www.addmtek.com copyright ? 2008 addtek corp. 1 v1.2 -- december 2008 A707 h igh v oltage b oost d river w ith 3 c hannels c onstant c urrent r egulators description features high frequency dc/dc converter for leds. integrated 40v power mosfet. 4.5v ~ 25v wide input voltage range. 3 constant-current output channels. output current adjustable through external resistor. constant output current range: 5ma~30ma. 40v output sustaining voltage for up to 10 pcs of leds in series. led open/short protection. tssop-14l green package. applications the A707 is a high voltage boost driver with 3 channels adjustable constant current regulators for notebook led backlight applications. three regulated current ports are designed to provide uniform and pure dc constant current sinks for driving leds within a large range v f variations. it can drive a number of leds in series/parallel configuration users may adjust the output current from 5ma to 30ma through an external resistor, r set , which gives users flexibility in controlling the light intensity of leds. it also could adjust led brightness via pwm pin with pulse width modulation signal. a feedback circuit is built in the between of boost driver and the current regulators. it could sense the lowest dropout voltage among used channels to boost driver in order to maintain the output voltage in optimal level. an ovp circuit is built for open-loop protection when any string becomes open. the thermal protection function protects ic from over temperature damage. also, the exposed thermal pad enhances the package power dissipation. automotive interior lighting led backlight driver for nb and monitors. typical application circuit package pin out d f l v in =4.5v~25v r p c p1 c in c out out3 out2 out1 comp pwm shdn byp vin rt cvfb iset s w A707 r set c bp r 1 r 2 on/off pwm r t c ss v out v led ss gnd r ss tssop-14 (top view) 1 2 3 4 14 13 12 11 shdn gnd out3 sw out2 byp pwm v in 5 6 7 10 9 8 cvfb ss comp out1 iset rt order information tssop f 14 pin A707fgt note: the letter ?g? is marked for green parts, and letter ?t? is marked for tape & reel.
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