As OBC and DC/DC power density rises, teams must choose between 2 oz boards, heavy-copper PCBs and locally reinforced SMT busbars. A production-ready decision puts switching loops, cooling, insulation and assembly sequence on the same drawing.
Map the real current path from the topology
Mark continuous current, peak current and pulse duration across rectification, switching devices, magnetics, DC-link capacitors and output terminals. Do not use a short lab peak as a continuous rating. For high di/dt loops, also capture loop area, branch length and commutation-node location.
Coordinate SMT busbars with terminals
SMT busbars add conductive cross-section on a standard PCB and can transfer heat toward a chassis or heat spreader. Screw or solder terminals provide the external transition. Check segmented pads, paste volume, coplanarity, nozzle access and tool clearance together so the electrical solution remains reflowable.
- Record continuous and peak current, pulse duration and allowable rise
- Define interface materials between busbar, PCB, chassis and terminal
- Measure four-wire voltage drop and thermal images on prototypes
RFQ inputs that reduce quotation ambiguity
The RFQ should include 2D/3D data, material grade, plating boundaries, insulation keep-outs, PCB land pattern, packaging orientation and annual volume. For high-voltage OBC assemblies, add target creepage, dielectric test conditions and ambient range. Every current and temperature value needs its test condition.