profile, small sized inductor output capacitor used. Also integrated d

The Datasheet Archive - 100 Million Datasheets from 7500 Manufacturers.

profile, small sized inductor output capacitor used. Also integrated d

Datasheet Thumbnail

Top Searches for this datasheet

AND8171/D NCP1421/2 Reference Designs High-Power White Flash Applications
profile, small sized inductor output capacitor used. Also integrated disconnect switch provides "true cutoff" isolating output from battery during shutdown. NCP1421 comes Micro-8 package, NCP1422 comes package. Because these features NCP1421/2 well suited provide current regulation biasing high current white LED's portable flash applications. Figure illustrates this circuit. summary reference voltage split between current sense resistor, divided down voltage from white with resistors This helps remove some dependence NCP1421/2's output voltage, thus current, LED's forward voltage, This also helps prevent lot-to-lot variation affecting brightness. Figure shows typical circuit which, with Bill Materials shown Table provide currents 200, design uses NCP1422 because smaller footprint, designs NCP1421 NCP1422 respectively showcase load current limits each device. higher currents (600 assume that will pulsed steady state. pulses LBI/EN were used analysis these circuits. NCP1421/2 takes (nominal) turn after LBI/EN driven high.
attached design illustrates NCP1421/2 boost converters configured current regulator biasing high current white LED's. Typical boost converters, such these, have reference voltage Since this current sourcing application, more straightforward approach directly sensing boost converter's reference voltage (Vref), which across sense resistor would dissipate much power currents required drive high-power White LED's. Also, lot-to-lot forward voltage variation high simply regulate fixed voltage with current limiting resistor. Therefore, this paper describes technique that reduces both power loss sense resistor lot-to-lot variation effect LED. This applications shows implementations this concept. Figure shows simple boost converter configured various current levels uses Lumileds LXHL- WW06 white LED. Figure shows circuit that switches between current focus lighting high current flash uses Lumileds LXCL-PWF1 white LED.
Overview
NCP1421 NCP1422 monolithic boost converter IC's uniquely suited power higher current portable applications (600 maximum). Their high switching frequency MHz) allows
NCP1422 VOUT LBI/EN
100k
Pulse
Figure NCP1422 Configured Drive High Current White
Semiconductor Components Industries, LLC, 2004
November, 2004 Rev.
Publication Order Number: AND8171/D
AND8171/D
1000 OUTPUT CURRENT (mA) EFFICIENCY
INPUT VOLTAGE
INPUT VOLTAGE
Figure Output Current Input Voltage
EFFICIENCY
Figure Converter Efficiency Input Voltage
INPUT VOLTAGE
Figure Electrical Optical Efficiency Input Voltage Design Steps
following steps show determine critical components this circuit. (R2, This shows version example: Step current Step From datasheet, (Find value mA). Step Step Vref which This places equal dependence variation tolerance reference could increase output voltage making voltage across (VR4) larger decrease power dissipation lowering VR4. Step Step Now, plus divided voltage must equal that Step (VF/(Vref VR4)) (3.5/0.6) Step Then choose standard value which close above calculated value. Choose Step Pick input voltage range. These circuits assume one-cell Li-ion battery pack 3-cell NiMH pack
input voltage assumed been optimized around this point. Step Determine output voltage. Output voltage will chosen above because this circuit decreases current increases from designed value. This shown following equation: 1/R4*(Vref VF*(R3/R2 R3)) Conversely increases current decreases from designed value, then difference between Vout less, peak current reduced. Step NCP1421 NCP1422 datasheet determine appropriate this application, were found work well over load line range. Step Determine inductor saturation current. this circuit ILavg Iout (1-D) where (1-Vin/Vout). Therefore ILavg mA/(1-(1-Vin/Vout)) Step margin this ILavg pick inductor with Isat
http://onsemi.com
AND8171/D
Finally, Figure shows Focus/Flash application where NCP1422 drives external MOSFET changes resistance vary current. pulses were used this design.
NCP1422 VOUT LBI/EN
100k
Enable Signal
Pulse
Figure 200/600 Focus/Flash Application
Figure Current Ripple Voltage with 200/600 Focus/Flash Pulse (CH2 Vin, ac-coupled mV/div; ILED mA/div)
http://onsemi.com
AND8171/D
Table Bill Materials Figure
Part Number Description Design NCP1422MNR2 LXHL-WW06 VLP5610T-6R8 CRCW0402104. CRCW04025603. CRCW04021503. DCRCW12062R70. C1608X5R1A224K C2012X5R0J226M C2012X5R0J226M NCP1422 Boost Converter White Inductor (X5R Ceramic) (X5R Ceramic) Design NCP1421DMR2 LXHL-WW06 VLP6214T-6R8 CRCW0402104. CRCW04025603. CRCW04021503. CRCW12061R00. C1608X5R1A224K C2012X5R0J226M C2012X5R0J226M NCP1421 Boost Converter White Inductor (X5R Ceramic) (X5R Ceramic) Design NCP1422DMR2 LXHL-WW06 VLP6214T-6R8 CRCW0402104. CRCW04025603. CRCW04021503. CRCW12061R50.* C1608X5R1A224K C2012X5R0J226M C2012X5R0J226M NCP1422 Boost Converter White Inductor 0.75 (X5R Ceramic) (X5R Ceramic) (6.2 0402 0402 0402 1206 0603 0805 0805 DFN-10 Semiconductor Lumileds Vishay Vishay Vishay Vishay (6.2 0402 0402 0402 1206 0603 0805 0805 Micro-8 Semiconductor Lumileds Coilcraft Vishay Vishay Vishay Vishay (5.6 0402 0402 0402 1206 0603 0805 0805 DFN-10 Semiconductor Lumileds Vishay Vishay Vishay Vishay Footprint Manufacturer
resistors were used parallel.
http://onsemi.com
AND8171/D
Table Bill Materials Figure
200/600 Design NCP1422MNR2 LXCL-PWF1 NTJS3157N VLP5610-6R8 CRCW0402104. CRCW04025603. CRCW04021503. CRCW12062R00.* CRCW12062R00. C1608X5R1A224K C2012X5R0J226M C2012X5R0J226M NCP1422 Boost Converter White N-Channel MOSFET Inductor (X5R Ceramic) (X5R Ceramic) DFN-10 (1.64 2.04 SC-88 (5.6 0402 0402 0402 1206 1206 0603 0805 0805 Semiconductor Lumileds Semiconductor Vishay Vishay Vishay Vishay Vishay
resistors were used parallel.
http://onsemi.com
AND8171/D
Semiconductor registered trademarks Semiconductor Components Industries, (SCILLC). SCILLC reserves right make changes without further notice products herein. SCILLC makes warranty, representation guarantee regarding suitability products particular purpose, does SCILLC assume liability arising application product circuit, specifically disclaims liability, including without limitation special, consequential incidental damages. "Typical" parameters which provided SCILLC data sheets and/or specifications vary different applications actual performance vary over time. operating parameters, including "Typicals" must validated each customer application customer's technical experts. SCILLC does convey license under patent rights rights others. SCILLC products designed, intended, authorized components systems intended surgical implant into body, other applications intended support sustain life, other application which failure SCILLC product could create situation where personal injury death occur. Should Buyer purchase SCILLC products such unintended unauthorized application, Buyer shall indemnify hold SCILLC officers, employees, subsidiaries, affiliates, distributors harmless against claims, costs, damages, expenses, reasonable attorney fees arising directly indirectly, claim personal injury death associated with such unintended unauthorized use, even such claim alleges that SCILLC negligent regarding design manufacture part. SCILLC Equal Opportunity/Affirmative Action Employer. This literature subject applicable copyright laws resale manner.
PUBLICATION ORDERING INFORMATION
LITERATURE FULFILLMENT: Literature Distribution Center Semiconductor P.O. 61312, Phoenix, Arizona 85082-1312 Phone: 480-829-7710 800-344-3860 Toll Free USA/Canada Fax: 480-829-7709 800-344-3867 Toll Free USA/Canada Email: orderlit@onsemi.com American Technical Support: 800-282-9855 Toll Free USA/Canada Japan: Semiconductor, Japan Customer Focus Center 2-9-1 Kamimeguro, Meguro-ku, Tokyo, Japan 153-0051 Phone: 81-3-5773-3850 Semiconductor Website: http://onsemi.com Order Literature: http://www.onsemi.com/litorder additional information, please contact your local Sales Representative.
http://onsemi.com
AND8171/D

profile, small sized inductor output capacitor used. Also integrated d

Top Searches for this datasheet

Other recent searches