Basic Knowledge

Explanations for the basic elements, designing, and evaluation methods for power supply ICs and power devices, needed for power supplies and power conversion/switching circuits.

SiC Power Device

Basic

Introduction

Introduction

What is SiC (silicon carbide)?

What is silicon carbide?
Development Background and Advantages of SiC Power Devices

SiC Schottky Barrier Diode

What are SiC Schottky barrier diodes? – Features of SiC SBDs and Comparison with Si Diodes
What are SiC Schottky barrier diodes? – Reverse Recovery Characteristics of SiC-SBDs and Si-PNDs
What are SiC Schottky barrier diodes? – Forward Voltages of SiC SBD and Si PND
What are SiC Schottky barrier diodes? – Evolution of SiC-SBDs
What are SiC Schottky barrier diodes? – Advantages of using SiC-SBDs
What are SiC Schottky barrier diodes? – Reliability Tests

SiC-MOSFET

What are SiC-MOSFETs? – SiC-MOSFET Features
What are SiC-MOSFETs? – Comparison of Power Transistor Structures and Features
What are SiC-MOSFETs? – Differences with Si-MOSFET
Differences with IGBTs
Body Diode Characteristics
Trench-structure SiC-MOSFETs and Actual Products
SiC Application Examples
Reliability of SiC-MOSFETs

Full-SiC Power Modules

What are Full-SiC Power Modules?
Switching Losses in Full-SiC Power Modules
Tips for Practical Use
Support Tools： Full SiC Module Loss Simulator

Summary

Summary

Application

SiC MOSFETs: Behavior of Gate-Source Voltage in a Bridge Configuration

Introduction
SiC MOSFET Bridge Configuration
SiC MOSFET Gate Driving Circuit and Turn-On/Turn-Off Operation
Currents and Voltages Occurring Due to Switching in Bridge Circuits
Behavior of the Gate-Source Voltage During Low-side Switch Turn-on
Behavior of the Gate-Source Voltage During Low-side Switch Turn-off
Summary

Si Power Device

Basic

Introduction

Introduction

Si Diodes

What are diodes? – Properties and Characteristics
What are diodes? – Comparison of Features of Rectified Diodes
What are diodes? – Features of Si Schottky Barrier Diodes
What are diodes? – Characteristics of Si Fast Recovery Diodes

Si Transistors

What are Transistors? – Categories and Features of Si Transistors
What are MOSFETs? – MOSFET Parasitic Capacitance and Its Temperature Characteristic
What are MOSFETs? – MOSFET Switching Characteristics and Temperature Characteristics
What are MOSFETs? – MOSFET Threshold Values, ID-VGS Characteristics, and Temperature Characteristics
What are MOSFETs? – Super-junction MOSFET
What are MOSFETs? – Types and Features of High Voltage Super-Junction MOSFET
What are MOSFETs? – Fast trr SJ-MOSFET：PrestoMOS ™
Hybrid MOS Combines the Advantages of Both MOSFET and IGBT
Terminology Relating to MOSFET Specifications
MOSFET Thermal Resistance and Power Dissipation
- Packages Capable of Back-Surface Heat Dissipation

Confirming the Suitability of a Transistor in Actual Operation

Confirmation of Suitability in Actual Operation and Preparations
Confirmation that Absolute Maximum Ratings are Satisfied
Confirmation that Operation is within the SOA (Safe Operating Area)
Confirmation that Operation is within the SOA Derated at the Actual Operating Temperature
Confirmation that Average Power Consumption is within the Rated Power
Confirmation of the Chip Temperature
Summary

Application Examples that Exploit Feature

What is PFC?
Boundary Current Mode PFC：Examples of Efficiency Improvement Using Diodes
Continuous Current Mode PFC：Examples of Efficiency Improvement Using Diode
LED Illumination Circuits：Example of Efficiency Improvement and Noise Reduction Using MOSFETs
PFC Circuits for Air Conditioners：Example of Efficiency Improvement Using MOSFETs and Diodes

Summary

Summary

Evaluation

Evaluating MOSFET Recovery Characteristics Using Double-Pulse Tests

About Double-Pulse Tests
Recovery Characteristic Evaluation Using Double-Pulse Tests
Mechanism of Self Turn-on Occurrence
Summary

Improving the Power Conversion Efficiency of Phase Shift Full Bridge Circuits

Basic Configuration of a PSFB Circuit
Basic Operation of PSFB Circuits

Thermal-design

Basics

Thermal Design of Semiconductor Components in Electronic Equipment

About Thermal Design
Changes in Engineering Trends and Thermal Design
A Mutual Understanding of Thermal Design
Fundamentals of Thermal Resistance and Heat Dissipation
- About Thermal Resistance
- Heat Transmission and Heat Dissipation Paths
Fundamentals of Thermal Resistance and Heat Dissipation
Thermal Resistance Data

Simulation

Basics

Foundations of Electronic Circuit Simulation

About SPICE
SPICE Simulators and SPICE Models
Types of SPICE simulation
- DC Analysis, AC Analysis, Transient Analysis
- Monte Carlo
Convergence Properties and Stability of SPICE Simulations
Types of SPICE Model
SPICE Device Models
- Diode Example–Part 1
- Diode Example–Part 2
SPICE Subcircuit Models
About Thermal Models
About Thermal Dynamic Model
Summary

ROHM Solution Simulator

Optimization of PFC Circuits

Introduction
PFC Simulation Circuits Using Solution Circuits
PFC Circuits

Switching Noise - EMC

Basics

Basics of EMC

What is EMC?
Basics of Spectrum
Differential (Normal) Mode Noise and Common Mode Noise－Causes and Measures
What is Crosstalk?
Noise Occurring in Switching Power Supplies

Noise Countermeasures

Procedures in Noise Countermeasures
Basics of Noise Countermeasures in Switching Power Supplies
Input Filters for Switching Power Supplies

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

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
Points to be Noted
- Crosstalk and Noise from GND Lines
Dealing with Noise Using Common Mode Filters
Summary of Dealing with Noise Using Inductors

Other Noise Countermeasures

RC Snubber Circuit

Summary

Basics of EMC – Summary

Transfer Function

DC/DC Converters: Common Approach to Transfer Functions for Control Systems

Introduction

Introduction

What are transfer functions?

What are transfer functions? – Basic Approach to Transfer Functions and their Derivation
What are transfer functions? – Kirchhoff’s Laws and Impedance
What are transfer functions? – Frequency Characteristics of Transfer Functions

Amplifier Transfer Functions

Derivation of the Transfer Functions for Error Amplifiers, Voltage Amplifiers, Current Amplifiers
Amplifier Virtual Short
Slope Transfer Functions
Switching Transfer Functions
- Derivation of Step-down Mode Transfer Functions Serving as a Foundation
The Reason Why Compensation Ramp Slope Must Be At Least 1/2 Down Slope
Switching Transfer Functions

Transfer function of each converter

Introduction
Example of Derivation for a Step-Down Converter
Example of Deviation for a Step-up Converter
Example of Derivation for a Step-Up/Step-Down Converter – 1
Example of Derivation for a Step-Up/Step-Down Converter – 2
Effect of the ON-Resistance of a Switch on the Transfer Functions

AC/DC

Basics

AC/DC Basics

Transformer System
AC/DC Basics
What is Switching System?
Transformer vs Switching

DC/DC Conversion (Regulated) System after Smoothing

What are Linear Regulators?
What is Flyback System?
DC/DC Conversion (Regulated) System after Smoothing
What is Forward System?
What is Buck (step- down, non-isolated) system?

Design Procedure for AC/DC Conversion Circuits (Overview)

Design Procedure for AC/DC Conversion Circuits (Overview)
Firming up the Specifications
Selecting a Power Supply Control IC
Design and Peripheral Components Selection
Prototyping and Evaluation
Mass Production Design, Evaluation, and Shipment Inspection

Issues and considerations in AC/DC Conversion Circuit Design

Issues and considerations in AC/DC Conversion Circuit Design
Discrete Configuration vs. Power Supply IC
Efficiency
Downsizing – Number of Parts and Their Sizes
Protection Functions
Certifications and Regulations

Summary

Summary

Design

Design Method of PWM AC/DC Flyback Converters

Overview of Design Method of PWM AC/DC Flyback Converters
Want are Isolated Flyhback Convertors?
Isolated Flyback Converter Basics
Design Procedure
Determining Power Supply Specifications
Choosing an IC for Design
Designing Isolated Flyback Converter Circuits
Example Board Layout
Summary

Design Examples of Non-isolated Buck Converters

Overview of Design Examples of AC/DC Non-isolated Buck Converters
What are Buck Converters? – Basic Operation and Discontinuous Mode vs. Continuous Mode
Selection of Power Supply ICs and Design Examples
Selecting Critical Components
EMI Countermeasures
Board Layout and Summary

Design Example of Isolated Quasi-Resonant Converters Using SiC MOSFET

Introduction
Power Supply ICs Used in Design
- Optimized for SiC MOSFETs
Transformer T1 Design – 1
Transformer T1 Design – 2
Selecting Critical Components
Selecting Critical Components： Components for Dealing with EMI and Output Noise
PCB Layout Example
Example Circuit and Component List
Evaluation Results
- Efficiency and Switching Waveform
Summary

Design of a Secondary-Side Synchronous Rectifying Circuit to Improve the Efficiency of an AC/DC Converter

Introduction
Design Procedure
IC Used in Design
Power Supply Specifications and Replacement Circuit
Synchronous Rectifying Circuit Section
- Selection of Synchronous Rectifying MOSFET
Synchronous Rectification Circuit Section
Shunt Regulator Circuit Section
- Selection of Peripheral Circuit Components
Troubleshooting ①： Case When Secondary-Side MOSFET Suddenly Turns OFF
Troubleshooting ②： Case When Secondary-Side MOSFET Turns On Due to Resonance Under Light Loading
Troubleshooting ③： Case When, Due to Surge, VDS2 Rises to Above Secondary-Side MOSFET VDS Voltage
Comparison of Efficiency of Diode Rectification and Synchronous Rectification
Points to Note Relating to PCB Layout
Summary

Evaluation

Isolated Flyback Converters: Performance Evaluation and Check Points

What are Isolated Flyback Converters Performance Evaluation and Checkpoints?
Overview and important features of a power supply IC used in example performance evaluation
Performance evaluation using an evaluation board
- Measurement method and results
Design goals and circuits in performance evaluation
Critical checkpoint
Summary

DC/DC

Basics

Linear Regulator Basics

Linear Regulator Basics
Operating Principles of Linear Regulator
Types of Linear Regulators
Its Circuit Configuration and Features
Advantages vs Disadvantages, and Applications
Important Specifications
Efficiency and Thermal Calculation

Switching Regulator Basics

Switching Regulator Basics
Types of Switching Regulators
Advantages vs Disadvantages in Comparison with Linear Regulator
Operating Principles of Buck Switching Regulator
Differences between Synchronous and Nonsynchronous Rectifying DC/DC Conversion
Efficiency Improvements at Light Load for the Synchronous Rectifying Type
Control Methods (Voltage Mode, Current Mode, Hysteresis Control)
Protective and Sequencing Functions
Considerations on Switching Frequencies
Behavior when Vin Falls Below Vout
Supplement－Protective Function
- Output Pre-bias Protection
Supplement－Current Paths during Synchronous Rectifying Step-Down Converter Operation

Summary

Concluding Remarks

Design

Selection of Inductors and Capacitors for DC/DC Converters

Overview of Selection of Inductors and Capacitors for DC/DC Converters
Basic Operation of Step-Down Converters
Inductor Selection
Selection of Output Capacitors
Selection of Input Capacitors
Summary
Supplement－Selection of Input Capacitors

DC/DC Converter PCB Layout

Overview of DC/DC Converter PCB Layout
Current Paths During Step-Down Converter Operation
Ringing at switching nodes
Placement of input capacitors and output diodes
Placement of Thermal Vias
Placement of Inductors
Placement of Output Capacitors
Feedback Path Wiring
Ground
Resistance and Inductance of Copper Foil
Noise countermeasures
- corner wiring, conducted noise, radiated noise
- snubber, bootstrap resistor, gate resistor
Summary

PCB Layout of a Step-Up DC/DC Converter

The Importance of PCB Layout Design
Current Paths in Step-up DC/DC Converters
PCB Layout Procedure
Placement of Input Capacitors
Inductor Placement
Placement of Output Capacitors and Freewheel Diodes
Placement of Thermal Vias
Feedback Path Wiring
Ground
Layout for Synchronous Rectification Designs
Resistance and Inductance of Copper Foil
Relationship Between Corner Wiring and Noise
Summary

Evaluation

Characteristics and Evaluation Method of Switching Regulators

Overview of Characteristics and Evaluation Method of Switching Regulators
Switching Regulator Basics
How to Read Power Supply IC Datasheets
Evaluating a Switching Regulator

Examination of Losses

Introduction
Definitions and Heat Generation
Conduction Losses in Synchronous Rectifying Step-Down Converters
Losses in Synchronous Rectifying Step-Down Converters
Switching Losses in Synchronous Rectifying Step-Down Converters
Dead Time Losses in Synchronous Rectifying Step-Down Converters
Controller IC Power Consumption Losses in a Synchronous Rectifying Step-Down Converter
Gate Charge Losses in a Synchronous Rectifying Step-Down Converter
Conduction Losses due to the Inductor DCR
Example of Power Loss Calculation for a Power Supply IC
Simplified Method of Loss Calculation
Heat Calculation for Package Selection
- Example 1
- Example 2
Loss Factors
Matters to Consider When Studying Miniaturization by Raising the Switching Frequency
Important Matters when Studying High Input Voltage Applications
Important Matters when Studying Large Output Currents Applications
- Part 1
- Part 2
Summary