RDK-248

Reference Design Report for a Low-Power, Title Low-Cost 180 W PFC Front End Using HiperPFS PFS708EG Specification 90 VAC 264 VAC Input; 380 VDC Output Application PFC Front End Author Applications Engineering Department Document RDR-248 Number Date March 25, 2011 Revision 1.0 Summary and Features Low component count, low-cost, low-power PFC EN61000-3-2 Class-D compliance High PFC efficiency enables 80+ PC Main design Frequency sliding maintains high efficiency across load range Feed forward line sense gain maintains relatively constant loop gain over entire operating voltage range Excellent transient load response Power Integration eSIP low-profile controller package Integrated +15 VDC auxiliary power supply on board 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-248 180 W Low-Power Low-Cost PFC Using PFS708EG 25-Mar-11 Table of Contents 1 Introduction.................................................................................................................5 2 Design Goals..............................................................................................................5 3 Power Supply Specification ........................................................................................7 4 Schematic...................................................................................................................8 5 Circuit Description ......................................................................................................9 5.1 Input EMI Filter and Rectifier...............................................................................9 5.2 PFS708EG Boost Converter ...............................................................................9 5.3 Input Feed Forward Sense Circuit.....................................................................10 5.4 Output Feedback...............................................................................................10 5.5 Bias Supply .......................................................................................................10 5.5.1 Input EMI Filtering ......................................................................................10 5.5.2 TNY274GN Primary ...................................................................................10 5.5.3 Output Rectification....................................................................................11 5.5.4 Output Feedback........................................................................................11 5.5.5 Overvoltage Shutdown...............................................................................11 5.5.6 Design Aspects for EMI..............................................................................11 5.5.7 Undervoltage Lockout ................................................................................11 5.6 Bias Supply Series Regulator............................................................................12 6 PCB Layout ..............................................................................................................13 7 Bill of Materials .........................................................................................................14 8 Transformer Design Spreadsheet (T2) .....................................................................17 9 Inductor Design Spreadsheet (L5)............................................................................20 10 Auxiliary Supply Transformer Specification...........................................................23 10.1 Electrical Diagram .............................................................................................23 10.2 Electrical Specifications.....................................................................................23 10.3 Materials............................................................................................................23 10.4 Transformer Build Diagram ...............................................................................24 10.5 Transformer Construction..................................................................................24 10.6 Transformer Illustrations....................................................................................25 11 Switching Inductor Specification ...........................................................................28 11.1 Electrical Diagram .............................................................................................28 11.2 Electrical Specifications.....................................................................................28 11.3 Materials............................................................................................................28 11.4 Inductor Winding Instruction..............................................................................29 12 EMI Differential Inductor Specification ..................................................................32 12.1 Electrical Diagram .............................................................................................32 12.2 Electrical Specifications.....................................................................................32 12.3 Materials............................................................................................................32 12.4 Inductor Winding Instruction..............................................................................33 12.5 Inductance Value and Mounting........................................................................34 13 Heat Sink Specification .........................................................................................35 13.1 eSIP U1 Heat Sink ............................................................................................35 13.2 eSIP U1 Heat Sink Assembly............................................................................36 13.3 eSIP U1 Heat Sink Assembly and Mounting Hardware.....................................37 Power Integrations, Inc. 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