PT4102 Datasheet

时间: 2009-06-26 来源: Seawin 浏览量:

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   Step-Up DC/DC Converter for White LED Driver
GENERAL DESCRIPTION
The PT4102 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 PT4102 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. Dimming can be easily achieved using either a DC voltage or a pulse width modulated (PWM) signal. Its low 88mV or 104mV feedback voltage reduces power loss and improves efficiency. The PT4102 is available in SOT23-5 and SC70 packages.
FEATURES
¨          Drives up to 5 series white LEDs from 2.5V input
¨          Drives up to 8 series white LEDs from 4.2V input
¨          Up to 87% efficiency
¨          1.2MHz fixed switching frequency
¨          Low 88mV/104mV feedback voltage
¨          PWM or DC voltage dimming
¨          SOT23-6 and SC70 packages
APPLICATIONS

¨          Cell phones
¨          Handheld computers and PDAs
¨          Digital cameras
¨          Small LCD displays

TYPICAL APPLICATIONS