PT4101 Datasheet Text
PT4101
White LED Step-Up Converter
GENERAL DESCRIPTION
The PT4101 is a step-up DC/DC converter designed for driving up to 5 white LEDs in series from a single cell Lithium Ion battery with constant current. Because it directly regulates output current, the PT4101 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 2mA and 20mA, which can then be easily adjusted using either a DC voltage or a pulse width modulated (PWM) signal up to 100KHz. 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 PT4101 is available in SOT23-6 packages.
Features z z z z z z z Drives Up to 5 Series White LEDs from 3V Up to 87% Efficiency 1.25MHz Fixed Switching Frequency Low 104mV Feedback Voltage Open Load Shutdown PWM Dimming SOT23-6 Packages
APPLICATIONS z z z z Cell Phones Handheld puters and PDAs Digital Cameras Small LCD Displays
ORDERING INFORMATION
PACKAGE SOT23-6 TEMPERATURE RANGE -40 oC to 85 oC ORDERING PART NUMBER PT4101B23F TRANSPORT MEDIA Tape and Reel 3000 units MARKING 4101
TYPICAL APPLICATIONS
0.89
Vin=3.6V
0.88 0.87 0.86
Efficiency
0.85 0.84 0.83 0.82 0.81 0.80 2mA
2- LED 3- LED 4- LED 5- LED
5mA
10mA
15mA
20mA
Iout (mA)
Figure 1. Li-Ion Driver for Four White LEDs
Figure 2. Efficiency vs Number of LEDs
China Resources Powtech (Shanghai) Limited
PT4101_DS Rev EN_2.2
.CRPOWTECH.
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PT4101
White LED Step-Up Converter
PIN ASSIGNMENT
PIN DESCRIPTION...