Fuji Switching Power Supply Control IC - Green Mode Quasi-Resonant IC - Application Note - AN-022E Rev. 1.5 April 2011

Oct 12, 2026

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Application Note AN-022E Rev.1.5 (April 2011) for Fuji switching power supply control ICs FA5571/71A/72/73/74/5570/5671. It provides cautionary guidance on data usage, product specification updates, intellectual property, and required safety measures for various reliability levels. The note describes overview and key features including quasi-resonant switching, standby performance, low power consumption, frequency limitation, light-load operation modes, direct MOSFET drive capability, and built-in protection functions, followed by document sections for diagrams, pin functions, ratings, operation, design advice, and application circuitry.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages36

Reading Time1 h 31 min

AccessFree to download

1. Description

2. Features

3. Outline drawing

4. Block diagram

5. Functional description of pins

6. Rating and Characteristics

7. Characteristic curve

8. Basic operation

9. Description of the function

10. Method for using each pin

11. Advice for designing

12. Precautions for us

13. Example of application circuit

FA5571／71A／72／73／74／5570／5671 Fuji Switching Power Supply Control IC Green mode Quasi-resonant IC FA5571/71A/72/73/74/ 5570/5671 Application Note April 2011 Fuji Electric Co. , Ltd. Fuji Electric Co., Ltd. AN-022E Rev.1.5 April 2011 1 [http://www.fujielectric.co.jp/products/semiconductor/](http://www.fujielectric.co.jp/products/semiconductor/) [http://store.iiic.cc/](http://store.iiic.cc/) FA5571／71A／72／73／74／5570／5671 Caution 1. The contents of this note (Product Specification, Characteristics, Data, Materials, and Structure etc. ) were prepared in April 2011 . The contents will subject to change without notice due to product specification change or some other reasons. In case of using the products stated in this document, the latest product specification shall be provided and the data shall be checked. 2. The application examples in this note show the typical examples of using Fuji products and this noteshall neither assure to enforce the industrial property including some other rights nor grant the license. 3. Fuji Electric Co. , [Ltd. is](Ltd. is) always enhancing the product quality and reliability. However, semiconductor products may get out of order in a certain probability. Measures for ensuring safety, such as redundant design, spreading fire protection design, malfunction protection design shall be taken, so that Fuji Electric semiconductor product may not cause physical injury, property damage by fire and social damage as a result. 4. Products described in this note are manufactured and intended to be used in the following electronic devices and electric devices in which ordinary reliability is required: -Computer -OA equipment -Communication equipment (Terminal) -Measuring equipment -Machine tool -Audio Visual equipment -Home appliance -Personal equipment - Industrial robot etc. 5. Customers who are going to use our products in the following high reliable equipments shall contact us surely and obtain our consent in advance. In case when our products are used in the following equipment, suitable measures for keeping safety such as a back-up-system for malfunction of the equipment shall be taken even if Fuji Electric semiconductor products break down: -Transportation equipment (in-vehicle, in-ship etc . ) -Communication equipment for trunk line -Traffic signal equipment -Gas leak detector and gas shutoff equipment -Disaster prevention/Security equipment -Various equipment for the safety. 6. Products described in this note shall not be used in the following equipments that require extremely high reliability: -Space equipment -Aircraft equipment -Atomic energy control equipment -Undersea communication equipment -Medical equipment. 7. When reprinting or copying all or a part of this note, our company’s acceptance in writing shall be obtained. 8. If obscure parts are found in the contents of this note, contact Fuji Electric Co. , Ltd. or a sales agent before using our products. Fuji Electric Co. , Ltd. and its sales agents shall not be liable for any damage that is caused by a customer who does not follow the instructions in this cautionary statement. Fuji Electric Co., Ltd. AN-022E Rev.1.5 April 2011 2 [http://www.fujielectric.co.jp/products/semiconductor/](http://www.fujielectric.co.jp/products/semiconductor/) [http://store.iiic.cc/](http://store.iiic.cc/) FA5571／71A／72／73／74／5570／5671 Contents 1. Description 2. Features 3. Outline drawing 4. Block diagram 5. Functional description of pins 6. Rating and Characteristics 7. Characteristic curve 8. Basic operation 9. Description of the function 10. Method for using each pin 11. Advice for designing 12.Precautions for us 13. Example of application circuit ・・・・・・・・・・・・・・・・・ 4 ・・・・・・・・・・・・・・・・・ 4 ・・・・・・・・・・・・・・・・・ 4 ・・・・・・・・・・・・・・・・・ 5-6 ・・・・・・・・・・・・・・・・・ 6 ・・・・・・・・・・・・・・・・

FAQs

What is the purpose of this application note for FA5571/71A/72/73/74/5570/5671?

It documents product usage guidance and technical information for Fuji quasi-resonant switching power supply control ICs, including key features, functional descriptions, and design-related content.

What safety and reliability precautions does the note emphasize?

It states that the note’s contents may change, requires checking the latest specification, and instructs on safety measures such as redundant design and malfunction protection. It also restricts use in equipment requiring extremely high reliability and specifies consent/consultation for high-reliability applications.

Which main features are highlighted for these ICs?

The note highlights quasi-resonant switching with excellent standby characteristics, low power and low operation current, built-in startup and maximum frequency limitation, light-load burst or frequency reduction, direct MOSFET drive capability, and built-in overload/latch protection options depending on the model.

Oct 12, 2026

Upload by Adam