Power Module Design with Thick Copper PCB: A Case Study in Thermal & Electrical Integration

This case study documents the engineering process of migrating a high-current power module design from discrete busbars and wiring to an integrated thick copper PCB solution. We detail the specific design objectives: maximizing current density, creating an efficient thermal path from power semiconductors to a heatsink, and ensuring long-term reliability under thermal cycling. The study provides quantitative results on electrical performance (reduced voltage drop) and thermal management (lower peak temperatures and gradients).

• Application Requirement: High-current inverter for EV/industrial drive.
• PCB Stack-up & Material: Selection of high-Tg laminate and 4oz copper layers.
• High-Current Path Design: Power plane optimization and grounding strategy for low inductance.
• Thermal Solution: Direct thermal pad design under MOSFETs/IGBTs, connected to a filled thermal via array and an integrated heatsink.
• Insulation & Safety: Managing creepage and clearance for high-voltage isolation.
• Manufacturing Implementation: Addressing lamination and drilling challenges for the thick copper structure.
• Validation Results: Cross-section analysis, thermal imaging data, and thermal cycling test results.