Boards for high voltage systems can be space constrained and they carry important safety requirements. They also need to be highly reliable to ensure they will have a long life when run at high voltage and current. With so many design demands on high voltage PCBs, layout engineers need a complete set of design tools to help them satisfy all design constraints. High voltage circuit boards are normally used in power systems, such as in power generation, conversion, or distribution.
These tasks may involve a range of voltages, and the PCB for this equipment must accommodate a range of power levels simultaneously. Here are a few of the points that need to be determined before starting any high voltage PCB layout:. The electronics industry has addressed these aspects of high voltage design and many more by creating industry standards. These standards are intended to ensure the reliability and safety of high voltage power products.
When you have the best set of PCB design tools, the requirements in these important design standards can be encoded in your PCB project as design rules. This helps you design to the level of reliability and safety required in high voltage PCB designs. Learn more about designing to IPC standards. Learn more about setting trace and pad clearance rules to prevent shorts. Learn more about substrate material options for high voltage PCB design. The spacing between these conductors should be carefully checked to prevent ESD during operation.
For example, equipment like power supplies and high-power regulators need to receive a high voltage and may convert it to moderate voltage at high current. As such, some sections of the PCB may need to be designed to withstand the heat generated by high current.
When high current PCB design rules are used with the clearances defined for high voltage PCB designs, a designer can rest assured their board will be safe and will provide high current without excessive temperature rise. However, a designer needs to determine the maximum temperature rise they can tolerate in the board to ensure reliability. Once this is determined, the trace width and other required heat dissipation measures can be determined.
Once high voltage and high current design rules for your circuit board are determined, the best design software will check your PCB layout against these rules automatically. Learn more about determining the minimum trace width in a high-current circuit board. Addressing these issues as you design will prevent a redesign once you send your board to your manufacturer.
Following important IPC standards on design and fabrication also helps ensure you have the highest possible board yield. Learn more about appropriate tolerances in different IPC class products. Via design is an important aspect of reliability in different IPC class products. Much like other industries, major electronics companies have collaborated to define a range of standards governing electronics design, fabrication, assembly, and testing.
Some of these other groups of standards include:. The design standards specified directly and indirectly by these organizations can be encoded as design rules in Altium Designer, just like your other important IPC standards for PCB design. It is up to you as a designer to determine which standards are most important for your product.
Altium Designer includes all the design tools you need to ensure your physical layout will comply with any of these design requirements thanks to its integrated underlying design engine.
As you create your circuit board, the online DRC engine in Altium Designer checks your PCB layout against your design rules as you create your circuit board. Every design feature in the program reads from these design rules as you build your board. The verification features automatically check your design against standard and customized design rules, helping you remain compliant with IPC standards for PCB design.
Learn more about sharing your projects with Altium With the rules-driven design engine in Altium Designer, you can ensure important IPC standards for PCB design are automatically checked as you create your circuit board. Altium Designer on Altium delivers an unprecedented amount of integration to the electronics industry until now relegated to the world of software development, allowing designers to work from home and reach unprecedented levels of efficiency.
We have only scratched the surface of what is possible to do with Altium Designer on Altium You can check the product page for a more in-depth feature description or one of the On-Demand Webinars. Zachariah Peterson has an extensive technical background in academia and industry.
He currently provides research, design, and marketing services to companies in the electronics industry. Prior to working in the PCB industry, he taught at Portland State University and conducted research on random laser theory, materials, and stability. His background in scientific research spans topics in nanoparticle lasers, electronic and optoelectronic semiconductor devices, environmental sensors, and stochastics. Mobile menu. Explore Products. Altium Community. How to Create a Footprint.
About Author Zachariah Peterson has an extensive technical background in academia and industry. Among the list of minimum electrical conductor spacing values defined in IPC, there is one set of requirements that is intended to prevent metal migration failure.
Metal migration is one of many failure mechanisms in high voltage designs with high conductor density. When two conductors are brought up to a high potential, electrochemical growth of metallic dendrites can occur when the conductors contain residues with water-soluble salts; an SEM image of dendritic growth between two solder balls is shown below. These metallic dendrites can short out two points on a high density PCB. This is actually an electric field effect, which explains why there is a minimum spacing requirement; increasing the spacing between conductors for a given potential difference reduces the field between the conductors, which inhibits dendrite growth.
SEM image showing dendritic growth between two solder balls. Image source. In the case that your product is not covered by the more stringent UL or IEC standards see more on this below , there is a simple set of data and a formula you can use to determine the minimum conductor spacing in your PCB. This data is a function of the peak voltage being used and whether a coating is present on your board, as shown in the following table.
If you need to determine the minimum conductor spacing between two voltage values, you can use a linear approximation interpolation between two successive entries. IPCB conductor spacing requirements. IPCB standard provides conductor spacing requirements for power conversion devices. These standards are quite consistent when graphed alongside the required conductor spacing specified in IPCB. The table below specifies the spacing requirements under IPCB.
Note that this defines the minimum required trace spacing as a function of peak voltage values. IPCB conductor spacing requirements for power conversion devices. Both sets of standards include formulas that can be easily programmed into a calculator application.
This type of software encodes the required clearance as a design rule, which is automatically checked as you create your PCB layout. As you place components and route traces in your high voltage PCB, clearances can be checked automatically as you build your board. The ability to automatically check clearances between traces and components saves you from making a mistake and reduces the extent of any required placement changes. Working with design tools that allow you to specify clearances reduces these risks and helps you remain productive.
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