Hot spot analysis in integrated circuit substrates by laser mirage effect

3 páginas, 2 figuras.This work shows an analytical and experimental technique for characterizing radial heat flow present in integrated circuits (ICs) when power is dissipated by integrated devices. The analytical model comes from the resolution of the Fermat equation for the trajectory of rays and supposing a spherical heat source dissipating a time-periodic power. An application example is presented; hence demonstrating how hot spots and heat transfer phenomena in the IC substrate can be characterized. The developed method may become a practical alternative to usual off-chip techniques for inspecting hot spots in ICs and to experimentally characterize heat flow in the semiconductor substrate.This work has been partially supported by the Consejo Superior de Investigaciones Científicas (CSIC) (under contract “Junta para la Ampliación de Estudios,” JAEDoc No. E-08–2008–0637732) and the Spanish Ministry of Science and Innovation (research programs THERMOS TEC2008- 05577, RUE CSD2009-00046, TERASYSTEMS TEC2008- 01856, and Ramón y Cajal RYC-2010-07434).Peer reviewe

Reduced-Order Thermal Behavioral Model Based on Diffusive Representation

14 páginas, 15 figuras, 2 tablas.-- et al.The virtual prototyping of power electronic converters requires electrothermal models with various abstraction levels and easy identification. Numerous methods for the construction of compact thermal models have been presented in this paper. Few of them propose state-space models, where the model order can be controlled according to the necessity of the virtual prototyping analyses. Moreover, the model reduction methods require the experience of the engineer and previous calibration. Diffusive representation (DR) is proposed here as an original and efficient method to build compact thermal models as state-space models. The model reduction is obtained through the model parameter identification and/or the time horizon of the measurement data provided for the identification. Instead of eigenvalue elimination, the method enables to specify adequately inside the model the frequency domain wished for the virtual analysis at hand. The proposed method is particularly dedicated to the system optimization phases. Experimental and simulation results are in good agreement. The advantages and limitations of the DR are discussed in comparison to published methods.Peer reviewe

High-power test device for package thermal assessment and validation of thermal measuremetn tecniques

This paper describes the structure and thermal behavior of a high-power thermal test chip (up to 200 W/cm2) designed for power electronics package assessment, which has also been used for the validation of thermal measurement techniques. In particular, we show two application examples where the proposed device allowed the assessment of different power substrate technologies, and the validation of temperature measurement techniques used to characterize the high frequency behavior of circuits and devices in the frequency domain using the heterodyne technique.Postprint (published version

Analysis of solid state relay solutions based on different semiconductor technologies

This paper provides an analysis on the design, implementation and operation of Bi-Directional Switches (BDS) based on power semiconductor devices intended to replace Electro Mechanical Relays (EMR) in home appliances. Static and dynamic characterizations of test vehicles developed using different power device semiconductor technologies (TRIAC, Super Junction (SJ) MOSFET, IGBT...) are presented. At this time, emerging Gallium Nitride High Electron Mobility Transistors (GaN HEMTs) seem to be very suitable for the mentioned applications. Actually, GaN HEMTs based BDS has demonstrated to be the best solution to replace EMRs, with a high expectation to a significant cost reduction

Single-MOSFET DC thermal sensor for RF-amplifier central frequency extraction

© 2017 Elsevier B.V. A DC thermal sensor based on a single metal-oxide-semiconductor field-effect transistor (MOSFET) is proposed to extract high-frequency electrical features of embedded circuits. The MOSFET sensor is monolithically integrated with the circuit under test (CUT) and then monitors by thermal means the DC power dissipated by the CUT, which carries high-frequency electrical information. After explaining the theory behind this testing approach, the paper demonstrates the feasibility of the proposed MOSFET sensor through simulations and experiments. These are carried out using a radio-frequency (RF) power amplifier as a CUT and thermally extracting its central frequency (440 MHz). The MOSFET sensor results are assessed using an infrared camera as a reference. The main advantage of the proposed sensing method is that the impact on the integrated circuit (IC) layout area is minimum, which is crucial when testing RF-ICs. Moreover, in comparison with previous works, the cost and complexity of the required instrumentation is lower.Postprint (author's final draft

Output Power and Gain Monitoring in RF CMOS Class A Power Amplifiers by Thermal Imaging

© 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The viability of using off-chip single-shot imaging techniques for local thermal testing in integrated Radio Frequency (RF) power amplifiers (PA’s) is analyzed. With this approach, the frequency response of the output power and power gain of a Class A RF PA is measured, also deriving information about the intrinsic operation of its transistors. To carry out this case study, the PA is heterodynally driven, and its electrical behavior is down converted into a lower frequency thermal field acquirable with an InfraRed Lock-In Thermography (IR-LIT) system. After discussing the theory, the feasibility of the proposed approach is demonstrated and assessed with thermal sensors monolithically integrated in the PA. As crucial advantages to RF-testing, this local approach is noninvasive and demands less complex instrumentation than the mainstream commercially available solutions.Peer ReviewedPostprint (author's final draft

MOSFET dynamic thermal sensor for IC testing applications

This paper analyses how a single metal-oxide-semiconductor field-effect transistor (MOSFET) can be employed as a thermal sensor to measure on-chip dynamic thermal signals caused by a power-dissipating circuit under test (CUT). The measurement is subjected to two low-pass filters (LPF). The first LPF depends on the thermal properties of the heat-conduction medium (i.e. silicon) and the CUT-sensor distance, whereas the second depends on the electrical properties of the sensing circuit such as the bias current and the dimensions of the MOSFET sensor. This is evaluated along the paper through theoretical models, simulations, and experimental data resulting from a chip fabricated in 0.35 mu m CMOS technology. Finally, the proposed thermal sensor and the knowledge extracted from this paper are applied to estimate the linearity of a radio-frequency (RF) amplifier. (C) 2016 Elsevier B.V. All rights reserved.Peer ReviewedPostprint (author's final draft

Direct Visualization of Anti-Ferroelectric Switching Dynamics via Electrocaloric Imaging

The large electrocaloric coupling in PbZrO allows using high-speed infrared imaging for visualizing anti-ferroelectric switching dynamics via the associated temperature change. It is found that in ceramic samples of homogeneous temperature and thickness, switching is fast due to the generation of multiple nucleation sites, with devices responding in the millisecond range. By introducing gradients of thickness, however, it is possible to change the dynamics to propagation limited, whereby a single-phase boundary sweeps across the sample like a cold front, at a speed of ≈20 cm s. Additionally, introducing thermostatic temperature differences between two sides of the sample enables the simultaneous generation of a negative electrocaloric effect on one side and a positive one on the other, yielding a Janus-like electrocaloric response.The authors acknowledge financial support to ICN2, which is funded by the CERCA programme/Generalitat de Catalunya and by the Severo Ochoa programme of the Spanish Ministry of Economy, Industry and Competitiveness (MINECO, Grant No. SEV-2017-0706). The authors also acknowledge the support of Plan Nacional (MINECO, Grant Nos. MAT2016-77100-C2-1-P and BES-2016-077392), as well as the Agencia Estatal de Investigacion (Grant No. PID2019-108573GB-C21). R.F. and E.D. thank the Luxembourg National Research Fund (FNR) for funding part of this research through the projects CAMELHEAT/C17/MS/11703691/Defay. This work was also supported in part by the Spanish Ministry of Science, Innovation and Universities under the HIPERCELLS project (RTI2018-098392-B-I00), the Regional Government of the Generalitat de Catalunya under Grant Nos. 2017 SGR 1384 and 2017 SGR 00579. This work was also supported by the National Science Centre, Poland, within the Project No. 2016/21/B/ST3/02242

Origin of the Large Negative Electrocaloric Effect in Antiferroelectric PbZrO3

We have studied the electrocaloric response of the archetypal antiferroelectric PbZrO3 as a function of voltage and temperature in the vicinity of its antiferroelectric-paraelectric phase transition. Large electrocaloric effects of opposite signs, ranging from an electro-cooling of -3.5 K to an electro-heating of +5.5 K, were directly measured with an infrared camera. We show by calorimetric and electromechanical measurements that the large negative electrocaloric effect comes from an endothermic antiferroelectric-ferroelectric switching, in contrast to dipole destabilization of the antiparallel lattice, previously proposed as an explanation for the negative electrocaloric effect of antiferroelectrics.Comment: Article (17 pages) and supplemental material (12 pages) present in .pdf fil

Estratègies de disseny de bombetes LED d'alta lluminositat i baix cost, compatibles amb casquet E27

Avui en dia, l'ús de LEDs com a font de llum ofereix una solució més sostenible i eficient comparat amb altres tipus d'il·luminació. Tanmateix, l'eficiència de la bombeta ve limitada per l'eficiència de l'electrònica necessària per alimentar els LEDS i els elements òptics necessaris per obtenir llum blanca. Per tant, encara es genera una gran quantitat de pèrdues en forma de calor. En aquest treball doncs, s'han estudiat diverses estratègies per al disseny tèrmic d'una nova bombeta amb el clàssic casquet de rosca E27 i amb una alta capacitat lumínica, aconseguint uns resultats prometedors