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Dealing with Noise Using Capacitors
2022.04.20
In the article “Input Filters for Switching Power Supplies,” we explained that capacitors, inductors, ferrite beads, and resistors are used in differential mode filters for the input stage of switching power supplies. From here, we discuss measures to address noise using capacitors and inductors, explaining what might be called the fundamentals of noise countermeasures. Here we use a simple four-element model. In order to represent resonances at still higher frequencies, models based on still more elements may be used.
First, we will start with noise suppression using capacitors. The explanation is given in the following sections.
- ・Understanding the Frequency Characteristics of Capacitors, Relative to ESR and ESL
- ・Measures to Address Noise Using Capacitors
- ・Effective Use of Decoupling (Bypass) Capacitors Point 1
- ・Effective Use of Decoupling Capacitors Point 2
- ・Effective Use of Decoupling Capacitors, Other Matters to be Noted
- ・Effective Use of Decoupling Capacitors, Summary
【Download Documents】 Switching Power Supply Basic of EMC and Noise Countermeasures
This is a handbook on the basics of EMC (electromagnetic compatibility) and noise countermeasures for switching power supplies. Based on the understanding of the basics of noise, it explains the noise countermeasures using capacitors and inductors in switching power supplies.
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Electrical Circuit Design
- Soldering Techniques and Solder Types
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Basic Alternating Current (AC)
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Basic Direct Current (DC)
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About Thermal Design
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Switching Noise
- Procedures in Noise Countermeasures
- What is EMC?
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Dealing with Noise Using Capacitors
- Understanding the Frequency Characteristics of Capacitors, Relative to ESR and ESL
- Measures to Address Noise Using Capacitors
- Effective Use of Decoupling (Bypass) Capacitors Point 1
- Effective Use of Decoupling Capacitors Point 2
- Effective Use of Decoupling Capacitors, Other Matters to be Noted
- Effective Use of Decoupling Capacitors, Summary
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Dealing with Noise Using Inductors
- Frequency-Impedance Characteristics of Inductors and Determination of Inductor’s Resonance Frequency
- Basic Characteristics of Ferrite Beads and Inductors and Noise Countermeasures Using Them
- Dealing with Noise Using Common Mode Filters
- Points to be Noted: Crosstalk and Noise from GND Lines
- Summary of Dealing with Noise Using Inductors
- Other Noise Countermeasures
- Basics of EMC – Summary
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Foundations of Electronic Circuit Simulation Introduction
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About the ROHM Solution Simulator
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