TPS60231
www.ti.com
SLVS544 – OCTOBER 2004
WHITE LED CHARGE PUMP CURRENT SOURCE
WITH PWM BRIGHTNESS CONTROL
FEATURES
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Regulated Output Current With 0.4%
Matching
Drives up to 3 LEDs at 25 mA Each
LED Brightness Control Through PWM
Control Signal
High Efficiency by Fractional Conversion
With 1x and 1.5x Modes
1 MHz Switching Frequency
2.7 V to 6.5 V Operating Input Voltage Range
Internal Softstart Limits Inrush Current
Low Input Ripple and Low EMI
Overcurrent and Overtemperature Protected
Undervoltage Lockout With Hysteresis
Ultra-Small 3mm x 3mm QFN Package
DESCRIPTION
The TPS60231 charge pump is optimized for white
LED supplies in color display backlight applications.
The device provides a constant current for each LED,
which the initial value can be set by an external
resistor. The supply voltage ranges from 2.7 V to
6.5 V and is ideally suited for all applications powered
by a single LI-Ion battery cell or three to four NiCd,
NiMH, or alkaline battery cells. Over an input voltage
range from 3.1 V to 6.5 V, the device provides a high
output current of up to 25 mA per LED with a total of
75 mA. High efficiency is achieved by utilizing a
1x/1.5x fractional conversion technique in combi-
nation with very low dropout current sources. In
addition, the current controlled charge pump ensures
low input current ripple and EMI. Only two external
1 µF and two 0.47 µF capacitors are required to build
a complete small and low cost power supply solution.
To reduce board space to a minimum, the device
switches at 1 MHz operating frequency and is avail-
able in a small 16-pin QFN (RGT) package.
VIN
VIN = 2.7 V
to 6.5 V
C1+
0.47
mF
C1−
0.47
mF
1
mF
C2+
C2−
EN1
EN2
GND
ISET
PGND
VOUT
D1
D2
D3
1
mF
APPLICATIONS
White LED Backlight for Color Displays in
Cellular Phones, Smart Phones, PDAs,
Handheld PCs, Digital Cameras, and
Camcorders
Keypad Backlight
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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2004, Texas Instruments Incorporated
TI [ TEXAS INSTRUMENTS ]
