AC-DC|Design
Overview of Design Method of PWM AC-DC Flyback Converters
2015.12.10
In this serial, with the topic “Design Method of PWM Type AC-DC Flyback Converters,” we describe a design procedure and method using AC-DC converter ICs.
Demand for power savings in electronic devices has become increasingly challenging, requiring both high efficiency and a low power consumption at standby. For AC-DC converters, there is a crying need for on-board design and further optimization.
Because designing an AC-DC converter involves dealing with high voltages and requires transformer design, designers tend to shy away from the task. The task, however, may be worth the challenge if it leads to the fabrication of optimal AC-DC converters capable of meeting the demand for a high degree of power savings. As an added incentive, increasing numbers of control ICs have come into play that permit the construction of AC-DC converters in relatively simple manner.
Given these conditions, starting with an overview of a procedure for designing an AC-DC converter, we will describe how to verify the specifications for the power supply unit to be designed, how to select the specific IC to be used, and discuss actual design examples.
Each explanation that we provide consists of several subsections. Also, since the design process follows a certain procedure, we will describe the process in logical sequence. For an overall understanding of what follows, we recommend that you read the material that following in the sequence in which it is presented. Although some subsections stand by themselves, you may find it easy to follow the design examples by viewing them in the sequence in which they are given. As a helpful tip, the list below provides an overall structure of the material presented in this section.
<Design Method of PWM AC-DC Flyback Converters>
- 1. Isolated Flyback Converter Basics
- Switching AC-DC Conversion
- Fyback converter: Characteristics
- Fyback converter: Operation and Snubber
- Discontinuous & Continuous Modes
- 2. Design Procedure
- 3. Determining Power Supply Specifications
- 4. Choosing an IC for Design
- 5. Designing Isolated Flyback Converter Circuits
- Transformer Design (Calculating numerical values)
- Transformer Design (Structural design) – 1
- Transformer Design (Structural design) – 2
- Selecting Critical Components ? MOSFET related – 1
- Selecting Critical Components ? MOSFET related – 2
- Selecting Critical Components ? CIN and Snubber
- Selecting Critical Components ? Output Rectifier and Cout
- Selecting Critical Components ? IC VCC related
- Selecting Critical Components ? Setting up an IC, and Miscellaneous
- Addressing EM and Output Noise
- 6. Example Board Layout
- 7. Summary
【Download Documents】Design Example for PWM Flyback Converter
ROHM’s seminar materials provided at the seminar venue. Explanation how to design a flyback converter using a power supply IC.
List of articles related to the「Overview of Design Method of PWM AC-DC Flyback Converters」
- Want are Isolated Flyhback Convertors?
- Isolated Flyback Converter Basics: What is Switching AC-DC Conversion?
- Isolated Flyback Converter Basics: What are Characteristics of Flyback Converter?
- Isolated Flyback Converter Basics: Flyback Converter Operation and Snubber
- Isolated Flyback Converter Basics: What are Discontinuous Mode and Continuous Mode?
- Design Procedure
- Determining Power Supply Specifications
- Choosing an IC for Design
- Designing Isolated Flyback Converter Circuits
- Designing Isolated Flyback Converter Circuits: Transformer Design (Calculating numerical values)
- Designing Isolated Flyback Converter Circuits: Transformer Design (Structural Design) – 1
- Designing Isolated Flyback Converter Circuits: Transformer Design (Structural Design) – 2
- Designing Isolated Flyback Converter Circuits: Selecting Critical Components ? MOSFET related – 1
- Designing Isolated Flyback Converter Circuits: Selecting Critical Components ? MOSFET related – 2
- Designing Isolated Flyback Converter Circuits: Selecting Critical Components ? CIN and Snubber
- Designing Isolated Flyback Converter Circuits: Selecting Critical Components ? Output Rectifier and Cout
- Designing Isolated Flyback Converter Circuits: Selecting Critical Components ? VCC of IC
- Designing Isolated Flyback Converter Circuits: Selecting Critical Components – IC Settings Etc.
- Designing Isolated Flyback Converter Circuits: Addressing EMI and Output Noise
- Example Board Layout
- Summary
Download Technical Documents
Design Example for PWM Flyback Converter
ROHM’s seminar materials provided at the seminar venue. Explanation how to design a flyback converter using a power supply IC.
AC-DC
- Basic
-
Design
-
Overview of Design Method of PWM AC-DC Flyback Converters
- Want are Isolated Flyhback Convertors?
- Isolated Flyback Converter Basics: What is Switching AC-DC Conversion?
- Isolated Flyback Converter Basics: What are Characteristics of Flyback Converter?
- Isolated Flyback Converter Basics: Flyback Converter Operation and Snubber
- Isolated Flyback Converter Basics: What are Discontinuous Mode and Continuous Mode?
- Design Procedure
- Determining Power Supply Specifications
- Choosing an IC for Design
- Designing Isolated Flyback Converter Circuits
- Designing Isolated Flyback Converter Circuits: Transformer Design (Calculating numerical values)
- Designing Isolated Flyback Converter Circuits: Transformer Design (Structural Design) – 1
- Designing Isolated Flyback Converter Circuits: Transformer Design (Structural Design) – 2
- Designing Isolated Flyback Converter Circuits: Selecting Critical Components ? MOSFET related – 1
- Designing Isolated Flyback Converter Circuits: Selecting Critical Components ? MOSFET related – 2
- Designing Isolated Flyback Converter Circuits: Selecting Critical Components ? CIN and Snubber
- Designing Isolated Flyback Converter Circuits: Selecting Critical Components ? Output Rectifier and Cout
- Designing Isolated Flyback Converter Circuits: Selecting Critical Components ? VCC of IC
- Designing Isolated Flyback Converter Circuits: Selecting Critical Components – IC Settings Etc.
- Designing Isolated Flyback Converter Circuits: Addressing EMI and Output Noise
- Example Board Layout
- Summary
-
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: Input Capacitor C1 and VCC Capacitor C2
- Selecting Critical Components: Inductor L1
- Selecting Critical Components: Current Sense Resistor R1
- Selecting Critical Components: Output Capacitor C5
- Selecting Critical Components: Output Rectifying Diode D4
- EMI Countermeasures
- Board Layout and Summary
-
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: Power Supply IC Selection
- Synchronous Rectification Circuit Section: Selection of Peripheral Circuit Components-C1, R3 at MAX_TON Pin, and VCC Pin
- Synchronous Rectification Circuit Section: Selection of Peripheral Circuit Components-D1, R1, R2 at DRAIN Pin
- 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
-
Introduction
- Power Supply ICs Used in Design: Optimized for SiC MOSFETs
- Design Example Circuit
- Transformer T1 Design – 1
- Transformer T1 Design – 2
- Selecting Critical Components: MOSFET Q1
- Selecting Critical Components: Input Capacitor and Balancing Resistor
- Selecting Critical Components: Switch Setting Resistors for Overload Protection Points
- Selecting Critical Components: VCC-Related Components of Power Supply ICs
- Selecting Critical Components: Components Related to Power Supply IC BO (Brownout) Pins
- Selecting Critical Components: Components Related to Snubber Circuits
- Selecting Critical Components: MOSFET Gate Drive Adjustment Circuit
- Selecting Critical Components: Output Rectifying Diode
- Selecting Critical Components: Output Capacitors, Output Setting and Control Components
- Selecting Critical Components: Current Sense Resistors and Components Related to Detection Pins
- 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
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Overview of Design Method of PWM AC-DC Flyback Converters
- Evaluation
- Product Information
- FAQ