LM27964 Datasheet, PDF (1/22 Pages) National Semiconductor (TI) – White LED Driver System with I2C Compatible Brightness Control

LM27964
www.ti.com
SNOSAL6D – MAY 2005 – REVISED MAY 2013
LM27964 White LED Driver System with I2C Compatible Brightness Control
Check for Samples: LM27964
FEATURES
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•2 87% Peak LED Drive Efficiency
• 0.2% Current Matching between Current Sinks
• Drives 6 LEDs with up to 30mA per LED in
Two Distinct Groups, for Backlighting Two
Displays (main LCD and sub LCD)
• Dedicated Keypad LED Driver with up to 80mA
of Drive Current
• Independent Resistor-Programmable Current
Settings
• I²C Compatible Brightness Control Interface
• Adaptive 1×- 3/2× Charge Pump
• Extended Li-Ion Input: 2.7V to 5.5V
• Small Low Profile Industry Standard Leadless
Package, WQFN-24 : (4mm x 4mm x 0.8mm)
• LM27964SQ-I LED PWM Frequency = 10kHz,
LM27964SQ-C LED PWM frequency = 23kHz
APPLICATIONS
• Mobile Phone Display Lighting
• Mobile Phone Keypad Lighting
• PDAs Backlighting
• General LED Lighting
DESCRIPTION
The LM27964 is a charge-pump-based white-LED
driver that is ideal for mobile phone display
backlighting. The LM27964 can drive up to 6 LEDs in
parallel along with multiple keypad LEDs, with a total
output current up to 180mA. Regulated internal
current sources deliver excellent current matching in
all LEDs.
The LED driver current sources are split into two
independently controlled groups. The primary group
(4 LEDs) can be used to backlight the main phone
display and the second group (2 LEDs) can be used
to backlight a secondary display. A single Keypad
LED driver can power up to 16 keypad LEDs with a
current of 5mA each. The LM27964 has an I²C
compatible interface that allows the user to
independently control the brightness on each bank of
LEDs.
Typical Application Circuit
MAIN DISPLAY
SUB DISPLAY
KEYPAD LEDs
D1A D2A D3A D4A
V_IN
D1B D2B
V_IN
C_IN
C₁
C₂
LM27964
DKEY
P_OUT
C_OUT
I²C Compatible
Interface
SCL
SDIO
VIO
GND ^ISETA
R_SETA
I_SETB
R_SETB
I_SETK
R_SETK
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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.
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