NCL30088LED1GEVB 18 W High Power Factor LED Driver Evaluation Board User'sManual Overview www.onsemi.com This manual covers the specification, theory of operation, testing and construction of the NCL30088LED1GEVB demonstration board. The NCL30088 board demonstrates a 18 W high PF buck boost LED driver in a typical T8 outline. EVAL BOARD USER’S MANUAL Table 1. SPECIFICATIONS Key Features Parameter Value Input voltage (Class 2 Input, no ground) 100 − 277 V ac Line Frequency Power Factor (100% Load) THD (Load > 30%) Output Voltage Range Output Current Efficiency Start Up Time EMI (conducted) Comment As illustrated, the key features of this evaluation board include: • Wide Mains • Low THD across Line and Load • High Power Factor across Wide Line and Load • Integrated Auto Recovery Fault Protection (can be latched by Choice of Options) ♦ Over Temperature on Board (a PCB mounted NTC) ♦ Over Current ♦ Output and Vcc Over Voltage 50 Hz / 60 Hz 0.9 Min 20% Max 90 − 180 V dc 100 mA dc ±2% 92% Typical < 500 msec Typical Class B FCC/CISPR Figure 1. Evaluation Board Picture (Top View) © Semiconductor Components Industries, LLC, 2014 November, 2014 − Rev. 0 1 Publication Order Number: EVBUM2285/D NCL30088LED1GEVB THEORY OF OPERATION Power Stage Auxiliary Winding The power stage for the demo board is a non−isolated buck−boost based. The controller has a built in control algorithm that is specific to the flyback transfer function. Specifically: The auxiliary winding has 3 functions: 1. CrM timing 2. Vcc Power 3. Output voltage sense Vout + Duty (1*Duty) Vin CrM Timing In the off time, the voltage on the transformer/inductor forward biases Dout and D9. When the current in the magnetic has reached zero, the voltage collapses to zero. This voltage collapse triggers a comparator on the ZCD pin to start a new switching cycle. The ZCD pin also counts rings on the auxiliary winding for higher order valley operation. A failure of the ZCD pin to reach a certain threshold also indicates a shorted output condition. This is applicable to flyback, buck−boost, and SEPIC converters. The control is very similar to the control of the NCL30080−83 with the addition of a power factor correction control loop. The controller has a built in hardware algorithm that relates the output current to a reference on the primary side. Iout + Vref Nps 2 Rsense Nps + Npri Nsec Vcc Power The auxiliary winding forward biases D9 to provide power for the controller. This arrangement is called a “bootstrap”. Initially the Cvcc, is charged through R4 and R5. When the voltage on Cvcc reaches, the startup threshold, the controller starts switching and providing power to the output circuit and the Cvcc. Cvcc discharges as the controller draws current. As the output voltage rises, the auxiliary winding starts to provide all the power to the controller. Ideally, this happens before Cvcc discharges to the under voltage threshold where the controller stops operating to allow Cvcc to recharge once again. The size of the output capacitor will have a large effect on the rise of the output voltage. Since the LED driver is a current source, the rise of output voltage is directly dependent on the size of the output capacitor. There are tradeoffs in the selection of Cout and Cvcc. A low output ripple will require a large Cout value. This requires that Cvcc be large enough to support Vcc power to the controller while Cout is charging up. A large value of Cvcc requires that R4 and R5 be lower in value to allow a fast enough startup time. Smaller values of R4 and R5 have higher static power dissipation which lowers efficiency of the driver. Where Npri = Primary Turns and Nsec = Secondary Turns We can now find Rsense for a given output current. Rsense + Vref Nps 2 Iout Line Feedforward The controller is designed to precisely regulate output current but variation input line voltage do have an impact. R3 sets the line feedforward and compensates for power stage delay times by reducing the current threshold as the line voltage increases. R3 is also used by the shorted pin detection. At start up the controller puts out a current to check for a shorted pin. If R3 is zero, the current sense resistor is too low a value and the controller will not start because it will detect a shorted pin. So R3 is required to make the controller operate properly. In practice, R3 should be greater than 250 W. Voltage Sense The voltage sense pin has several functions: 1. Basis for the reference of the PFC control loop 2. Line Range detection Output Voltage Sense The auxiliary winding voltage is proportional to the output voltage by the turns ratio of the output winding and the auxiliary winding. The controller has an overvoltage limit on the Vcc pin at about 26 V minimum. Above that threshold, the controller will stop operation and enter overvoltage fault mode such as when an open LED string occurs. In cases where the output has a lot of ripple current and the LED has high dynamic resistance, the peak output voltage can be much higher than the average output voltage. The auxiliary winding will charge the Cvcc to the peak of the output voltage which may trigger the OVP sooner than expected so in this case the peak voltage of the LED string is critical. The reference scaling is automatically controller inside the controller. While the voltage on Vs is not critical for the PFC loop control, it is important for the range detection. Generally the voltage on Vs should be 3.5 V peak at the highest input voltage of interest. The voltage on Vs determines which valley the power stage will operate in. At low line and maximum load, the power stage operates in the first valley (standard CrM operation). At the higher line range, the power stage moves to the second valley to lower the switching frequency while retaining the advantage of CrM soft switching. http://onsemi.com 2 NCL30088LED1GEVB SD Pin 2.5 V, the SD pin detects an OVP and shuts down the controller. Typically, a zener to Vcc is used for this. In this way, the designer can set the OVP to a lower value that the OVP threshold built into the Vcc pin. The SD pin is a multi−function protection input. 1. Thermal Foldback Protection 2. Programmable OVP Thermal Protection There is an internal current source from the SD pin. Placing an NTC from the SD pin to ground will allow the designer to choose the level of current foldback protection from over temperature. Below 0.5 volts on SD, the controller stops. Series or parallel resistors on the NTC and shape the foldback curve. In the event that the pin is left open, there is a soft voltage clamp at 1.35 V (nominal). Output current is reduced when the voltage on the SD pin drops below 1 V. Circuit Modifications Output Current The output current is set by the value of Rsense as shown above. It’s possible to adjust the output current by changing R7. Since the magnetic is designed for 18 W, it is possible to increase the current while reducing the maximum LED forward voltage within limits. Changes of current of ±10% are within the existing EMI filter design and magnetic, changes of more than 10% may require further adjustments to the transformer or EMI filter. Programmable OVP While the SD pin has a current source for the OTP, it can be overcome raising the voltage on the SD pin. At about http://onsemi.com 3 NCL30088LED1GEVB SCHEMATIC +HVDC R10 L3 +HVDC_iso 1.5mH 5.1k AC_L L2 F1 1 AC_N L1 1 C4 D4 3.3mH FUSE AC1 + AC2 − C5 120nF 450V 120nF 450V MB6S 3.3mH R11 5.1k Figure 2. Input Circuit +HVDC_iso 1 LED− R14 Rzcd 75k 1/2W T1 D9 R15 BAS21DW5T1G 1 Meg R5 Cout 18uF 200V 4.7 75k 1/2W R1 + 620k Dout 1 CVcc1 6.8uF C12 R2 US1K−TP U2 1n 1 10k 2 3 4 C11 1n ZCD Vcc Vs Drv Comp Gnd SD Cs 8 Q1 7 STU8N80K5 6 5 R3 NCL30088D C10 620 1uF Rtco R16 + 56k R4 t 10 100k Ohm NTC Rsens 1.00 Figure 3. Main Schematic http://onsemi.com 4 LED+ NCL30088LED1GEVB BILL OF MATERIAL Table 2. BILL OF MATERIAL* Qty Reference Part Manufacturer Mfr_PN PCB Footprint Substitution Allowed 1 Cvcc1 6.8 mF TDK C3216X7R1V685K160AC 1206 Yes 1 Cout 18 mF 200 V Rubycon 200LLE18MEFC10X12.5 ALEL_10X12M5_V ERT Yes 2 C4, C5 120 nF 450 V Panasonic ECW−FD2W124KQ CAP_BOX_12M6X 4M6_LS10 Yes 1 C10 1 mF Taiyo Yuden TMK105BJ105MV−F 402 Yes 2 C11, C12 1n Kemet C0402C102K3GACTU 402 Yes 1 Dout US1K−TP MCC US1K−TP SMA Yes 1 D4 MB6S MCC MB6S MB6S Yes 1 D9 BAS21DW5T1G ON Semiconductor BAS21DW5T1G SC−88A No 1 F1 FUSE Littelfuse 0263.500WRT1L FUSE−HAIRPIN−L S250 Yes 2 L1, L2 3.3 mH Wurth 744772332 RAD_IND_LS5 Yes 1 L3 1.5 mH Wurth 744772152 RAD_IND_LS5 Yes 1 Q1 STU8N80KS ST STU8N80K5 IPAK Yes 1 Rtco 100 kW NTC Epcos B57331V2104J60 603 Yes 1 Rzcd 56k Yaego RC1206FR−0756KL 1206 Yes 1 R1 620k Yaego RC1206FR−07620KL 1206 Yes 1 R2 10k Yaego RC0402FR−0710KL 402 Yes 1 R3 620 Yaego RC0402FR−07620RL 402 Yes 1 R5 4.7 Yaego RC1206FR−074R7L 1206 Yes 2 R10, R11 5.1k Yaego RC1206FR−075K1L 1206 Yes 2 R14, R15 75k ½ W Stackpole RNCP1206FTD75K0 1206 Yes 1 R16 1 Meg Yaego RC1206JR−071ML 1206 Yes 1 T1 XFRM_LINEAR Wurth 750314731 RM6_4P Yes 6” W1 Wire, Red, 24AWG McMaster Carr 7587K922 UL1569 Yes 6” W2 Wire, Blk, 24AWG McMaster Carr 7587K921 UL1569 Yes 12” W3, W4 Wire, Wht, 24AWG McMaster Carr 7587K924 UL1569 Yes *All Components to comply with RoHS 2002/95/EC Construction Options NCL30088B Revision 00 1 U2 NCL30088B ON Semiconductor NCL30088B SO8 No 1 Rsens 1.13 Yaego RC1206FR−071R13L 1206 Yes 1 R4 No Stuff Yaego RC0805JR−0710RL 805 Yes NCL30088D Revision 01 1 U2 NCL30088D ON Semiconductor NCL30088D SO8 No 1 Rsens 1 Yaego RC1206FR−071RL 1206 Yes 1 R4 10 Yaego RC0805JR−0710RL 805 Yes http://onsemi.com 5 NCL30088LED1GEVB GERBER VIEWS Figure 4. Top Side PCB Figure 5. Bottom Side PCB Figure 6. PCB Outline http://onsemi.com 6 NCL30088LED1GEVB White Wires Here Mark the appropriate Revision Here Red Wire Here 1. Strip and tin lead wires to 6” ± 0.5” 4 Places. Notch Here Figure 7. Assembly Notes http://onsemi.com 7 Black Wire Here NCL30088LED1GEVB CIRCUIT BOARD FABRICATION NOTES 11. Size tolerance of plated holes: ±0.003 in. : non−plated holes ±0.002 in. 12. All holes shall be ±0.003 in. of their true position U.D.S. 13. Construction to be SMOBC, using liquid photo image (LPI) solder mask in accordance with IPC−SM−B40C, Type B, Class 2, and be green in color. 14. Solder mask mis-registration ±0.004 in. max. 15. Silkscreen shall be permanent non−conductive white ink. 16. The fabrication process shall be UL approved and the PCB shall have a flammability rating of UL94V0 to be marked on the solder side in silkscreen with date, manufactures approved logo, and type designation. 17. Warp and twist of the PCB shall not exceed 0.0075 in. per in. 18. 100% electrical verification required. 19. Surface finish: electroless nickel immersion gold (ENIG) 20. RoHS 2002/95/EC compliance required. 1. Fabricate per IPC−6011 and IPC6012. Inspect to IPA−A−600 Class 2 or updated standard. 2. Printed Circuit Board is defined by files listed in fileset. 3. Modification to copper within the PCB outline is not allowed without permission, except where noted otherwise. The manufacturer may make adjustments to compensate for manufacturing process, but the final PCB is required to reflect the associated gerber file design ±0.001 in. for etched features within the PCB outline. 4. Material in accordance with IPC−4101/21, FR4, Tg 125°C min. 5. Layer to layer registration shall not exceed ±0.004 in. 6. External finished copper conductor thickness shall be 0.0026 in. min. (ie 2oz) 7. Copper plating thickness for through holes shall be 0.0013 in. min. (ie 1oz) 8. All holes sizes are finished hole size. 9. Finished PCB thickness 0.031 in. 10. All un-dimensioned holes to be drilled using the NC drill data. http://onsemi.com 8 NCL30088LED1GEVB BUCK BOOST INDUCTOR SPECIFICATION http://onsemi.com 9 NCL30088LED1GEVB ECA PICTURES Figure 8. Top View Figure 9. Bottom View TEST PROCEDURE • LED Load – 10 V – 30 V @ 1 A Equipment Needed • AC Source – 90 to 305 V ac 50/60 Hz Minimum 500 W • • • Test Connections capability AC Wattmeter – 300 W Minimum, True RMS Input Voltage, Current, Power Factor, and THD 0.2% accuracy or better DC Voltmeter – 300 V dc minimum 0.1% accuracy or better DC Ammeter – 1 A dc minimum 0.1% accuracy or better AC Power AC Source Wattmeter 1. Connect the LED Load to the red (+) and black (−) leads through the ammeter shown in Figure 10. CAUTION: Observe the correct polarity or the load may be damaged. 2. Connect the AC power to the input of the AC wattmeter shown in Figure 10. Connect the white leads to the output of the AC wattmeter 3. Connect the DC voltmeter as shown in Figure 10. UUT DC Ammeter DC Voltmeter NOTE: Unless otherwise specified, all voltage measurements are taken at the terminals of the UUT. Figure 10. Test Set Up http://onsemi.com 10 LED Test Load NCL30088LED1GEVB Functional Test Procedure 1. Set the LED Load for 26 V output. 2. Set the input power to 120 V 60 Hz. CAUTION: Do not touch the ECA once it is energized because there are hazardous voltages present. LINE AND LOAD REGULATION Table 3. 120 V / MAX LOAD Output Current 100 mA + 3 mA Output Power Power Factor THD < 20% Output Current 100 mA + 3 mA Output Power Power Factor THD < 20% 90 V 135 V 180 V Table 4. 230 V / MAX LOAD 90 V 135 V 180 V Efficiency + Vout Iout Pin 100% http://onsemi.com 11 NCL30088LED1GEVB TEST DATA Figure 11. Power Factor over Line and Load Figure 12. THD over Line and Load http://onsemi.com 12 NCL30088LED1GEVB Figure 13. Efficiency over Line and Load Figure 14. Regulation over Line http://onsemi.com 13 NCL30088LED1GEVB Figure 15. Start Up with AC Applied 120 V Maximum Load Figure 16. Start Up with AC Applied 230 V Maximum Load http://onsemi.com 14 NCL30088LED1GEVB Figure 17. Conducted EMI Pre−compliance QP Data 150 kHz − 1 MHz Figure 18. Conducted EMI Pre−compliance Peak Data 150 kHz − 30 MHz http://onsemi.com 15 NCL30088LED1GEVB ON Semiconductor and the are registered trademarks of Semiconductor Components Industries, LLC (SCILLC) or its subsidiaries in the United States and/or other countries. SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of SCILLC’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. SCILLC reserves the right to make changes without further notice to any products herein. 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