rt9271白光led電源芯片應用電路

thert9271is a step-up dc/dc converter specifically
designed to drive white leds with a constant current.
the device can drive one to three leds in series from a
li-ion cell. series connection of the leds provides
identical led currents resulting in uniform brightness and
eliminating the need for ballast resistors. the rt9271
switches at 1.1 mhz, allowing the use of tiny external
components. the input and output capacitor can be as
small as 1uf, saving space and cost versus alternative
solutions. a low 0.25v feedback voltage minimizes power
loss in the current setting resistor for better efficiency.
the rt9271 is available in low profile sot-26 package.