Application Note 2069 LM3445 - 230VAC, 6W- 15W …

1 LM3445 Application Note 2069 LM3445 - 230 VAC, 6W- 15W Isolated Flyback LED DriverLiterature Number: SNVA447 BLM3445 - 230 VAC, 6W- 15 WIsolated Flyback LED DriverNational SemiconductorApplication Note 2069 Montu DoshiNovember 23, 2010 IntroductionThis demonstration board highlights the performance of aLM3445 based Flyback LED driver solution that can be usedto power a single LED string consisting of 4 to 10 series con-nected LEDs from an 180 VRMS to 265 VRMS, 50 Hz inputpower supply. The key performance characteristics undertypical operating conditions are summarized in this applica-tion is a four-layer board using the bottom and top layer forcomponent placement.

2 The demonstration board can bemodified to adjust the LED forward current, the number of se-ries connected LEDs that are driven and the switching fre-quency. Refer to the LM3445 datasheet for detailed bill of materials is included that describes the parts used onthis demonstration board. A schematic and layout have alsobeen included along with measured performance Features Drop-in compatibility with TRIAC dimmers Line injection circuitry enables PFC values greater Adjustable LED current and switching frequency Flicker free operationApplications Retro-fit TRIAC Dimming Solid State Lighting Industrial and Commercial Lighting Residential LightingPerformance SpecificationsBased on an LED Vf = voltage180 VRMS230 VRMS265 VRMSVOUTLED string voltage13 V20 V27 VILEDLED string average current-350 mA-POUTO utput W-fswSwitching frequency-67 kHz-Demo Board30126904 Dimming Characteristics30126924 2010 National Semiconductor - 230 VAC.

3 6W- 15W Isolated Flyback LED DriverAN-2069LM3445 230 VAC, 8W Isolated Flyback LED Driver Demo Board Schematic30126901 Warning:The LM3445 evaluation board has exposed high voltage components that present a shock hazard. Caution must be taken when handling the evaluationboard. Avoid touching the evaluation board and removing any cables while the evaluation board is :The ground connection on the evaluation board is NOT referenced to earth ground. If an oscilloscope ground lead is connected to the evaluationboard ground test point for analysis and the mains AC power is applied (without any isolation), the fuse (F1) will fail open. For bench evaluation, eitherthe input AC power source or the bench measurement equipment should be isolated from the earth ground connection.

4 Isolating the evaliation board(using 1:1 isolation line isolation transformer) rather than the oscilloscope is highly :The LM3445 evaluation board should not be powered with an open load. For proper operation, ensure that the desired number of LEDs are connectedat the output before applying power to the evaluation Device Pin-Out30126902 Pin Description 10 Pin MSOPPin #NameDescription1 ASNSPWM output of the triac dim decoder circuit. Outputs a 0 to 4V PWM signal with a duty cycle proportional to the triacdimmer filter input. The 120Hz PWM signal from ASNS is filtered to a DC signal and compared to a 1 to 3V, kHzramp to generate a higher frequency PWM signal with a duty cycle proportional to the triac dimmer firing angle.

5 Pullabove (typical) to tri-state dual function dim pin. This pin can be driven with an external PWM signal to dim the LEDs. It may alsobe used as an output signal and connected to the DIM pin of other LM3445 or LED drivers to dim multiple LEDcircuits time setting pin. A user set current and capacitor connected from the output to this pin sets the constant OFFtime of the switching filter input. A capacitor tied to this pin filters the PWM dimming signal to supply a DC voltage to control theLED current. Could also be used as an analog dimming ground current sense pin. Connect a resistor from main switching MOSFET source, ISNS to GND to set the maximumLED MOSFET driver pin.

6 This output provides the gate drive for the power switching MOSFET of the voltage pin. This pin provides the power for the internal control circuitry and gate pin. Provides the input signal to the angle detect circuitry as well as a current path through a switched230 resistor to ensure proper firing of the triac of MaterialsDesignatorDescriptionManufactur erPart NumberRoHSAA1 Printed Circuit Board -YU1 Triac dimmable offline LED Driver, PowerWiseNationalSemiconductorLM3445 MMYC1 Ceramic, X7R, 250 VAC, 10%Murata ElectronicsNorth AmericaDE1E3KX332MA5BA01YC2 Ceramic, Polypropylene, 400 VDC, 10% , CERM, 330pF, 630V, +/-5%, C0G/NP0, 1206 TDKC3216C0G2J331 JYC4 Ceramic, X7R, 250V, X2, 10%, 2220 Murata ElectronicsNorth AmericaGA355DR7GF472KW01 LYC5 CAP, Film, F, 630V, +/-10%, THEPCOS IncB32921C3333 KYC6 CAP, CERM, F, 500V, +/-10%, X7R.

7 1812 Vishay/VitramonVJ1812Y223 KBEAT4 XYC7-DNPCAP, CERM, F, 630V, +/-10%, X7R, 1812 MuRataGRM43DR72J104KW01 LYC8 CAP, CERM, F, 630V, +/-10%, X7R, 1812 MuRataGRM43DR72J104KW01 LYC9, C11 CAP, CERM, 1 F, 50V, +/-10%, X7R, 1210 MuRataGRM32RR71H105KA01 LYC10 CAP, CERM, F, 50V, +/-10%, X7R, 0805 MuRataGRM21BR71H474KA88 LYC12 Aluminium Electrolytic, 680uF, 35V, 20%,NichiconUHE1V681 MHD6YC13 CAP, CERM, 1 F, 35V, +/-10%, X7R, 0805 Taiyo YudenGMK212B7105KG-TYC14 CAP, CERM, F, 25V, +/-10%, X7R, 0603 MuRataGRM188R71E104KA01 DYC15 CAP, TANT, 47uF, 16V, +/-10%, ohm, 6032-28 SMDAVXTPSC476K016R0350YC16 CAP, CERM, F, 16V, +/-10%, X7R, 0603 MuRataGRM188R71C474KA88 DYC17 CAP, CERM, F, 16V, +/-10%, X7R, 0603 TDKC1608X7R1C224 KYC18 CAP, CERM, 2200pF, 50V, +/-10%, X7R, 0603 MuRataGRM188R71H222KA01 DYC20 CAP, CERM, 330pF, 50V, +/-5%, C0G/NP0, 0603 MuRataGRM1885C1H331JA01 DYD1 DIODE TVS 250V 600W UNI 5% SMDL ittelfuseP6 SMB250 AYD2 Diode, Switching-Bridge, 600V, , MiniDIPD iodes , Silicon, 1000V, 1A, SOD-123 Comchip TechnologyCGRM4007-GYD4 Diode, Schottky, 100V, 1A, SMASTM icroelectronicsSTPS1H100 AYD5, D10 Diode, Zener, 13V, 200mW, SOD-323 Diodes IncDDZ13BS-7YD6 Diode, Zener, 36V, 550mW, SMBON Semiconductor1 SMB5938BT3 GYD7, D8, D9 Diode, Schottky, 100V, 150 mA, SOD-323 STMicroelectronicsBAT46 JFILMYF1 Fuse, 500mA, 250V, Time-Lag, SMTL ittelfuse , H2, H5.

8 H6 Standoff, Hex, "L #4-40 NylonKeystone1902 CYH3, H4, H7, H8 Machine Screw, Round, #4-40 x 1/4, Nylon, PhilipspanheadB&F Fastener SupplyNY PMS 440 0025 PHYJ1, J2 Conn Term Block, 2 POS, PCBP hoenix Contact1715721YL1, L2 Inductor, Radial Lead Inductors, Shielded, ,130mA, , Radial,TDK CorporationTSL0808RA-472JR17-PFYLED+, LED-,TP7, TP8 Terminal, 22 Gauge Wire, Terminal, 22 Guage Wire3M923345-02-CYQ1 MOSFET, N-CH, 600V, 200mA, SOT-223 FairchildSemiconductorFQT1N60 CTF_WSYQ2 Transistor, NPN, 300V, 500mA, SOT-23 Diodes , N-CH, 650V, 800mA, IPAKI nfineonTechnologiesSPU01N60C3YQ4 MOSFET N-CH 100V 170MA SOT23-3 Diodes , 221 ohm, 1%, , 1206 Vishay-DaleCRCW1206221 RFKEAYR2, R7 RES, 200k ohm, 1%, , 1206 Vishay-DaleCRCW1206200 KFKEAYR3, R8 RES, 309k ohm, 1%, , NumberRoHSR4, R12 RES, 10k ohm, 5%, , 1206 Vishay-DaleCRCW120610K0 JNEAYR5-DNPRES, 680 ohm, 5%, 1W, 2512 Vishay/DaleCRCW2512680 RJNEGYR6 RES, 820 ohm, 5%, 1W, 2512 Vishay/DaleCRCW2512820 RJNEGYR10 RES, 430 ohm, 5%, 1W, 2512 Vishay/DaleCRCW2512430 RJNEGYR11 RES, ohm, 1%, , 0805 Vishay-DaleCRCW080549K9 FKEAYR13 RES, ohm, 1%, , 1206 Vishay-DaleCRCW120633R0 FKEAYR14 RES, 10 ohm, 5%, , 0805 Vishay-DaleCRCW080510R0 JNEAYR15 RES, ohm, 1%, , 0603 Vishay-DaleCRCW060310K0 FKEAYR16 RES, 280k ohm, 1%, , 0603 Vishay-DaleCRCW0603280 KFKEAYR17 RES, 475k ohm, 1%.

9 0603 Vishay-DaleCRCW0603475 KFKEAYR18 RES, ohm, 1%, , 0603 Vishay-DaleCRCW060349K9 FKEAYR19 RES, 10 ohm, 5%, , 0603 Vishay-DaleCRCW060310R0 JNEAYR20 RES, ohm, 1%, , 0603 Vishay-DaleCRCW06031K91 FKEAYR21 RES, ohm, 1%, , 1206 PanasonicERJ-8 RQF2R7 VYR22 RES, ohm, 1%, , 0805 Vishay-DaleCRCW080510R7 FKEAYR23 RES, 324k ohm, 1%, , 0603 Vishay-DaleCRCW0603324 KFKEAYRT1, RT2 Current Limitor Inrush, 60 Ohm, 20%, 5mm RaidalCanthermMF72-060D5YT1 FLBK TFR, mH, Np=140T, Ns=26T, Na= 20 TWurth Elektornik750815040 REV 1 YTP9, TP10 Terminal, Turret, TH, DoubleKeystone Electronics1502-2 YVR1 Varistor 275V 55J 10mm DISCEPCOS DesignMfg: Wurth Electronics, Part #: 750815040 Rev. 0130126909 ParameterTest Resistance (3-1)20 10% Resistance (6-4)20 10% Resistance (10-13)20 10%Inductance (3-1)10 kHz, 100 mH 10%Inductance (6-4)10 kHz, 100 H 10%Inductance (10-13)10 kHz, 100 H 10%Leakage Inductance (3-1)100 kHz, 100 mAVAC (tie 6+4, 10+13) H Typ.

10 , H (1-13)tie (3+4), 4500 VAC, 1 second4500 VAC, 1 minuteTurns Ratio(3-1):(6-4)7:1 1%Turns Ratio(3-1):(10:13) :1 1% Board Wiring Overview30126903 Wiring Connection DiagramTest PointNameI/ODescriptionTP8, TP10 LED +OutputLED Constant Current SupplySupplies voltage and constant-current to anode of LED , TP9 LED -OutputLED Return Connection (not GND)Connects to cathode of LED string. Do NOT connect to Line VoltageConnects directly to AC line or output of TRIAC dimmer of a 230 VAC NeutralConnects directly to AC neutral of a 230 VAC Board Assembly30126905 Top View30126906 Bottom Performance Characteristics(Note 1, Note 2, Note 3)Efficiency vs. Line VoltageOriginal Circuit180 190 200 210 220 230 240 250 VOLTAGE (VRMS)10 LEDs8 LEDs6 LEDs4 LEDs30126910 Efficiency vs.