Title Reference Design Report for a 7 W NonDimmable, Non-Isolated Buck LED Driver Using LYTSwitchTM-0 LYT0006D Specification 190 VAC - 265 VAC Input; 85 V, 82 mA Output Application Author Document Number Date Revision A17 / A19 LED Driver Lamp Replacement Applications Engineering Department RDR-378 October 4, 2013 1.0 Summary and Features Single-stage power factor corrected ( >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% across VAC input range Fast start-up time (<100 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 . Power Integrations 5245 Hellyer Avenue, San Jose, CA 95138 USA. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D 04-Oct-13 Table of Contents 1 2 3 4 Introduction ................................................................................................................. 3 Power Supply Specification ........................................................................................ 5 Schematic ................................................................................................................... 6 Circuit Description ...................................................................................................... 7 4.1 Input EMI Filtering ............................................................................................... 7 4.2 LYTSwitch-0 ........................................................................................................ 7 4.3 Output Rectification ............................................................................................. 7 4.4 Output Feedback ................................................................................................. 7 4.5 No-Load Protection ............................................................................................. 8 5 PCB Layout ................................................................................................................ 9 6 Bill of Materials ......................................................................................................... 10 7 Inductor Design Spreadsheet ................................................................................... 11 8 Performance Data .................................................................................................... 13 8.1 Active Mode Efficiency ...................................................................................... 14 8.2 Output Current Regulation................................................................................. 15 8.2.1 Output Current Regulation Across Line and Load ...................................... 15 9 Thermal Performance ............................................................................................... 16 9.1 Equipment Used ................................................................................................ 16 9.2 Thermal Result .................................................................................................. 18 9.2.1 Load: 85 V / 82 m A LED Load. .................................................................. 18 9.3 Thermal Scan .................................................................................................... 19 10 Waveforms ............................................................................................................ 20 10.1 Drain Voltage, Current Normal Operation.......................................................... 20 10.2 Drain Voltage and Current When Output Short ................................................. 21 10.3 Drain Voltage and Current Start-up Profile ........................................................ 21 10.4 Output Current Start-up Profile .......................................................................... 22 10.5 Input-Output Profile ........................................................................................... 23 10.6 Line Sag and Surge ........................................................................................... 24 10.7 One Shot No-Load Protection ........................................................................... 25 10.8 Brown-out / Brown-in ......................................................................................... 26 11 Line Surge............................................................................................................. 27 12 Conducted EMI ..................................................................................................... 29 13 Revision History .................................................................................................... 32 Important Note: 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. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 2 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D 1 Introduction This document describes a cost-effective power supply utilizing the LYTSwitchTM-0 family (LYT0006D) in a highly compact buck topology. Figure 1 - Populated Circuit Board This power supply operates over an input voltage range of 190 VAC to 265 VAC. The DC bus voltage is high enough to support an 85 V output when using a buck topology - in a buck converter the output voltage must always be lower than the input voltage. The output voltage is also limited by the maximum duty cycle of the LYTSwitch-0 (which also requires the input voltage to be larger than the output voltage). The reference design is not limited for retrofit lamp application; the design layout can be easily modified to fit in LED tube or ballast applications. Page 3 of 33 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D 04-Oct-13 Figure 2 - Populated Circuit Board, Top View. Figure 3 - Populated Circuit Board, Bottom View. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 4 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D 2 Power Supply Specification The table below represents the minimum acceptable performance for the design. Actual performance is listed in the results section. Description Symbol Min Input Voltage Operation VIN 190 Frequency fLINE 47 50/60 VOUT IOUT 83 85 82 Output Output Voltage Output Current Total Output Power Continuous Output Power Efficiency 240 VAC; 85 V LED Typ 7 POUT 91 PF 0.5 Max Units Comment 265 VAC 2 Wire - no P.E. Operating frequency is not limited. Adjust sense resistor if application is for 400 Hz line. Hz 88 V mA 4% at 200 VAC - 240 VAC W % Measured at POUT, 25 C Power Factor 240 VAC; 85 V LED Measured at POUT, 25 C Environmental Conducted EMI Meets CISPR22B / EN55015B Line Surge Differential Mode (L1-L2) Page 5 of 33 2.5 kV 500 A short circuit Series Impedance: Differential Mode: 2 25 0.5 Ring Wave (100 kHz) Differential Mode (L1-L2) Ambient Temperature kV 1.2/50 s surge, IEC 1000-4-5, Series Impedance: Differential Mode: 2 TAMB -10 C Free convection, sea level Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D 04-Oct-13 3 Schematic Figure 4 - Schematic. Zener Diode VR1 is Optional, Providing One-time No-load Protection. Refer to AN-60 for Additional OVP Options. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 6 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D 4 Circuit Description The power supply shown in Figure 3 uses the LYT0006D (U1) in a high-side buck configuration to deliver a constant 82 mA current at an output voltage of 85 VDC. The power supply is designed for driving LEDs, which should always be driven with a constant current (CC). 4.1 Input EMI Filtering Fuse RF1 provides short circuit protection. Bridge BR1 provides full wave rectification for good power factor. Capacitor C1, C2 and common-mode choke L1 form a filter in order meet conducted EMI standards. Capacitor C1 and C2 are also used for energy storage reducing line noise and protecting against line surge. 4.2 LYTSwitch-0 The LYTSwitch-0 family is fully optimized to enable the design of a simple, cost-effective LED driver with good line and temperature regulation from 0 to 100 C (LYTSwitch-0 case temperature). The PIXls spreadsheet was used to achieve the best possible line regulation by optimizing the choices of power inductor and sense resistor. Optimize the total input capacitance to design for the highest possible power factor and line load regulation. The LYTSwitch-0 family has a built-in thermal limit to protect the power supply in the event that temperature rises beyond the suitable level of operation. The buck converter stage consists of the integrated power MOSFET switch within LYT0006D (U1), a freewheeling diode (D1), sense resistors (R2, R3), power inductor L2 and output capacitor (C5). The converter is operating mostly in discontinuous mode (DCM) in order to limit the cycles of reverse current. A fast freewheeling diode was selected to minimize switching losses. A standard off-the-shelf inductor was used in the power converter to reduce cost. 4.3 Output Rectification Fast output diode (D1) was used to achieve good efficiency and for thermal management. Normally for LED applications, the ambient temperature is above 70 C. A device with low tRR (<35 ns) is recommended. 4.4 Output Feedback Regulation is maintained by skipping switching cycles. As the output current rises, the voltage into the FEEDBACK (FB) pin also rises. If this voltage exceeds VFB then subsequent switching cycles will be skipped until the voltage drops below VFB. Current is sensed via R2, R3 and filtered by C4, then fed to the FB pin for accurate regulation. The key to achieving good line regulation is in balancing the power inductor and sense resistor values after the minimum inductance has been calculated. Page 7 of 33 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D 04-Oct-13 The bypass capacitor (C4) is connected between the FB pin and the SOURCE (S) pin and helps reduce power loss during output current sensing. The capacitor acts to sample-and-hold the feedback current information for the FB pin. No limiting resistor is required between the FB pin and C4, because the peak voltage will not exceed the maximum rating of the device. 4.5 No-Load Protection An optional, one-shot, no-load protection circuit is incorporated into the design. In case of accidental no-load operation, the output capacitor is protected by VR1. Zener diode VR1 would need to be replaced after a failure. Refer to AN-60 for other OVP design options. In operation (LED retrofit lamp), the load is always connected, so VR1 could be removed to save cost. If this option is utilized, to protect during board level testing (in manufacturing) 70 VAC can be applied to the input; if no output current is measured then the load is not connected. This test will allow safe, non-destructive initial power up of the board, without the need of an OV protection circuit. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 8 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D 5 PCB Layout Figure 5 - Printed Circuit Layout, Top View. Figure 6 - Printed Circuit Layout, Bottom View. Page 9 of 33 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D 04-Oct-13 6 Bill of Materials Item Qty Ref Des Description Manufacturer P/N Manufacturer B10S-G Comchip Technology Electrical 1 1 BR1 2 1 C1 1000 V, 0.8 A, Bridge Rectifier, SMD, MBS-1, 4-SOIC 100 nF, 450 V, Film MEXXD31004JJ1 Duratech 3 1 C2 330 nF, 450 V, METALPOLYPRO ECW-F2W334JAQ Panasonic Vishay 4 1 C3 100 nF, 25 V, Ceramic, X7R, 0603 VJ0603Y104KNXAO 5 1 C4 22 F, 16 V, Ceramic, X7R, 0805 C2012X5R1C226K TDK 6 1 C5 68 F, 100 V, Electrolytic, Gen. Purpose, (10 x 16) UHE2A680MPD Nichicon 7 1 D1 600 V, 1 A, Ultrafast Recovery, 30 ns, SOD57 BYV26C Philips 8 1 L1 10 mH, 0.076 A, 20% RL-5480-3-10000 Renco Elect 9 1 L2 1.5 mH, 0.250 A, 10% RL-5480HC-3-1500 Renco Elect 10 1 R1 4.7 k, 5%, 1/8 W, Thick Film, 0805 ERJ-6GEYJ472V Panasonic 11 2 R2 R3 53.6 , 1%, 1/8 W, Thick Film, 0805 ERJ-6ENF53R6V Panasonic 12 1 RF1 10 , 5%, 2 W, Wirewound, Fusible FW20A10R0JA Bourns 13 1 RV1 275 V, 23 J, 7 mm, RADIAL V275LA4P Littlefuse 14 1 U1 LYTSwitch-0, SMD-8C LYT0006D Power Integrations 15 1 VR1 100 V, 5%, 1 W, DO-41 1N4764A-TAP Vishay Anixter Mechanical 16 1 WIRE(V-) Wire, UL1007,# 24 AWG, Blk, PVC, 4" 1007-24/7-0 17 1 WIRE (L) Wire, UL1007, #24 AWG, Blu, PVC, 4" 1007-24/7-6 Anixter 18 1 WIRE(V+) Wire, UL1007, #24 AWG, Red, PVC, 4" 1007-24/7-2 Anixter 19 1 WIRE(N) Wire, UL1007, #24 AWG, Wht, PVC, 4" 1007-24/7-9 Anixter 20 1 PCB FR4, 0.31, 1 Oz Cu (0.51" X 2.1") Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 10 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D 7 Inductor Design Spreadsheet ACDC_LYTSwitchZero_052813; Rev.0.8; Copyright Power Integrations 2013 INPUT VARIABLES VACMIN VACNOM VACMAX FL VO IO Pout OUTPUT UNIT LYTSwitchZero_Rev_0-8.xls: LYTSwitchZero Design Spreadsheet 190 230 265 50 85 82 190 230 265 50 85 82 6.97 Volts Minimum AC Input Voltage Volts Hertz Volts mA W Maximum AC Input Voltage Line Frequency Output Voltage Output Current EFFICIENCY 0.91 0.91 CIN 0.43 0.43 uF Input Stage Resistance 4.7 4.7 ohms Switching Topology DC INPUT VARIABLES VMIN VMAX LYTSwitchZero LYTSwitchZero ILIMIT ILIMIT_MIN ILIMIT_MAX FSMIN INPUT INFO Buck Overall Efficiency Estimate (Adjust to match Calculated, or enter Measured Efficiency) Input Filter Capacitor Input Stage Resistance, Fuse & Filtering Type of Switching topology 85 374.766594 Volts Volts Minimum DC Bus Voltage LYT0006 0.375 0.33275 0.401 62000 Amps Amps Amps Hertz IRMS 85.25298 mA VDS 4.8375 Volts Typical Current Limit Minimum Current Limit Maximum Current Limit Minimum Switching Frequency Expected RMS current through LYTSwitch Maximum On-State Drain To Source Voltage drop VD 0.7 Volts VRR 600 Volts 1 Amps LYT0006 DIODE IF Diode Recommendation OUTPUT INDUCTOR Core type BYV26C Off-theShelf Off-the-Shelf Core size Custom Core AE LE AL BW NL BP LG N/A N/A N/A N/A N/A N/A N/A OD N/A INS N/A Page 11 of 33 mm^2 mm nH/T^2 mm Gauss mm Freewheeling Diode Forward Voltage Drop Recommended PIV rating of Freewheeling Diode Recommended Diode Continuous Current Rating Suggested Freewheeling Diode Select core type between Ferrite and Off-the-Shelf Select core size Enter custom core description (if used) Core Effective Cross Sectional Area Core Effective Path Length Ungapped Core Effective Inductance Bobbin Physical Winding Width Number of turns on inductor Peak flux density Gap length Maximum Primary Wire Diameter including insulation Estimated Total Insulation Thickness Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D 04-Oct-13 (= 2 * film thickness) DIA N/A AWG N/A CM N/A CMA N/A L N/A LP 1350 Bare conductor diameter Primary Wire Gauge (Rounded to next smaller standard AWG value) Bare conductor effective area in circular mils !!! INCREASE CMA > 200 (increase L(primary layers),decrease NS, use larger Core) 1350 uH IO_Average 82.52548 mA ILRMS 176.4503 mA Output Inductor, Recommended Standard Value Average output current Estimated RMS inductor current (at VMAX) FEEDBACK COMPONENTS RFB 26.8 CFB OUTPUT REGULATION IO_VACMIN IO_VACNOM IO_VACMAX Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com 26.8 Ohms 22 uF Feedback Resistor. Use closest standard 1% value Feedback Capacitor 82.52548 80.51328 79.12785 mA mA mA Output Current at VACMIN Output Current at VACNOM Output Current at VACMAX Page 12 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D 8 Performance Data All measurements performed at room temperature (25 C) unless otherwise specified. Input VAC Freq (VRMS) (Hz) 190 50 200 50 220 50 230 50 265 50 190 50 200 50 220 50 230 50 265 50 190 50 200 50 220 50 230 50 265 50 Input Measurement VIN IIN PIN (VRMS) (mARMS) (W) 190.20 54.85 7.449 220.35 53.19 7.388 230.22 52.27 7.332 240.23 51.60 7.279 265.25 50.39 7.100 190.16 55.32 7.669 220.35 52.81 7.598 230.21 52.40 7.570 240.23 52.08 7.545 265.28 52.16 7.473 190.17 55.92 7.937 220.35 53.01 7.833 230.22 52.54 7.798 240.34 52.22 7.773 265.26 51.80 7.719 PF 0.714 0.630 0.609 0.587 0.531 0.729 0.653 0.628 0.603 0.540 0.746 0.671 0.645 0.619 0.562 LED Load Measurement VOUT IOUT POUT (VDC) (mADC) (W) 81.4500 83.680 6.832 81.4400 82.620 6.740 81.4400 82.000 6.688 81.4300 81.390 6.637 81.4000 79.050 6.442 84.4900 83.260 7.052 84.4800 82.290 6.964 84.4800 81.840 6.925 84.4700 81.390 6.885 84.4600 80.300 6.790 87.5700 83.230 7.306 87.5500 81.780 7.173 87.5400 81.480 7.144 87.5400 81.180 7.117 87.5300 80.430 7.048 Efficiency (%) Regulation (%) 91.72 91.23 91.22 91.18 90.73 91.95 91.66 91.48 91.25 90.86 92.05 91.57 91.61 91.56 91.31 2.05 0.76 0.00 -0.74 -3.60 1.54 0.35 -0.20 -0.74 -2.07 1.50 -0.27 -0.63 -1.00 -1.91 Table 1 - Raw Data of Unit. Page 13 of 33 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D 8.1 04-Oct-13 Active Mode Efficiency 93.0 82 V 85 V 88 V 92.5 Efficiency (%) 92.0 91.5 91.0 90.5 90.0 180 190 200 210 220 230 240 250 260 270 280 Input Voltage (VRMS) Figure 7 - Efficiency with Respect to AC Input Voltage, 190-265 VAC (60 Hz) Input. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 14 of 33 04-Oct-13 8.2 RDR-378 7 W Non-Isolated Buck Using LYT0006D Output Current Regulation 8.2.1 Output Current Regulation Across Line and Load 5 82 V 85 V 88 V 4 3 Regulation (%) 2 1 0 -1 -2 -3 -4 -5 180 190 200 210 220 230 240 250 260 270 Input Voltage (VRMS) Figure 8 - Load Regulation, Room Temperature. Page 15 of 33 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com 280 RDR-378 7 W Non-Isolated Buck Using LYT0006D 04-Oct-13 9 Thermal Performance 9.1 Equipment Used Chamber: AC Source: Tenney Environmental Chamber Model No: TJR-17 942 Chroma Programmable AC Source Model No: 6415 Wattmeter: Data Logger: Yokogawa Power Meter Model No: WT2000 Agilent Figure 9 - Thermal Chamber Set-up Showing Box Used to Prevent Airflow Over UUT. Open Frame Set-up Measurement. Figure 10 - Thermal Measurement, Thermocouple Set-up. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 16 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D Figure 11 - Enclosed Thermal Measurement Set-up. Note: Typical A19 enclosure is used in the test; the housing may be identical to lamps available in the market but it does not limit its application. It is up to the end customer to enclose the driver and design the housing. Page 17 of 33 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D 9.2 04-Oct-13 Thermal Result 9.2.1 Load: 85 V / 82 m A LED Load. Remarks Normal Operation Open Frame in the Thermal Chamber 190 V / 50 Hz OTP; 190 V / 50 Hz Recovery; 190 V / 50 Hz 190 V / 50 Hz Enclosed (30 C External Ambient) 265 V / 50 Hz Enclosed (30 C External Ambient) Internal Ambient C -10 0 10 20 30 40 50 60 70 80 90 100 110 117 53 BR C LYT0006D C 4.91 14.36 23.80 33.37 43.09 52.69 62.33 71.65 81.40 91.33 101.09 110.97 121.03 129.15 62.83 L2;Power Inductor C -2.24 6.81 15.71 25.10 34.45 43.71 53.12 61.98 71.32 80.89 90.23 99.85 109.71 117.55 65.18 Output Capacitor C -10.24 -0.98 8.23 17.89 27.58 37.16 46.80 55.77 65.44 75.19 85.05 94.78 105.11 112.42 61.33 Output Diode C -0.15 9.28 18.29 28.07 37.70 47.12 56.79 66.10 75.87 85.60 95.59 105.34 115.51 123.19 61.86 -5.77 3.92 13.39 23.10 32.95 42.64 52.30 61.92 71.69 81.52 91.01 101.31 111.48 119.28 58.08 64 54.28 78.39 74.10 70.15 67.79 65 54.30 81.11 76.26 71.11 69.66 Table 2 - Thermal Measurement. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 18 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D 9.3 Thermal Scan Open-frame thermal measurement at 25C ambient. UUT was soaked for 1 hour to achieve steady-state before the measurements were made. Figure 12 - Temperature (C) at Bottom Side of PCB. SP1 - U1, LYT0006D. SP2 - BR1, Bridge Rectifier. SP3 - Ambient. Figure 13 - Temperature (C) at Top Side of PCB. SP1 - Output Capacitor. SP2 - L2, Power inductor. SP3 - D1, Freewheeling Diode. SP4 - Ambient. Page 19 of 33 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D 04-Oct-13 10 Waveforms 10.1 Drain Voltage, Current Normal Operation Missing pulses are normal and are used to regulate the output current. These missing pulses are present every time the sense resistors (R2, R3) voltage-drop reaches 1.65 V. The unit will enter into auto-restart if there is not at least one missing pulse within a 50 ms period. For some designs where the power inductance is high and the circuit is operating (mostly) in CCM, a period of reverse current may be present. This can be avoided by increasing the device size or increase input capacitance or adding a drain blocking diode. See AN-60 for additional information. Figure 14 - 190 VAC, 50 Hz, Nominal VLED Load. F1 (Orange): VD-S, 200 V / div. Ch1 (Yellow): VD-G, 100 V / div. Ch3 (Blue): IDRAIN, 100 mA / div. Time Scale: 1 ms / div. Figure 15 - 265 VAC, 50 Hz, Nominal VLED Load. F1 (Orange): VD-S, 200 V / div. Ch1 (Yellow): VD-G, 100 V / div. Ch3 (Blue): IDRAIN, 100 mA / div. Time Scale: 1 ms / div. Figure 16 - 190 VAC, 50 Hz, Nominal VLED Load. F1 (Orange): VD-S, 200 V / div. Ch3 (Blue): IDRAIN, 100 mA / div. Time Scale: 20 s / div. Figure 17 - 265 VAC, 50 Hz, Nominal VLED Load. F1 (Orange): VD-S, 200 V / div. Ch3 (Blue): IDRAIN, 100 mA / div. Time Scale: 20 s / div. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 20 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D 10.2 Drain Voltage and Current When Output Short Device is operating within range, no inductor saturation was observed. Figure 18 - LYT0006D Output Short. 265 VAC. Ch3: IDRAIN, 0.5 A / div. Time Scale: 2 ms / div. Z4: VD-S, 0.5 A / div. Zoom Time Scale: 10 s / div. Figure 19 - LYT0006D Output Short. 265 VAC. Ch4: IDRAIN, 0.2 A / div. Time Scale: 10 s / div. Z4: VD-S, 0.2 A / div. Zoom Time Scale: 500 ns / div. 10.3 Drain Voltage and Current Start-up Profile Device is operating within range, no inductor saturation was observed. Figure 20 - 265 VAC / 50 Hz Start-up. Ch1: Bulk Input, 500 V / div. Ch3: Z4: IDRAIN, 0.5 A / div. Time Scale: 200 s / div. F1: VD-S, 500 V / div. Zoom Time Scale: 200 s / div. Page 21 of 33 Figure 21 - 265 VAC / 50 Hz Start-up. Ch1: Bulk Input, 500 V / div. Ch3: Z4: IDRAIN, 0.5 A / div. Time Scale: 200 s / div. F1: VD-S, 500 V / div. Zoom Time Scale: 200 s / div. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D 04-Oct-13 10.4 Output Current Start-up Profile Output current/light is present within one AC cycle (<100 ms). Figure 22 - 190 VAC, 50 Hz, Nominal VLED Load. Ch1 (Yellow): VIN, 100 V / div. Ch2 (Red): VOUT, 20 V. Ch3 (Blue): IIN, 50 mA / div. Ch4 (Green): IOUT, 20 mA / div, 20 ms / div. Figure 23 - 230 VAC, 50 Hz, Nominal VLED Load. Ch1 (Yellow): VIN, 100 V / div. Ch2 (Red): VOUT, 20 V. Ch3 (Blue): IIN, 50 mA / div. Ch4 (Green): IOUT, 20 mA / div, 20 ms / div. Figure 24 - 240 VAC, 50 Hz, Nominal VLED Load. Ch1 (Yellow): VIN, 100 V / div. Ch2 (Red): VOUT, 20 V. Ch3 (Blue): IIN, 50 mA / div. Ch4 (Green): IOUT, 20 mA / div, 20 ms / div. Figure 25 - 265 VAC, 50 Hz, Nominal VLED Load. Ch1 (Yellow): VIN, 100 V / div. Ch2 (Red): VOUT, 20 V. Ch3 (Blue): IIN, 50 mA / div. Ch4 (Green): IOUT, 20 mA / div, 20 ms / div. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 22 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D 10.5 Input-Output Profile There is no limitation to the amount of output capacitance that can be added. If the application requires less output current ripple then increasing the output capacitance is straightforward. Note that the output current waveform below will change depending on LED load impedance which varies according to LED type. Figure 26 - 190 VAC / 50 Hz, Nominal VLED Load. Ch1 (Yellow): VIN, 100 V / div. Ch2 (Red): VOUT, 20 V. Ch3 (Blue): IIN, 50 mA / div. Ch4 (Green): IOUT, 20 mA / div, 10 ms / div. Figure 27 - 230 VAC / 50 Hz, Nominal VLED Load. Ch1 (Yellow): VIN, 100 V / div. Ch2 (Red): VOUT, 20 V. Ch3 (Blue): IIN, 50 mA / div. Ch4 (Green): IOUT, 20 mA / div, 10 ms / div. Figure 28 - 240 VAC / 50 Hz, Nominal VLED Load. Ch1 (Yellow): VIN, 100 V / div. Ch2 (Red): VOUT, 20 V. Ch3 (Blue): IIN, 50 mA / div. Ch4 (Green): IOUT, 20 mA / div, 10 ms / div. Figure 29 - 265 VAC / 50 Hz, Nominal VLED Load. Ch1 (Yellow): VIN, 100 V / div. Ch2 (Red): VOUT, 20 V. Ch3 (Blue): IIN, 50 mA / div. Ch4 (Green): IOUT, 20 mA / div, 10 ms / div. Page 23 of 33 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D 04-Oct-13 10.6 Line Sag and Surge An inherent advantage of the buck converter implemented with the LYTSwitch-0 family is the imperceptible start-up delay, the driver will turn-on within 100 ms as shown below. No failure of any component occurred during line fluctuation tests. Figure 30 - Line Sag Test at 230 - 0 V at 0.1 Second Interval. Ch1: VIN, 100 V / div. Ch2: VOUT, 20 V / div. Ch4: IOUT, 50 mA / div. Time Scale: 500 ms / div. Figure 32 - Line Surge Test at 230 - 190 V at 0.1 Second Interval. Ch1: VIN, 100 V / div. Ch2: VOUT, 20 V / div. Ch4: IOUT, 50 mA / div. Time Scale: 500 ms / div. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Figure 31 - Line Surge Test at 230 - 265 V at 0.1 Second Interval. Ch1: VIN, 100 V / div. Ch2: VOUT, 20 V / div. Ch4: IOUT, 50 mA / div. Time Scale: 500 ms / div. Figure 33 - Line Sag Test at 230 - 0 V at 1 Second Interval. Ch1: VIN, 100 V / div. Ch2: VOUT, 20 V / div. Ch4: IOUT, 50 mA / div. Time Scale: 2 s / div. Page 24 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D 10.7 One Shot No-Load Protection The reference design is protected with one shot no-load protection. Zener diode VR1 will need to be replaced after the fault. Figure 34 - No-Load Protection When Load is Disconnected. 265 V / 50 Hz. Ch2: VOUT, 20 V / div. Ch3: IDRAIN, 100 mA / div. Ch3: IOUT, 50 mA / div. Time Scale: 200 ms / div. Page 25 of 33 Figure 35 - No-Load Start-Up. 265 V / 50 Hz. Ch2: VOUT, 20 V / div. Ch3: IDRAIN, 100 mA / div. Ch3: IOUT, 50 mA / div. Time Scale: 200 ms / div. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D 04-Oct-13 10.8 Brown-out / Brown-in No failure of any component during brownout test of 1 V / sec and 10 V / sec AC cut-in and cut-off. Consider the peak current at 132 mApk with an average of 75 mAAVG during brown-out for LED absolute maximum rating. Figure 36 - Brown-out Test at 1 V / s and 10 V / s. The Unit is Able to Operate Normally Without Any Failure and Without Flicker. 230 V - 0 - 230 V Ch1: VIN, 100 V / div. Ch1: VOUT, 20 V / div. Ch3: IOUT, 20 mA / div. Time Scale: 100 s / div. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Figure 37 - Brown-out Test at 1 V / s and 10 V / s. The Unit is Able to Operate Normally Without Any Failure and Without Flicker. 230 V - 0 - 230 V Ch1: VIN, 100 V / div. Ch1: VOUT, 20 V / div. Ch3: IOUT, 20 mA / div. Time Scale: 100 s / div. Page 26 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D 11 Line Surge Differential input line 500V / 50 s surge testing was completed on a single test unit following the test method described in IEC61000-4-5. Input voltage was set at 230 VAC / 60 Hz. Full output load applied and operation was verified following each surge event. Surge Level (V) +500 -500 +500 -500 +500 -500 Input Voltage (VAC) 230 230 230 230 230 230 Injection Location Injection Phase () Test Result (Pass/Fail) L to N L to N L to N L to N L to N L to N 90 90 270 270 0 0 Pass Pass Pass Pass Pass Pass Unit passed testing under all conditions. Differential ring input line surge testing was completed on a single test unit following the test method described in IEC61000-4-5. Input voltage was set at 230 VAC / 60 Hz. Full output load was applied and operation was verified following each surge event. Surge Level (V) +2500 -2500 +2500 -2500 +2500 -2500 Input Voltage (VAC) 230 230 230 230 230 230 Injection Location Injection Phase () Test Result (Pass/Fail) L to N L to N L to N L to N L to N L to N 90 90 270 270 0 0 Pass Pass Pass Pass Pass Pass Unit passed testing under all conditions. Page 27 of 33 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D 04-Oct-13 Figure 38 - Differential Line Surge at 500 V / 90. Peak Drain Voltage Recorded is 680 V. Ch1: VBULK, 100 V / div. F1: VDRAIN, 200 V / div. Time Scale: 100 s / div. Figure 39 - Differential Line Surge at 500 V / 90. Peak Drain Voltage Recorded is 427 V. Ch1: VBULK, 100 V / div. F1: VDRAIN, 200 V / div. Time Scale: 100 s / div. Figure 40 - Differential Ring Surge at 2500 V / 90. Peak Drain Voltage Recorded is 505 V. Ch1: VBULK, 100 V / div. F1: VDRAIN, 200 V / div. Time Scale: 500 s / div. Figure 41 - Differential Ring Surge at 2500 V / 0. Peak Drain Voltage Recorded is 404 V. Ch1: VBULK, 100 V / div. F1: VDRAIN, 200 V / div. Time Scale: 500 s / div. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 28 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D 12 Conducted EMI Figure 42 - The Retrofit Lamp was Verified Inside a Conical Metal Cone as per EN55015. Page 29 of 33 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D Power Integrations 03.Jul 13 21:00 RBW MT 04-Oct-13 9 kHz 500 ms Att 10 dB AUTO dBV 100 kHz 120 EN55015Q 110 1 QP CLRWR LIMIT CHECK 1 MHz PASS 10 MHz SGL 100 90 2 AV CLRWR TDF 80 70 60 EN55015A 50 6DB 40 30 20 10 0 -10 -20 9 kHz 30 MHz Figure 43 - Conducted EMI, Maximum Steady State Load, 230 VAC, 60 Hz, and EN55015 B Limits. Enclosed Unit in a Typical A19 Bulb Replacement Housing. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 30 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D Trace1: EN55015Q Trace2: EN55015A Trace3: --- TRACE FREQUENCY LEVEL dBV DELTA LIMIT dB 2 Average 9.09 kHz 23.57 N gnd 2 Average 125.720633819 kHz 28.32 N gnd 2 Average 129.530094744 kHz 27.83 L1 gnd 2 Average 192.364799253 kHz 30.64 L1 gnd -23.29 2 Average 256.711570318 kHz 35.38 N gnd -16.15 1 Quasi Peak 259.278686021 kHz 46.59 L1 gnd -14.85 1 Quasi Peak 310.135545783 kHz 42.05 L1 gnd -17.90 2 Average 322.728292586 kHz 30.28 N gnd -19.35 1 Quasi Peak 389.890938834 kHz 39.15 L1 gnd -18.90 2 Average 452.651275966 kHz 28.63 N gnd -18.19 1 Quasi Peak 457.177788726 kHz 40.31 N gnd -16.42 1 Quasi Peak 505.008700673 kHz 40.18 L1 gnd -15.81 2 Average 510.05878768 kHz 28.59 N gnd -17.40 1 Quasi Peak 586.299423673 kHz 39.77 L1 gnd -16.22 1 Quasi Peak 647.639315505 kHz 43.74 L1 gnd -12.25 2 Average 647.639315505 kHz 30.70 N gnd -15.29 1 Quasi Peak 680.675429436 kHz 38.42 L1 gnd -17.57 1 Quasi Peak 908.363999266 kHz 47.31 L1 gnd -8.68 2 Average 908.363999266 kHz 33.01 N gnd -12.98 1 Quasi Peak 1.06512822736 MHz 39.04 L1 gnd -16.95 Table 3 - Conducted EMI, Maximum Steady State Load, 230 VAC, 60 Hz, and EN55015 B Limits. Enclosed Unit in a Typical A19 Bulb Replacement Housing. Page 31 of 33 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-378 7 W Non-Isolated Buck Using LYT0006D 04-Oct-13 13 Revision History Date 04-Oct-13 Author JDC Revision 1.0 Description & changes Initial Release Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Reviewed Apps & Mktg Page 32 of 33 04-Oct-13 RDR-378 7 W Non-Isolated Buck Using LYT0006D For the latest updates, visit our website: 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. POWER INTEGRATIONS MAKES NO WARRANTY HEREIN AND SPECIFICALLY DISCLAIMS ALL WARRANTIES INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT OF THIRD PARTY RIGHTS. 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 http://www.powerint.com/ip.htm. 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