YB1315

Preliminary YB1315 High Efficiency Charge Pump White LED Driver Description The YB1315 charge pump is designed to drive up to 5 white LEDs with regulated constant current in backlight display application. The device can provide up to 25mA per LED for a total 5 channels. The output current can also be combined into one single channel with 125mA output current for flash-light applications. The input voltage ranges from 2.7V to 5.5V and is ideal for applications powered by a single Li-Ion or 3 to 4 NiCd, NiMH or Alkaline batteries. YB1315 monitors the power-supply input voltage and LED forward voltage and current, and does an automatic selection to a switching mode that is optimized for the power conversion efficiency as well as battery operating time. The 1MHz fixed frequency switching allows for tiny external components, and the regulation scheme is optimized to ensure low EMI and low input ripple. Internal soft-start circuitry effectively reduces the in-rush current. YB1315 also provides short circuit protection, over-temperature protection and over-voltage protection. In shutdown mode, the shutdown current is less than 1μA. YB1315 is available in a TQFN-16 3x3 package. Features „ Voltage Input Range From 2.7V to 5.5V „ Drives From 3 to 5 LEDs at Up to 25mA „ „ „ „ „ „ Each Fractional Conversion Modes for High Conversion Efficiency, 1x and 1.5x 1MHz Internal Oscillator Thermal Protection Shutdown Output Short-circuit Current Limit and Over-Voltage Protection Under-Voltage L...