High-Current PCB Design: Trace Width, Thermal Rise & Via Optimization

Designing PCBs for tens or hundreds of amperes requires a shift in thinking from signal integrity to thermal-electrical co-design. This guide focuses on the quantitative methods for determining conductor width, copper weight, and via arrays to manage I²R losses and temperature rise. We analyze the trade-offs between external and internal layer routing, the role of power planes in heat spreading, and provide practical strategies for connector and solder joint reliability under high-current stress.

• Thermal-Electrical Coupling: Joule heating (I²R) as the primary design constraint.
• Conductor Sizing: Applying IPC-2152 standards for trace width vs. temperature rise, considering copper thickness.
• Layer Location Effects: Current derating for internal layers vs. external layers.
• Via Current Capacity: Calculating via barrel resistance, using parallel arrays, and managing hotspots.
• Power & Ground Planes: Design for low-impedance distribution and thermal spreading.
• Component & Connector Interfaces: Pad design, solder joint reliability, and contact resistance minimization.
• Voltage Drop (IR Drop): Calculation and mitigation strategies.