unisonic technologies co., ltd l5100 linear integrated circuit www.unisonic.com.tw 1 of 7 copyright ? 2010 unisonic technologies co., ltd qw-r103-024.c white led step-up converter ? description the utc l5100 is a step-up dc/dc converter and designed for driving white leds with a constant current. it can drive several leds in series by a li-ion cell. utc l5100 switches at a high frequency 1.2mhz, so it can allow the use of tiny external components. the output capacitor can be as small as 0.22 f; saving space and cost compare with alternative other solutions. the low 95mv feedback voltage minimizes power loss in the current setting resistor can have better efficiency. ? features * inherently matched led current * high efficiency: 83% typical * drives up to four leds from a 3.2v supply * drives up to six leds from a 5v supply * 36v rugged bipolar switch * 1.2mhz switching frequency * uses tiny 1mm tall inductors * output capacitor can be small to only 0.22 f ? ordering information ordering number package packing l5100g-af5-r sot-25 tape reel ? marking
l5100 linear integrated circuit unisonic technologies co., ltd 2 of 7 www.unisonic.com.tw qw-r103-024.c ? pin configuration ? pin description pin no. pin name description 1 sw switch. connect inductor/diode here. minimize trace area at this pin to reduce emi. 2 gnd ground. connect directly to local ground plane. 3 fb feedback. reference voltage is 95mv. c onnect cathode of lowest led and resistor here. calculate resistor value according to the formula: r fb = 95mv/i led 4 shdn shutdown. connect to 1.5v or higher to enable device; 0.4v or less to disable device. 5 v in input supply pin. must be locally bypassed.
l5100 linear integrated circuit unisonic technologies co., ltd 3 of 7 www.unisonic.com.tw qw-r103-024.c ? block diagram
l5100 linear integrated circuit unisonic technologies co., ltd 4 of 7 www.unisonic.com.tw qw-r103-024.c ? absolute maximum ratings parameter symbol ratings unit input voltage v in 12 v switch voltage v sw 36 v feedback voltage v fb 12 v shutdown voltage shdn v 12 v junction temperature t j +125 c operating junction temperature t j -40~+85 c storage temperature range t stg -65~+150 c note: absolute maximum ratings are those values beyond which the device could be permanently damaged. absolute maximum ratings are stress ratings only and functional device oper ation is not implied. ? thermal data parameter symbol ratings unit junction to ambient (in free air) ja 256 c/w ? electrical characteristics (ta=25c, v in =3v, shdn v =3v, unless otherwise specified.) parameter symbol test conditions min typ max unit operating voltage v in 2.5 12 v feedback voltage v fb i sw =100ma, duty cycle=66% 87 95 104 mv shutdown voltage on v on 1.5 v shutdown voltage off v off 0.3 v switch v cesat v cesat(sw) i sw =250ma 360 mv switch current limit i sw 320 ma 1.8 2.5 ma supply current i cc shdn =0v 0.1 1.0 a switch leakage current i sw(off) v sw =5v 0.01 5 a shutdown pin bias current shdn i 60 a feedback pin bias current i fb 10 45 100 na switching frequency f osc 0.8 1.2 1.6 mhz maximum duty cycle dc 85 90 %
l5100 linear integrated circuit unisonic technologies co., ltd 5 of 7 www.unisonic.com.tw qw-r103-024.c ? typical application circuits efficiency(%) efficiency (%) efficiency (%)
l5100 linear integrated circuit unisonic technologies co., ltd 6 of 7 www.unisonic.com.tw qw-r103-024.c ? typical application circuits (cont. ) efficiency(%) load current (ma) 5 0 70 1 5 65 80 85 seven led efficiency 75 1 0 v in sw shdn fb gnd r1 4 c out 0. 22f c in 1f v in 5v d 5k 90k v dc dimming 5 v to seven white leds l=22 h
l5100 linear integrated circuit unisonic technologies co., ltd 7 of 7 www.unisonic.com.tw qw-r103-024.c ? typical characteristics 2.2 v in (v) 2 0 0 0.8 6 4 0. 4 1. 2 1.6 2.0 quiescent current 10 i q (ma) 25 80 1.8 1.4 1.0 0.6 0.2 8 350 20 0 0 60 40 100 200 300 250 150 80 100 current limit vs duty cycle duty cycle (%) current limit (ma) 50 * utc l5100 is guaranteed the operating temperature range of 0c ~ 75c. utc assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all utc products described or contained herein. utc products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. the information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.
|
