2009 autumn cmos step-up dc-dc converter ic/white led driveric cmos NR dc-dc ` ic/ ? led ? ic TK65604AB6 (fc3050a-8) description TK65604AB6 white led driver ic has been optimized for battery-controlled systems where power consumption and size are primary concerns. high efficiency has been optimized for this application. also, an added load disconnect feature improves the dimming performance of the converter when a pwm signal is applied to the enable bump. the miniature flip chip package device, together with the miniature toko db3015c type coil, further helps system designers reduce the space requi red to drive the white leds. with the synchronous rectifier and load disconnect switch being internal to the ic, the power fets are controlled such that the current path to the output load is disconnected during disable mode and also intermittently during short circuit protection mode. the ic uses current-mode pwm (pulse width modulation) method of regulat ing the current through the string of leds. this time-proven method of regulation works at a fixed switching frequency, which is preferred in rf systems. TK65604AB6 ???e? led ? ic ?M??g??????`? Cm??????`? ?i`????C??? enable ??? pwm {??????? ??`?????????`?? ? ( |u db3015c) ?M??? led ? ??g?gF?? ` (ic off) r?`?o`?r ??i??`????? ????x?? ic ?` pwm ???? ?? rf ????y?? ??? features ? improved pwm dimming performance with ? less c out voltage ripple ? square wled current waveforms ? less peak in-rush currents ? efficiency as high as 84% ? led current regulated ? internal synchronous rectifier ? short-circuit protection ? over-voltage protection ? can drive multiple strings of 4 wled in series ? 1. 3 mhz pwm operation ? low supply current ? ? pwm { ? c out ???R ? ?? led ? ? ? ? 84% ? led ? ?i ? `?o ? ^?Ro ? led 4 ? 2 K?? ? pwm ?? 1.3mhz ? ? selection chart C?E dc-dc converter white led driver type osc system type switching tr. v out switching current num. of white led system efficiency v op t op p d f op TK65604AB6 pwm step- up internal adjustable 400ma series 1 to 4 inductive external schottky 84% 2.7 to 5.5 v ?30 to +85 c 660mw 1.3mhz
2009 autumn pin configration top view a1 a2 b3 c3 b1 c1 c2 a3 block diagram
|
