What Is a High Current PCB?
As the electrification of automobiles such as hybrids, EVs, and PHEVs advances, printed circuit boards (PCBs) are required to support high current PCBs.
Although it is possible to respond to high current PCBs by increasing the pattern width, there is a limit to the pattern of expansion width in the current situation, where smaller electronic components are required at the same time.
However, the current demand for miniaturization of electronic components has limited the ability to expand the pattern width.
While the copper thickness of a typical PCB is 35 µm, high current PCBs are capable of handling high currents by realizing circuits with a copper thickness of up to 2000 µm.
Uses of High Current PCBs
They are used for miniaturization of electrical components with large electrical loads, such as high-current control circuits, high-power supplies, switching and motor circuits, breakers, fuse boxes, etc., for electric vehicles, hybrids, PHEVs, robots, as well as gasoline engine vehicles, which are becoming more and more electronic.
They are also used as printed circuit boards with excellent thermal diffusion and dissipation as part of LED heat dissipation measures for power devices that generate heat at high temperatures, such as IGBTs, power MOSFETs, Schottky diodes, and thyristors, as well as for traffic signals and outdoor billboards.
Principle of High Current PCBs
Compared to ordinary PCBs, high current PCBs need to carry much higher current, for example, 2A to 100A for automotive electronic devices, and it is necessary to create a copper pattern cross-sectional area that matches the amount of current flowing in the pattern.
An important point in designing high current PCBs is that the etching method (dissolving copper foil), which is the general manufacturing method for current PCBs, creates a pattern by etching copper based on an etch resist pattern drawn on the copper surface. However, since the copper foil thickness of high-current boards is thick, dissolution proceeds from the top of the copper foil in this method, resulting in etching not only in the depth direction but also between patterns, resulting in a trapezoidal cross-section of the pattern and a loss of cross-sectional area accuracy.
Therefore, it is not desirable to design high current PCBs using the same method as that used for ordinary printed circuit boards for signals.
However, there are significant advantages for users who mass-produce high current PCBs, and we expect that improvements in materials and manufacturing methods will lead to lower costs and increased use of high current PCBs in the future. However, it is a big advantage for users who mass-produce high-current products.