DN05031/D Design Note – DN05031/D 25 watt Offline Hi-Power Factor LED Driver Device NCL30000 Application LED Driver Input Voltage 90 – 305 V ac Output Power 25 watts Output Current Ripple Nominal Voltage Max Voltage Topology Flyback I/O Isolation Yes 700 mA 413 mA pk-pk 36 volts 44 volts Typical Power Factor Typical THDi Typical Efficiency Inrush Limiting / Fuse Operating Temp. Range 0.997 5.6% 88.0% 1 Amp fuse -40 to 70 ºC Circuit Description Recently, new generations of high power chip-on-board LED products have entered the markets that integrate a large number of LED on a single substrate. These devices have high lumen output and can be optimized for either high efficacy or high CRI with a wide range of color temperatures so they can be used in indoor applications like retail downlighting as well as outdoor applications like wall washers for example. The focus of this design note is the development of an offline, high power factor corrected single stage driver which can support extended wide AC mains from 90-305 V ac. This addresses standard global AC line voltages as well as the 277 V ac commercial input required for the United States. High power factor and low harmonic content are typically required for commercial lighting. In the US, LED luminaires that meet Energy star requirements need to have a PF ≥ 0.9 and globally EN61000-3-2 Class C lighting requirements define lower thresholds for harmonic currents when the input power is > 25 W. One example of this class of LEDs is the Sharp Mega ZENIGATA family. For this design, the 25 watt version was selected which consists of an array of 168 LEDs which comprises 14 strings of 12 LEDs in series. Since this appears as a single LED assembly, a single channel constant current driver is required. June 2012, Rev. 0 The Sharp GW5D series (image above) is rated at typically 2300-2600 lumens at 25 ºC case temperature when driven at 700 mA and the forward voltage range is 34-40 V dc under those conditions. Shown below are the design guidelines for this driver: • • • • • • • Input range: 90 – 305 V ac Output current: 700 mA Output voltage: 36 volts typical Efficiency: >87% Power Factor: >0.95 Isolated Output Open/Short Circuit protection The NCL30000LED3GEVB demonstration board was used as the development platform. This demo board was selected as it provides wide input voltage range covering 100 to 277 volt applications with applicable tolerance. www.onsemi.com 1 DN05031/D The low profile design provides a compact solution. The high efficiency of this converter minimizes thermal issues. With a few modifications, this demo board will provide the increased power and exceed the performance objectives. Note that the original transformer for this demo board was designed to accommodate 4-15 series LEDs at up to 18 watts of output power. By targeting a specific number of LEDs, the power available from the same size core can be increased. Transformer construction details are provided at the end of this document. The open load protection threshold of the original board was reduced due to lower output voltage for this LED module. D12 was changed to 43 V. Power switch maximum on-time capacitor C9 controls the minimum ac line input voltage. The redesigned transformer requires a shorter maximum on-time at this power level. C9 was changed to 390 pF. High power factor single stage converters generally have no energy storage in the primary side circuit. As such, storage is required on the secondary side and typically in the form of capacitance in parallel with the LED load. Ripple current is nearly sinusoidal at twice the applied ac input frequency. The ripple amplitude is inversely proportional to the total capacitance, that is, increasing the filter capacitance will reduce ripple current. Maximum forward current for this LED is 1050 mA. Subtracting the target output current of 700 mA nets a difference of 350 mA. Ripple current must therefore be limited to 350 mA peak or 700 mA peak-to-peak to stay within the manufacturers rating. Two 470 µF capacitors were used in order to maintain the low profile design. Testing shows this capacitance results in ripple current of up to 480 mA peak-to-peak with 100 V ac 60 Hz input as shown in Figure 1. The zero reference is indicated on the first horizontal gradicule. The output current sense resistor R29 was reduced from 0.2 ohms to 0.1 ohms to provide the required 700 mA average output current. Two resistors were connected in parallel for thermal spreading. Converter startup time is controlled by the bias capacitor C8 and the startup resistors. For this application, the startup resistors R12 and R13 were increased in value to reduce dissipation. This increases the converter startup time somewhat. June 2012, Rev. 0 Figure 1: LED ripple current The power switching FET was changed to a higher current device to support the increased output power level. Current sense resistor R20 was reduced in value due to higher primary current. In addition, the output rectifier was changed to a Schottky type to reduce power loss and increase efficiency. Increased power level means the input filter must support more switching current. The filter capacitors were increased to minimize ripple voltage and maintain compliance with conducted EMI limits. Capacitors C1 and C2 were increased to 100 nF and C4 was increased to 220 nF. High power factor is maintained by operating in critical conduction mode (CrM). In the case of the NCL30000, this is accomplished with a constant on-time architecture. Details of operation can be found in Application Note AND8451. Moreover, line harmonics in compliance with JIS/EN61000-3-2 Class C are easily met, as shown in Figure 2. Power factor and Total Harmonic Distortion of input current are shown in Figure 3. PF exceeds the target value and for operation below 140 V ac is above 0.99. Efficiency over the input line range is shown in Figure 4. For the range of 115 to 230 V ac, efficiency is well above target being greater than 88%. Note that the LED current remains virtually unchanged over the entire input voltage range. A scan of conducted emissions shows greater than 6 dB of margin for the CISPR 22 Class B limits. See Figure 5. A bill of materials is provided in Figure 6. The highlighted components have been changed from the standard demo board. Details on power transformer construction are provided at the end of this document. www.onsemi.com 2 DN05031/D 1 F1 100nF C1 2 1 Zero 1 amp R1 D7 BAW56 R10 L1 27mH 3 4 L2 R2 800uH 5K6 C2 100nF R3 L3 D1 MRA4007 D3 D4 V300LA4 RV1 MRA4007 5K6 D2 800uH R5 MRA4007 Not Fitted R15 C8 10uF MRA4007 R12 Q2 100K R13 100K R11 100K MMBTA06 100K R17 100 1 2 3 4 C9 390pF C3 MFP R4 C4 GND DRV Vcc 220nF U1 Comp Ct ZCD 10pF CZCD NCL30000 CS Not Fitted J1-1 Line J1-2 1 Neutral R8 C7 6.2K R14 D8 4.7K C6 1nF D9 MMBZ5245 15V BZX84C5V1 Q1 5.1V MMBTA06 T 10uF R9 6.2K RT1 Not Fitted 8 7 6 5 C5 4700 pF D5 ES1M D6 BAS21 R16 47K 47K R6 R7 47K Q3 10 100 SPP06N80 R19 R18 R20 0.25 OHM T1A T1B T1C T1D + D10 C11 470uF 4.7 nF T1E C10 U2 PS2561L_1 + MBR20200 C12 470uF R21 22K D11 BZX84C5V6 5.6V R22 1K C13 100nF Q4 MMBTA06 R23 1K D12 BZX84C43 43V D13 8 R25 1K R26 16K R27 C14 200 3 2 100pF IN1+ IN1- 4 5 6 U3 VCC IN2+ IN2GND R28 1 7 OUT1 OUT2 470 BAW56 C15 LM2904 Q5 220nF MMBTA06 R24 47K U4 TL431A 0.2 ohm R29 0.2 ohm R29A R30 24K R31 C16 100nF 24K 1 J2-1 LED Anode LED Cathode J2-2 1 3 www.onsemi.com June 2012, Rev. 0 1 2 4 3 Not Fitted DN05031/D Schematic Harmonic Current Percentage of Fundametal (%) 30 25 20 15 10 Limit (%) Measured (%) 5 0 2 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 Harmonic Figure 2: EN61000-3-2 Class C Input Current Harmonic Test (Vin=230 Vac, 50 Hz, Iout =704 mA @36.1V) Figure 3: Power Factor and THDi June 2012, Rev. 0 www.onsemi.com 4 DN05031/D Figure 4: Efficiency and Line Regulation Figure 5: Conducted EMI Signature (Average Scan) June 2012, Rev. 0 www.onsemi.com 5 DN05031/D Designator Value C1, C2 C3 C4 C5 C6 C8 C7 C9 CZCD C10 C11 C12 C13 C14 C15 C16 D1 D2 D3 D4 D5 D6 D7 D13 D8 D9 D10 D11 D12 F1 J1, J2 L1 L2,L3 100nF Q1 Q2 Q4 Q5 Q3 R1 R2,R3 R4 R5 R6 R7 R11 R15 R12 R13 R9 R10 R14 R16 R24 R17 R18 R19 R20 R21 R22 R23 R25 R26 R27 R28 R29 R29A R30 R31 RT1 RV1 U1 U2 U3 U4 T1 Description 300 VAC X1 Polyester Film Not Fitted 220nF 250/275VAC Polyester Film 4700 pF Ceramic 2000V Y5U 10uF 50V Electrolytic, 5mm dia 1nF 50V Ceramic X7R 390pF 50V Ceramic C0G,NPO 10pF 50V Ceramic C0G,NPO 4.7 nF 250VAC Y5U X1Y1 (LS=10mm) 470uF 63V Aluminum Electrolytic Y5U 100nF 25V Ceramic X7R 100pF 50V Ceramic COG,NPO 220nF 25V Ceramic X7R 100nF 100V Ceramic X7R MRA4007 Rectifier,1000V,1A ES1M Fast Rectifier 1A 1000V BAS21 250V,200mA BAW56 70V,200MA BZX84C5V1 5.1V ZENER MMBZ5245 15V ZENER MBR20200 Schottky, 200V 20A BZX84C5V6 5.6V ZENER BZX84C43 43V ZENER Slow Blow 1A TE5 Series Screw Connector (0.2" Pitch) 27mH Common Mode Choke 800uH Shielded radial inductor MMBTA06 SPP06N80 0 ohm 5K6 NPN, 80V, 500mA N-Channel 800V,6A, 0.9R Wire Jumper 1/10W Not Fitted 47K 1/4W 100K 1/10W 100K 1/4W 6K2 1/10W 4K7 1/10W 47K 1/10W 100 1/10W 10 1/10W 0.25 1/4W 22K 1/4W 1K 1/10W 16K 1/10W 200 1/10W 470 1/10W 0.2 1/4W 0.2 1/4W 24K 1/10W PRF21BC PTC 470 OHM 85C V300LA4P 300V 25 Joule (LS= 7mm) NCL30000 Single Stage PFC LED Driver PS2561L_1 80V, 50mA LM2904 Dual Op Amp TL431A Programmable Reference XFMR Transformer, EFD25, 25 watt June 2012, Rev. 0 Part Number Footprint Manufacturer Box Panasonic Box Radial Disc Radial 0603 SMD 0603 SMD 0603 SMD Radial Radial 0603 SMD 0603 SMD 1206 SMD 1206 SMD SMA SMA SOT23 SOT23 SOT23 SOT23 TO-220 SOT23 SOT23 Axial Through Hole Through Hole Through Hole Panasonic AVX Panasonic Panasonic Murata Murata Panasonic Panasonic Panasonic Panasonic Panasonic Panasonic ON Semiconductor Micro Commercial ON Semiconductor ON Semiconductor ON Semiconductor ON Semiconductor ON Semiconductor ON Semiconductor ON Semiconductor Littelfuse Weidmuller Wurth Midcom Renco ECQ-U2A224ML 5SS472SBHCA EEU-EB1H100S ECJ-1VB1H102K GRM1885C1H391JA01D GRM1885C1H1000JA01D CD16-E2GA472MYNS ECA-1JHG471 ECJ-1VB1E104K ECJ-1VC1H101J ECJ-3VB1E224K ECJ-3YB2A104K MRA4007T3 ES1M BAS21LT1G BAW56LT1G BZX84C5V1LT1G MMBZ5245BLT1 MBR20200CTG BZX84C5V6LT1G BZX84C43LT1G 3691100044 1716020000 7446620027 RL-8054-3-821KR38-S SOT23 TO-220 0603 SMD ON Semiconductor Infineon Panasonic MMBTA06LT1G SPD06N80C3 ERJ-3GEYJ562V 1206 SMD 0603 SMD 1206 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 1206 SMD 1206 SMD 0603 SMD 0603 SMD 0603 SMD 0603 SMD 1206 SMD 1206 SMD 0603 SMD 0603 SMD Radial SOIC8 SMT4 SOIC8 SOIC8 EFD25 Panasonic Panasonic Panasonic Panasonic Panasonic Panasonic Panasonic Panasonic Yageo Panasonic Panasonic Panasonic Panasonic Panasonic Rohm Semi Rohm Semi Panasonic Murata Littelfuse ON Semiconductor NEC Electronics ON Semiconductor ON Semiconductor Custom ERJ-8GEYJ473V ERJ-3EKF1003V ERJ-8GEYJ104V ERJ-3EKF6201V ERJ-3EKF4701V ERJ-3EKF4702V ERJ-3EKF1000V ERJ-3EKF10R0V PT1206FR-070R25L ERJ-8GEYJ223V ERJ-3EKF1001V ERJ-3EKF1602V ERJ-3EKF2000V ERJ-3EKF4700V MCR18EZHFLR200 MCR18EZHFLR200 ERJ-3EKF2402V PRF18BE471QB1RB V300LA4P NCL30000DR2G PS2561L-1 LM2904DR2G TL431ACDG www.onsemi.com ECQ-U3A104MG 6 DN05031/D 1 1 © 2012 ON Semiconductor. Disclaimer: ON Semiconductor is providing this design note “AS IS” and does not assume any liability arising from its use; nor does ON Semiconductor convey any license to its or any third party’s intellectual property rights. This document is provided only to assist customers in evaluation of the referenced circuit implementation and the recipient assumes all liability and risk associated with its use, including, but not limited to, compliance with all regulatory standards. ON Semiconductor may change any of its products at any time, without notice. Design note created by Jim Young, e-mail: [email protected] June 2012, Rev. 0 www.onsemi.com 7