High current printed circuit boards (PCBs) are a unique type of circuit board. Built with heavy copper material, they offer additional resistance to thermal fluctuations that can accompany high currents. A number of applications require high current PCBs, which vary in industry and complexity.
High Current PCBs Defined
This class of PCBs is suitable for applications that require transferring high power loads. Due to the amount of copper used in their design, high current PCBs offer additional resistance to thermal fluctuations that can accompany high currents. They can conduct hundreds or even thousands of amps of current for extended periods, powering devices and systems with more demanding power consumption requirements.
What Are Heavy Copper PCBs?
Heavy copper PCBs are a subtype of high current PCBs that contain at least 3 ounces of copper in both the external and internal layers of the board. They offer several advantages for high current projects, including:
Structural simplicity: Heavy copper PCBs can be made denser with fewer layers, which creates a compact and simple structure.
Lower failure rate: Copper is an excellent thermal conductor, which makes heavy copper PCBs more effective at drawing heat away from sensitive board components and reducing the risk of failure.
Cost savings: Although copper is a more costly material than others, heavy copper PCBs enable you to use less of it throughout the rest of your application and cut costs.
They also have several drawbacks that are important to consider, including a higher capital investment. It’s also important to ensure your board uses the right substrate, as the thermal expansion of the copper can cause thermal stress to the substrate.
High Current PCB Design Considerations
In high-power applications, maintaining power integrity is critical to prevent voltage drops or even permanent damage to the board’s components. Some of the most important design considerations for high current and heavy copper PCBs include:
Location of sensitive components: Positioning heat-sensitive components away from traces can help you minimize the risk of damage by thermally isolating them.
Substrate: Substrates with higher thermal conductivity, such as ceramic-filled polytetrafluoroethylene, can enhance heat dissipation.
Trace length: Shorter traces have lower resistance, which reduces power loss and heat generation in applications requiring high power.
Trace width: Wider traces provide higher current-carrying capacity and lower resistance for optimal board function.
Copper bus bars: For especially demanding applications with currents over 100 amps, thick traces aren’t enough. Using solderable copper bus bars instead can support much larger currents for longer periods of time.
Electroplating: Electroplating a printed circuit board can help reduce trace resistance, improve heat conduction and enhance heat dissipation.
Advanced etching techniques: Standard etching techniques on heavy copper can lead to poor results, such as uneven edges and over-etching in the margins.
Board layers: Multilayer boards with power/ground planes create low-impedance return paths for currents across the board, enhancing flow and providing versatility for more complex applications.
Decoupling capacitors: Strategically placing decoupling capacitors close to power supplies can help prevent voltage drops by serving as local charge reservoirs and supplying additional current when needed.
Thermal vias and copper pours: Arranging thermal vias and copper pours near board hotspots helps spread heat more efficiently and reduce thermal resistance, improving overall heat dissipation.
Applications requiring especially complex high-voltage PCB design benefit most from outsourced design and assembly services because they ensure higher quality and greater efficiency.
What Structures Are Best for High Current PCBs?
High current PCBs can come in several forms, which can be useful in different situations. Some examples include:
Single-sided: This simple board type has all its conductive pathways and electronic components on one side of the board.
Double-sided: A double-sided PCB has a conductive layer on both sides of the board, which enables you to create more complex circuits with higher component density.
Multilayer: A multilayer PCB contains three or more layers of copper foil, allowing for a highly compact construction for use in sophisticated electronics.
Rigid-flex: A rigid-flex PCB combines a flexible substrate layer with a rigid substrate to provide extra versatility and optimize board strength.
Users can achieve multiple functions and relay greater currents with a more complex board.
High Current PCB vs. High Voltage PCB: Key Design Differences
PCB design for high power applications can be complex due to various reasons, such as the specific type of electrical phenomena the board is intended to withstand. Voltage requires specific design elements to improve its capacity, while current requires different elements.
High voltage PCBs space traces out from each other to handle high electrical voltage without arcing. They also use specialized insulating materials to contain voltage within the board.
High current PCBs use wide traces or solderable copper bars to support larger currents without overheating or electronic failure. They typically use thicker advanced substrate materials than high voltage PCBs, which enables higher heat conductivity and dissipation.
Applications for High Current PCBs
A number of applications require high current PCBs with varying levels of complexity:
Automotive: High current PCBs can withstand the high power required for electric vehicle components, including the motor, battery and infotainment system.
Industrial machinery: Heavy equipment and factory machinery need high current PCBs to run smoothly without overheating.
Telecommunication: The rise of 5G has significantly increased power demand for telecommunications equipment such as routers and base stations, and high current PCBs are essential for handling this demand without damage.
Renewable energy: High current PCBs enable companies to use the power generated by solar panels, wind turbines and hydroelectric dams.
Consumer electronics: High-performance computers, household appliances, gaming systems and other electronics use high current PCBs to ensure smooth operation and reduce the risk of failure.
Power supplies: High current PCBs manage the flow of electricity in high-power devices like servers and networking equipment.
Contact Via Technology, Inc. for High Current PCB Design and Manufacturing
Partnering with a team of experts in PCB layout and design can help you ensure your PCB matches the needs of your application regardless of its scale. If you’re interested in building projects with high current PCBs, Via Technology can help you get started. Our experienced team of engineers will also work on isolating high voltage areas and noise sources to produce high-quality PCBs for your products.
We have more than 30 years of experience developing PCB solutions for various industries, including the military, life sciences, commercial products and more. From military grade electronics to commercial aviation products, our high current PCBs are thoroughly tested and carefully designed. Contact us to learn more about how we can assist with your project, or request your free quote today.
