NCP1421LEDEVB NCP1421 High Current LED Driver Evaluation Board User's Manual http://onsemi.com EVAL BOARD USER’S MANUAL Description The NCP1421 is a monolithic, micro-power, high-frequency, step-up switching converter IC designed for battery operated hand-held electronic products with up to 600 mA loading. It integrates a synchronous rectifier (Sync-Rect) to improve efficiency and to eliminate the external Schottky Diode. The NCP1421’s high switching frequency (up to 1.2 MHz) allows for a low profile, small sized inductor and output capacitor to be used. When the device is disabled, the internal conduction path from the battery to the load is fully blocked, which isolates the load from the battery. This True-Cutoff function reduces the shutdown current to typically only 50 nA. A Ring-Killer is also integrated to eliminate high-frequency ringing in discontinuous conduction mode. Finally, a Low-Battery Detector, Logic-Controlled Shutdown, Cycle-by Cycle Current Limiting and Thermal Shutdown provide value-added features for various battery operated applications. With all these functions on, the quiescent supply current is typically only 8.5 mA. This device is available in the compact and low profile Micro8t package. The NCP1421LED evaluation board uses the NCP1421 to drive a high power, white LED. The circuit is configured to minimize power dissipation in the current sense resistor and the effects of lot-to-lot LED forward voltage (VF) variation on LED current. Figure 1. NCP1421LED Evaluation Board Test Procedure 1. Set DC Power Supply to 3.6 Vdc and Current Limit to 2 A 2. Move Jumper on J3 to OFF Position 3. Connect DC Power Supply to J1 and J2 (Positive on J1 (Vbat), Negative on J2 (GND)) 4. LED Should be Off 5. Remove Jumper Completely from J3 6. LED Should still be Off 7. Set Jumper on J3 to the ON Position 8. LED Should be On (CAUTION, DO NOT LOOK DIRECTLY AT THE LED. IT IS EXTREMELY BRIGHT) 9. Measure Voltage from J5 (VFB) to J6 (GND). It Should be between 500−700 mV Features Capable of driving White LEDs up to 600 mA High Switching Frequency, up to 1.2 MHz True-Cutoff Function Reduces Device Shutdown Current to Typically 50 nA Semiconductor Components Industries, LLC, 2012 September, 2012 − Rev. 1 1 Publication Order Number: EVBUM2135/D NCP1421LEDEVB J1 Vba t C2 J2 22uF/6.3V GND GND C5 Vba t 7 Lx REF 8 Vout D1 J5 N/C C6 C4 GND 22uF/6.3V 1 FB C3 GND D2 6 LUXEON Med.PWR 220nF C1 4 J4 Vout 475k GND LBO R2 3 LBI /EN 100k 2 100k R3/ D 2 R1 L1 3 1 2 6.8 uH J3 5 N/C STOP ENABLE RUN Provision to put Luxeon Star/O N/C U1 NCP 1421 LUXEON Star GND RS 2.2R VFB J6 GND GND Figure 1. NCP1421LED Evaluation Board Schematic Table 1. NCP1421LED EVALUATION BOARD BILL OF MATERIALS Designator Qty. Description Value Tolerance Footprint Manufacturer Manufacturer Part Number Substitution Allowed Lead Free U1 1 Boost Converter NA NA Micro8t ON Semiconductor NCP1421DMR2 No No D1/D2 1 High Power White LED NA NA NA Lumiled LXHL−BW01/2 Yes No L1 1 SMD Inductor 6.8 mH, 1.6 A 20% 5.8 6.2 1.4 mm TDK VLP6214T−6R8M1R2 Yes Yes C1 1 Ceramic Chip Capacitor 220 nF 10% 0603 TDK C1608X5R1C224MT Yes No C2, C3 2 Ceramic Chip Capacitor 22 mF, 6.3 V 20% 0805 TDK C2012X5R0J226M Yes No C4 0 Ceramic Feedforward Cap − − − − − − − R1, R3 2 Chip Resistor 100 kW, 1/8 W 1% 0805 Yageo−America 9C08052A1003FKHFT Yes No R2 1 Chip Resistor 475 kW, 1/8 W 1% 0805 Yageo−America 9C08052A4753FKHFT Yes No RS 1 Chip Resistor 1.0 W, 1.0 W 1% 1218* Vishay CRCW12181R00FT Yes No J1 1 4MM PCB Socket, Black NA NA NA Deltron Emcon 571−0100 Yes No J2 1 4MM PCB Socket, Red NA NA NA Deltron Emcon 571−0500 Yes No J3 1 Header Pins, 3 Positions 1” Pitch NA NA Tyco Electronics/AMP 4−103239−0 Yes No J4, J5 2 Header Pins, 1 Position 1” Pitch NA NA Tyco Electronics/AMP 4−103239−0 Yes No J3 1 Jumper, 2 Positions 1” Pitch NA NA Sullins Electronics SPC02SYAN Yes No J6 1 Un-insulated Plug NA NA 10.16 9.0 mm Harwin D3082−05 Yes No *2 1206, 2 W resistors were placed in parallel on this board http://onsemi.com 2 NCP1421LEDEVB Micro8 is a trademark of International Rectifier. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). 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. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner. PUBLICATION ORDERING INFORMATION LITERATURE FULFILLMENT: Literature Distribution Center for ON Semiconductor P.O. Box 5163, Denver, Colorado 80217 USA Phone: 303−675−2175 or 800−344−3860 Toll Free USA/Canada Fax: 303−675−2176 or 800−344−3867 Toll Free USA/Canada Email: [email protected] N. American Technical Support: 800−282−9855 Toll Free USA/Canada Europe, Middle East and Africa Technical Support: Phone: 421 33 790 2910 Japan Customer Focus Center Phone: 81−3−5817−1050 http://onsemi.com 3 ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative EVBUM2135/D