. The reproducibility of the experiment is also checked.

Thermal Performance of Microelectronic Substrates With Submillimeter Integrated Vapor Chamber

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Sangbeom Cho ◽  
Yogendra Joshi
Keyword(s):  
Heat Transfer ◽  
Thermal Performance ◽  
Printed Circuit Board ◽  
Mechanical Design ◽  
Three Dimensional ◽  
Circuit Board ◽  
Working Fluid ◽  
Vapor Chamber ◽  
Conduction Model ◽  
Printed Circuit

We develop a vapor chamber integrated with a microelectronic packaging substrate and characterize its heat transfer performance. A prototype of vapor chamber integrated printed circuit board (PCB) is fabricated through successful completion of the following tasks: patterning copper micropillar wick structures on PCB, mechanical design and fabrication of condenser, device sealing, and device vacuuming and charging with working fluid. Two prototype vapor chambers with distinct micropillar array designs are fabricated, and their thermal performance tested under various heat inputs supplied from a 2 mm × 2 mm heat source. Thermal performance of the device improves with heat inputs, with the maximum performance of ∼20% over copper plated PCB with the same thickness. A three-dimensional computational fluid dynamics/heat transfer (CFD/HT) numerical model of the vapor chamber, coupled with the conduction model of the packaging substrate is developed, and the results are compared with test data.

A Novel Discrete Passives Integration on Organic Substrate

2005 ◽  
Author(s):  
Vasudivan Sunappan ◽  
Chee Wai Lu ◽  
Lai Lai Wai ◽  
Wei Fan ◽  
Boon Keng Lok
Keyword(s):  
Integrated Circuits ◽  
Printed Circuit Board ◽  
Organic Substrate ◽  
Temperature Cycling ◽  
Circuit Board ◽  
Electrical Performance ◽  
Core Material ◽  
Bottom Surface ◽  
Passive Components ◽  
Printed Circuit

A novel process has been developed to embed discrete (surface mountable) passive components like capacitors, resistors and inductors using printed circuit board fabrication technology. The process comprises of mounting passive components on top surface of a core PCB (printed circuit board) material using surface mount technology. The passive components mounting were designed in multiple clusters within the PCB. Dielectric sheets are sandwiched between top surface of core PCB and second PCB material for lamination process. A direct interconnection of the passive components to one or more integrated circuits (IC) is further accomplished by mounting the ICs on the bottom surface of the core material in an area directly under the passive components. The close proximity of the embedded passive components such as capacitors to an IC improved electrical performance by providing impedance reduction and resonance suppression at high frequency range. The reliability of solder joints was evaluatedd by temperature cycling test.

An Experimental Assessment of Numerical Predictive Accuracy for Electronic Component Heat Transfer in Forced Convection—Part II: Results and Discussion

2003 ◽  
Vol 125 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Peter J. Rodgers ◽  
Vale´rie C. Eveloy ◽  
Mark R. Davies
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Printed Circuit Board ◽  
Predictive Accuracy ◽  
Numerical Models ◽  
Circuit Board ◽  
Junction Temperature ◽  
Electrical Performance ◽  
Test Cases ◽  
Computational Fluid Dynamics Cfd

Numerical predictive accuracy is assessed for component-printed circuit board (PCB) heat transfer in forced convection using a widely used computational fluid dynamics (CFD) software. In Part I of this paper, the benchmark test cases, experimental methods and numerical models were described. Component junction temperature prediction accuracy for the populated board case is typically within ±5°C or ±10%, which would not be sufficient for temperature predictions to be used as boundary conditions for subsequent reliability and electrical performance analyses. Neither the laminar or turbulent flow model resolve the complete flow field, suggesting the need for a turbulence model capable of modeling transition. The full complexity of component thermal interaction is shown not to be fully captured.

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