2006. 4. 13 1/6 semiconductor technical data KIB3401F bicd linear integrated circuit revision no : 3 white led step-up converter the KIB3401F is a monolithic step-up dc/dc converter specifically designed to drive white leds with a constant current from li-ion cell. relative large 320mv feedback voltage & it?s high accuracy help you setting led current with a external resistor. KIB3401F is available in a extremely low profile & small ts-6 package. a 10 h inductor is sufficient for most application. features inherently matched led current. high efficiency : 85% (max.) built in a open circuits protection for the leds fail. drives up to four leds without external zener diode. drives up to six leds with external zener diode. built in a n-channel mosfet switch. fast 1.1mhz(typ.) switching frequency. uses tiny 1mm tall inductors. bulit in thermal protection. wide dimming control range : 25%~100%. extremely low height & small packaging. applications celluars phones pdas digital cameras mp3 players, color displays dim millimeters a b d e ts6 2.9 0.2 1.6+0.2/-0.1 0.70 0.05 0.4 0.1 2.8+0.2/-0.3 1.9 0.2 0.95 0.16 0.05 0.00-0.10 0.25+0.25/-0.15 c f g h i j k 0.60 l 0.55 a f g g d k k b e c l h j j i 2 3 5 16 4 + _ + _ + _ + _ + _ figure1. 4series white led driver in thin ts6 0 c1, c2 : x5r or x7r dielectric d1 : kec kdr730e/kdr720e (low v ) l1 : murata lqh32cn100k53l or equivalent gnd sw l1 c1 on shutdown and dimming control off c2 21.5? r1 KIB3401F d1 ctl fb f ovd led1 led2 led3 led4 load current (ma) 10 conversion efficiency efficiency (%) 75.00 77.00 79.00 81.00 83.00 85.00 87.00 05 20 15 25 3.0v vin 3.6v 4.3v 1 2 4 3 6 5 v cc 4.7 h~10 h 1 f v in 1 f typical application marking lot no. type name 401 123 654
2006. 4. 13 2/6 KIB3401F revision no : 3 charateristics symbol rating unit input voltage v cc -0.3 ~ 6.0 v switching pin voltage v sw -0.3 ~ 22 v ovd pin voltage v ovd -0.3 ~ 22 v operating temperature range topr -40 ~ 85 storage temperature range tstg -40 ~ 150 maximum junction temperature tj 150 charateristics symbol condition min. typ. max. unit input voltage v cc - 2.8 - 5.5 v ctl pin voltage for full led current v ctl h v cc =3.0v 2.7 - - v ctl pin voltage to shutdown chip v ctl l - - 0.5 v ctl pin input pulse width t pw(ctl) both positive and negative pulse 33 - - led current if v cc =3.6v, r sense =16 , topr =25 , four led - 20 - ctl response delay (when power on.) t pd ctl - 2 - - maximum ratings (ta=25 ) recommended operating conditions (t opr =-40~85 ) one shot one shot sw out out ovd vref vth 320mv fb(rsense) gnd ctl adc + - out + - + - + _ + - + _ + - + - + - 2 3 6 4 1 5 v cc block diagram figure 2. KIB3401F block diagram
2006. 4. 13 3/6 KIB3401F revision no : 3 electrical characteristic (topr=-40~85 , v cc =2.8~5.5v, r sense =16 , unless otherwise noted.) charateristics symbol condition min. typ. max. unit input voltage v cc - 2.8 - 5.5 v supply current i cc v cc = 3.6v, v ctl =3.6v - 0.9 1.5 v ctl = 0v - 0.5 1 feedback voltage v fb v cc =v ctl =3.0v, t opr = 25 , l =10 h 294 320 346 ctl pin bias current i ctl v cc = 3.0v, v ctl = 3.0v - 20 - switching frequency f osc v ctl = 3.0v 0.77 1.1 1.43 switching pin current i o(sw) - 400 - switch rds(on) r on i o(sw) 400 - 0.7 1.5 switch leak current i oz(sw) - - 0.5 1 ovd pin voltage v ovd - 16 20 22 v ovd pin leak current i oz(ovd) - - 0.5 1 thermal shutdown tsd - - 150 180 switching pin ovp v o(sw) - 25 - - v ctl pin voltage for full led current v ctl h v cc = 3.0v 2.7 - - v ctl pin voltage to shutdown chip v ctl l - - 0.5 v feedback bias current i fb - - 0.5 1 maximum duty cycle d max - 85 90 - % no. symbol function and connection. 1 ctl control pin : shutdown or dimming control. connect external enable or dimming circuits. shutdown mode (if = 0) : v ctl <1.0v dimming control mode : (if = 20% ~ 100%, depend on v ctl ) 1.0v < v ctl < 2.5v, when v ctl is above 2.5v if keep its maximum value(100%). filtered pwm signal, above 33us of pulse width, can be used for dimming control. 2 ovd over output voltage detect pin. connect cathode of schottky diode and anode of highest led. 3 sw switch pin. connect inductor/diode here. minimize trace area at this pin to reduce emi. 4 fb feedback pin. reference voltage is 320mv. connect cathode of lowest led and resistor here. 5 gnd ground pin. connect directly to local ground plane, 6 v cc input supply pin. must be locally bypassed. pin functions
2006. 4. 13 4/6 KIB3401F revision no : 3 application information inductor selection a 10 h inductor is sufficient for most application. the efficiency comprison of different value inductors help you design your application circuits. capacitor selection a 1 input capacitor and output capacitor above 1 are sufficient for most KIB3401F application. diode selection for diode selection, both forward voltage drop and diode capacitance need to be considered. shottky diodes with higher current ratings usually have lower forward voltage and larger diode capacitance, which can cause significant switching losses. a schottky diode rated at 100 to 200 is sufficient for most KIB3401F applications. table 1. recommended schottky diodes led current control the led current is controlled by the feedback resistor(rsense in figure 1). the feedback reference is 320 . the led current is 320 /r sense . the tolerance of led current is depends on tolerance of r sense and feedback reference. open-circuits protection in the case of output open circuit, when leds are disconnected from the circuit or the leds fail, the feedback voltage will be zero. the kib3041f will then switch at a high duty cycle resulting in a high output voltage, but internal over voltage protection circuits prevent output voltage ascending over ovd pin voltage( 16v ~ 22v see fig.4 ). this circuits is valid when driving up to 4 leds in series. but, when driving more than 4 leds in series, normal output voltage could be over ovd pin voltage. in this case, zener diode can be used to limit output voltage, but check connection of ovd pin to vcc.(see fig.5) load current (ma) 10 efficiency (%) 70.00 72.00 74.00 76.00 78.00 80.00 82.00 84.00 86.00 88.00 90.00 05 20 15 25 4.7uh vin=3.6v, 4led inductor=murata 10uh figure3. efficiency comaprison of different value inductors figure4. 4leds driver with open-circuit protection. figure5. 6leds driver with open-circuit protection. 0 gnd sw dz l1 c1 c2 21.5 ? sense r KIB3401F d1 ctl fb ovd led1 led2 led3 led4 0 gnd sw l1 c1 c2 16 ? r1 KIB3401F d1 ctl fb led1 led2 led5 led6 led3 led4 ovd 1 2 4 3 6 5 1 2 4 3 6 5 v cc v cc 1 f 4.7 h~10 h 4.7 h~10 h 1 f 1 f 1 f v in v in dimming control there are 4 different type of dimming control circuits: 1. using a dc voltage to ctl pin. table 2 ctl pin voltage vs i led description v ctl unit 0v~0.5v 1v~2.5v v ctl >2.5v rate of the led current 0 25 ~ 100 100 % example : r sense = 16 0 5 ~ 20 20 ma part no. reverse voltage (v) forward current (ma) voltage drop (v) package kdr730e 30 200 ma 0.6v (max) at 200 ma 1.60 1.20 0.80 0.30 1 2 kdr720e 30 200 ma 0.5v(max) at 200 ma 1.60 1.20 0.80 0.30 1 2 kdr412 20 500 ma 0.5v(max) at 500 ma 0.30 1.25 1.70 2.50
2006. 4. 13 5/6 KIB3401F revision no : 3 2. using a pwm signal to ctl pin. with the pwm signal applied to the ctl pin, the KIB3401F is turned on or off by the signal. typical frequency range of the pwm signal is 15khz to 30khz. the switching waveforms of the ctl pin pwm control are shown in figure 7(a) and 7(b) figure 7. using a pwm signal to ctl pin. 3. using a dc voltage to fb pin. the dimming control using a dc control voltage to fb pin of the KIB3401F is shown in figure. the led current can be varied applying a dc voltage to the fb pin. the voltage can come from a filtered pwm signal. it can be used to replace the variable dc voltage source in dimming control. 4. using a logic signal to fb pin. for applications that need to adjust the led current in discret steps, a logic signal can be used as shown in figure 9. figure6. using a dc signal to ctl pin. 0 gnd sw l1 c1 c2 21.5? r sense KIB3401F d1 dc ctl fb ovd led1 led2 led3 led4 1 2 4 3 6 5 v cc 1 f 4.7 h~10 h 1 f v in 0 gnd sw l1 c1 c2 21.5? r sense v in KIB3401F d1 pwm ctl fb ovd led1 led2 led3 led4 1 2 4 3 6 5 v cc 1 f 4.7 h~10 h 1 f v sw 5v/div v ctl 5v/div (a) 1khz (2ms/div) 0 figure8. using dc voltage to fb pin. 0 gnd sw l1 c1 c2 r1 r2 KIB3401F d1 ctl fb sense r dc ovd led1 led2 led3 led4 0 0 1 2 4 3 6 5 v cc 1 f 1 f v in 0 figure9. using a logic signal to fb pin. gnd v cc sw l1 1uf c1 1uf c2 dim r logic ktk5132v KIB3401F d1 ctl fb r sense ovd led1 led2 led3 led4 1 2 4 3 6 5 v in
2006. 4. 13 6/6 KIB3401F revision no : 3 v (v) 01234 0 v (mv) fb 400 300 200 100 0 icc ( a) -10 110 70 30 -50 temp ( c) quiescent current vs temperature thermal shut down v vs v fb fb ctl ctl 300 50 350 200 250 100 150 5 -60 -10 40 90 efficicncy (%) 50 55 60 65 70 75 80 85 90 95 140 500 temperature ( c) efficicncy vs temperature vcc (v) 1.5 2.5 3.5 4.5 5.5 frequency (mhz) switching frequency (mhz) frequency vs vcc 0.91 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99 1.00 1.01 6.5 -50 0 50 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 100 temperature ( c) switching frequency vs temperature temp ( c) 350 300 0 v (mv) fb 125 185 175 165 145 115 155 135 105 400 200 150 100 50 250 vin=3.0v vin=3.6v vin=4.3v v f v in= 2.7v vin=3 .6v vin=4.3v
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