power&rf 2006 summer bipolar white led flash driver ic ?`? led ??? ic TK11893AM8 (hson3030b-10) description the TK11893AM8 type is a step-up dc-dc converte r designed for camera lights of mobile phones and portable equipment, using constant frequency pwm architecture, with the following built in: current r egulator up to 0.8a, a very high current switching transistor (2.0a peak), a very high speed oscillator (2.0mhz), a switch over current detector, a lo w voltage reference depended on led current, a pwm comparator, open-circuit prot ection and on/off control. the TK11893AM8 can drive one or two high current white leds in series in a high power flash mode or a low powe r torch mode using the cont pi n. the on/off control is built-in and the circuit current can be decreased when the en pin is low (shutdown mode). during shutdown, the leds are disconnected from the input to avoid leakage current path to gnd. the device operates with 2.0m hz fixed switching frequency to allow for the use of small external components. the operating supply voltage rang e is 2.5v~6.0v. the white leds are connected in series and driven at a constant current, resulting in uniform brightness and high efficiency. the built-in zener diode can be used for open-circuit protection in case the output load is disconnected, such as the string of leds opened. the internal open-circuit protection reduces the external component count. the TK11893AM8 is available in the hson3030b-10 surface mount package. TK11893AM8 ??`?C _k?NR dc-dc ` ic ? features ? can drive 2 high current leds in series ? ? 2 ?l? ? independently set flash/torch currents and shutdown ? ?? / ?`??? ? high frequency 2.0mhz pwm operation. ? ? 2mhz ? built-in current regulator ? ?`i ? led disconnect during shutdown ? ?? led ??A ? over voltage protection (ovp) ? ovp C ? wide operating voltage range (2.5 to 6.0v) ? ??R 2.5~6.0v ? uses small inductor ? ??? ? internal switching transistor (max. 2.0a) ? ??????i ( 2.0a) ? small outline non-leaded package hson3030b-10 ? ?`???` hson3030b-10 absolute maximum ratings parameter ? symbol rating unit remarks q operating voltage range ?R v op 2.5 to 6.0 v operating temperature range ?? t op -30 to +85 c power dissipation SM p d 1000 mw operating frequency range ? f op 2 mhz
power&rf 2006 summer electrical characteristics v in =3v, t a =25 c (unless otherwise noted) parameter ? symbol min. typ. max. unit remarks q oscillator section operating frequency f 1.6 2.0 2.4 mhz led current setting section 1 (i set 1 pin) iset1 pin voltage 1_50 v set1-50 - 495 - mv led current ratio 1_50(iled-50/iset1-50) 1-50= i led- 50/ i set1-50 - 3970 - - led current set value 1_50 *note1 1-50 v set1- 50 1838 1965 2092 (v) i set1 =-50 a v fb =1.0v iset1 pin voltage 1_160 v set1-160 - 452 - mv led current ratio 1_160(iled-160/iset1-160) 1-160= i led- 160/ i set1-160 - 3142 - - led current set value 1_160 *note1 1- 160 v set1- 160 1328 1420 1512 (v) i set1 =-160 a, vfb=1.0v led current setting section 2 (iset2 pin) iset2 pin voltage 2_50 v set2-50 - 495 - mv led current ratio 2_50 (iled-50/iset2-50) 2-50 =i led- 50 /i set2-50 - 3970 - - led current set value 2_50 *note1 2-50 v set2- 50 1838 1965 2092 (v) i set2 =-50 a, v fb =1.0v iset2 pin voltage 2_160 v set2-160 - 452 - mv led current ratio 2_160 (iled-160/iset2-160) 2-160 =i led- 160 /i set2-160 - 3142 - - led current set value 2_160 *note1 2- 160 v set2- 160 1328 1420 1512 (v) i set2 =-160 a, v fb =1.0v dead time control section d max 76 83 95 % vfb=0v maximum duty cycle cont section (cont pin) input voltage + v cont,high 1.2 - 19 v input voltage - v cont,low 0 - 0.3 v input bias current i contin - 25 50 a vcont=3v shutdown section (en pin) input voltage + v en,high 1.2 - 19 v on mode input voltage - v en,low 0 - 0.3 v shutdown mode input bias current i enin - 25 50 a ven=3v output switch section (sw pin) switch current limit i sw,limit 2.0 2.9 - a switch saturation voltage 1 v sw,sat1 - 0.05 0.20 v i sw =200ma switch saturation voltage 2 v sw,sat2 - 0.13 0.50 v i sw =500ma switch leakage current i sw,off - 0.10 2.0 a v fb =1v, v sw =10v open circuit protection section ovp voltage v ovp 11.6 13.6 15.6 v v fb =open *note2 error amplifier section (vfb1 pin,ea out pin) threshold voltage 1 v ea1 191 225 259 mv i set =-50 a threshold voltage 2 v ea2 365 430 495 mv i set =-160 a v in section (vin pin) low voltage stop v in,low 2.00 2.20 2.50 quiescent supply current i in,on 8.0 11.4 15.0 ma v fb =1v, no load shutdown supply current i in,off - 0.01 1.0 a v en =0v *note 1: output led current is calculated by ?led current set value? and program resistor rset that is connected from iset pin to gnd. i led = v set /r set *note 2: open-circuit voltage (ovp) is a m easurement value by "9-2. test circuit". (the other characteristics are measur ement value by "9-1. test circuit".)
power&rf 2006 summer block diagram 0.6v error amp pwm comp over current detector open circuit protection oscillator 10 6 3 2 1 5 9 8 7 pgnd v in en cont v fb i set1 sw ea out gnd i set2 4 uvlo bias thermal shutdown output driver control current regurator low voltage reference led current control pin description 1 2 3 4 56 7 8 9 10 pin no. #1 sw switch pin (connect sw to inductor and diode) #2 pgnd power ground #3 vin power supply voltage input #4 en enable (on/off) input #5 eaout error amplifier output #6 cont flash/torch control input #7 iset2 led current program pin #8 iset1 led current program p #9 gnd ground #10 vfb current regulator output and boost converter feedback pin (connect vfb to the cathode of led) application 10k ? 3k ? 0.1 f 4.7 f 6.3v 2.0 h (toko de2812c type) 10 f 16v v in sw v in en cont gnd pgnd v fb ea out i set1 i set2 on/off flash/torch TK11893AM8 * 100 in i in v led i out v (%) efficiency ? ? = * 100 in i in v led i led v (%) efficiency led ? ? = efficiency vs. input voltage (led current 500ma) 50 60 70 80 90 100 2.5 3.0 3.5 4.0 4.5 input voltage (v) efficiency (%) led efficiency efficiency
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