Title Reference Design Report for a 6 W NonDimmable, Non-Isolated Buck LED Driver Using LYTSwitchTM-0 LYT0006P Specification 90 VAC – 265 VAC Input; 54 V, 110 mA Output Application GU10 LED Driver Lamp Replacement Author Applications Engineering Department Document Number Date Revision RDR-355 June 18, 2013 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 <http://www.powerint.com/ip.htm>. Power Integrations 5245 Hellyer Avenue, San Jose, CA 95138 USA. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 Table of Contents 1 2 3 4 Introduction ................................................................................................................. 4 Power Supply Specification ........................................................................................ 6 Schematic ................................................................................................................... 7 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. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 2 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P 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. Page 3 of 40 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 1 Introduction This document describes a cost effective power supply utilizing the LYTSwitchTM-0 family (LYT0006P) in a highly compact buck topology. This power supply operates over an input voltage range of 90 VAC to 264 VAC. The DC bus voltage is high enough to support a 54 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. Figure 1 – Populated Circuit Board Photograph, Top. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 4 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P Figure 2 – Populated Circuit Board Photograph, Bottom. Page 5 of 40 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 2 Power Supply Specification Description Symbol Min Input Voltage Operation VIN 90 Frequency fLINE 47 50/60 VOUT IOUT 52 54 110 56 6 6.5 Output Output Voltage Output Current Total Output Power Continuous Output Power Efficiency 120 VAC; 54 V LED POUT Typ 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 V mA W 91 % 90 % 120 VAC; 54 V LED PF 0.75 240 VAC; 54 V LED PF 0.5 240 VAC; 54 V LED ±4% at 100 VAC - 240 VAC º Measured at POUT 25 C Power Factor º Measured at POUT 25 C Environmental Conducted EMI Meets CISPR22B / EN55015B Line Surge Differential Mode (L1-L2) 0.5 Ring Wave (100 kHz) Differential Mode (L1-L2) 2.5 Ambient Temperature TAMB -10 Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com 25 kV 1.2/50 s surge, IEC 1000-4-5, Series Impedance: Differential Mode: 2 kV 500 A short circuit Series Impedance: Differential Mode: 2 º C Free convection, sea level UUT can start-up at – (neg) 40 ºC Page 6 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P 3 Schematic Figure 3 – Schematic. T1 can be replaced by a drum core inductor if final casing/housing has sufficient room to avoid shorting the magnetic flux. Zener diode VR1 is an option and provides one-time no-load protection. Page 7 of 40 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 4 Circuit Description The power supply shown in Figure 3 uses the LYT0006P (U1) in a high-side buck configuration to deliver a constant 110 mA current at an output voltage of 54 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 π 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 LYTSwitch-0 is optimized to achieve a simple and cost effective LED driver with good line and temperature regulation from 0 to 100C (LYTSwitch-0 case temperature). The PIXls spreadsheet was used to achieve the best line regulation by balancing the power inductor and the sense resistor. The total input capacitance will also have some effect but it can be compensated for by adjusting the sense resistor (R2/R3) to optimize performance. The LYTSwitch-0 family has built-in thermal limit to protect the power supply in case the bulb is subjected to an excessive operating temperature. The buck converter stage is consists of the integrated power MOSFET switch within LYT0006P (U1), a freewheeling diode (D1), sense resistor (R2), power inductor L2 and output capacitor (C5). The converter is operating mostly in DCM in order to limit the cycles of reverse current. A fast freewheeling diode was selected to minimize the switching losses. Inductor L2 is a standard EE10 which will constrain the flux path and ensure the right inductance in any casing. It can be replaced by a lower cost drum-core inductor once positioned in a specific enclosure that has a known effect on the magnetic flux of the inductor. 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 70C. 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 FB pin will rise. If this exceeds VFB then subsequent cycles will be skipped until the voltage reduces below VFB. Current is sensed from R2 and filtered by Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 8 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P 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. The bypass capacitor (C4) is connected between the FEEDBACK pin and the SOURCE 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 Optional, one shot, no-load protection circuit is incorporated in this 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. In operation (LED retrofit lamp), the load is always connected, so VR1 can be removed to save cost. To protect during board level testing (in manufacturing) 40 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. Page 9 of 40 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 5 PCB Layout Figure 4 – Printed Circuit Layout. Top view. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 10 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P Figure 5 – Printed Circuit Layout. Bottom View. Page 11 of 40 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 6 Bill of Materials Item Qty Ref Des 1 1 BR1 Description 2 1 C1 47 nF, 630 V, Film 3 1 C2 330 nF, 450 V, METALPOLYPRO 4 1 C3 100 nF, 25 V, Ceramic, X7R, 0603 VJ0603Y104KNXAO Vishay 5 1 C4 22 F, 16 V, Ceramic, X5R, 1206 EMK316BJ226ML-T Taiyo Yuden 6 1 C5 47 F, 63 V, Electrolytic, Gen. Purpose, (6.3 x 13) 63YXJ47M6.3X11 Rubycon 7 1 D1 600 V, 1 A, Ultrafast Recovery, 35 ns, SMB Case MURS160T3G On Semi 8 1 L1 4.7 mH, 0.150 A, 20% RL-5480-3-4700 Renco 600 V, 0.5 A, Bridge Rectifier, SMD, MBS-1, 4-SOIC Manufacturer P/N Manufacturer MB6S-TP Micro Commercial ECQ-E6473KF Panasonic ECW-F2W334JAQ Panasonic 9 1 R1 4.7 k, 5%, 1/8 W, Thick Film, 0805 ERJ-6GEYJ472V Panasonic 10 1 R2 18.7 , 1%, 1/4 W, Thick Film, 1206 ERJ-8ENF18R7V Panasonic 11 1 RF1 4.7 , 5%, 2 W, Metal Film Fusible 12 1 RV1 13 1 T1 275 V, 23 J, 7 mm, RADIAL EE10, Bobbin Inductor LinkSwitch-0, DIP-8B 14 1 U1 15 1 VR1 62 V, 5%, 1 W, DO-41 Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com FW20A4R70JA Bourns V275LA4P Custom SNX-R1699 LYT0006P Littlefuse Kunshan Fengshunhe Santronics USA Power Integrations 1N4759A Vishay Page 12 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P 7 Inductor Specification 7.1 Electrical Diagram Figure 6 – Inductor Electrical Diagram. 7.2 Electrical Specifications Primary Inductance 7.3 Pins 4-5, all other windings open, measured at 100 kHz, 0.4 VRMS. 1.4 mH ±7% Materials Item [1] [2] [3] [4] [5] Description Core: EE10; TDK-PC40EE10/11-Z; or equivalent. Bobbin: EE10; 8 pins (4/4), Horizontal, PI#: 25-00956-00. Magnet Wire: #31 AWG, double coated. Tape: Polyester film, 3M 1350-1, 6.5mm wide. Varnish. Page 13 of 40 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 7.4 18-Jun-13 Inductor Build Diagram Finish (P5) Start (P4) Figure 7 – Inductor Build Diagram. 7.5 Transformer Construction Winding Preparation Winding Tape Final Assembly Place bobbin item [2] on the mandrel with pin side 1-4 on the right side. Winding direction is clockwise direction. Start pin 4, wind 150 turns of wire item [3] from right to left then left to right in ~6 layers and finish at pin 5. Secure winding with tape item [4]. Gap cores to get the 1.35 mH inductance. Apply tape to secure both cores. Remove pins: 2 and 3. Figure 8 – Transformer Assembly Sample. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 14 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P 8 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 90 120 265 60 54 110 90 120 265 60 54 110 5.94 Volts Minimum AC Input Voltage Volts Hertz Volts mA W Maximum AC Input Voltage Line Frequency Output Voltage Output Current EFFICIENCY 0.9 0.9 CIN 0.38 0.38 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 54.00068302 374.766594 Volts Volts Minimum DC Bus Voltage LYT0006 0.375 0.33275 0.401 62000 Amps Amps Amps Hertz 4.8375 Volts Typical Current Limit Minimum Current Limit Maximum Current Limit Minimum Switching Frequency Maximum On-State Drain To Source Voltage drop VD 0.7 Volts VRR 600 Volts 1 Amps LYT0006 VDS DIODE IF Diode Recommendation OUTPUT INDUCTOR BYV26C Core type Ferrite Ferrite Core size EE10 EE10 Custom Core AE LE AL BW NL BP LG 12.1 26.1 850 6.6 149.6667555 3100 2.253983597 OD 0.132293908 INS 0.031219467 Page 15 of 40 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 (= 2 * film thickness) Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P DIA 18-Jun-13 0.101074441 AWG 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) 39 CM 12.69920842 CMA 0.112907248 L 3 LP L_R IO_Average Output Inductor, Recommended Standard Value DC Resistance of Inductor Average output current Estimated RMS inductor current (at VMAX) 1400 1400 uH 2 2 112.474696 Ohms 112.474696 mA 18.7 Ohms 22 uF Feedback Resistor. Use closest standard 1% value Feedback Capacitor 109.393596 112.474696 114.3382366 mA mA mA Output Current at VACMIN Output Current at VACNOM Output Current at VACMAX ILRMS FEEDBACK COMPONENTS RFB 18.7 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 Page 16 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P 9 Performance Data All measurements performed at room temperature (≈25 ºC) otherwise specified. Input VAC Freq (VRMS) (Hz) 90 60 100 60 115 60 120 60 132 60 190 50 200 50 220 50 230 50 240 50 265 50 Input Measurement VIN IIN PIN (VRMS) (mARMS) (W) 90.07 82.57 6.480 100.11 78.53 6.584 110.12 73.24 6.555 120.12 69.70 6.566 135.16 67.07 6.564 190.30 57.15 6.386 200.41 56.02 6.359 220.35 54.16 6.308 230.37 53.68 6.286 264.15 55.86 6.726 90.07 82.57 6.480 Page 17 of 40 PF 0.871 0.838 0.813 0.784 0.724 0.587 0.566 0.529 0.508 0.456 0.871 LED Load Measurement VOUT IOUT POUT (VDC) (mADC) (W) 54.0400 108.050 5.918 54.1400 110.150 6.024 54.1400 110.080 6.006 54.1600 110.500 6.021 54.1600 110.590 6.015 54.0200 107.810 5.836 53.9900 107.310 5.805 53.9400 106.430 5.749 53.9200 106.010 5.723 54.2500 112.380 6.098 54.0400 108.050 5.918 Efficiency (%) Regulation (%) 91.33 91.49 91.62 91.70 91.64 91.39 91.29 91.14 91.04 90.66 91.33 -1.77 0.14 0.07 0.45 0.54 -1.99 -2.45 -3.25 -3.63 2.16 -1.77 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 9.1 18-Jun-13 Active Mode Efficiency Figure 9 – Efficiency with Respect to AC Input Voltage. 90-132 VAC (50 Hz) and 190-265 VAC (60 Hz) Input. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 18 of 40 18-Jun-13 9.2 RDR-355 6 W Non-Isolated Buck Using LYT0006P Output Current Regulation 9.2.1 Input Line and Load Voltage to Output Current Regulation Figure 10 – Load Regulation, Room Temperature. Page 19 of 40 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 10 Thermal Performance 10.1 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 Yokogawa Model: 2008-3-4-2-2-1D SN: S5L409310 Figure 11 – Thermal Chamber Set-up Showing Box Used to Prevent Airflow Over UUT. Figure 12 – Thermal Unit Thermocouple Measurement Set-up. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 20 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P 11 Thermal Result Input: 90 VAC / 60 Hz Load: 54 V / 110 m A LED load. Location Temperature Thermal Shutdown Thermal Recovery Ambient 23.3 38.7 47.9 58.4 70.0 80.0 90.0 100.0 107.9 40.5 Bridge 37.8 52.4 60.8 70.9 80.7 89.6 99.0 108.5 115.1 64.4 L1 37.2 52.7 60.9 71.2 81.9 90.6 100.4 109.9 117.8 60.2 L2 39.4 54.6 63.7 73.9 84.7 93.4 103.2 112.7 120.6 63.0 IC 40.9 56.9 66.1 76.9 87.6 97.5 107.5 117.8 125.0 61.7 Diode 38.0 53.5 62.8 73.5 83.9 93.3 103.1 113.0 120.1 59.4 Table 1 – Thermal Measurement. Note: Unit will start reliably at -40 C. Tests were performed but are not shown here. 140 IC Bridge L2 L1 O/P Diode 130 Device Temperature (ºC) 120 110 100 90 80 70 60 50 40 30 20 10 20 30 40 50 60 70 80 90 100 110 Ambient (ºC) Figure 13 – Thermal Performance Curve. Page 21 of 40 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com 120 RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 11.1 Thermal Scan Open-frame thermal measurement at 25C ambient. UUT was soaked for 1 hour to achieve steady-state before the measurement. Figure 14 – Temperature (C) at Top Side of PCB. SP1 – U1, LYT0006P. SP2 – L2, Power Inductor. SP3 – L1, EMI Choke. SP4 – FR1, Fusible Resistor. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Figure 15 – Temperature (C) at Bottom Side of PCB. SP1 – BR1, Bridge Rectifier. SP2 – PCB, Trace Temperature. SP3 – D1, Freewheeling Diode. Page 22 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P 12 Waveforms 12.1 Drain Voltage Normal Operation Figure 16 – 90 VAC, 60Hz, Full Load F1(Orange): VDRAIN-SOURCE, 100 V / div. Ch1(Yellow): VDRAIN-GND, 100 V / div. Ch2(Red): VSOURCE-GND, 100 V, 2 ms / div. Figure 17 – 265 VAC, Full Load F1(Orange): VDRAIN-SOURCE, 200 V / div. Ch1(Yellow): VDRAIN-GND, 200 V / div. Ch2(Red): VSOURCE-GND, 200 V, 2 ms / div. Figure 18 – 90 VAC, 60Hz, Full Load F1(Orange): VDRAIN-SOURCE, 50 V / div. Ch1(Yellow): VDRAIN-GND, 50 V / div. Ch2(Red): VSOURCE-GND, 50 V, 2 ms / div. Z1(Yellow): VDRAIN-GND, 50 V / div. Z2(Red): VSOURCE-GND, 50 V, 20 s / div. Figure 19 – 265 VAC, Full Load F1(Orange): VDRAIN-SOURCE, 200 V / div. Ch1(Yellow): VDRAIN-GND, 200 V / div. Ch2(Red): VSOURCE-GND, 200 V, 2 ms / div. Z1(Yellow): VDRAIN-GND, 200V / div. Z2(Red): VSOURCE-GND, 200 V, 20 s / div. Page 23 of 40 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 12.2 Drain Current at Normal Operation Missing pulses are normal and are used to regulate the output current. These missing pulses are present every time the sense resistor (R2) voltage-drop reaches 1.65 V. The unit will enter into auto-restart if there is not at least one missing pulse within 50 ms. For some designs wherein the power inductance is high and operating mostly in CCM, a reverse current may be present. One way to avoid this is by increasing the device size or increase input capacitance or adding a blocking diode in the drain. See AN-60 for more details. Figure 20 – 90 VAC, 60 Hz, 54 VLED Ch2(Red): VBULK, 50V / div. Ch4(Green): IDRAIN, 200 mA / div., 1 ms / div. Z2(Green): IDRAIN, 100 mA / div., 20 s / div. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Figure 21 – 115 VAC, 60 Hz, 54 VLED Ch2(Red): VBULK, 50 V / div. Ch4(Green): IDRAIN, 200 mA / div., 1 ms / div. Z2(Green): IDRAIN, 100 mA / div., 20 s / div. Page 24 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P Figure 22 – 240 VAC, 60 Hz, 54 VLED Ch2(Red): VBULK, 50 V / div. Ch4(Green): IDRAIN, 200 mA / div., 1 ms / div. Z2(Green): IDRAIN, 100 mA / div., 20 s / div. Page 25 of 40 Figure 23 – 265 VAC, 60 Hz, 54 VLED Ch2(Red): VBULK, 50 V / div. Ch4(Green): IDRAIN, 200 mA / div., 1 ms / div. Z2(Green): IDRAIN, 100 mA / div., 20 s / div. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 12.3 Drain Voltage and Current When Output Short Device is operating within the range and no inductor saturation was observed. Figure 24 – LYT0006P Output Short. Ch4: IDRAIN; 0.2 A / div. Time Scale: 20 ms / div. Z4: VDS; 0.2 A / div. Zoom Time Scale: 5 s / div. Figure 25 – LYT0006P Output Short. Ch4: IDRAIN; 0.2 A / div. Time Scale: 20 ms / div. Z4: VDS; 0.2 A / div. Zoom Time Scale: 2 s / div. 12.4 Drain Voltage and Current Start-up Profile Device is operating within the range and no inductor saturation was observed. Figure 26 – 265 VAC / 50 Hz Start-up. Ch1, Z1: SOURCE Pin to Ground; 100 V / div. Ch2, Z2: Bulk Input; 100 V / div. Ch4, Z4: IDRAIN; 0.2 A / div. Time Scale: 100 s / div. F1: VDS; 100 V / div. Zoom Time Scale: 500 ns / div. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Figure 27 – 265 VAC / 50 Hz Start-up. Ch1: SOURCE Pin to Ground; 100 V / div. Ch2: Bulk Input; 100 V / div. Ch4: IDRAIN; 0.2 A / div. Time Scale: 500 ns / div. F1: VDS; 100 V / div. F2: Switching Power; 500 W / div. Zoom Time Scale: 500 ns / div. Page 26 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P 12.5 Output Current Start-up Profile Output current/light is present in just one AC cycle. <20 ms Figure 28 – 90 VAC, 60Hz, Full Load Ch1(Yellow): VIN, 200 V / div. Ch2(Red): VOUT, 20 V, Ch3(Blue): IIN, 0.5 A / div. Ch4(Green): IOUT, 100 mA / div., 20 ms / div. Page 27 of 40 Figure 29 – 265 VAC, Full Load Ch1(Yellow): VIN, 200 V / div. Ch2(Red): VOUT, 20 V, Ch3(Blue): IIN, 0.5 A / div. Ch4(Green): IOUT, 100 mA / div., 20 ms / div. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 12.6 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 straight forward. Note that the output current waveform below will vary depending on LED load impedance and will vary according to LED type. Figure 30 – 120 VAC, 60 Hz, Full Load Ch1(Yellow): VIN, 200 V / div. Ch2(Red): VOUT, 20 V. Ch3(Blue): IIN, 0.5 A / div. Ch4(Green): IOUT, 100 mA / div, 10 ms / div. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Figure 31 – 240 VAC, Full Load Ch1(Yellow): VIN, 200 V / div. Ch2(Red): VOUT, 20 V. Ch3(Blue): IIN, 0.5 A / div. Ch4(Green): IOUT, 100 mA / div, 10 ms / div. Page 28 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P 12.7 Line Sag and Surge The inherent advantage of the buck converter implemented with LYTSwitch-0 is the imperceptible start-up delay, the driver will turn-on within 20 ms as shown in the figures below. No failure of any component occurred during line fluctuation tests. Figure 32 – Line sag test at 230 - 0 V at 1 Sec Interval. Ch1: VIN; 100 V / div. Ch2: IOUT; 50 mA / div. Time Scale: 5 s / div. Figure 34 – Line Surge Test at 230 - 265 V at 1 Sec Interval. Ch1: VIN; 100 V / div. Ch2: IOUT; 50 mA / div. Time Scale: 5 s / div. Page 29 of 40 Figure 33 – Line Surge Test at 230 - 265 V at 1 Sec Interval. Ch1: VIN; 100 V / div. Ch2: IOUT; 50 mA / div. Time Scale: 5 s / div. Figure 35 – Line Sag Test at 230 - 265 V at 1 Sec Interval. Ch1: VIN; 100 V / div. Ch2: IOUT; 50 mA / div. Time Scale: 5 s / div. Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 12.8 Brown-out/ Brown-in No failure of any component during brownout test of 0.5 V / sec AC cut-in and cut-off. Figure 36 – Brown-out Test at 0.5 V / s. The Unit is Able to Operate Normally Without Any Failure and Without Flicker. Ch1: VIN; 100 V / div. Ch2: IOUT; 50 mA / div. Time Scale: 100 s / div. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 30 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P 13 Line Surge Differential input line 1.2 kV / 50 s surge testing was completed on a single test unit to IEC61000-4-5. Input voltage was set at 230 VAC / 60 Hz. Output was loaded at full load 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 under all test conditions. Differential ring input line surge testing was completed on a single test unit to IEC610004-5. Input voltage was set at 230 VAC / 60 Hz. Output was loaded at full load 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 under all test conditions. Page 31 of 40 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P Figure 37 – Differential Line Surge at 500 V / 90. Peak Drain Voltage Recorded is 678 V. Ch1: VIN; 200 V / div. Ch2: VDRAIN; 200 V / div. Ch3: VBULK; 200 V / div. Time Scale: 1 ms / div. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com 18-Jun-13 Figure 38 – Differential Ring Surge at 2500 V / 90. Peak Drain Voltage Recorded is 468 V. Ch1: VIN; 200 V / div. Ch2: VDRAIN; 200 V / div. Ch3: VBULK; 200 V / div. Time Scale:1 ms / div. Page 32 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P 14 Conducted EMI Att 10 dB AUTO dBµV 100 kHz 120 EN55015Q LIMIT CHECK 110 1 QP CLRWR 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 26 – Conducted EMI, Maximum Steady State Load, 120 VAC, 60 Hz, and EN55015 B Limits. Trace1: EDIT PEAK LIST (Final Measurement Results) EN55015Q Trace2: EN55015A Trace3: --- TRACE Page 33 of 40 FREQUENCY LEVEL dBµV DELTA LIMIT dB 2 Average 9.9415991287 kHz 22.25 N gnd 2 Average 67.8393045788 kHz 23.52 N gnd 2 Average 134.789536006 kHz 38.77 N gnd 1 Quasi Peak 165.693318812 kHz 47.45 L1 gnd -17.72 2 Average 167.350252 kHz 33.66 N gnd -21.42 2 Average 200.175581485 kHz 38.55 N gnd -15.05 1 Quasi Peak 204.199110673 kHz 45.87 N gnd -17.56 2 Average 267.135089486 kHz 34.58 N gnd -16.62 1 Quasi Peak 272.504504785 kHz 44.83 N gnd -16.20 2 Average 397.727746704 kHz 31.37 N gnd -16.53 1 Quasi Peak 401.705024172 kHz 41.34 N gnd -16.47 1 Quasi Peak 475.741040231 kHz 40.79 N gnd -15.62 1 Quasi Peak 536.076911993 kHz 39.85 N gnd -16.14 1 Quasi Peak 610.105531335 kHz 41.66 N gnd -14.33 1 Quasi Peak 806.126927408 kHz 43.14 N gnd -12.85 2 Average 806.126927408 kHz 33.29 N gnd -12.70 1 Quasi Peak 1.00339897152 MHz 39.33 N gnd -16.66 2 Average 2.03372014292 MHz 26.57 N gnd -19.42 1 Quasi Peak 29.2697736439 MHz 43.21 L1 gnd -16.78 2 Average 29.5624713804 MHz 34.37 L1 gnd -15.62 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 Table 2 – Conducted EMI, Maximum Steady State Load, 120 VAC, 60 Hz, and EN55015 B Limits. Power Integrations 17.Oct 12 21:24 RBW MT 9 kHz 500 ms Att 10 dB AUTO dBµV 100 kHz 120 EN55015Q LIMIT CHECK 110 1 QP CLRWR 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 27 – Conducted EMI, Maximum Steady State Load, 230 VAC, 60 Hz, and EN55015 B Limits. Trace1: EDIT PEAK LIST (Final Measurement Results) EN55015Q Trace2: EN55015A Trace3: --- TRACE FREQUENCY LEVEL dBµV DELTA LIMIT dB 2 Average 134.789536006 kHz 37.65 L1 gnd 2 Average 200.175581485 kHz 41.49 N gnd -12.10 2 Average 267.135089486 kHz 39.23 N gnd -11.97 2 Average 332.507282579 kHz 35.66 N gnd -13.72 2 Average 475.741040231 kHz 33.70 N gnd -12.71 1 Quasi Peak 592.16241791 kHz 45.66 N gnd -10.33 2 Average 592.16241791 kHz 35.36 N gnd -10.63 1 Quasi Peak 667.263434405 kHz 48.66 N gnd -7.33 2 Average 667.263434405 kHz 36.60 N gnd -9.39 1 Quasi Peak 744.444692652 kHz 48.12 N gnd -7.87 1 Quasi Peak 872.919948931 kHz 50.67 N gnd -5.32 2 Average 872.919948931 kHz 38.46 N gnd -7.53 1 Quasi Peak 954.699692378 kHz 47.91 N gnd -8.08 1 Quasi Peak 1.02356729084 MHz 47.16 N gnd -8.83 1 Quasi Peak 1.55458365781 MHz 43.77 N gnd -12.22 1 Quasi Peak 2.50634031306 MHz 42.47 N gnd -13.53 2 Average 2.93888112801 MHz 31.88 N gnd -14.11 1 Quasi Peak 29.2697736439 MHz 48.08 L1 gnd -11.91 2 Average 29.2697736439 MHz 40.24 L1 gnd -9.75 Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 34 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P Table 3 – Conducted EMI, Maximum Steady State Load, 230 VAC, 60 Hz, and EN55015 B Limits. 15 Audible Noise Input voltage were sweep from 90V to 265Vac at 60Hz line input. +80 +70 +60 +50 +40 d B r +30 +20 A +10 +0 -10 -20 -30 2k 4k 6k 8k 10k 12k 14k 16k 18k 20k 22k Hz Color Line Style Thick Data Axis Cyan Green Yellow Solid Solid Solid 1 1 1 Fft.Ch.1 Ampl Fft.Ch.1 Ampl Fft.Ch.1 Ampl Left Left Left PI Standard Audio Noise (do not edit).at2 Figure 39 – Noise from the UUT at 1 cm from the Center of the Board to Microphone Receiver Position. Page 35 of 40 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 16 Appendix Types of overvoltage protection for a buck converter: Figure 40 – Simple and cheapest approach is to add a Zener diode across the output terminals. In case of no load, the Zener diode will short in order and protect the output capacitor. IC U1 will be limited by the primary current limit. Note that the Zener diode will need to be replaced after this event. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 36 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P Figure 41 – Auto-recovery OVP latch protection. Once AC input is recycled for 2s, the unit will function normally once load is connected. Advantage is lowest no-load consumption and non-damaging failure. Page 37 of 40 Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 Figure 42 – Constant voltage (CV) mode protection. Load can be connected anytime without AC recycle. Disadvantage is it will require some pre-load in order to regulate, which decreases efficiency. Pre-load can be replaced by a appropriately rated Zener in series with a resistor if efficiency is a concern. OVP Protection Zener SCR Latch Constant Voltage Mode 1. 2. 1. 2. 3. Pros Cheapest and simple. VOUT 0 V at no-load; safe. Auto-recovery. Lowest no-load consumption. VOUT 0 V at no-load; safe. 1. Hot-plug, load can be connected anytime. 1. 1. 2. 1. 2. 3. Cons Non-auto recovery. Replace Zener once fault is removed. Cost. Requires AC recycle for recovery. Consumes extra power. Residual voltage at no-load. Cost. Table 4 – Overvoltage Protection Comparison. Power Integrations, Inc. Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com Page 38 of 40 18-Jun-13 RDR-355 6 W Non-Isolated Buck Using LYT0006P 17 Revision History Date 18-Jun-13 Page 39 of 40 Author JDC Revision 1.0 Description & changes Initial Release Reviewed Apps & Mktg Power Integrations Tel: +1 408 414 9200 Fax: +1 408 414 9201 www.powerint.com RDR-355 6 W Non-Isolated Buck Using LYT0006P 18-Jun-13 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. The PI Logo, TOPSwitch, TinySwitch, LinkSwitch, LYTSwitch, DPA-Switch, PeakSwitch, CAPZero, SENZero, LinkZero, HiperPFS, HiperTFS, HiperLCS, Qspeed, EcoSmart, Clampless, E-Shield, Filterfuse, StackFET, PI Expert and PI FACTS are trademarks of Power Integrations, Inc. Other trademarks are property of their respective companies. ©Copyright 2013 Power Integrations, Inc. Power Integrations Worldwide Sales Support Locations WORLD HEADQUARTERS 5245 Hellyer Avenue San Jose, CA 95138, USA. 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