白光驱动ic ld7209

general description

ld7209 is a step-up dc/dc converter, specially designed to drive white leds with constant current. the device can drive 3 to 8 leds in series from one li-ion cell. ld7209 implements with the constant frequency, 1mhz pwm control scheme. the high frequency pwm operation reduces the board space with less external component counts. a low 0.3v feedback voltage minimizes power loss in the current setting resistor for better efficiency. internal soft start function eliminates inrush current during startup.

ld7209 is available in a space-saving 8 pin 3mm x 3mm dfn package.

features

• drive up to 8 leds at 25ma
• 90% high efficiency
• 1.7% current-regulation accuracy
• output over-voltage protection
• direct 200hz to 200khz pwm dimming control by ctrl pin
• 1mhz switching frequency
• internal soft start eliminate inrush current
• 2.6v to 5.5v input range
• 40v internal power nmos
• over-temperature protection

applications

• led driver
• cell phones, pda

typical application

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