-
-
News
News Highlights
- Books
Featured Books
- design007 Magazine
Latest Issues
Current IssueRigid-flex: Designing in 3D
In this month’s issue, our expert contributors share their best tips, tricks and techniques for designing rigid-flex circuits. If you’re a rigid board designer considering moving into the 3D world of rigid-flex, this issue is just what the doctor ordered!
Simulation, Analysis, and AI
Getting today’s designs “right the first time” is critical, especially with costly advanced PCBs. Simulation and analysis software tools can help you in the fight to eliminate respins. They’re not magical, but they can predict the future of your design.
Advanced, Complex & Emerging Designs
This month, our contributors focus on designing PCBs with advanced, complex and emerging technologies. We investigate design strategies for boards that are on the cutting edge of technology, or crazily complex, or so new that designers are still writing the rules as they go.
- Articles
- Columns
Search Console
- Links
- Events
||| MENU - design007 Magazine
High-Voltage Circuit Design Guidelines and Materials
February 8, 2022 | Celso Faia and Davi Correia, Cadence Design SystemsEstimated reading time: 2 minutes

The Hubble telescope, the Cassini-Huygens mission, and other exploratory spacecraft utilize high-voltage DC power supplies for everything from vidicon camera tubes and mass spectrometers to radar and laser technologies. NASA has experienced performance problems with the 1.5 kV supplies because—as a 2006 report stated—“designers did not take the high-voltage problems seriously in the initial design.” The report cited very narrow parts parameters, electrical insulation problems in dielectrics, ceramics, bad geometries, small spacing, the use of the wrong insulating materials, and thermal expansion as causes for the power supply failures.
Designing a circuit that includes high-voltages requires a different—and much more rigorous—approach than seen with other PCB designs. And the need for more attention increases for high-density designs. Along with that approach, design teams also must become familiar with terminology that covers insulation, board materials, clearance, creepage, and altitude. Designers also should have an overall knowledge of regulations that can impact the circuit.
High-Voltage Design Problem-Solving Begins With the PCB Layout
All of us know that proper trace spacing in a PCB design maintains signal integrity and helps with preventing the propagation of electromagnetic interference. In high-voltage PCB design, trace spacing becomes even more important. If we rightfully consider the board as a series of conductive elements, the possibility of differences in potential—creating high-voltage flashover with narrow trace spacing—becomes a certainty.
Along with the IPC-2221 Generic Standard on Printed Board Design that establishes the design principles for interconnections on PCBs, the International Electrotechnical Commission (IEC) and the Underwriters Laboratories (UL) also produced IEC/UL 60950-1, the “Safety of Information Technology Equipment” standard, that describes safety requirements for products and details minimum allowed PCB spacing requirements. As a combination, the standards also set guidelines for PCB layouts that include two important parameters called clearance and creepage.
Using the IEC 60950 definition, clearance equals the shortest distance between two conductive parts, or between a conductive part and the bounding surface of the equipment, measured through air. A small clearance value between two conductors establishes the environment for a high-voltage flashover or arc. Clearance values vary according to the type of PCB material used for the circuit, the voltages, and operating environment conditions such as humidity and dust. Those environmental factors—and others—decrease the breakdown voltage of air and increase the opportunities for a high-voltage flashover and a short circuit.
We can address clearance issues through ECAD/MCAD design principles. Since the bounding surface described in the IEC definition is the outer surface of an electrical enclosure, we can use 3D design tools and design rules to establish the clearance between enclosures and components for rigid and rigid-flex circuits. We can also apply good PCB design principles by isolating high-voltage circuits from low-voltage circuits. Fabricators often recommend placing the high-voltage components on the top side of a multilayer board and the low voltage circuits on the bottom side of the PCB. Other methods involve placing the appropriate insulating materials between high-voltage nodes and over any exposed high-voltage leads.
To read this entire article, which appeared in the January 2022 issue of Design007 Magazine, click here.
Suggested Items
Cadence Completes Acquisition of Intrinsix
10/03/2023 | Cadence Design Systems, Inc.Cadence Design Systems, Inc. and CEVA, Inc. announced that Cadence has completed its acquisition of Intrinsix Corporation from CEVA.
Book Excerpt: 'The Printed Circuit Designer's Guide to... Designing for Reality', Introduction
10/03/2023 | I-Connect007 Editorial TeamBased on the wisdom of 50 years of PCB manufacturing at Sunstone Circuits, this book is a must-have reference for designers understanding the PCB manufacturing process as it relates to their design. Designing for manufacturability requires understanding the production process fundamentals and factors within the process that often lead to variations in manufacturability, reliability, and cost of the board.
I-Connect007 Editor’s Choice: Five Must-Reads for the Week
09/29/2023 | Andy Shaughnessy, I-Connect007This week’s must-reads cover a little bit of everything: advanced packaging substrates, rigid-flex design, the potential loss of tribal knowledge, ultra HDI processing, and the need for fabricators to begin utilizing Smart systems. In a few weeks, we’ll be attending SMTA International in Minneapolis, and then productronica in Munich. We hope to see you on the road!
Siemens, TSMC Collaborate to Help Mutual Customers Optimize Designs Using Foundry's Newest Advancements
09/29/2023 | SiemensSiemens Digital Industries Software announced new certifications and collaborations with longtime partner TSMC, resulting in the successful qualification of multiple industry-leading Siemens EDA product lines for the foundry’s latest process technologies.
Cadence Expands Support for 3Dblox 2.0 Standard with New System Prototyping Flows
09/29/2023 | Cadence Design Systems, Inc.Cadence Design Systems, Inc. announced the availability of new system prototyping flows based on the Cadence® Integrity™ 3D-IC Platform that support the 3Dblox 2.0 standard.