05. - 07.06.2018
PCIM Europe 2018
Power Electronics | Intelligent Motion | Renewable Energy | Energy Management


Tutorial 6

Switchmode Printed Circuit Board Design and Layout for Low EMI


Monday, 04.06.2018, 09:00 - 17:00 hrs


Arvena Park Hotel Nuremberg, Görlitzer Str. 51, 90473 Nuremberg


09:00 Switchmode Printed Circuit Board Design and Layout for Low EMI
B.Sc. Bruce Carsten, Bruce Carsten Associates, Corvallis, USA
Although related to previous comprehensive EMI seminar versions by the instructor, the focus of this new tutorial is on the physical design and layout of a PCB to minimize Electromagnetic Interference (EMI). A great deal of switchmode EMI can be produced or avoided in the layout and construction of a Printed Circuit Board (PCB), and EMI from a poor layout is usually very difficult to fix without a redesign. This tutorial contains extracts from the original tutorials, but focuses on the printed circuit board, including the magnetic and electric shielding benefits of ground planes, and the use of "switching cell macros" to assist in a low EMI layout. New material for this tutorial illustrates the significant magnetic field reduction above and behind a PCB with a ground plane.
A good PCB layout for low EMI is a technically demanding design task, ideally performed by one versed in the physics and visualization of electric and magnetic fields. Unfortunately, PCB layout is increasingly performed by someone trained only in the use of layout software, where arbitrary component placement and the use of auto-routing of conductor traces can be deadly to EMI performance.
The tutorial will begin with physical demonstrations of energy coupling by changing magnetic and electric fields to aid in the comprehension of EMI generation. A full set of tutorial notes will be provided, but some subjects maybe gone over lightly or even skipped due to the limited time.
Questions and comments from attendees are strongly encouraged.

Topics include:
- Definition of EMI, and how it is measured
- How EMI is generated by changing voltages and currents
- Magnetic field coupling from a current loop to a pickup loop
- Electric field coupling from one surface to another
- Illustration of energy coupling through changing electric and magnetic fields
- Why EMI is so hard to prevent; a "parts per trillion" phenomena
- "Switching Cells" as the principal source of EMI
- Conductive shielding of Magnetic Fields
- Faraday shielding of Electric Fields
- The many benefits of a Ground Plane (expanded from last year)
- Layout of switching cells as a "macro" or "component", which can be moved but not pulled apart
- Locating sources of EMI with H-field and E-field probes

Who should attend?
This tutorial is directed largely towards the switchmode design engineer who is either directly involved in PCB layout, or needs to direct and assist layout technicians. However, the tutorial will also be of some value to layout software users without an engineering background.


Speaker detail

Mr. Bruce Carsten
B.Sc. Bruce Carsten
Bruce Carsten Associates, Corvallis, USA
Bruce Carsten has 48 years of design and development experience in switchmode power converters at frequencies from 20 kHz to 1 MHz. In 1982 he designed a 48 Vdc, 200 A, 50 kHz natural convection cooled switchmode telecom rectifier which met the FCC Class A requirements for conducted and radiated emissions. His seminars target the practicing design engineer, and emphasize an intuitive understanding of phenomena involved.