arXiv subjects

V. Szekely

Publications and source records attributed to V. Szekely.

6 recordsLinked to original sources

arXiv2008

Improvements of the Variable Thermal Resistance

A flat mounting unit with electronically variable thermal resistance [1] has been presented in the last year [2]. The design was based on a Peltier cell and the appropriate control electronics and software. The device is devoted especially to the thermal characterization of packages, e.g. in dual cold plate arrangements. Although this design meets the requirements of the static measurement we are intended to improve its parameters as the settling time and dynamic thermal impedance and the range of realized thermal resistance. The new design applies the heat flux sensor developed by our team as well [3], making easier the control of the device. This development allows even the realization of negative thermal resistances.

physics.gen-ph↗

arXiv2007

Contactless Thermal Characterization Method of PCB-s Using an IR Sensor Array

In this paper the feasibility study of an IR sensor card is presented. The methodology and the results of a quasi real-time thermal characterization tool and method for the temperature mapping of circuits and boards based on sensing the infrared radiation is introduced. With the proposed method the IR radiation-distribution of boards from the close proximity of the sensor card is monitored in quasi real-time. The proposed method is enabling in situ IR measurement among operating cards of a system e.g. in a rack.

cs.OH↗

arXiv2007

Contactless Thermal Characterization Method of PCB-s Using Different IR Sensor Arrays

In this paper the methodology and the results of a quasi real-time thermal characterization tool and method for the temperature mapping of circuits and boards based on sensing the infrared radiation will be introduced. With the proposed method the IR radiation-distribution of boards from the close proximity of the sensor card is monitored in quasi real-time. The proposed method is enabling in situ IR measurement among operating cards of a system e.g. in a rack, enabling the immediate detection of potential hot spots in the system. . The elevated temperature encountered in different packaged electronic devices, like digital processors, high power amplifier, high power switches, etc., demands the application of careful temperature-aware design methodologies and the electro-thermal simulations of PCBs. The results of different electro-thermal simulations and modeling in most of the cases give good approximating results and consider the coupled effects of the real surroundings of these cards and other dissipation elements in an operating system. However the simulation time may take hours, and different systems, different surroundings should be simulated again and again. In our expectation, by using contactless temperature measurement procedure the heat distribution and the places of high dissipation elements on an operating PCB board (PCI or AGP cards in a rack-house of a PC) can be measured and localized in a dense rack system, where only a thin measuring board can be inserted between the cards during operation.

cond-mat.mtrl-sci↗

arXiv2007

Design issues of a variable thermal resistance

Some years ago we have proposed a thermal mount with electronically variable thermal resistance [1]. In this earlier work the feasibility of such a structure has been demonstrated. Now we intend to realize this mount in a maturated form, suitable to the everyday use in the practice of package thermal qualification and modeling. The design of such a device raises a number of new questions and problems. The present paper is dealing with these problems and the possible solutions.

cond-mat.mtrl-sci↗

arXiv2007

Reducing the Possibility of Subjective Error in the Determination of the Structure-Function-Based Effective Thermal Conductivity of Boards

The thermal response function given to a unit-step dissipation accurately characterizes the thermal system. Instead of the thermal response function the so-called structure function describing three-dimensional as the equivalent model of one-dimensional heat-spreading, created from the thermal response function with the help of complex mathematical procedures, is often used. Using the structure function the partial thermal capacity and partial heat resistance of certain elements of the thermal system can be identified. If the geometrical measurements of a thermal system of simple geometry and homogeneous material (such as a homogeneous rod or board, etc.) are known, the coefficient of thermal conductivity of the material in question can be determined from two points of the structure function at 2-5 per cent of accuracy. In this paper a method is presented which applies a wide range/section instead of two points of the cumulative structure function to determine the thermal coefficient, thus reducing the subjective error deriving from the selection of the two points. The above method is presented and illustrated in simulated as well as measured thermal transient responses.

cond-mat.mtrl-sci↗

arXiv2007

A More Flexible Realization of The SUNRED Algorithm

The high dissipation of integrated circuits means serious problems for packaging and for the design of complex electronic systems. Another important area of research and development nowadays is the integration of sensors and micromechanical systems (MEMS) with electronic circuits. The original Successive Node Reduction (SUNRED) algorithm handles well the first area but require revision for electro-thermal or mechanical fields. As a first stage the updated algorithm is able to solve thermal fields as the original, but with the application of flexible boundary connection handling, it can be much faster than the original. By using object-oriented program model the algorithm can handle non-rectangular 3D fields, and SUNRED mesh resolution is arbitrary, not have to be the power of two anymore.

cond-mat.mtrl-sci↗