LM27965 Datasheet, PDF (1/23 Pages) National Semiconductor (TI) – Dual Display White LED Driver with I2C Compatible Brightness Control

LM27965
www.ti.com
SNVS380B – MAY 2006 – REVISED FEBRUARY 2013
LM27965 Dual Display White LED Driver with I2C Compatible Brightness Control
Check for Samples: LM27965
FEATURES
1
•2 91% Peak LED Drive Efficiency
• No Inductor Required
• 0.3% Current Matching
• Drives LEDs with up to 30mA per LED
• 180mA of total drive current
• I²C Compatible Brightness Control Interface
• Adaptive 1× - 3/2× Charge Pump
• Resistor-Programmable Current Settings
• External Chip RESET Pin
• Extended Li-Ion Input: 2.7V to 5.5V
• Small low profile industry standard leadless
package, WQFN 24 : (4mm x 4mm x 0.8mm)
• 25mm² total solution size
• Two I²C Compatible Chip Address Options:
0x36 for LM27965SQ and 0x38 for
LM27965SQ-M
APPLICATIONS
• Mobile Phone Display Lighting
• PDA Backlighting
• General LED Lighting
DESCRIPTION
The LM27965 is a highly integrated charge-pump-
based dual-display LED driver. The device can drive
up to 9 LEDs in parallel with a total output current of
180mA. Regulated internal current sinks deliver
excellent current and brightness matching in all LEDs.
The LED driver current sinks are split into three
independently controlled groups. The primary group
can beconfigurabled with 4 or 5 LEDs, for
backlighting a larger main display and the second
group can be configured with 2 or 3 LEDs, for
backlighing a smaller secondary display. An
additional, independently controlled led driver is
provided for driving an indicator or general purpose
LED. The LM27965 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 LM27965 is available in a small 24-pin WQFN-24
package.
TYPICAL APPLICATION CIRCUIT
MAIN DISPLAY
INDICATOR
SUB DISPLAY
LED
D1A D2A D3A D4A D5A
V_IN
D1B D2B D3B
D1C
P_OUT
V_IN
C_IN
1 PF
C₁
1 PF
C₂
1 PF
LM27965
C_OUT
1 PF
I²C
Compatible
Interface
SCL
SDIO
VIO
RESET
GND
I_SET
R_SET
Capacitors: TDK C1608X5R1A105k ,
or equivalent
1
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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