Book Excerpt: Thermal Management With Insulated Metal Substrates, Part 4


Reading time ( words)

The following is an excerpt from Chapter 4 of "The Printed Circuit Designer's Guide to... Thermal Management With Insulated Metal Substrates," written by Ventec International Group’s Didier Mauve and Ian Mayoh. In this free eBook, the authors provide PCB designers with the essential information required to understand the thermal, electrical, and mechanical characteristics of insulated metal substrate laminates.

Chapter 4: Application Examples

Main Application Areas
Insulated metal substrates find many applications in automotive and industrial LED, power conversion, general lighting, street safety, backlight unit, and e-vehicle sectors (Figure 4.1).

ventec_ch4_fig1.jpg 

Figure 4.1: Primary applications for IMS.

Headlamps
Compact LED lamp units give car stylists extra freedom. Bright lighting at near-daylight color temperatures gives drivers a clear view. However, as much as 80% of the electrical power supplied is dissipated as heat, which presents engineers with severe thermal management challenges.

Matrix headlamps feature multiple closely-spaced emitters on a single substrate. A substrate of high thermal conductivity, featuring either an aluminum or copper baseplate, and dielectric thickness of about 0.002” (0.05 mm) is a typical choice to ensure long-term reliability. A non-reinforced dielectric minimizes stressors due to CTE mismatch between the copper foil and aluminum baseplate. A copper baseplate may be used if the matrix density is extremely high and the power is very high to address potential CTE mismatches. Spotlights with multiple boards, each containing two or three emitters, concentrate the thermal challenge on smaller substrates featuring an aluminum baseplate and 2–3 W/mK overall thermal conductivity including the dielectric layer, which is typically about 0.003–0.004” (0.075–0.010 mm).

Automotive Turn Signals
LEDs for turn signals are typically in the 3W power range. A three-emitter unit dissipates about 7 watts of thermal energy that must be extracted from the component. IMS is often the most efficient and cost-effective thermal connection to the metallic chassis. Extreme size and shape constraints can direct designers toward a substrate with 3 W/ mK thermal conductivity and 0.002” or 0.003” (0.05–0.075 mm) dielectric.

High-Power Motor Drive for Electric Power Steering
Electric power steering (EPS) and other motor-driven mechanisms, including high-power electric-traction inverters in EVs, can present even tougher thermal management challenges. Targets for module size and reliability can be met cost-effectively using a high-performing IMS with thermal conductivity of 3–4.2 W/mK and 0.004”–0.006” (0.10–0.15 mm) dielectric. Direct bonded copper (DBC) is an alternative. In extremely high-power applications, such as inverters, power transistors may be soldered to the IMS/DBC circuit layer as bare die, and a liquid-cooled heat sink attached to the baseplate. In some modules, such as combined onboard charger (OBC) and DC/DC-converter units for EVs, the baseplate is integrated with a cast metal chassis, and the specification determined in consultation with the foundry.

To download this free eBook, published by I-Connect007, click here.

To view the entire I-Connect007 eBook library, click here.

 

Share




Suggested Items

Plating on Silver: What’s Old is New Again

07/07/2022 | Denis Jacques, Technic Inc.
About three decades ago, immersion silver, a nitrate-based process, gained a lot of market share in the world of PCB final finishes. More economical than ENIG, flat, solderable, and conductive, it had everything going for it—everything but corrosion resistance in a harsh environment, that is. Champagne voids were also an issue, along with line reduction. But the worst drawback, the characteristic that made the part short over time, was creep corrosion. A build-up of copper sulfide salt that grows in contact with a sulfur-rich environment, heat, and moisture resulted in failures in the field. This was enough to scar the process for good.

EIPC Summer Conference 2022: Day 2 Review

06/29/2022 | Pete Starkey, I-Connect007
Örebro, Sweden on June 15 brought a bright and early start to Day 2 of the EIPC Summer Conference for those who had enjoyed the previous evening’s networking dinner, but had resisted the temptation to over-indulge or to carry on their long-awaited catch-up conversations with old friends into the small hours. All but a few were in their seats for 9 a.m., awake and attentive for Session 4 of the conference, on the theme of new process technologies, moderated by Martyn Gaudion, CEO of Polar Instruments.

EIPC Summer Conference 2022: Day 1 Review

06/28/2022 | Pete Starkey, I-Connect007
At last, a live EIPC conference and this time in the Swedish city of Örebro, “where history and contemporary culture converge,” a pleasant and convenient location for an event that included a privileged visit to the Ericsson facility in Kumla. Around 100 delegates made the journey and the Örebro Scandic Grand Hotel was an excellent conference venue for the June 14-15 conference.



Copyright © 2022 I-Connect007. All rights reserved.