RDK-313

Reference Design Report for a 30 W Single Title Output Flyback Converter Using TM LinkSwitch -HP LNK6766E Specification 90 VAC 265 VAC Input 12 V, 2.5 A Output Application Adapter Author Applications Engineering Department Document RDR-313 Number Date September 14, 2012 Revision 1.2 Summary and Features Primary side regulated isolated flyback converter with 5% regulation. 132 kHz switching frequency for small transformer and output filter size Full load continuous conduction mode operation for improved efficiency and reduced output capacitor ripple currents Multimode operation maximizes efficiency over full load range Below 30 mW power consumption with 230 VAC. Extensive protection features including OVP, OTP, brown-in/out, line overvoltage, and lost- regulation (auto-restart) Meets EN-550022 and CISPR-22 Class B conducted EMI with 5 dB margin. Meets IEC61000-4-5, 1 kV / 2 kV surge. 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-313 30 W Single Output Flyback Supply 14-Sep-12 Table of Contents 1 Introduction ................................................................................................................. 4 2 Power Supply Specification ........................................................................................ 5 3 Schematic ................................................................................................................... 6 4 Circuit Description ...................................................................................................... 7 4.1 Input Rectification and Filtering ........................................................................... 7 4.2 LinkSwitch-HP Primary ........................................................................................ 7 4.3 Primary RZCD Clamp .......................................................................................... 7 4.4 Output Rectification ............................................................................................. 7 4.5 External Current Limit Setting- ............................................................................ 8 4.6 Feedback and Compensation Network ............................................................... 8 5 PCB Layout ................................................................................................................ 9 6 Bill of Materials ......................................................................................................... 10 7 Transformer Design Spreadsheet ............................................................................. 11 8 Transformer Specification ......................................................................................... 14 8.1 Electrical Diagram ............................................................................................. 14 8.2 Electrical Specifications ..................................................................................... 14 8.3 Materials ............................................................................................................ 14 8.4 Transformer Build Diagram ............................................................................... 15 9 Heat Sink Assemblies ............................................................................................... 16 9.1 eSIP Heat Sink .................................................................................................. 16 9.1.1 eSIP Heat Sink Fabrication Drawing .......................................................... 16 9.1.2 eSIP Heat Sink Assembly Drawing ............................................................ 17 9.1.3 ESIP and Heat Sink Assembly Drawing ..................................................... 18 9.2 Diode Heat Sink ................................................................................................ 19 9.2.1 Diode Heat Sink Fabrication Drawing ......................................................... 19 9.2.2 Diode and Heat Sing Assembly Drawing .................................................... 20 10 Performance Data ................................................................................................. 21 10.1 Active Mode Efficiency ...................................................................................... 21 10.2 No-Load Input Power ........................................................................................ 23 10.3 Line Regulation ................................................................................................. 25 10.4 Load Regulation ................................................................................................ 26 10.5 Power Limit ........................................................................................................ 27 11 Waveforms ............................................................................................................ 28 11.1 Drain Voltage and Current, Normal Operation ................................................... 28 11.2 Drain Voltage and Current, Overload Power ..................................................... 28 11.3 Voltage Stress, Overload Power ....................................................................... 29 11.4 Drain Voltage and Current Start-up Profile ........................................................ 29 11.5 Load Transient Response ................................................................................. 31 11.6 Output Ripple and Noise Measurements ........................................................... 32 11.6.1 Ripple Measurement Technique ................................................................ 32 11.6.2 Ripple and Noise Measurement Results .................................................... 33 12 Protection Feature ................................................................................................ 34 12.1 Auto-Restart under Short-Circuit Condition ....................................................... 34 12.2 Latching Protection under Overvoltage (Open Loop Test) ................................ 34 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 2 of 42