LNK500P

Design Example Report Title Specification Application Author Document Number Date Revision 2.4W Charger using LNK500P Input: 90-264 VAC Output: 6V / 0.4A Cell Phone Charger Power Integrations Applications Department DER-12 February 4, 2004 1.0 Summary and Features This report details the design of an isolated Flyback converter for Wall mount adapter. • • • • • Uses LinkSwitch LNK500P (Low cost series) Universal input voltage Typical Efficiency 72 % Meets EN550022 Class B EMI tests with No Y1 capacitor Very low earth leakage current The products and applications illustrated herein (including circuits external to the products and transformer construction) 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 5245 Hellyer Avenue, San Jose, CA 95138 USA. Applications Hotline: Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 2.4W Cell Phone Charger using LNK500P February 4, 2004 Table Of Contents 1 2 3 4 5 6 Introduction................................................................................................................. 4 Power Supply Specification ........................................................................................ 4 Schematic................................................................................................................... 5 PCB Layout ................................................................................................................ 5 Bill Of Materials .......................................................................................................... 6 Transformer................................................................................................................ 7 6.1 Transformer Winding........................................................................................... 7 6.2 Electrical Specifications....................................................................................... 7 6.3 Transformer Construction.................................................................................... 8 6.4 Winding Instructions ............................................................................................ 8 6.5 Materials.............................................................................................................. 9 6.6 Design Notes:...................................................................................................... 9 7 Performance Data .................................................................................................... 10 7.1 Efficiency........................................................................................................... 10 7.2 Load Regulation ................................................................................................ 11 7.3 Line Regulation ................................................................................................. 11 7.4 No Load Input Power......................................................................................... 12 7.5 Output Ripple Measurements............................................................................ 13 7.5.1 Ripple Measurement Technique ................................................................ 13 7.5.2 Output Voltage Ripple ................................................................................ 14 8 Surge Test................................................................................................................ 14 9 EMI Tests ................................................................................................................. 15 10 Revision History.................................................................................................... 17 Page 2 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 2.4W Cell Phone Charger using LNK500P February 4, 2004 List Of Figures Figure 1 – Flyback Converter – 2.4W 6V 0.4A................................................................................................ 5 Figure 2 – PCB Layout .................................................................................................................................... 5 Figure 3 – Transformer Winding...................................................................................................................... 7 Figure 4 – Transformer construction ............................................................................................................... 8 Figure 5 – Efficiency Vs Output Current ........................................................................................................ 10 Figure 6 – Load Regulation ........................................................................................................................... 11 Figure 7 – Line Regulation ............................................................................................................................ 11 Figure 8 – No Load Input Power.................................................................................................................... 12 Figure 9 – Oscilloscope Probe Prepared for Ripple Measurement............................................................... 13 Figure 10 – Oscilloscope Probe with Probe Master 5125BA BNC Adapter .................................................. 13 Figure 11 – Output Voltage Ripple (worst case) at Vin = 90 Vac, Vo = 5.44 V, Io = 400 mA ....................... 14 Figure 12 – EN55022 Class B, Line, artificial hand connected to output return ........................................... 15 Figure 13 – EN55022 Class B, Neutral, artificial hand connected to output return....................................... 15 Figure 14 – EN55022 Class B, Line, with out artificial hand connected to output return .............................. 16 Figure 15 – EN55022 Class B, Neutral, with out artificial hand connected to output return ......................... 16 List Of Tables Table 1 – Power Supply Specification ______________________________________________________ 4 Table 2 – Bill of Materials ________________________________________________________________ 6 Table 3 – Transformer BOM______________________________________________________________ 9 Important Notes: Although this board is designed to satisfy safety isolation requirements, the engineering prototype has not been agency approved. Therefore, all testing should be performed using an isolation transformer to provide the AC input to the prototype board. Design Reports contain a power supply design specification, schematic, bill of materials, and transformer documentation. Performance data and typical operation characteristics are included. Typically only a single prototype has been built. Page 3 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 2.4W Cell Phone Charger using LNK500P February 4, 2004 1 Introduction This document is an engineering report giving performance characteristics of an isolated Flyback converter with universal input voltage and 6V 0.4A output CV/CC characteristics. This design uses LinkSwitch – an integrated IC comprising a high voltage MOSFET, PWM controller, using no optocoupler. The controller provides an I2f type characteristic to provide a constant current output current without secondary side sensing. This document contains the power supply specification, schematic, and bill of materials, transformer documentation, printed circuit layout, and performance data. 2 Power Supply Specification Description Input Voltage Output Output Voltage @ full load Output Voltage @ no load Output Ripple Voltage Total Output Power Continuous Output Power Constant Current Limit Output Constant Current Conducted EMI Margin Efficiency Ambient Temperature η TAMB -10 POUT 2.4 W Symbol VIN Vfl Vnl VRIPPLE1 Min 90 5.3 6.6 Typ Max 264 Units Vac V V mV at 400 mA load 20 MHz Bandwidth Comment 6.8 150 IOUT1 .4 .5 .65 A 2.5V – 4.5V 5 72 40 dB o EN550022 B, FCC B At full load Free convection, Sea level % C Table 1 – Power Supply Specification Page 4 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 2.4W Cell Phone Charger using LNK500P February 4, 2004 3 Schematic D3 1N4005 D1 1N4005 L RF1 8.2 Ohm 1W FUSIBLE + U1 LNK500P L1 1mH R3 1.5M C2 4.7uF 400V + D S T1 C 1 5 6V 400 mA C5 W 1,14T #28,TIW + C3 FL W 3,98T,#36 4 6 R4 1.5M R1 19.1K 0.22uF, 50V W 2,9T,#36x5 3 11DQ06 D6 R5 EE13 Lp=2450uH 20 C6 470 uF, 10V R6 24 D7 6.2Vz 85-265 VAC N C1 4.7uF 400V C4 0.1uF, 100V RTN 1000 pF, 100V D5 1N4937 D2 1N4005 L2 D4 1N4005 Ferrite Bead R2 100 Figure 1 – Flyback Converter – 2.4W 6V 0.4A. 4 PCB Layout Figure 2 – PCB Layout Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com Page 5 of 19 DER-12 2.4W Cell Phone Charger using LNK500P February 4, 2004 5 Bill Of Materials Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Qty 2 1 1 1 1 4 1 1 1 1 1 1 1 1 2 1 1 1 1 Ref. Des C1, C2 C3 C4 C5 C6 D1, D2, D3, D4 D5 D6 D7 L1 L2 RF1 R1 R2 R4, R3 R5 R6 T1 U1 Part Description 4.7 µF, 400V, AL Electrolytic capacitor 0.22 µF, 50V, Ceramic capacitor 0.1 µF, 100V, Film capacitor 470 µF, 10V, Low ESR AL Electrolytic capacitor 1000 pF, 100V, Ceramic capacitor 1N4005, Diode GP 1A 600V 1N4937, Diode FR 1A 600V 11DQ06, Diode Schottky 1A 60V 6.2Vz, Diode Zener, 500 mW, 1% 1 mH, Inductor drum core Ferrite Bead 8.2 Ω 1W, Resistor fusible 19.1 KΩ, Resistor 1/4 W, 1% 100 Ω, Resistor, 1/8 W, 5% 1.5 MΩ, Resistor 1/8 W, 5% 20 Ω, Resistor, 1/8 W, 5% 24 Ω, Resistor, 1/8 W, 5% Flyback Transformer LNK500P, LinkSwitch Table 2 – Bill of Materials Page 6 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 2.4W Cell Phone Charger using LNK500P February 4, 2004 6 Transformer 6.1 Transformer Winding 1 W3,Primary, 96T,#36 4 4 W2,Shield Wndg, 9T,#35x5 3 5 W1,Secondary, 13T,#28 TIW 6 Figure 3 – Transformer Winding 6.2 Electrical Specifications 60Hz 1minute, from Pins 1-4 to Pins 5-6 All windings open All windings open L13 with pins 5-6 shorted 3 kV for 1 minute 2.45 mH ± 7 % 300 kHz min. 50 µH max. Electrical Strength Primary Inductance (Pin 1 to Pin 3) Resonant Frequency Primary Leakage Inductance Page 7 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 2.4W Cell Phone Charger using LNK500P February 4, 2004 6.3 Transformer Construction Pins 5-8 Pins 1-4 0.29",2mils Insulation Tape, 1 layer 1 place, 2 layer 3 places, 3 layer 1 place W3-finish W3-start W2-finish W2-start W1-start W1-finish Flux Band Figure 4 – Transformer construction 6.4 Winding Instructions Place the bobbin on the winding machine with pins 1-4 on the right side and pins 5-8 on the left side. W1 (Secondary Winding) Basic Insulation W2 (Shield) Wind 13 turns with # 28 triple insulated wire from right to left starting temporarily from 1 and finishing at 5. Bring the starting end from pin 1 to pin 6. 2 layers of tape for insulation. Wind 9 turns with #35 x 5 (penta-filar) magnet wire from right to left starting from 4 and finishing at 3. Wind evenly across the width of the bobbin without any gaps on sides. 2 layers of tape for insulation. Wind 96 turns in 2 layers with # 36 AWG magnet wire – first layer 48T from right to left starting from pin 1 – one layer of insulation tape – second layer 48T from left to right and finishing at pin 4. 3 layers of tape for insulation. Assemble and secure core halves. Apply Flux band around assembled core and bobbin, and solder start and finish ends. Connect the flux band to pin 3 with a piece of #35 AWG magnet wire. 2 layers of tape for insulation. Solder the transformer pins and impregnate transformer uniformly with varnish. Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com Basic Insulation W3 (Primary Winding) Basic Insulation Core Assembly Flux Band Outer Insulation Final Assembly Page 8 of 19 DER-12 6.5 Materials Item [1] [2] [3] [4] [5] [6] [7] [8] 2.4W Cell Phone Charger using LNK500P February 4, 2004 Description Core: EE13, PC40EE13, TDK Gapped for AL = 222 nH/T2 ± 7 % Bobbin: Horizontal 8 pins Magnet Wire: #36 AWG Magnet Wire: #35AWG Triple Insulated wire: # 28 AWG Copper foil, 0.2 inch x 2 mils Tape: 3M 1298 Polyester Film (white) 0.29” x 2 mils Varnish Table 3 – Transformer BOM 6.6 Design Notes: LNK500P 42 KHz discontinuous 0.25 A 54 V 264 V 90 V Power Integrations Device Frequency of Operation Mode Peak Current Reflected Voltage (Secondary to Primary) Maximum AC Input Voltage Minimum AC Input Voltage Page 9 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 2.4W Cell Phone Charger using LNK500P February 4, 2004 7 Performance Data Measurements shown are of a typical unit. The output voltages are measured at the end of a 6-foot cable with 0.2 Ω total resistance. 7.1 Efficiency The measurements are made for various load and line conditions. The efficiencies are calculated and shown in Figure 5. Efficiency Vs Output Current 80.00 75.00 70.00 65.00 60.00 55.00 50.00 45.00 40.00 35.00 30.00 50 100 150 200 250 300 Output Current (mA) Efficiency (%) Vin = 90 Vac Vin = 120 Vac Vin = 230 Vac Vin = 264 Vac 350 400 Figure 5 – Efficiency Vs Output Current Page 10 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 7.2 2.4W Cell Phone Charger using LNK500P February 4, 2004 Load Regulation Load Regulation 7 6 Output Voltage (V) 5 4 3 2 1 0 0 100 200 300 400 500 600 Output Current (mA) Vin = 90 Vac Vin = 120 Vac Vin = 230 Vac Vin = 264 Vac Figure 6 – Load Regulation 7.3 Line Regulation Line Regulation 6.5 6.25 Output Voltage (V) 6 5.75 5.5 5.25 5 4.75 4.5 90 120 150 180 210 240 270 Input Voltage (Vac) Io = 100 mA Io = 200 mA Io = 300 mA Io = 400 mA Figure 7 – Line Regulation Page 11 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 2.4W Cell Phone Charger using LNK500P February 4, 2004 7.4 No Load Input Power No Load Input Power 500 450 400 350 300 250 50 100 150 200 250 300 Input Voltage (Vac) Io = 0 mA Input Power (mW) Figure 8 – No Load Input Power Page 12 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 7.5 2.4W Cell Phone Charger using LNK500P February 4, 2004 Output Ripple Measurements 7.5.1 Ripple Measurement Technique For DC output ripple measurements, a modified oscilloscope test probe must be utilized in order to reduce spurious signals due to pickup. Details of the probe modification are provided in Figure 9 and Figure 10. The 5125BA probe adapter is affixed with two capacitors tied in parallel across the probe tip. The capacitors include one (1) 0.1 µF/50 V ceramic type and one (1) 1.0 µF/50 V aluminum electrolytic. The aluminum electrolytic type capacitor is polarized, so proper polarity across DC outputs must be maintained (see below). Probe Ground Probe Tip Figure 9 – Oscilloscope Probe Prepared for Ripple Measurement. (End Cap and Ground Lead Removed) Figure 10 – Oscilloscope Probe with Probe Master 5125BA BNC Adapter (Modified with wires for probe ground for ripple measurement, and two parallel decoupling capacitors added). Page 13 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 2.4W Cell Phone Charger using LNK500P February 4, 2004 7.5.2 Output Voltage Ripple Figure 11 – Output Voltage Ripple (worst case) at Vin = 90 Vac, Vo = 5.44 V, Io = 400 mA 8 Surge Test Surge test was done as per IEC1000-4-5, but with 2.5kV line-line, 2 Ω impedance, with 8 strikes each at +2.5kV at 90º and –2.5kV at 270º. The unit passed without any failure. Page 14 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 2.4W Cell Phone Charger using LNK500P February 4, 2004 9 EMI Tests The EMI tests are done at 220 Vac input and 400 mA load. Figure 12 – EN55022 Class B, Line, artificial hand connected to output return Figure 13 – EN55022 Class B, Neutral, artificial hand connected to output return Page 15 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 2.4W Cell Phone Charger using LNK500P February 4, 2004 Figure 14 – EN55022 Class B, Line, without artificial hand connected to output return Figure 15 – EN55022 Class B, Neutral, without artificial hand connected to output return Page 16 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 2.4W Cell Phone Charger using LNK500P February 4, 2004 10 Revision History Date February 4, 2004 Author YG Revision 1.0 Description & changes Initial release Reviewed AM/VC Page 17 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 2.4W Cell Phone Charger using LNK500P Notes February 4, 2004 Page 18 of 19 Power Integrations Tel: +1 408 414 9660 Fax: +1 408 414 9760 www.powerint.com DER-12 2.4W Cell Phone Charger using LNK500P February 4, 2004 For the latest updates, visit our Web site: www.powerint.com Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability. Power Integrations does not assume any liability arising from the use of any device or circuit described herein, nor does it convey any license under its patent rights or the rights of others. The products and applications illustrated herein (including circuits external to the products and transformer construction) 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. The PI Logo, TOPSwitch, TinySwitch, LinkSwitch, and EcoSmart are registered trademarks of Power Integrations, Inc. PI Expert and DPA-Switch are trademarks of Power Integrations, Inc. © Copyright 2003, Power Integrations, Inc. WORLD HEADQUARTERS NORTH AMERICA - WEST Power Integrations, Inc. 5245 Hellyer Avenue San Jose, CA 95138 USA. 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