AFSEMI AF5121
The AF5121 is a step-up DC/DC converter specifically designed to drive up to 6 series white LEDs with constant current. The AF5121 switches at 1.4MHz, allowing the use of tiny external components. The OVP pin monitors the output voltage and turns off the converter whFEATURES
● Inherently Matched LED Current● High Efficiency:82%
● Drives Up to Six LEDs from 2.2V Supply
● 20V Over Voltage Protection
● Fast 1.4MHz Switching Frequency
● Requires Only 1μF Output Capacitors
● SOT-23-6 Package
APPLICATIONS
● Communication equipment● White LED Backlight Display for PDA
● Pocket PC
● Handheld Devices
● Cellular Phones
● White LED display backlighting
GENERAL DESCRIPTION
Series connection of the LEDs provides identical LED currents resulting in uniform brightness and eliminates the need for ballast resistors. A low 0.25V feedback voltage minimizes power loss in the current setting resistor for high efficiency.