vishay siliconix sip12401 document number: 73193 s-71822-rev. c, 03-sep-07 www.vishay.com 1 boost controller for doubl e aa cell or li-ion battery for white led application features ? voltage mode control with internal frequency compensation ? 1.8 v to 5.0 v input voltage range ? pwm control with 600 khz fixed switching frequency ? analog control of led intensity ? regulated output current ? integrated uvlo and soft-start ? logic controlled shutdown (< 1 a) ? high efficiency: typical 80 % ? powerpak ? mlp33-6 package applications ? white led backlighting ? lcd bias supplies ? handheld devices ? digital cameras ? portable applications description sip12401 is a boost controller ic for double cell nimh or alkaline battery and li ion battery, which can drive white leds connected in series to provide backlight in hand-held devices. series connection of the leds provides identical led currents resulting in uniform brightness and eliminating the need for ballast resist ors. for best efficiency performance, the sip12401 is designed to operate in pwm mode with 600 khz switching. the voltage-mode pwm design is internally compensated, reducing the external parts count. it accepts input voltages from 1.8 v to 5.0 v. the led current can be adjusted externally for its brightness control. sip12401 features low shutdown current of under 1 a. sip12401 is available in a le ad (pb)-free 6-pin, powerpak mlp33 package and is spec ified to operate over the industrial temperature range of - 40 c to 85 c. typical application circuit xshd agnd sip12401 pgnd v in ext fb 1 3 4 6 2 5 22 h xshd 10 f v in 4.7 f mbr0520 15 si2302ads rohs compliant
www.vishay.com 2 document number: 73193 s-71822-rev. c, 03-sep-07 vishay siliconix sip12401 notes: a. derate 20 mw/c above 70 c. b. device mounted with all leads soldered or welded to pc board. stresses beyond those listed under ?absolute maximum ratings? ma y cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other condit ions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. notes: a. full = - 40 to 85 c. b. the algebraic convention whereby the most negative value is a minimum and the most positive a maximum (- 40 to 85 c). c. typical values are for design aid only, not guaranteed nor subject to production testing. absolute maximum ratings (all voltages referenced to gnd = 0 v) parameter limit unit input voltage, v in - 0.3 to 6 v ext voltage - 0.3 to v in + 0.5 xshd voltage - 0.3 to v in + 0.5 fb voltage - 0.3 to v in + 0.5 maximum junction temperature 150 c storage temperature - 55 to 150 operating junction temperature 125 power dissipation a powerpak mlp33-6 (t a = 70 c) a 1100 mw thermal resistance b powerpak mlp33-6 50 c/w recommended operating range (all voltages referenced to gnd = 0 v) parameter limit unit input voltage, v in 1.8 to 5 v xshd, ext voltage 0 v to v in lx voltage 0 to v out + 0.5 fb voltage 0 to 5 operating temperature range - 40 to 85 c specifications a parameter symbol test conditions unless specified v in = 3 v, t a = 25 c temp a limits unit min b typ c max b input voltage v in full 1.8 5 v uvlo v uvlo full 1.65 1.77 uvlo hysteresis v uvlohyst 0.1 feedback voltage v fb 0.291 0.3 0.309 full 0.282 0.318 feedback input current i fb v fb = 0.3 v 1na maximum pwm duty cycle maxdty 77 85 % pwm switching frequency f osc full 425 600 775 khz quiescent current i q v fb = 0.4 v 200 300 a stand-by current i stb xshd = 0 v full 1 xshd input high level v xshdh full 1.2 v xshd input low level v xshdl full 0.2 ext high on resistance r exth i ext = 10 ma 35 ext low on resistance r extl 30
document number: 73193 s-71822-rev. c, 03-sep-07 www.vishay.com 3 vishay siliconix sip12401 pin configuration and truth table pin functions xshd (pin 1) xshd is the logic controlled shutdown input pin. when xshd is low, the ic is shutdown and it?s quiescent current is less than 1 a. when xshd is high, the ic is working in normal operation. v in (pin 2) v in is the pin connected to batt ery input voltage. the ic gets its power supply from v in . fb (pin 3) fb is the feedback pin of the output voltage via resistor divider. fb is about 0.3 v and its difference from 0.3 v reference voltage is amplified by the error amplifier. agnd (pin 4) agnd is the pin for ground of controlling circuit. pgnd (pin 5) pgnd is the pin for ground of th e internal power mos driver. ext (pin 6) ext is the output pin of internal driver. it?s connected to the gate of external power mosfet. fb agnd 2 3 6 5 4 1 powerpak mlp33-6 top view v in xshd pgnd ext ordering information part number temperature range marking SIP12401DMP-T1-E3 - 40 to 85 c 2401 pin description pin number name function 1 xsdh logic controlled shutdown input, xshd = hi gh: normal operation, xshd = low: shutdown 2 v in battery input voltage 3 fb output voltage feedback pin 4 agnd signal ground 5 pgnd power ground 6 ext drive pin for external power mos
www.vishay.com 4 document number: 73193 s-71822-rev. c, 03-sep-07 vishay siliconix sip12401 functional block diagram detailed operation sip12401 is a 600 khz boost controller ic, packaged in 6-pin mlp33, for white led applicat ions. it features fixed frequency voltage mode pwm control with internal frequency compensation. with the low r ds(on) external power mosfet, this device maintains high efficiency over a wide range of load current. soft-start during soft-start, the loop compensation guarantees the slow increase of the output voltage and inrush current, so that no large voltage overshoot and inrush current occur when the soft-start is ended. pwm operation after soft-start, the device is working in pwm operation with a fixed frequency of 600 khz. application information white led brig htness control the current of white led can be adjusted by pwm signal on the xshd pin or by a variable dc voltage to control its brightness, (see figure 1.) as control voltage v ctrl increases, the voltage drop on r2 increases and the voltage drop on r1 decreases. thus, the led current decreases. the selection of r2 and r3 will make the current from v ctrl much smaller than led current and much larger than the fb pin bias current. compensation reference and soft-start oscillator driver - + pwm + - e/a v in agnd pgnd fb xshd ext xshd agnd sip12401 pgnd v in ext fb 1 3 4 6 2 5 22 h xshd 10 f v in 4.7 f mbr0520 15 si2302ads r3 3.9 k v ctrl r2 1 k i led 0.3 v 15 0.3 v ctrl 15 r2 r3 -
document number: 73193 s-71822-rev. c, 03-sep-07 www.vishay.com 5 vishay siliconix sip12401 typical characteristics maximum pwm duty cycle vs. temperature feedback voltage vs. temperature 80 81 82 83 84 85 -50-30-101030507090 temperature (c) e l c y c y t u d % -4 -3 -2 -1 0 1 2 3 4 -50 -30 -10 10 30 50 70 90 ) % ( y c a r u c c a e g a t l o v k c a b d e e f v in = 5 v temperature (c) v in = 2 v supply current vs. temperature shutdown threshold vs. temperature 180 185 190 195 200 205 210 215 220 -50 -30 -10 10 30 50 70 90 ) a m ( t m e r r u c y l p p u s temperature (c) 0.0 0.2 0.4 0.6 0.8 1.0 1.2 -50 -30 -10 10 30 50 70 90 temperature (c) ) v ( d l o h s e r h t n w o d t u h s v in = 5 v v in = 2 v
www.vishay.com 6 document number: 73193 s-71822-rev. c, 03-sep-07 vishay siliconix sip12401 typical waveforms vishay siliconix maintains worldwide manufacturing capability. products may be manufactured at one of several qualified locatio ns. reliability data for silicon technology and package reliability represent a composite of all qualified locations. for related documents such as package/tape drawings, part marking, and reliability data, see http://www.vishay.com/ppg?73193 . figure 1. pwm dimming control 200 hz 50 % duty cycle pwm signal on xshd pin 1 ms/div v xshd 2 v/div v out 2 v/div v fb 0.2 v/div v in = 3.6 v four leds in series figure 3. switching waveforms: v in , v out and v ext v in = 3.6 v, l = 22 h, c out = 4.7 f, four leds in series 1 s/div v in 20 mv/div ac coupled v out 50 mv/div ac coupled v ext 2 v/div
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