Liquid Cooling in an LTCC-Module for a Switched Mode Amplifier

2017 ◽  
Vol 2017 (NOR) ◽  
pp. 1-7
Author(s):  
Peter Uhlig ◽  
Alexandra Serwa ◽  
Ulrich Altmann ◽  
Tilo Welker ◽  
Jens Müller ◽  
...  
Keyword(s):  
Close Contact ◽  
Junction Temperature ◽  
Liquid Cooling ◽  
Millimetre Wave ◽  
Active Devices ◽  
Cooling Channels ◽  
Security Applications ◽  
Micro Channels ◽  
Convection Cooling ◽  
Forced Air

Abstract Low Temperature Co-fired Ceramic (LTCC) is a proven packaging technology for microwave and millimetre-wave applications. Advanced low-loss material systems and improved manufacturing technology facilitate economic and highly reliable packaging solutions for automotive, telecom, medical and security applications. The fact that the substrate is hermetic facilitates unique packaging concepts where the LTCC multilayer is part of a hermetic package. However, there is a trade-off for the increasing complexity of these modules: When active devices are involved, the density of power dissipation is also rising. Liquid cooling provides an alternative where (forced air) convection cooling is not possible for lack of space or because of other limitations. With the integration of micro-channels into the LTCC-multilayer-stack the microwave-substrate becomes part of the piping for liquid cooling and brings the coolant in close contact to the heat source. As an example for such a solution a switched mode amplifier shall be presented that uses liquid cooling for the power transistor. Two different approaches for the routing of the cooling channels inside the LTCC are compared with cooling on a metal block at constant temperature. For the exact determination of all parameters, dissipated power and temperature on the die (junction temperature) a thermal test die is used instead of the transistor for the test vehicles.

Thermal Characterization of Micro-Channels Heat Exchanger for High-End Processors

2007 ◽  
Author(s):  
Khalid Sheltami ◽  
Gamal Refai-Ahmed
Keyword(s):  
Heat Exchanger ◽  
Form Factors ◽  
Thermal Characterization ◽  
Cooling Capacity ◽  
Junction Temperature ◽  
Market Demand ◽  
Liquid Cooling ◽  
Hydraulic Impedance ◽  
Micro Channels

With the market demand of more performance at smaller form factors, the technology direction is moving into increasing the transistors in semiconductor devices by a significant percentage, which translates into increasing the heat flux by a substantial amount. Thermal management of these devices, within a compact form factors, at an acceptable junction temperature, is a challenging task for the industry and researchers alike. This paper presents the significant increase in cooling capacity by using micro-channels technology in liquid cooling and highlights the advantages of this solution over macro-channels. The current study has examined the effects of both the channel width and its wall thickness on the heat transfer coefficient and hydraulic impedance. The present investigation is supported by CFD simulations and experimental results. The preliminary results of this study show that micro-channels technology could improve the heat exchanger performance by 64%. Finally, this paper proposes an empirical model to account for the effects of the geometric parameters of the heat exchanger on its thermal performance, as well as, its hydraulic characteristic.

Cooling of Thermal Enhanced BGA Package Using Foam Metal Heat Sinks

2000 ◽  
Author(s):  
Jenn-Jiang Hwang ◽  
Chung-Hsing Chao
Keyword(s):  
Heat Sink ◽  
Power Dissipation ◽  
Thermal Characterization ◽  
Junction Temperature ◽  
Pin Fin ◽  
Bga Packages ◽  
Plastic Ball ◽  
Bga Package ◽  
Foam Metal ◽  
Forced Air

Abstract This study reported thermal performance of a thermally enhanced plastic ball grid array (PBGA), namely T2-BGA™ which incorporates a heat slug in package, with a foam-metal heat sink on the top of this package. Experimental measurement of junction-to-ambient thermal resistance is performed in accordance with the SEMI standards of G38-0996 and G42-0996 for thermal characterization of BGA packages. Allowable power dissipation is subject to the constraint of junction temperature (Tj) at 95°C and ambient temperature (Ta) in chassis at 35 °C under free and forced air (0 ∼ 3 m/s) conditions. Based on this constraint, allowable power dissipation of a regular PBGA with a commercial pin fin heat sink under free and 3 m/s forced air is 5.45 W and 9.17 W compared with those of T2-BGA with a foam heat sink of 6.80 W and 19.6 W respectively. This results show that T2-BGA™ with a foam heat sink offers enormous potential to high power package applications.

Direct Liquid Cooling of High Flux LED Systems: Hot Spot Abatement

2013 ◽  
Author(s):  
Enes Tamdogan ◽  
Mehmet Arik ◽  
M. Baris Dogruoz
Keyword(s):  
Hot Spots ◽  
Hot Spot ◽  
Heat Removal ◽  
Heat Fluxes ◽  
Light Extraction ◽  
Junction Temperature ◽  
System Level ◽  
Design Parameters ◽  
Liquid Cooling ◽  
Wide Range

With the recent advances in wide band gap device technology, solid-state lighting (SSL) has become favorable for many lighting applications due to energy savings, long life, green nature for environment, and exceptional color performance. Light emitting diodes (LED) as SSL devices have recently offered unique advantages for a wide range of commercial and residential applications. However, LED operation is strictly limited by temperature as its preferred chip junction temperature is below 100 °C. This is very similar to advanced electronics components with continuously increasing heat fluxes due to the expanding microprocessor power dissipation coupled with reduction in feature sizes. While in some of the applications standard cooling techniques cannot achieve an effective cooling performance due to physical limitations or poor heat transfer capabilities, development of novel cooling techniques is necessary. The emergence of LED hot spots has also turned attention to the cooling with dielectric liquids intimately in contact with the heat and photon dissipating surfaces, where elevated LED temperatures will adversely affect light extraction and reliability. In the interest of highly effective heat removal from LEDs with direct liquid cooling, the current paper starts with explaining the increasing thermal problems in electronics and also in lighting technologies followed by a brief overview of the state of the art for liquid cooling technologies. Then, attention will be turned into thermal consideration of approximately a 60W replacement LED light engine. A conjugate CFD model is deployed to determine local hot spots and to optimize the thermal resistance by varying multiple design parameters, boundary conditions, and the type of fluid. Detailed system level simulations also point out possible abatement techniques for local hot spots while keeping light extraction at maximum.

LTCC Based Highly Integrated SiPM Module With Integrated Liquid Cooling Channels for High Resolution Molecular Imaging

2017 ◽  
Vol 2017 (1) ◽  
pp. 000398-000405
Author(s):  
Rainer Dohle ◽  
Ilaria Sacco ◽  
Thomas Rittweg ◽  
Thomas Friedrich ◽  
Gerold Henning ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Positron Emission Tomography ◽  
Magnetic Resonance ◽  
Flip Chip ◽  
Emission Tomography ◽  
Resonance Imaging ◽  
Liquid Cooling ◽  
Cooling Channels ◽  
Positron Emission ◽  
Ltcc Substrate

Abstract We present a very compact hybrid detection module based on an advanced liquid-cooled LTCC substrate. The double sided hybrid combines 144 photo detectors and 4 specialized flip-chip readout ASICs used for the readout of scintillation crystals with application in time-of-flight (TOF) Positron Emission Tomography (PET) combined with Magnetic Resonance Imaging (MRI). Positron Emission Tomography is mostly known for its use in oncology applications, cardiovascular disease, and imaging of brain functions. If MRI images and PET images are combined, completely new medical diagnostic and treatment prospects are feasible since MRI delivers precise anatomical information. One of the biggest challenges is the development of miniaturized detector modules that are highly functional and MRI compatible. Our SiPM module has an area of 32.8 by 32.0 mm2 and contains 12 × 12 SiPMs in a pitch of 2.5 mm2. The SiPM readout of the 144 channels is performed by four PETA6 ASICs. The LTCC substrate with 2.1 mm thickness has been manufactured using the most advanced technologies developed at MSE. In order to guarantee the manufacturability in serial or mass production, DP951 P2 green tape has been used. For the cooling channels, special technology has been developed by MSE. The liquid cooling channels inside the LTCC substrate provide excellent cooling for the ASICs, the SiPMs, and thermal insulation between ASICs and SiPMs and allow a very compact design of the detector modules, reducing their height by 50% compared with other technical solutions. This makes both smaller scanners and larger detector rings possible, the latter being needed for heavier patients. We can insert a ring of our modules in an existing MR scanner. Operating the SiPMs at low temperature improves their performance, reducing the effects of dark count rate and improving image quality. There is no heat sink, heat pipe, or other cooling element attached to the back side of the ASICs. In order to avoid interference between the PET and MRI system, short signal length is required for minimizing pickup loops and eddy currents. The 12 SiPM arrays with 2×6 geometry are wire bonded only at the edges of the SiPMs to the LTCC, enabling the use of nearly the whole detector area for photon detection, which is of paramount importance for excellent image quality. At the opposite side of the substrate, four ASICs with 272 μm bump pitch are flip-chip solder assembled to the LTCC substrate including underfilling, and a few SMD components are mounted. A scintillator crystal array on top of the SiPMs converts gamma-rays (511 keV photons produced from positron-electron annihilation) into light. LTCC substrates and all components are fully MRI compatible, which allows integration of PET with magnetic resonance imaging without mutual interference. The performance of a PET detector is characterized by its time resolution, energy resolution, detection efficiency, and spatial resolution. Each of these factors has a huge influence on the quality of the final PET image. All of these factors are improved with our novel technical solution. With measurements on prototypes, state-of-the-art coincidence time resolution (CTR) for pairs of identical detectors in combination with high spatial resolution have been obtained. The paper elucidates the impact of the employed technology on the performance of advanced PET/MRI detector modules. Novel features of the detector modules will help to enhance the “molecular sensitivity” of PET/MRI scanners.

scholarly journals Hybrid Battery Thermal Management System in Electrical Vehicles: A Review

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6257
Author(s):  
Chunyu Zhao ◽  
Beile Zhang ◽  
Yuanming Zheng ◽  
Shunyuan Huang ◽  
Tongtong Yan ◽  
...  
Keyword(s):  
Thermal Management ◽  
Management System ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Battery Thermal Management ◽  
Thermal Management System ◽  
Battery Thermal Management System ◽  
Cooling Phase ◽  
Li Ion ◽  
Forced Air

The Li-ion battery is of paramount importance to electric vehicles (EVs). Propelled by the rapid growth of the EV industry, the performance of the battery is continuously improving. However, Li-ion batteries are susceptible to the working temperature and only obtain the optimal performance within an acceptable temperature range. Therefore, a battery thermal management system (BTMS) is required to ensure EVs’ safe operation. There are various basic methods for BTMS, including forced-air cooling, liquid cooling, phase change material (PCM), heat pipe (HP), thermoelectric cooling (TEC), etc. Every method has its unique application condition and characteristic. Furthermore, based on basic BTMS, more hybrid cooling methods adopting different basic methods are being designed to meet EVs’ requirements. In this work, the hybrid BTMS, as a more reliable and environmentally friendly method for the EVs, will be compared with basic BTMS to reveal its advantages and potential. By analyzing its cost, efficiency and other aspects, the evaluation criterion and design suggestions are put forward to guide the future development of BTMS.

Numerical Study and Experimental Validation of the Thermal Performance for a Parallel Channel Optical Module

2003 ◽  
Author(s):  
Z. F. Shi ◽  
Albert C. W. Lu ◽  
Eric Tan ◽  
Ronson Tan
Keyword(s):  
Ambient Temperature ◽  
Thermal Performance ◽  
Numerical Study ◽  
High Ambient Temperature ◽  
Junction Temperature ◽  
Cavity Surface ◽  
Optical Interconnection ◽  
Laser Array ◽  
Optical Module ◽  
Forced Air

To meet the insatiable demand for data bandwidth in VSR (very short reach up to 300m) applications including server and routers, parallel optical interconnection offers a promising solution in terms of performance and cost effectiveness. A 12-channel pluggable paralle optical transmitter module has been developed to achieve a data rate of 2.5 Gb/s per channel. To maintain the robustness of the optical signal integrity under different environmental conditions, the thermal management is crucial. In this paper the thermal performance evaluation of the optical module was carried out through both numerical simulation and experimental verification. The optical module mainly consists of a VCSEL (vertical cavity surface emitting laser) array, a driver IC and a heat sink. Three types of heat sinks were integrated into the transmitter module separately. The thermal environments used for this evaluation include the normal and high ambient temperature, and both still-air and forced-air conditions. The ambient temperature and the wind speed were controlled by using a Wind Tunnel. The simulation was performed by using a CFD (computational fluid dynamics) program. In all the three modules, the simulation and experimental results of the junction temperature have shown good agreements. For Module 1 under the high ambient temperature, a forced-air condition was required to keep the junction temperature below 70°C. For Module 2 and Module 3, the junction temperature can be controlled below 70°C even under the high ambient temperature without using a fan.

Fabrication of Plastic Micro-Channels for Microfluidics Solvent Extraction

2015 ◽  
Author(s):  
Tatjana Dankovic ◽  
Gareth Hatch ◽  
Alan Feinerman
Keyword(s):  
Solvent Extraction ◽  
Close Contact ◽  
Middle Layer ◽  
Extraction Process ◽  
Immiscible Fluids ◽  
Immiscible Fluid ◽  
Intimate Contact ◽  
Two Fluids ◽  
Massively Parallel Systems ◽  
Micro Channels

In this work plastic micro channel systems were investigated as a potential device for micro solvent extraction of rare earth elements. The proposed microfluidic structures are made by laser welding of three layers of inexpensive thermoplastic films which form separate paths (top and bottom channels) for each of the immiscible fluids. The middle layer is perforated in order to provide contact between two fluids and to enable the extraction process. Experiments were performed to show that two different immiscible fluids (water and 1-octanol) can flow through the fabricated device and exit at separate outlets without mixing even when those fluids get into close contact within the main channel. Experimental results for single devices show that immiscible fluids can be brought into intimate contact and then separated with compliant polymeric microfluidic devices. The transfer of a compound from one immiscible fluid to the other was verified by dye exchange between the immiscible fluids. The same fabrication method is a promising technique for fabrication of massively parallel systems with larger throughput.

Integrated Micro-Channel Cooling in Industrial Applications

2004 ◽  
Author(s):  
C. C. S. Nicole ◽  
R. Dekker ◽  
A. Aubry ◽  
R. Pijnenburg
Keyword(s):  
Forced Convection ◽  
Flow Rate ◽  
Single Phase ◽  
Industrial Applications ◽  
Experimental Results ◽  
Junction Temperature ◽  
Micro Channel ◽  
Cooling Device ◽  
Micro Channels ◽  
Cooling Of Electronics

Experiments and simulations have been performed in order to assess the feasibility of integrated single phase forced convection in silicon micro-channels for the cooling of electronics. A silicon micro-channel device has been fabricated with channel size of 100 by 300 μm. Cooling has been achieved with a heater dissipating up to 370 W (750 W/cm2) with a flow rate of 0.1 1/min. In this case the maximum junction temperature was 130°C. This paper presents characteristics of such a cooling device as well as its description and fabrication. Experimental results are shown and compared with simulations. A description of a rough optimization of the channels size is given followed by comments describing the main advantages and drawbacks regarding industrial feasibility.

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