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In this paper, The relationship between the temperature rise of the heat generating components densely mounted in a grid pattern on the board and the various board design conditions was discussed. Based on the discussion, a simple estimation formula that can be used for temperature estimation for densely mounted components was derived.
In this paper, temperature estimation method of heat-generating components in dense mounting was discussed. Specifically, simulation of components arranged densely in a grid pattern on a PCB was carried out. The relationship between temperature rise around the heat generating portion and various conditions such as component pitch and pad size were clarified. Additionally, a temperature estimation...
In recent years, thermal management of electronic components is getting all the more important with the advance in downsizing and higher density packaging of electronics. The authors have proposed a concept of thermal network modeling to be used in estimating the temperature rise of small chip components to establish the copper pattern design rule. In this paper, based on the proposed concept, we...
General anesthesia affects the expression of clock genes in various organs. Expression of Per2, a core component of the circadian clock, is markedly and reversibly suppressed by sevoflurane in the suprachiasmatic nucleus (SCN), and is considered to be a biochemical marker of anesthetic effect in the brain. The SCN contains various types of neurons, and this complexity makes it difficult to investigate...
The circuit (printed board) designers play an important role in the recent thermal design of electronic devices. Generally, small chip type components have low heat generation. However, recently, the heat generation density of small chip type components is increasing along with the downsizing of electronics. Small chip type components have no cooling devices, and heat dissipation from the components...
This paper proposes a new compact thermal model (CTM) for the microprocessor package based on a one-dimensional thermal network with average temperature nodes. Different from the two-resistor model and the DELPHI model, the proposed CTM doesn't assume an isothermal surface, but sets plate heat sources along the top surface of the silicon die and the bottom surface of the solder balls layer. It is...
This paper describes the effect of the variation of energy relaxation time on thermal properties of power Si MOSFET (Metal - Oxide - Semiconductor Field-Effect Transistor) using Electro-Thermal Analysis. In our previous study, we investigated thermal properties of power Si MOSFET using Electro-Thermal Analysis. However, in these calculations, to reduce calculation cost, we assume energy relaxation...
Recently, thermal design of electrical equipment is important. Thermal contact resistance is one of the important parameters in the thermal design. However, thermal contact resistance is dependent on various factors, for example surface roughness, the contact pressure and the hardness of the material. Therefore, quantitative evaluation is difficult, and a little information can be obtained under high...
This paper describes the relationship between the boundary thermal resistance and the hot spot temperature in power Si MOSFET. Power Si MOSFET is widely used semiconductor device in various area, for example car electronics. Since high voltage is applied to power Si MOSFET, high electric field (more than 10 V/m) is generated. Under such high electric field, electron thermal energy becomes much higher...
This paper describes the effect of variation of doping density on thermal properties of power Si MOSFET. For accurate thermal design according to miniaturization of electronics, we should consider thermal properties of semiconductor devices in chips. Additionally, power Si MOSFET, which is a type of semiconductor devices, has large thermal problems. Then, we focus on power Si M OSFET, and investigate...
This paper describes the effect of cooling from a surface of power Si MOSFET on hot spot temperature. In traditional thermal design of electronics, the temperature distribution of chips is assumed to be uniform for simplicity of thermal design. However, in recent years, thermal problems of electronics are more serious, because electronics have been downsizing. Therefore, we should consider the temperature...
This paper investigates transient temperature prediction of microprocessor hot spot by utilizing one-dimensional thermal network with average temperature nodes. Different from traditional thermal network, introduced one-dimensional thermal network in this paper consists of not only material thermal resistances and material thermal capacitances but also thermal spreading resistances and a thermal local...
The heat flow distribution in IGBT package is significantly affected by its interfacing materials and dimension of metal frame. In order to increase heat-sink capability which is critical for kW IGBT device, lateral heat spreading technology is introduced. To design in such 3D heat flux structure in real power device package, accurate thermal distribution analysis is required. Using three dimensional...
This paper describes the effect of the boundary condition at the bottom surface of the power Si MOSFET on the analysis results of electro-thermal analysis of the power Si MOSFET. In general, the bottom surface of a semiconductor device is assumed 350 K to calculate the temperature distribution. However, in fact, the temperature of the bottom surface of the device is not constant, and the temperature...
Recently, a high accuracy soldering method is required. Then, laser soldering has attracted attention. In laser soldering, it is difficult to detect an optimal laser condition depending on production conditions, because the amount of heat transfer from solder through copper wiring is different in circuit boards and soldering positions. Laser condition should be adjusted according to the situation...
In recent years, thermal problem of electronics has been serious, and accurate thermal design has been required. In conventional thermal design of power Si MOSFET, which is widely used semiconductor device for current control in a lot of area, uniform heat generation has been assumed, and designer has employed average temperature of power Si MOSFET. However, for more accurate thermal design, the non-uniform...
This study describes fundamental melting phenomena of ring and cream solder and an evaluation of heat loss in laser soldering. Laser soldering is attractive from the viewpoint of minimum thermal impact on surrounding devices. However, detecting an appropriate laser irradiation condition is difficult since the heat loss is affected by several factors. Therefore, detecting an appropriate laser irradiation...
In recent years, electronics has been downsizing, and thermal problem becomes more serious. Therefore, more accurate thermal design is required for improvement of electronics reliability. For more accurate thermal design, we should consider temperature distribution of a chip. In a chip, a lot of semiconductor devices are mounted. Therefore, to investigate temperature distribution of a chip, temperature...
Electrical component temperature on Printed Circuit Board (PCB) becomes higher due to high density packaging of electrical equipments, and heat conduction through the PCB is used as one of the cooling solutions. However, temperature prediction with detailed model of complex wirings of PCB in Computational Fluid Dynamics (CFD) is high calculation load. To reduce the calculation load, temperature prediction...
This study describes the performance of cooling fans in terms of the P–Q curve and the maximum flow rate under various environmental conditions. It focuses on the relationship between fan performance and configuration factors such as the electronic enclosure. The presence of an enclosure wall increased the pressure characteristic of the fan performance. The presence of a narrow inlet decreased the...
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