LM3528 Datasheet, PDF (1/34 Pages) National Semiconductor (TI) – High Efficiency, Multi Display LED Driver with 128 Exponential Dimming Steps and Integrated OLED Power Supply in a 1.2mm × 1.6mm μSMD Package

LM3528
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SNVS513B – AUGUST 2008 – REVISED MAY 2013
LM3528 High Efficiency, Multi Display LED Driver with 128 Exponential Dimming Steps
and Integrated OLED Power Supply in a 1.2mm × 1.6mm DSBGA Package
Check for Samples: LM3528
FEATURES
1
•2 128 Exponential Dimming Steps
• Programmable Auto-Dimming Function
• Up to 90% Efficient
• Low Profile 12 Bump DSBGA Package (1.2mm
x 1.6mm x 0.6mm)
• Integrated OLED Display Power Supply and
LED Driver
• Programmable Pattern Generator Output for
LED Indicator Function
• Drives up to 12 LED’s at 20mA
• Drives up to 5 LED’s at 20mA and delivers 18V
at 40mA
• 1% Accurate Current Matching Between
Strings
• Internal Soft-Start Limits Inrush Current
• True Shutdown Isolation for LED’s
• Wide 2.5V to 5.5V Input Voltage Range
• 22V Over-Voltage Protection
• 1.25MHz Fixed Frequency Operation
• Dedicated Programmable General Purpose I/O
• Active Low Hardware Reset
APPLICATIONS
• Dual Display LCD Backlighting for Portable
Applications
• Large Format LCD Backlighting
• OLED Panel Power Supply
• Display Backlighting with Indicator Light
DESCRIPTION
The LM3528 current mode boost converter offers two
separate outputs. The first output (MAIN) is a
constant current sink for driving series white LED’s.
The second output (SUB/FB) is configurable as a
constant current sink for series white LED bias, or as
a feedback pin to set a constant output voltage for
powering OLED panels.
As a dual output white LED bias supply, the LM3528
adaptively regulates the supply voltage of the LED
strings to maximize efficiency and insure the current
sinks remain in regulation. The maximum current per
output is set via a single external low power resistor.
An I²C compatible interface allows for independent
adjustment of the LED current in either output from 0
to max current in 128 exponential steps. When
configured as a white LED + OLED bias supply the
LM3528 can independently and simultaneously drive
a string of up to 6 white LED’s and deliver a constant
output voltage of up to 21V for OLED panels.
10 PH
20 mA per string
2.7V to 5.5V
CIN
1 PF
10 k: 10 k:
SW
IN
OVP
VIO LM3528
SCL
SDA
GPIO
MAIN
SUB/FB
HWEN/PGEN/
GPIO
SET
GND
C
1 PF
RSET
12.1 k:
1 M:
Current
Limiting
Resistor
Indicator
LED
6.5mm
Dual White LED Bias Supply with Indicator LED
Figure 1. Typical Application Circuit
Figure 2. Typical PCB Layout
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.
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