Pub Date : 2013-12-02DOI: 10.1109/THERMINIC.2013.6675222
Travis Mikjaniec, Paul R. Blais, J. Parry
In a study by Ma et al. [1] in 2010, an innovative honeycomb heatsink design for an LED lighting system was analysed using computational fluid dynamics (CFD) and experimentation. When we looked critically at the images of the experiment in Ma's paper, we noted some discrepancies between the simulation model and the experimental setup. Although the experimental setup was not fully described, we were able to identify a number of issues and make near-exact estimates of the dimensions and other values needed to include their effects in the simulation. The resulting simulation matched the test data very well. In this paper, we present the rationale for applying a different approach to electronics thermal design. We also describe how alternative CFD technologies can handle fluid flow and heat transfer within complex geometries without simplification. This novel approach to electronics thermal design is illustrated using the honeycomb heatsink example.
{"title":"Numerical basis and validation of CAD-centric CFD: Honeycomb heatsink study","authors":"Travis Mikjaniec, Paul R. Blais, J. Parry","doi":"10.1109/THERMINIC.2013.6675222","DOIUrl":"https://doi.org/10.1109/THERMINIC.2013.6675222","url":null,"abstract":"In a study by Ma et al. [1] in 2010, an innovative honeycomb heatsink design for an LED lighting system was analysed using computational fluid dynamics (CFD) and experimentation. When we looked critically at the images of the experiment in Ma's paper, we noted some discrepancies between the simulation model and the experimental setup. Although the experimental setup was not fully described, we were able to identify a number of issues and make near-exact estimates of the dimensions and other values needed to include their effects in the simulation. The resulting simulation matched the test data very well. In this paper, we present the rationale for applying a different approach to electronics thermal design. We also describe how alternative CFD technologies can handle fluid flow and heat transfer within complex geometries without simplification. This novel approach to electronics thermal design is illustrated using the honeycomb heatsink example.","PeriodicalId":369128,"journal":{"name":"19th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126785166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-12-02DOI: 10.1109/THERMINIC.2013.6675183
E. Merten, M. A. Ras, T. von Essen, R. Schacht, D. May, T. Winkler, B. Michel
Commonly computational methods are used to determine and enhance the lifetime of electronics and electronic systems. The validity of such methods highly depends on the used material data and therefore on the quality of the accompanying experiments. For this reason different methods were combined to better determine the thermal state of a desired device of variable size, while providing this data within in a reasonable short time. The method allows the in-situ measurement of: · the surface temperature of the top and bottom side by IR thermography and a steady state technique · the junction temperature using transient method · the generated heat flow by the tested device The correlating temperatures of the heating and cooling phase can be monitored at different geometries and setups which allows to build up static and transient simulation models and therefore make the reliability assessment of the used setup or device for many application cases possible.
{"title":"Combined method for thermal characterization of high power semiconductors","authors":"E. Merten, M. A. Ras, T. von Essen, R. Schacht, D. May, T. Winkler, B. Michel","doi":"10.1109/THERMINIC.2013.6675183","DOIUrl":"https://doi.org/10.1109/THERMINIC.2013.6675183","url":null,"abstract":"Commonly computational methods are used to determine and enhance the lifetime of electronics and electronic systems. The validity of such methods highly depends on the used material data and therefore on the quality of the accompanying experiments. For this reason different methods were combined to better determine the thermal state of a desired device of variable size, while providing this data within in a reasonable short time. The method allows the in-situ measurement of: · the surface temperature of the top and bottom side by IR thermography and a steady state technique · the junction temperature using transient method · the generated heat flow by the tested device The correlating temperatures of the heating and cooling phase can be monitored at different geometries and setups which allows to build up static and transient simulation models and therefore make the reliability assessment of the used setup or device for many application cases possible.","PeriodicalId":369128,"journal":{"name":"19th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126595664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-12-02DOI: 10.1109/THERMINIC.2013.6675240
M. Kubicki, Miroslaw Malmski
The paper presents a new, nondestructive method of determination of the air-tightness of metal packagings of transistors. This method is based on the thermoacoustic approach with a microphone detection. Thermoacoustic approach means that the sound is generated by the periodical temperature of the element caused by the periodical electric power dissipation in it. In the paper both the experimental thermoacoustic frequency characteristics as also the theoretical approach applied for numerical interpretations of experimental data are presented and discussed.
{"title":"The nondestructive thermoacoustic method of determination of the air-tightness of metal packagings of transistors","authors":"M. Kubicki, Miroslaw Malmski","doi":"10.1109/THERMINIC.2013.6675240","DOIUrl":"https://doi.org/10.1109/THERMINIC.2013.6675240","url":null,"abstract":"The paper presents a new, nondestructive method of determination of the air-tightness of metal packagings of transistors. This method is based on the thermoacoustic approach with a microphone detection. Thermoacoustic approach means that the sound is generated by the periodical temperature of the element caused by the periodical electric power dissipation in it. In the paper both the experimental thermoacoustic frequency characteristics as also the theoretical approach applied for numerical interpretations of experimental data are presented and discussed.","PeriodicalId":369128,"journal":{"name":"19th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132276971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-12-02DOI: 10.1109/THERMINIC.2013.6675200
G. Greco, Giovanni Vinci, A. Raciti, D. Cristaldi
In recent years, the development of electronic systems that make use of high-rate power circuitry is increasingly frequent also for markets going beyond the typical industrial sector. So, the implementation of efficient electronic modules aimed at converting power, in ambits such as renewable energy equipment or hybrid-electric vehicle motor drives, represents a new challenge for designers. Often, the amount of power to be managed is very significant and no rarely it exceeds tens of kW. In this context, new concepts for manufacturing power converters are emerging and Integrated Power Electronics Modules (IPEM) represent a solution which guarantees better performances. The design of applications exploiting IPEM concept requires multi-domains simulation models able to predict the thermal behaviour of the module according to its electrical performances. In this work, a new methodology aimed at automatizing the synthesis of PSpice-like models able to reproduce both electrical and thermal dynamics is discussed. The model, generated by starting with a series of data retrieved by FEM simulations, exploits a mapping between electrical and thermal quantities and allows reproducing the characteristics of the module in a pure PSpice simulation environment. After a description of the electro-thermal model and the related developed EDA synthesis environment, a series of simulation issues are discussed.
{"title":"Generation of electro-thermal models of integrated power electronics modules using a novel synthesis technique","authors":"G. Greco, Giovanni Vinci, A. Raciti, D. Cristaldi","doi":"10.1109/THERMINIC.2013.6675200","DOIUrl":"https://doi.org/10.1109/THERMINIC.2013.6675200","url":null,"abstract":"In recent years, the development of electronic systems that make use of high-rate power circuitry is increasingly frequent also for markets going beyond the typical industrial sector. So, the implementation of efficient electronic modules aimed at converting power, in ambits such as renewable energy equipment or hybrid-electric vehicle motor drives, represents a new challenge for designers. Often, the amount of power to be managed is very significant and no rarely it exceeds tens of kW. In this context, new concepts for manufacturing power converters are emerging and Integrated Power Electronics Modules (IPEM) represent a solution which guarantees better performances. The design of applications exploiting IPEM concept requires multi-domains simulation models able to predict the thermal behaviour of the module according to its electrical performances. In this work, a new methodology aimed at automatizing the synthesis of PSpice-like models able to reproduce both electrical and thermal dynamics is discussed. The model, generated by starting with a series of data retrieved by FEM simulations, exploits a mapping between electrical and thermal quantities and allows reproducing the characteristics of the module in a pure PSpice simulation environment. After a description of the electro-thermal model and the related developed EDA synthesis environment, a series of simulation issues are discussed.","PeriodicalId":369128,"journal":{"name":"19th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124708448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-12-02DOI: 10.1109/THERMINIC.2013.6675235
F. Schindler-Saefkow, F. Rost, A. Otto, J. Keller, T. Winkler, B. Wunderle, B. Michel, S. Rzepka
The experimental observation of the actual thermo mechanical weak points in microelectronics packages remains a big challenge. Recently, a stress sensing system has been developed by a publicly funded project that allows measuring the magnitudes and the distribution of the stresses induced in the silicon dies by thermo-mechanical loads. Some application experiments will be presented, e.g. thermal loads, 4-point bending on CoB setups, and moisture swelling. The stress chip was detecting CTE mismatch, transition temperature, delamination, creep relaxations and volume swelling of moisture loads. All measurements are supplemented by finite element simulations based on calibrated models for in-depth analysis and for extrapolating the stress results to sites of the package that cannot measured directly. The methodology of closely combining stress measurements at inner points and FE simulation presented in this paper has been able to validate the stress sensing system for tasks of comprehensive design and process characterization as well as for health monitoring. It allows achieving both, a substantial reduction in time to- market and a high level of reliability under service conditions, as needed for future electronics and smart systems packages.
{"title":"Stress impact of thermal-mechanical loads measured with the stress chip","authors":"F. Schindler-Saefkow, F. Rost, A. Otto, J. Keller, T. Winkler, B. Wunderle, B. Michel, S. Rzepka","doi":"10.1109/THERMINIC.2013.6675235","DOIUrl":"https://doi.org/10.1109/THERMINIC.2013.6675235","url":null,"abstract":"The experimental observation of the actual thermo mechanical weak points in microelectronics packages remains a big challenge. Recently, a stress sensing system has been developed by a publicly funded project that allows measuring the magnitudes and the distribution of the stresses induced in the silicon dies by thermo-mechanical loads. Some application experiments will be presented, e.g. thermal loads, 4-point bending on CoB setups, and moisture swelling. The stress chip was detecting CTE mismatch, transition temperature, delamination, creep relaxations and volume swelling of moisture loads. All measurements are supplemented by finite element simulations based on calibrated models for in-depth analysis and for extrapolating the stress results to sites of the package that cannot measured directly. The methodology of closely combining stress measurements at inner points and FE simulation presented in this paper has been able to validate the stress sensing system for tasks of comprehensive design and process characterization as well as for health monitoring. It allows achieving both, a substantial reduction in time to- market and a high level of reliability under service conditions, as needed for future electronics and smart systems packages.","PeriodicalId":369128,"journal":{"name":"19th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130805028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-12-02DOI: 10.1109/THERMINIC.2013.6675246
G. Wagner, William Maltz
This study explores the limits of cooling for handheld devices based on both testing and simulation under various conditions and provides guidelines for maximizing the amount of power that can be dissipated in these small form-factor devices. The factors affecting the maximum possible power dissipation are the available surface area and surface finishes, selection of the outer shell materials, thermal interface materials, heat spreaders and air gaps. In most cases, the limiting factor in the thermal design of these devices is not the temperatures of the internal components but the temperature of the external surfaces since these are in direct contact with the skin of the user. There have been studies that address the maximum allowable comfortable touch temperature of a handheld device. This study presents methods for maximizing the internal power dissipation of these devices while limiting the touch temperatures to the maximum comfortable limits.
{"title":"Thermal management challenges in the passive cooling of handheld devices","authors":"G. Wagner, William Maltz","doi":"10.1109/THERMINIC.2013.6675246","DOIUrl":"https://doi.org/10.1109/THERMINIC.2013.6675246","url":null,"abstract":"This study explores the limits of cooling for handheld devices based on both testing and simulation under various conditions and provides guidelines for maximizing the amount of power that can be dissipated in these small form-factor devices. The factors affecting the maximum possible power dissipation are the available surface area and surface finishes, selection of the outer shell materials, thermal interface materials, heat spreaders and air gaps. In most cases, the limiting factor in the thermal design of these devices is not the temperatures of the internal components but the temperature of the external surfaces since these are in direct contact with the skin of the user. There have been studies that address the maximum allowable comfortable touch temperature of a handheld device. This study presents methods for maximizing the internal power dissipation of these devices while limiting the touch temperatures to the maximum comfortable limits.","PeriodicalId":369128,"journal":{"name":"19th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128380185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-12-02DOI: 10.1109/THERMINIC.2013.6675242
W. Jaber, A. Assy, S. Lefèvre, S. Gomés, P. Chapuis
Various techniques allow measuring the thermal conductivity of materials ranging from bulk to thin-film sizes. Among them, one can find the 3ω method, scanning thermal microscopy or Raman thermometry. The standard 3ω method is not spatially-resolved since it requires a long deposited metallic wire. It is also intrusive. In contrast, the two other techniques have spatial resolution ranging from few microns to submicronic one, depending on the conditions of operation. However, their sensitivity is altered by various parameters. For instance, scanning thermal microscopy signals depend strongly on the surface state. Here, by gathering results obtained with these techniques, we report on the comparison of the experimental determination of the thermal conductivity of various silicon-based and thermoelectric materials of strong interest for microelectronics. In particular, we highlight the evolution of the thermal conductivity with the temperature, which is customarily determined by the 3ω method. While it requires lithography, which can be considered as a drawback at first, the 3ω method is easier to use when varying the temperature. We conclude on the advantages and drawbacks of these techniques and provide a matrix of choices depending on the materials and conditions.
{"title":"Thermal conductivity measurements with the 3ω method and scanning thermal microscopy","authors":"W. Jaber, A. Assy, S. Lefèvre, S. Gomés, P. Chapuis","doi":"10.1109/THERMINIC.2013.6675242","DOIUrl":"https://doi.org/10.1109/THERMINIC.2013.6675242","url":null,"abstract":"Various techniques allow measuring the thermal conductivity of materials ranging from bulk to thin-film sizes. Among them, one can find the 3ω method, scanning thermal microscopy or Raman thermometry. The standard 3ω method is not spatially-resolved since it requires a long deposited metallic wire. It is also intrusive. In contrast, the two other techniques have spatial resolution ranging from few microns to submicronic one, depending on the conditions of operation. However, their sensitivity is altered by various parameters. For instance, scanning thermal microscopy signals depend strongly on the surface state. Here, by gathering results obtained with these techniques, we report on the comparison of the experimental determination of the thermal conductivity of various silicon-based and thermoelectric materials of strong interest for microelectronics. In particular, we highlight the evolution of the thermal conductivity with the temperature, which is customarily determined by the 3ω method. While it requires lithography, which can be considered as a drawback at first, the 3ω method is easier to use when varying the temperature. We conclude on the advantages and drawbacks of these techniques and provide a matrix of choices depending on the materials and conditions.","PeriodicalId":369128,"journal":{"name":"19th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115452580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-12-02DOI: 10.1109/THERMINIC.2013.6675231
P. Raynaud
Electro-thermal effects - both at the micro level of interconnects and devices and at the macro level of circuits and systems - is one of the critical issues for the future development of microprocessors, integrated networks, and other highly integrated circuits and systems. Simulation-based solutions for both design and validation have an important role to play. This paper investigates a new, highly-accurate AND high-performing electro-thermal simulation method and tools. In this paper, we describe the extension of an analog electrical simulator to handle simultaneously the electrical network and the thermal network. These innovations remove the constraint on the time constants and allow accurate validation of the electro-thermal behavior for even the most advanced designs - in all possible conditions of stimuli, temperature, supply voltage, and process corners.
{"title":"Single kernel electro-thermal IC simulator","authors":"P. Raynaud","doi":"10.1109/THERMINIC.2013.6675231","DOIUrl":"https://doi.org/10.1109/THERMINIC.2013.6675231","url":null,"abstract":"Electro-thermal effects - both at the micro level of interconnects and devices and at the macro level of circuits and systems - is one of the critical issues for the future development of microprocessors, integrated networks, and other highly integrated circuits and systems. Simulation-based solutions for both design and validation have an important role to play. This paper investigates a new, highly-accurate AND high-performing electro-thermal simulation method and tools. In this paper, we describe the extension of an analog electrical simulator to handle simultaneously the electrical network and the thermal network. These innovations remove the constraint on the time constants and allow accurate validation of the electro-thermal behavior for even the most advanced designs - in all possible conditions of stimuli, temperature, supply voltage, and process corners.","PeriodicalId":369128,"journal":{"name":"19th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124770913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-12-02DOI: 10.1109/THERMINIC.2013.6675178
P. Zając, M. Szermer, M. Janicki, C. Maj, P. Pietrzak, A. Napieralski
One of the interesting thermal management techniques for multi-core processors is core swapping. In this paper, using the published power data and floorplans for two modern high-performance processors, we employ the well-known HotSpot tool to perform the thermal simulation of the core swapping mechanism. Our transient simulations show that by using core swapping technique, it was possible to either minimize the hot spot temperature in the Ivy Bridge chip by 5°C or increase the operating frequency by 17% and maintain the same temperature as in the case without core swapping. We also derive an analytical model of the activity migration mechanism between two cores which may serve as a tool to calculate the swapping frequency given the desired maximal temperature drop. The model also allows for the correlation of the cooling effectiveness with the performance penalty induced by the swapping.
{"title":"Analysis of the effectiveness of core swapping in modern multicore processors","authors":"P. Zając, M. Szermer, M. Janicki, C. Maj, P. Pietrzak, A. Napieralski","doi":"10.1109/THERMINIC.2013.6675178","DOIUrl":"https://doi.org/10.1109/THERMINIC.2013.6675178","url":null,"abstract":"One of the interesting thermal management techniques for multi-core processors is core swapping. In this paper, using the published power data and floorplans for two modern high-performance processors, we employ the well-known HotSpot tool to perform the thermal simulation of the core swapping mechanism. Our transient simulations show that by using core swapping technique, it was possible to either minimize the hot spot temperature in the Ivy Bridge chip by 5°C or increase the operating frequency by 17% and maintain the same temperature as in the case without core swapping. We also derive an analytical model of the activity migration mechanism between two cores which may serve as a tool to calculate the swapping frequency given the desired maximal temperature drop. The model also allows for the correlation of the cooling effectiveness with the performance penalty induced by the swapping.","PeriodicalId":369128,"journal":{"name":"19th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":"264 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123398811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2013-12-02DOI: 10.1109/THERMINIC.2013.6675228
B. Ma, Kwanhoon Lee
In order to estimate exact thermal resistance of light-emitting diodes (LED), we introduced a new concept of effective internal optical power (IOP) of LED packages. It is because all photons generated at active region of LED chip cannot emit outside due to the difference of refractive index between a LED chip and an encapsulant material. The meaning of the effective IOP of LED package is non-thermal power of total power in LEDs. We derived a model for effective IOP and proposed a new thermal resistance using the effective IOP. To investigate pure thermal effect and distinguish optical effect in the LED packages, we carried out a computational fluidic dynamics simulations.
{"title":"Proposal of new thermal resistance for light-emitting diodes","authors":"B. Ma, Kwanhoon Lee","doi":"10.1109/THERMINIC.2013.6675228","DOIUrl":"https://doi.org/10.1109/THERMINIC.2013.6675228","url":null,"abstract":"In order to estimate exact thermal resistance of light-emitting diodes (LED), we introduced a new concept of effective internal optical power (IOP) of LED packages. It is because all photons generated at active region of LED chip cannot emit outside due to the difference of refractive index between a LED chip and an encapsulant material. The meaning of the effective IOP of LED package is non-thermal power of total power in LEDs. We derived a model for effective IOP and proposed a new thermal resistance using the effective IOP. To investigate pure thermal effect and distinguish optical effect in the LED packages, we carried out a computational fluidic dynamics simulations.","PeriodicalId":369128,"journal":{"name":"19th International Workshop on Thermal Investigations of ICs and Systems (THERMINIC)","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123418752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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