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LM27964 Datasheet Preview

LM27964 Datasheet

White LED Driver

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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
1
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
VIN
D1B D2B
VIN CIN C1
C2
LM27964
DKEY
POUT
COUT
I2C Compatible
Interface
SCL
SDIO
VIO
GND ISETA
RSETA
ISETB
RSETB
ISETK
RSETK
1
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.
All trademarks are the property of their respective owners.
2
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 © 2005–2013, Texas Instruments Incorporated




etcTI

LM27964 Datasheet Preview

LM27964 Datasheet

White LED Driver

No Preview Available !

LM27964
SNOSAL6D – MAY 2005 – REVISED MAY 2013
www.ti.com
DESCRIPTION (CONTINUED)
The LM27964 works off an extended Li-Ion input voltage range (2.7V to 5.5V). The device provides excellent
efficiency without the use of an inductor by operating the charge pump in a gain of 3/2, or in Pass-Mode. The
proper gain for maintaining current regulation is chosen, based on LED forward voltage, so that efficiency is
maximized over the input voltage range.
The LM27964 is available in TI's small 24-pin WQFN Package (WQFN-24).
Connection Diagram
6 5 43 2 1
123456
7 24 24 7
8 23 23 8
9
DAP
10
22 22
21 21
DAP
9
10
11 20 20 11
12 19
13 14 15 16 17 18
19 12
18 17 16 15 14 13
Top View
Bottom View
Figure 1. 24 Pin Quad WQFN Package
See Package Number RTW0024A
Pin #s
24
23
19, 22 (C1)
20, 21 (C2)
13, 14, 15, 16
4, 5
6
17
3
12
1
2
7
9, 10, 18, DAP
8, 11
Pin Names
VIN
POUT
C1, C2
Table 1. Pin Descriptions
Pin Descriptions
Input voltage. Input range: 2.7V to 5.5V.
Charge Pump Output Voltage
Flying Capacitor Connections
D4A, D3A, D2A, D1A LED Drivers - GroupA
D1B, D2B
LED Drivers - GroupB
DKEY
LED Driver - KEYPAD
ISETA
ISETB
ISETK
SCL
Placing a resistor (RSETA) between this pin and GND sets the full-scale LED current for Group
A LEDs. LED Current = 200 × (1.25V ÷ RSETA)
Placing a resistor (RSETB) between this pin and GND sets the full-scale LED current for Group
B LEDs. LED Current = 200 × (1.25V ÷ RSETB)
Placing a resistor (RSETK) between this pin and GND sets the total LED current for the
KEYPAD LEDs. Keypad LED Current = 800 × (1.25V ÷ RSETK)
Serial Clock Pin
SDIO
Serial Data Input/Output Pin
VIO Serial Bus Voltage Level Pin
GND
Ground
NC No Connect
2 Submit Documentation Feedback
Product Folder Links: LM27964
Copyright © 2005–2013, Texas Instruments Incorporated


Part Number LM27964
Description White LED Driver
Maker etcTI
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LM27964 Datasheet PDF






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