A New Power Design Methodology for PCB Designs


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Abstract

Advanced PCB design is an iterative process of analysis-fix-analysis. Historically, this process is very time-consuming, requiring analysis experts and PCB designers to work together to find and fix layout problems. This article describes a new PCB design methodology that allows a PCB designer to perform the power design without having to run expert-level analysis tools. This methodology provides the setup automation for advanced analysis without the need to understand every minute parameter, and can be completed in a few steps.

User-friendly analysis reports guide the PCB designer to the exact location where design changes must be made to meet specifications. IPC standard-based constraint of automatic calculations helps PCB designers understand how good is good enough for the layout changes. All violations of IPC standards can be marked directly in the layout, so PCB designers can easily find the problems in the layout and fix them before handing the design over to the power integrity (PI) experts. This allows PI experts focus on performance optimization, cost reduction, and other issues, so a high-quality design can be produced in a shorter amount of time.

For modern electronic systems, power design has become more important with the requirements of low power, minimization, high density and high-speed data rate for high-end applications. Usually, the planes, copper pours, routed power traces and vias on a PCB serve as power distribution, signal return paths, heat dissipation and so on.

The following questions must be considered:

  • How does the PI engineer communicate with the hardware engineer and PCB designer about problems with the design and guidance on how to fix it?
  • How does the PCB designer communicate with the PI engineer about solutions to those problems?
  • How can the design engineer and PCB designer determine whether a solution is good in the early stage?

Generally, PI engineers communicate with PCB designers by email, phone calls, or meeting face to face to discuss the issues and the solutions to fix problems with the layout.

Unlike when analyzing signal integrity, PI engineers are not usually involved in the early stages of the design because of the lack of pre-layout analysis tools for power analysis in the industry. The first cut of PCB power design usually is based on experience and industry conventions, so many power problems only surface late in the process, leaving PI engineers to focus mainly on the post-layout verifications for power systems. Also, PCB designers generally do not want to use professional analysis tools because of their complicated settings and different EDA tools/platforms.

This lag time greatly affects the efficiency of design and the time-to-market of the products.

To read this entire article, which appeared in the February 2016 issue of The PCB Design Magazine, click here.

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