System Level Transient Thermal Performance of High-Power Dynamic Microelectronics

Author(s):  
Victor Chiriac

System-level thermal transient analysis of High-Power Dynamic Microelectronics System is performed using numerical simulations. The SmartMOS-type device is packaged in 20 lead SOIC module with exposed copper slug. The package is attached to 4-layer PCB with embedded thermal vias. The challenge resides in the transient thermal interaction between the dynamic heat sources (high/low side motors), activated simultaneously at different powering profiles. Several operating steps are simulated, and the transient thermal behavior for each source is analyzed then optimized during the process. The low side motor reaches a peak temperature of ∼126.1°C at 2.25s, while the final temperature reached by the motor after one cycle (2.565 s) is ∼75.9°C. The DC current limit study indicates that the current over 1A exceeds the thermal budget. The case with 0.5A current limit reaches 135°C after 4 cycles, satisfying the thermal budget. Additional studies for an equivalent system were performed with only the high side driver actively dissipating 120W for 2.56 ms. The peak temperature reached by the system during the first cycle (2.56 us) is ∼65°C. Analytical study was performed to evaluate the steady state (final) temperature after a large number of dynamic powering cycles, based on heating/cooling behavior and superposition principle. The peak temperature reached by the IC will not exceed 92°C (using the steady state value and the temperature fluctuations per transient cycle). A correlation to predict the peak temperatures reached by the dynamic system after a long number of powering cycles is provided.

Author(s):  
Victor Chiriac

An extensive 3-D conjugate numerical study is conducted to assess the thermal performance of power packages for automotive applications. The automotive industry deals on a daily basis with various package and module-level thermal issues when managing the routing of very high current. The study provides a better understanding of the strengths and weaknesses of IC incorporation into a system module, for present and future product development. Several packages are investigated, ranging from smaller die/flag size to larger ones, single or multiple heat sources, operating under various powering and boundary conditions. The steady state and transient thermal impact of the thicker lead frame and die attach material on the overall thermal behavior is evaluated. The main concern is exceeding the thermal budget at an external ambient temperature of 85°C, specific for the relatively extreme automotive operating environments. Under one steady state (1W) operating scenario, the PQFN package reaches a peak temperature of ∼106.3°C, while under 37W@40ms of transient powering, the peak temperature reached by the corner FET is ∼260.8°C. With an isothermal boundary (85°C) attached to the board backside, the junction temperature does not change, as the PCB has no significant thermal impact. When the isothermal boundary is attached to package bottom, peak temperature drops by 20% after 40 ms. Additional system level with multiple optimized packages placed on a custom PCB is evaluated numerically and experimentally, placing an emphasis on the superior thermal performance of this new class of power packages for automotive applications. The optimized numerical model approximates closely the empirical results (121–126°C vs. 127.5°C), within 1–2%.


2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Emre Gurpinar ◽  
Burak Ozpineci ◽  
Shajjad Chowdhury

Abstract Direct bonded copper (DBC) substrates used in power modules have limited heat spreading and manufacturing capability due to ceramic properties and manufacturing technology. The ceramic and copper bonding is also subject to high mechanical stress due to coefficient of thermal expansion mismatch between the copper and the ceramic. For wide-bandgap (WBG) devices, it is of interest exploring new substrate technologies that can overcome some of the challenges of direct bonded copper substrates. In this technical paper, the design, analysis, and comparison of insulated metal substrates (IMSs) for high-power wide-bandgap semiconductor-based power modules are discussed. This paper starts with technical description and discussion of state-of-the-art DBC substrates with different ceramic insulators such as aluminum nitride (AlN), Al2O3, and Si3N4. Next, an introduction of IMSs and their material properties, and a design approach for SiC (silicon carbide) metal-oxide-semiconductor field-effect transistor (MOSFET)-based power modules for high-power applications is provided. The influence of dielectric thickness on the power handling capability of the substrate are also discussed. The designed IMS and DBC substrates were characterized in terms of steady-state and transient thermal performance using finite element simulation. Finally, the performance of the IMS and DBC are validated in an experimental setup under different loading and cooling temperature conditions. The simulation and experimental results showed that the IMS can provide high steady-state thermal performance for high-power modules based on SiC MOSFETs. Furthermore, the IMS provided enhanced transient thermal performance, which provided a reduced junction temperature when the module is operated at low fundamental output frequencies in traction drive systems.


2020 ◽  
Vol 142 (4) ◽  
Author(s):  
H. Peter de Bock ◽  
David Huitink ◽  
Patrick Shamberger ◽  
James Spencer Lundh ◽  
Sukwon Choi ◽  
...  

Abstract There are many applications throughout the military and commercial industries whose thermal profiles are dominated by intermittent and/or periodic pulsed thermal loads. Typical thermal solutions for transient applications focus on providing sufficient continuous cooling to address the peak thermal loads as if operating under steady-state conditions. Such a conservative approach guarantees satisfying the thermal challenge but can result in significant cooling overdesign, thus increasing the size, weight, and cost of the system. Confluent trends of increasing system complexity, component miniaturization, and increasing power density demands are further exacerbating the divergence of the optimal transient and steady-state solutions. Therefore, there needs to be a fundamental shift in the way thermal and packaging engineers approach design to focus on time domain heat transfer design and solutions. Due to the application-dependent nature of transient thermal solutions, it is essential to use a codesign approach such that the thermal and packaging engineers collaborate during the design phase with application and/or electronics engineers to ensure the solution meets the requirements. This paper will provide an overview of the types of transients to consider—from the transients that occur during switching at the chip surface all the way to the system-level transients which transfer heat to air. The paper will cover numerous ways of managing transient heat including phase change materials (PCMs), heat exchangers, advanced controls, and capacitance-based packaging. Moreover, synergies exist between approaches to include application of PCMs to increase thermal capacitance or active control mechanisms that are adapted and optimized for the time constants and needs of the specific application. It is the intent of this transient thermal management review to describe a wide range of areas in which transient thermal management for electronics is a factor of significance and to illustrate which specific implementations of transient thermal solutions are being explored for each area. The paper focuses on the needs and benefits of fundamentally shifting away from a steady-state thermal design mentality to one focused on transient thermal design through application-specific, codesigned approaches.


Author(s):  
Victor Chiriac ◽  
Tien-Yu Tom Lee

An extensive 3-D conjugate numerical study is conducted to assess the thermal performance of the novel Power Quad Flat No Lead (PQFN) packages for automotive applications. Several PQFN packages are investigated, ranging from smaller die/flag size to larger ones, single or multiple heat sources, operating under various powering and boundary conditions. The steady state and transient thermal performance are compared to those of the classical packages, and the impact of the thicker lead frame and die attach material on the overall thermal behavior is also evaluated. Under one steady state (1W) operating scenario, the PQFN package reaches a peak temperature of ~106.3°C, while under 37W@40ms of transient powering, the peak temperature reached by the corner FET is ~260.8°C. With an isothermal boundary (85°C) attached to the board backside, the junction temperature does not change, as the PCB has no significant thermal impact. However, when the isothermal boundary is attached to package bottom, it leads to a drop in by almost 20% after 40 ms. Additional transient cases are evaluated, with an emphasis on the superior thermal performance of this new class of power packages for automotive applications.


Author(s):  
Daniel Tang ◽  
Mike Evans ◽  
Paul Briskham ◽  
Luca Susmel ◽  
Neil Sims

Self-pierce riveting (SPR) is a complex joining process where multiple layers of material are joined by creating a mechanical interlock via the simultaneous deformation of the inserted rivet and surrounding material. Due to the large number of variables which influence the resulting joint, finding the optimum process parameters has traditionally posed a challenge in the design of the process. Furthermore, there is a gap in knowledge regarding how changes made to the system may affect the produced joint. In this paper, a new system-level model of an inertia-based SPR system is proposed, consisting of a physics-based model of the riveting machine and an empirically-derived model of the joint. Model predictions are validated against extensive experimental data for multiple sets of input conditions, defined by the setting velocity, motor current limit and support frame type. The dynamics of the system and resulting head height of the joint are predicted to a high level of accuracy. Via a model-based case study, changes to the system are identified, which enable either the cycle time or energy consumption to be substantially reduced without compromising the overall quality of the produced joint. The predictive capabilities of the model may be leveraged to reduce the costs involved in the design and validation of SPR systems and processes.


1990 ◽  
Vol 37 (4) ◽  
pp. 902-907 ◽  
Author(s):  
A. Haji-Sheikh
Keyword(s):  

Author(s):  
Mathias Ziegler ◽  
Fritz Weik ◽  
Jens W. Tomm ◽  
Thomas Elsaesser ◽  
Wlodzimierz Nakwaski ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document