LM27966 Datasheet, PDF (1/20 Pages) National Semiconductor (TI) – White LED Driver with I2C Compatible Interface

LM27966
www.ti.com
SNVS448B – JULY 2006 – REVISED MAY 2013
LM27966 White LED Driver with I2C Compatible Interface
Check for Samples: LM27966
FEATURES
1
•2 91% Peak LED Drive Efficiency
• No Inductor Required
• 0.3% Current Matching
• Drives 6 LEDs with up to 30mA per LED
• 180mA of total driver current
• I²C Compatible Brightness Control Interface
• Adaptive 1×- 3/2× Charge Pump
• Resistor-Programmable Current Settings
• External Chip RESET Pin (RESET)
• Extended Li-Ion Input: 2.7V to 5.5V
• Small low profile industry standard leadless
package, WQFN 24 : (4mm x 4mm x 0.8mm)
APPLICATIONS
• Mobile Phone Display Lighting
• PDAs Backlighting
• General LED Lighting
DESCRIPTION
The LM27966 is a highly integrated charge-pump-
based display LED driver. The device can drive up to
6 LEDs in parallel with a total output current of
180mA. Regulated internal current sources deliver
excellent current and brightness matching in all LEDs.
The LED driver current sources are split into two
independently controlled groups. The primary group,
which can be configured with 4 or 5 LEDs, can be
used to backlight the main phone display. An
additional, independently controlled led driver is
provided for driving an indicator or other general
purpose LED function. The LM27966 has an I²C
compatible interface that allows the user to
independently control the brightness on each bank of
LEDs.
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 LM27966 is available in a small 24-pin Leadless
Leadframe WQFN-24 package.
Typical Application Circuit
MAIN DISPLAY
AUXILIARY
LED
C_IN
V_IN
1 PF
I²C
Compatible
Interface
D1
V_IN
C₁
1 PF
C₂
1 PF
SCL
SDIO
VIO
RESET
D2 D3 D4 D5
D_AUX
LM27966
GND
P_OUT
C_OUT
1 PF
I_SET
R_SET
Capacitors: TDK C1608X5R1A105K
or equivalent
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 © 2006–2013, Texas Instruments Incorporated