AC-DC｜Evaluation
What are Isolated Flyback Converters Performance Evaluation and Checkpoints?
2017.02.09
Points of this article
・An essential step in fashioning a product is to evaluate whether the designed isolated flyback converter is operating properly and it has achieved design-goal performance levels.
・The evaluation process involves the use of checkpoints based on technical expertise, and by bringing the technical expertise to bear on the evaluation process, Time to Product can be reduced.
This section begins a new “Evaluation Edition” relating to AC-DC converters. Under the title “Isolated Flyback Converters Performance Evaluation and Checkpoints”, the section describes measurement method for evaluating isolated flyback AC-DC converter circuit performance and shows examples of measurement data. In addition, for evaluation, beyond the performance aspects we will discuss critical checkpoints for the verification of whether the circuits are operating successfully.
In the performance evaluation process, the first step would be to understand the features of the power supply IC with which the circuit to be evaluated is constructed. As was explained in the “Design Method of PWM AC-DC Flyback Converters” part of the “Design Edition”, in newer power supply designs an adequate understanding of the power supply IC is an essential requirement.
In succession, we make decisions on design goals for a power supply unit, such as the accuracy of output voltage, and perform a circuit design to achieve those goals. Since the objective of this chapter is to make sure that the reader learns something about evaluation methods, we will skip a discussion of the design itself; nevertheless, we will check out the power supply circuits on which evaluations are to be conducted.
Finally, using the power supply IC evaluation board using that circuit, we will verify whether the design goals have been attained.
In the next section, we explain the checkpoints to ascertain whether the designed circuit is operating correctly and methods that are employed to measure the performance. Although mostly there are no problems if the design goals are attained, mass production cannot be justified and the product cannot be shipped unless margins and potential issues are properly identified. These checkpoints represent the type of experience and skills that goes with the production of a product. The checkpoints make it possible to accurately and quickly uncover potential issues, based upon experience and actual past performance.
- ・Overview and important features of a power supply IC used in example performance evaluation
- ・Design goals and circuits in performance evaluation
- ・Performance evaluation using an evaluation board: Measurement method and results
- ・Critical checkpoint: Output transient response and rising output voltage waveform
- ・Critical checkpoint: Measuring temperature and loss
- ・Critical checkpoint: Aluminum electrolytic capacitors
- ・Summary
- ・Critical checkpoint: Transformer saturation
- ・Critical checkpoint: MOSFET VDS and IDS, and rated voltage of output rectifier diode
- ・Critical checkpoint: Vcc voltage
【Download Documents】 Isolated Flyback Converters: Performance Evaluation and Checkpoints
This handbook explains how to evaluate the performance of isolated flyback type AC-DC converters using power supply ICs, with examples of actual measurement data. Important checkpoints are also explained.
AC-DC
Basic
- AC-DC Basics
- DC-DC Conversion (Regulated) System after Smoothing
- Design Procedure for AC-DC Conversion Circuits (Overview)
- Issues and considerations in AC-DC Conversion Circuit Design
- Summary
- Extra Plus Basic Knowledge
Design
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Overview of Design Method of PWM AC-DC Flyback Converters
- Isolated Flyback Converter Basics: Flyback Converter Operation and Snubber
- Isolated Flyback Converter Basics: What are Discontinuous Mode and Continuous Mode?
- Want are Isolated Flyhback Convertors?
- Design Procedure
- Isolated Flyback Converter Basics: What is Switching AC-DC Conversion?
- Determining Power Supply Specifications
- Designing Isolated Flyback Converter Circuits
- Isolated Flyback Converter Basics: What are Characteristics of Flyback Converter?
- Designing Isolated Flyback Converter Circuits: Transformer Design (Calculating numerical values)
- Choosing an IC for Design
- 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
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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
- Troubleshooting ①： Case When Secondary-Side MOSFET Suddenly Turns OFF
- Synchronous Rectification Circuit Section: Selection of Peripheral Circuit Components－C1, R3 at MAX_TON Pin, and VCC Pin
- 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
- Synchronous Rectification Circuit Section: Selection of Peripheral Circuit Components－D1, R1, R2 at DRAIN Pin
- Shunt Regulator Circuit Section: Selection of Peripheral Circuit Components
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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
Evaluation
-
What are Isolated Flyback Converters Performance Evaluation and Checkpoints?
- Overview and important features of a power supply IC used in example performance evaluation
- Design goals and circuits in performance evaluation
- Performance evaluation using an evaluation board: Measurement method and results
- Critical checkpoint: Output transient response and rising output voltage waveform
- Critical checkpoint: Measuring temperature and loss
- Critical checkpoint: Aluminum electrolytic capacitors
- Summary
- Critical checkpoint: Transformer saturation
- Critical checkpoint: MOSFET VDS and IDS, and rated voltage of output rectifier diode
- Critical checkpoint: Vcc voltage
Product Information
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