LED背光控制器 ,1.25MHz固定开光频率,低反馈电压支持开路保护,软启动和脉宽调制调光PT4103

GENERAL DESCRIPTION
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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 cons tant 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 eas ily 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 z RoHS compliant APPLICATIONS z Cell Phones z Handheld Computers and PDAs z Digital Cameras z Small LCD Displays    
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