GENERAL DESCRIPTION

The PT4103 is a step-up DC/DC converter designed for

driving up to 8 white LEDs in series from a single cell

Lithium Ion battery with constant current. Because it

directly regulates output current, the PT4103 is ideal for

driving light emitting diodes (LEDs) whose light

intensity is proportional to the current passing through

them, not the voltage across their terminals. A single

external resistor sets LED current between 5mA and

20mA, which can then be easily adjusted using either a

DC voltage or a pulse width modulated (PWM) signal.

Its low 104mV feedback voltage reduces power loss

and improves efficiency. The OV pin monitors the

output voltage and turns off the converter if an

over-voltage condition is present due to an open circuit

condition. The PT4103 is available in SOT23-6

packages

FEATURES

z Drives Up to 5 Series White LEDs from 2.5V

z Drives Up to 8 Series White LEDs from 3.6V

z Up to 87% Efficiency

z 1.2MHz Fixed Switching Frequency

z Low 104mV Feedback Voltage

z Open Load Shutdown

z Soft Start/PWM Dimming

z SOT23-6 Packages

APPLICATIONS

z Cell Phones

z Handheld Computers and PDAs

z Digital Cameras

z Small LCD Displays