White LED Charge Pump Current Source
Description
SGM3124
White LED Charge Pump Current Source with PWM Brightness Control
GENERAL DESCRIPTION
The SGM3124 is a charge pump with PWM brightness control for white LED supplies in LCD display backlight applications.
The supply voltage ranges from 2.
7V to 5.
5V, it is ideally suited for all applications powered by a single Li-ion battery cell or three to four NiCd, NiMH, or alkaline battery cells.
The device provides a constant current for each LED, and the initial current value can be set by an external resistor.
High efficiency is achieved by utilizing a 1×/1.
5× fractional conversion technique in combination with very low dropout current sources.
The SGM3124 is capable of driving up to three channels of LEDs at 30mA per channel from a 2.
7V to 5.
5V input.
Additionally, the current controlled charge pump ensures low input current ripple and EMI.
A low external part count (two 0.
47µF flying capacitors and two small 1µF capacitors at VIN and VOUT) makes this part ideally suited for small, battery-powered applications.
The SGM3124 is available in a Green, space-saving TQFN-3×3-16L package, and is rated over the -40℃ to +85℃ temperature range.
FEATURES
Input Voltage Range: 2.
7V to 5.
5V Drives up to 3 LEDs at 30mA Each LED Brightness Control Through PWM Control
Signal High Efficiency by Fractional Conversion with 1×
and 1.
5× Modes Switching Frequency: 1MHz Regulated Output Current with 0.
5% Matching Internal Soft-Start Limits Inrush Current Low Input Ripple and Low EMI Over-Current and Over-Temperature Protected Under-Voltage Lockout With Hysteresis Green TQFN-3×3-16L Package
APPLICATIONS
Cellular Phones Smart Phones Digital Cameras Handheld PCs Camcorders PDAs Keypad Backlight
SG Micro Corp www.
sg-micro.
com
REV.
A.
1
SGM3124
White LED Charge Pump Current Source with PWM Brightness Control
PACKAGE/ORDERING INFORMATION
ORDER NUMBER SGM3124YTQ16G/TR
PACKAGE DESCRIPTION
TQFN-3×3-16L
SPECIFIED TEMPERATURE
RANGE
-40℃ to +85℃
PACKAGE OPTION
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