RDK-752 Power Integrations

Reference Design Report for a 15 W Wide Range Input, Dual Output, Non-Isolated Title TM Flyback Converter Using InnoSwitch 3-EP INN3673C-H601 85 VAC 277 VAC Input 5 V / 1.2 A and 12 V / Specification 0.75 A Outputs Application Embedded Power Supply Author Applications Engineering Department Document RDR-752 Number Date June 11, 2020 Revision 1.1 Summary and Features High standby mode efficiency design to deliver up to 49 mA from 5 V with 0.3 W input power at 230 VAC Less than 50 mW no-load consumption across input range Using highly integrated solution with 725 V rated power MOSFET >83% average efficiency at 115 VAC and 230 VAC >6 dB conducted EMI margin Over-temperature protection with hysteretic recovery Auto-restart output short-circuit and open-loop protection PATENT INFORMATION The products and applications illustrated herein (including transformer construction and circuits external to the products) may be covered by one or more U.S. and foreign patents, or potentially by pending U.S. and foreign patent applications assigned to Power Integrations. A complete list of Power Integrations patents may be found at www.power.com. Power Integrations grants its customers a license under certain patent rights as set forth at RDR-752 15 W 5 V 1.2 A 12 V 0.75 A using INN3673C-H601 11-Jun-20 Table of Contents 1 Introduction ......................................................................................................... 5 2 Power Supply Specification ................................................................................... 6 3 Schematic Diagram .............................................................................................. 7 4 Circuit Description ................................................................................................ 8 4.1 Input Filter and Rectifier ................................................................................ 8 4.2 InnoSwitch3-EP Primary-Side ......................................................................... 8 4.3 InnoSwitch3-EP Secondary-Side ..................................................................... 9 4.4 Design Key Points .......................................................................................... 9 4.4.1 Transformer Design ................................................................................ 9 4.4.2 Primary Clamp ...................................................................................... 10 4.4.3 Primary Bias ......................................................................................... 10 4.4.4 Secondary Rectification ......................................................................... 10 4.4.5 Filter Components ................................................................................. 10 5 PCB Layout ........................................................................................................ 11 6 Bill of Materials .................................................................................................. 12 7 Transformer Specification ................................................................................... 13 7.1 Electrical Diagram ........................................................................................ 13 7.2 Electrical Specification .................................................................................. 13 7.3 Material List ................................................................................................ 13 7.4 Transformer Build Diagram .......................................................................... 14 7.5 Transformer Instructions .............................................................................. 14 7.6 Winding Illustrations .................................................................................... 15 8 Transformer Design Spreadsheet ........................................................................ 19 9 Performance Data .............................................................................................. 24 9.1 Efficiency .................................................................................................... 24 9.1.1 Average Efficiency Measured across PCB Connector ................................ 24 9.1.2 Full Load Efficiency vs. Line ................................................................... 26 9.1.3 Efficiency vs. Load ................................................................................ 27 9.1.4 Standby Mode Efficiency ........................................................................ 28 9.2 No-Load Input Power ................................................................................... 30 9.3 Line Regulation............................................................................................ 31 9.4 Load Regulation .......................................................................................... 32 9.4.1 5 V Load Regulation with Balanced Load ................................................ 32 9.4.2 12 V Load Regulation with Balanced Load............................................... 33 9.4.3 5 V Load Regulation with Fixed Full Load Across 12 V Output .................. 34 9.4.4 5 V Load Regulation with Fixed Minimum Load Across 12 V Output .......... 35 9.4.5 12 V Load Regulation with Fixed Full Load Across 5 V Output .................. 36 9.4.6 12 V Load Regulation with Fixed Minimum Load Across 5 V Output .......... 37 10 Test Waveforms .............................................................................................. 38 10.1 Load Transient Response ............................................................................. 38 10.1.1 5 V and 12 V 0% - 100% Load Change .................................................. 38 10.1.2 5 V and 12 V 0% - 50% Load Change .................................................... 39 10.1.3 5 V 0% - 100% Load Change, 12 V Fixed 100% Load ............................. 40 Power Integrations, Inc. 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