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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