文档介绍：Explain and design of Switching
Power Supply EMI
世纪电源网2011(深圳)电源技术研讨会
2011年10月15日
Leo Liang(梁晓军)
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EMC standards overview
Agenda
EMC standards overview
The Basics
Coupling mechanisms
Signal analysis
Mechanical design, shielding
Cables
Appliance design
Components under EMC aspects
Capacitors
Inductors
Resistors
Overvoltage protectors
Filters
Basic function
Different designs
Layout
Applications
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Standardization
Standardization
Conducted and radiated Conducted and radiated
ic influence ic emission
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Standardization
Noise spectrum example
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Standdardization
EMI to ILS navigation from on-board FM receiver
Controlled by federal regulation
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The Basics: Coupling mechanisms
Coupling path
Sink of disturbance
Disturbance source
load
Systems
Origin of Peripheral System /
Appliance
Disturbance Appliance
Module
Cables / PCB traces
Disturbance
Disturbance can be:
Voltage
Current
ic field
Combination of above
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The Basics: Coupling mechanisms
Coupling path
Sink of disturbance
Disturbance source
load
• Coupling
- Capacitive to parallel laying cables
- Inductive by di/dt (ic field) in the ground wires
- radiation in the near field of the spark
• Propagation
- galvanic via conductors in the cable system
- unsymmetric (line to earth/ground)
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Disturbance path, four coupling types
Disturbed / affected cable
Data line in parallel to power and
Data- / Sensor line
Sourec of
di