EPP Europe P2.2023

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» PCB & ASSEMBLY Typical EV power scheme Source: Ventec International Group Thermal management using insulated metal substrates Applying IMSs in lighting and power conversion The first article in this two-part series described the composition, principles, and thermal properties of insulated metal substrates (IMSs). This article looks at use cases in power conversion and lighting, the effects of high-emissivity coating, and often overlooked design considerations. » Chris Hanson, Global Head IMS Technology, Ventec International Group LED lighting dominates new designs for building and automotive applications. However, excessive operating temperature can change the chromaticity of the emitted light, reduce lifetime, and may destroy the LED. Proper thermal management must therefore restrict the temperature to below the safe maximum for a semiconductor device. Applications Among automotive lighting applications, matrix headlamps contain multiple emitters closely spaced on a single substrate to provide a high lumen output. Typically, a high-conductivity IMS featuring either an aluminium or copper baseplate is used. Non-reinforced dielectric, usually about 0.05mm-thick, minimizes CTE-related stresses between an aluminium baseplate and copper foil. In very high-power applications, a copper baseplate can avoid excessive stress due to CTE mismatch. Spotlights or daytime running lamps (DRLs) often comprise multiple small boards, each containing two or three emitters. An IMS aluminium baseplate and 0.075–0.010 mm dielectric, resulting in thermal conductivity of 2–3 W/m.K is commonly used in these cases. Turn signals are often subject to extreme constraints in size and shape because of their placement on a vehicle’s extremities. A three-emitter unit would need to dissipate about 7 watts, which can be achieved using an IMS with 0.05–0.075 mm dielectric thickness and thermal conductivity of about 3 W/m.K. Attaching the IMS to the vehicle chassis further enhances thermal dissipation. General lighting and power conversion Applications such as street lighting require powerful, reliable illumination with extended replacement intervals. An IMS with thermal conductivity of about 3 W/m.K and a 0.075–0.10 mm dielectric effectively limits the LED temperature and preserves chromaticity, while allowing a high drive current. In very high-power applications such as industrial welders, where the torch can draw 50 A to 400 A or more from chopper or inverter circuits, a heavy-duty copper foil, high-voltage dielectric, and a high-conductivity baseplate are combined with heatsinks and oil cooling. High-power air-conditioners commonly use IMSs 22 EPP Europe » 11 | 2023
to connect power inverters and triac circuits to the air-cooled chassis or heatsink. An aluminium baseplate and conductivity of up to 10 W/m.K are typical. Automotive electrification In addition to LED lighting, electric power steering (EPS) and electrical pumps and fans are replacing traditional mechanical or hydraulic units in today’s cars. Additionally, electric and hybrid vehicles contain AC/DC converters for regenerative braking and on-board chargin; DC/DC converters for dual-battery management and bi-directional power supply; highvoltage batteries, and traction motors. The power semiconductors in these systems can dissipate total power from several hundred watts up to tens of kilowatts. Targets for module size and reliability can be met cost-effectively using a high-performing IMS with thermal conductivity of 3–4.2 W/m.K and 0.10–0.15 mm dielectric. Power transistors can be soldered to the IMS circuit layer as bare die. The baseplate is often integrated with a cast metal chassis or may be attached to a liquid-cooled heatsink. Source: Ventec International Group Maximising IMS performance The application depicted above in the diagram shows a small automotive lighting assembly originally built using FR-4 board fitted with a heatsink. Exchanging this for IMS as seen in the lower image with a high-emissivity surface treatment helped achieve a Automotive lighting assembly with heatsink (above), and equivalent with high-emissivity IMS (below) PIEK Training & Certification IPC Training & Certification Consultancy Test Center PB’s & PBA’s Audit services IPC Validation Services PIEKTRAINING.com EPP Europe » 11 | 2023 23
Page 1 and 2: Issue 11 | 2023 www.epp-europe.eu E
Page 3 and 4: » EDITORIAL Dear readers, Waste no
Page 5 and 6: The NEXT EVOLUTION of SOLDER Single
Page 7 and 8: SPECIAL Road to sustainability ASMP
Page 9 and 10: the cost of capital; 88 percent sho
Page 11 and 12: Expanding digital twin applications
Page 13 and 14: Source: Pixabay IPC August 2023 Eco
Page 15 and 16: industrial automation is also an im
Page 17 and 18: AT A GLANCE Here, Koh Young explain
Page 19 and 20: Source: Koh Young Using advanced 3D
Page 21: Zusammenfassung Im Zeitalter der in
Page 25 and 26: Product Updates « PCB & ASSEMBLY R
Page 27 and 28: Human error and inconsistency Manua
Page 29 and 30: Easy to integrate Laser marking met
Page 31 and 32: Source: Siemens With the shift to h
Page 33 and 34: Electronics production process Sour
Page 35 and 36: Source: Indium Corporation Many par
Page 37 and 38: Source: Indium Corporation The 0.00
Page 39 and 40: Forces in X direction (transport di
Page 41 and 42: Yield points of various solder past
Page 43 and 44: Product Updates « PCB & ASSEMBLY O
Page 45 and 46: 5S and cleaning processes One of th
Page 47 and 48: PCB & ASSEMBLY « Shitsuke / Sustai
Page 49 and 50: gineering tools or line code, there
Page 51 and 52: Product Updates « PCB & ASSEMBLY E
Page 53 and 54: changes in inspection technologies
Page 55 and 56: Inspection solutions on display in
Page 57 and 58: Runtime tool to measure the force a
Page 59 and 60: ecwc16 ELECTRONIC CIRCUITS WORLD CO

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