G5121

Global Mixed-mode Technology Inc. G5121 Fixed Frequency White LED Step-Up Converter Features „ Inherently Matched LED Current „ High Efficiency: 87% „ Drives Up to Five LEDs from 2.5V Supply „ 24V Internal Power Switch „ Fast 1MHz Switching Frequency „ Uses Tiny 1mm Tall Inductors „ Requires Only 1µF Output Capacitors „ 19.5V Over Voltage Protection „ SOT-23-6 Package Applications „ White LED Backlight Display for PDA „ Pocket PC „ Smart Phones „ Handheld Devices „ Cellular Phones General Description The G5121 is a step-up DC/DC converter specifically designed to drive up to 5 series white LEDs with constant current. Series connection of the LEDs provides identical LED currents resulting in uniform brightness and eliminates the need for ballast resistors. The G5121 switches at 1MHz, allowing the use of tiny external components. A low 0.254V feedback voltage minimizes power loss in the current setting resistor for high efficiency. The OVP pin monitors the output volta...