RDK-355

Reference Design Report for a 6 W Non- Title Dimmable, Non-Isolated Buck LED Driver TM Using LYTSwitch -0 LYT0006P Specification 90 VAC 265 VAC Input 54 V, 110 mA Output Application GU10 LED Driver Lamp Replacement Author Applications Engineering Department Document RDR-355 Number Date June 18, 2013 Revision 1.0 Summary and Features Single-stage power factor corrected (>0.75 at 120 V and >0.5 at 230 V) and accurate constant current (CC) output Low cost, low component count and small PCB footprint solution Highly energy efficient, >91 % at 120 VAC input Highly energy efficient, >90 % at 240 VAC input Superior performance and end user experience Fast start-up time (<20 ms) no perceptible delay Integrated protection and reliability features Single shot no-load protection / output short-circuit protected with auto-recovery Auto-recovering thermal shutdown with large hysteresis protects both components and PCB No damage during brown-out conditions Meets IEC ring wave, differential line surge and EN55015 conducted EMI 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-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 Table of Contents 1 Introduction ................................................................................................................. 4 2 Power Supply Specification ........................................................................................ 6 3 Schematic ................................................................................................................... 7 4 Circuit Description ...................................................................................................... 8 4.1 Input EMI Filtering ............................................................................................... 8 4.2 LYTSwitch-0 ........................................................................................................ 8 4.3 Output Rectification ............................................................................................. 8 4.4 Output Feedback ................................................................................................. 8 4.5 No-Load Protection ............................................................................................. 9 5 PCB Layout .............................................................................................................. 10 6 Bill of Materials ......................................................................................................... 12 7 Inductor Specification ............................................................................................... 13 7.1 Electrical Diagram ............................................................................................. 13 7.2 Electrical Specifications ..................................................................................... 13 7.3 Materials ............................................................................................................ 13 7.4 Inductor Build Diagram ...................................................................................... 14 7.5 Transformer Construction .................................................................................. 14 8 Inductor Design Spreadsheet ................................................................................... 15 9 Performance Data .................................................................................................... 17 9.1 Active Mode Efficiency ...................................................................................... 18 9.2 Output Current Regulation ................................................................................. 19 9.2.1 Input Line and Load Voltage to Output Current Regulation ........................ 19 10 Thermal Performance ........................................................................................... 20 10.1 Equipment Used ................................................................................................ 20 11 Thermal Result ...................................................................................................... 21 11.1 Thermal Scan .................................................................................................... 22 12 Waveforms ............................................................................................................ 23 12.1 Drain Voltage Normal Operation ....................................................................... 23 12.2 Drain Current at Normal Operation .................................................................... 24 12.3 Drain Voltage and Current When Output Short ................................................. 26 12.4 Drain Voltage and Current Start-up Profile ........................................................ 26 12.5 Output Current Start-up Profile .......................................................................... 27 12.6 Input-Output Profile ........................................................................................... 28 12.7 Line Sag and Surge ........................................................................................... 29 12.8 Brown-out/ Brown-in .......................................................................................... 30 13 Line Surge ............................................................................................................. 31 14 Conducted EMI ..................................................................................................... 33 15 Audible Noise ........................................................................................................ 35 16 Appendix ............................................................................................................... 36 17 Revision History .................................................................................................... 39 Power Integrations, Inc. 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