RDK-531 Power Integrations

Reference Design Report for a Dual Output TM Title 17.5 W Power Supply Using InnoSwitch - EP INN2904K 85 VAC 484 VAC Input Specification 12 V, 1.25 A and 5 V, 0.5 A Outputs Application Embedded Power Supply Author Applications Engineering Department Document RDR-531 Number Date September 7, 2016 Revision 1.3 Summary and Features InnoSwitch-EP - industry first AC/DC ICs with isolated, safety rated integrated feedback 900 V rated MOSFET Built in synchronous rectification for higher efficiency All the benefits of secondary side control with the simplicity of primary side regulation Insensitive to transformer variation Extremely fast transient response independent of load timing Meets output cross regulation requirements without linear regulators Primary sensed output overvoltage protection (OVP) eliminates optocoupler for fault protection Accurate thermal protection with hysteretic shutdown Input voltage monitor with accurate brown-in/brown-out and overvoltage 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.powerint.com. Power Integrations grants its customers a license under certain patent rights as set forth at <RDR-531 17.5 W InnoSwitch-EP Dual Output Supply 12-Jul-16 Table of Contents 1 Introduction ......................................................................................................... 4 2 Power Supply Specification ................................................................................... 5 3 Schematic ............................................................................................................ 6 4 Circuit Description ................................................................................................ 7 4.1 Input EMI Filtering ......................................................................................... 7 4.2 InnoSwitch-EP Primary ................................................................................... 7 4.3 InnoSwitch-EP Secondary ............................................................................... 7 5 PCB Layout .......................................................................................................... 9 6 Bill of Materials .................................................................................................. 10 7 Transformer (T1) Specification ............................................................................ 12 7.1 Transformer Electrical Diagram ..................................................................... 12 7.2 Electrical Specifications ................................................................................ 12 7.3 Material List ................................................................................................ 12 7.4 Transformer Build Diagram .......................................................................... 13 8 Common Mode Choke (L1) Specification .............................................................. 14 8.1 Electrical Diagram ........................................................................................ 19 8.2 Electrical Specifications ................................................................................ 19 8.3 Material List ................................................................................................ 19 8.4 Winding Instructions .................................................................................... 19 8.5 Illustrations ................................................................................................. 19 9 Transformer Design Spreadsheet ........................................................................ 19 10 Performance Data ........................................................................................... 24 10.1 Full Load Efficiency vs. Line .......................................................................... 24 10.2 No-Load Input Power ................................................................................... 25 10.3 Line and Load Regulation ............................................................................. 26 10.3.1 Line Regulation (Full Load) .................................................................... 26 10.3.2 Cross Load Regulation ........................................................................... 27 11 Thermal Performance ...................................................................................... 30 11.1 85 VAC........................................................................................................ 30 11.2 484 VAC ...................................................................................................... 31 12 Output Power vs. Thermal Rise at 85 Ambient for Different AC Input Voltages .. 32 13 Waveforms ..................................................................................................... 33 13.1 Load Transient Response ............................................................................. 33 13.1.1 5 V Load Transient (No-Load to Full Load) and No-Load on 12 V Output .. 33 13.1.2 5 V Load Transient (No-Load to Full Load) and Full Load on 12 V Output . 34 13.1.3 12 V Load Transient (No-Load to Full Load) and No-Load on 5 V Output .. 34 13.1.4 12 V Load Transient (No-Load to Full Load) and Full Load on 5 V Output . 35 13.2 Switching Waveforms ................................................................................... 36 13.2.1 InnoSwitch-EP Waveforms ..................................................................... 36 13.2.2 SR FET Waveforms ............................................................................... 37 13.2.3 Output Voltage and Current Waveforms During Start-Up ......................... 38 13.3 Output Ripple Measurements ........................................................................ 39 Power Integrations, Inc. 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