AIC1647

AIC1647 White LED Step-Up Converter in SOT23 FEATURES 1.2MHz Fixed Frequency Current-Mode PWM Operation. Efficiency Up to 84% at VIN=4.2V, 3LEDs, ILED=20mA Drives Up to 6LEDs in series Low Supply Current: 70µA Matches LED Current Require Tiny Inductors and Capacitors Tiny TSOT-23-5, and SOT-23-5 Packages APPLICATIONS Cellular Phones PDAs Digital Still Cameras Handheld Devices White LED Display Backlighting DESCRIPTION AIC1647 is a fixed frequency step-up DC/DC converter designed to drive white LEDs with a constant current to provide backlight in handheld devices. Series connection of the LEDs provides identical LED currents resulting in uniform brightness. This configuration eliminates the need for ballast resistors. Low 95mV feedback voltage minimizes power loss in the current setting resistor for better efficiency. AIC1647 is a step-up PWM converter, which includes an internal N-channel MOSFET switch for high efficiency. The high switching frequency, 1.2MHz, allows the use of tiny...