Cheikh Tidiane Dia

Delphi style compact modeling by means of genetic algorithms of system in Package devices using composite sub-compact thermal models dedicated to model order reduction

Nowadays a high-level integration with unprecedented functionality and efficient performances is achieved through 3D packaging techniques known as System-In-Package (SIP). The paper describes the reduction process conducted on a realistic SIP module case in order to establish a behavioral thermal network having a large number of power sources. Besides this device has been slightly modified to focus on the recent 3D integration techniques such as the stacking of chip, multi-chips side by side architecture or the embedding of conventional individually-packaged Integrated Circuits (IC). These works compared the prediction of a DELPHI style Compact Thermal Model (CTM) to a numerical Detailed Thermal Model with for aim to illustrate the diminution of computation delays, the expected accuracy and some efficient ways to improve it. Then it describes the performance of a novel methodology that nests a set of Sub-Compact Thermal Models (SCTM) within the detailed numerical model, far less grid-intensive, and its ability to preserve the final SIP CTM quality.

Electronic board modeling by the means of DELPHI compact thermal model of components

Board-level simulation considers the challenging process of analysing the impact of the vicinity of high and medium powered devices on the sensitive ones. This level of design is often considered in the industry sector as an unnecessary luxury. This damaging approach is becoming untenable with the rising use of miniaturized high-powered devices and High density Interconnection electronic board, which intensifies the coupling effect of neighbouring components. So, perform board-level thermal simulation at the earliest stage of the design process makes sense today, more than ever. To minimize the computation times, from days to minutes, the concept of compact thermal model was defined in 1996, by the European consortium DELPHI1 Unfortunately, DELPHI project ended with a methodology restricted to steady-state compact thermal model for mono-chip electronic component. Emerging problematic such as multi-chips module or transient thermal model were not addressed, which remains today for worldwide companies a non-trivial challenge. Since 2009, Thales is implementing these missing methods. The present paper summarizes the comparison of a “state-of-the-art” numerical detailed model and its deducted compact model with the help of infrared experimental results in order to promote a modelling guideline. (1)DEvelopment of Library of Physical model for an Integrated design environment.

Investigation of Delphi compact thermal model style for modeling surface-mounted Soft Magnetic Composite inductor

Recent works on System-In-Package component pointed out that its in-package inductor is the hottest part. It occurs that thermal stresses due to joule heating and magnetic losses can be damaging. The present study focuses on low profile, surface-mounted, Soft Magnetic Composite inductors to define their thermal behaviour and then to propose a guideline to create pertinent models.Results highlight the impact of thermal conductivity of composite core on temperatures and the lack of properties data of iron-resin mixtures. Using mixture model, a calculation of effective thermal conductivity is proposed.To minimize the expensive meshing of the fine detailed simulations and the computation time, a novel Compact Thermal Model for inductor, based on DELPHI methodology, was established. The predictions of CTM model show good agreement, less than 10% of divergence. Further works must be done to really master the coupled interaction of magnetic, joule effect, thermal phenomenon as well as material properties.

Dynamic Compact Thermal Model for stacked-die components

The present work proposes an approach to generate Dynamic Compact Thermal Models or “DCTMs” dedicated to electronic components. This one is based on the European project DELPHI, which defined the first comprehensive methodology concerning the generation of thermal behavioral model, Boundary Condition Independent, called Compact Thermal Models or “CTMs”. Unfortunately, the scope of “CTMs” was limited to the steady state as well as for single chip packages. But, the latest trend toward higher and higher density packaging using several chips requires henceforth a methodology capable to take into account the transient regime for 3D integration technologies like stacked-die solution. Following the CTMs modus operandi the DCTMs were conceived to propose a RC network able to predict a set of sensitive component temperatures with a minimized difference during component duty cycle. This work suggests the use of the genetic algorithms fitting technique that turns out relevant for the realization of DCTM, as well as the conventional DELPHI CTM.

Dynamic sub-compact model and global compact model reduction for multichip components

The trend at the level of electronic component is to gather several active chips inside the same enclosing package. The thriving development of this technology allows reducing the volume in space as well as shortening the interconnection between the elements of the device. In this article, we analyze two methods of reduction of a detailed representation of a component, embedding three chips. The first approach is based upon the sub-compact vision, which consists in generating thermal compact models of different pseudo parts and plugged them within the over-molding resin of the package. This one gives good results but the size of the deducted model remains large. The second way uses a global reduction process by generating a whole network at once by means of genetic algorithm and superposition principle. The predictions of the behavioral models are relevant, poorly dependant of boundary conditions but the number of mandatory fitting scenarios becomes quite significant as well as the parameters to be optimized.

Experimental characterization of the predictive thermal behaviour model of a surface-mounted soft magnetic composite inductor

Abstract The latest low-profile high-power inductors, used in DC-DC converters to power an assortment of applications, are going endlessly smaller and submitted to larger amount of current. This surface-mounted magnetic component is commonly constructed using a wound copper coil which is over-moulded in a Soft Magnetic Composite (SMC) based on an iron-resin material mixture. The performances of that high-power density device depend closely on the coupled interaction of magnetic phenomenon, joule effect and thermal behaviour, which is difficult to apprehend at board level simulation. Thus, the present study highlights the electromagnetic phenomena encountered by SMC inductor devices and their influence on the temperatures of the iron-based core and copper-based coil. In order to better characterize the behaviour of high-power inductor devices, a set of coupled electromagnetic and thermal simulations were performed on the case of an industrial demonstration electronic board. Consequently, the influence of surrounding active electronic components upon the acceptable temperature rise of the inductor parts has been investigated. The numerical simulations were completed by electrical characterizations and thermal measurements on the test vehicle for various operating conditions with the purpose to establish a more realistic thermal model of the inductor device. The agreement of the fine detailed model with experiment results is quite relevant: the divergence is lower than 10%. Further, for minimizing the expensive meshing of the finely detailed simulations and the computation time, a novel concept of compact thermal model for inductor device, based on DELPHI methodology, was used. The deducted two-heating-source DELPHI-style model adequately correlates the physical behaviour of all heat paths of the inductor device, our purpose.