Dual White LED Bias Supply with Indicator LED

SW

IN

OVP

MAIN

SUB/FB

SCL

SDA

GND

VIO

SET

LM3528

10 PH

1 PF

1 PF

20 mA per string

C

12.1 k:

2.7V to 5.5V

10 k:

10 k:

HWEN/PGEN/

GPIO

GPIO

1 M:

Current

Limiting

Resistor

Indicator

LED

6.5mm

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

1

FEATURES

APPLICATIONS

2

•

128 Exponential Dimming Steps

•

Dual Display LCD Backlighting for Portable

Applications

•

Programmable Auto-Dimming Function

•

Large Format LCD Backlighting

•

Up to 90% Efficient

•

OLED Panel Power Supply

•

Low Profile 12 Bump DSBGA Package (1.2mm

x 1.6mm x 0.6mm)

•

Display Backlighting with Indicator Light

•

Integrated OLED Display Power Supply and

DESCRIPTION

LED Driver

The LM3528 current mode boost converter offers two

•

Programmable Pattern Generator Output for

separate outputs. The first output (MAIN) is a

LED Indicator Function

constant current sink for driving series white LED’s.

•

Drives up to 12 LED’s at 20mA

The second output (SUB/FB) is configurable as a

constant current sink for series white LED bias, or as

•

Drives up to 5 LED’s at 20mA and delivers 18V

a feedback pin to set a constant output voltage for

at 40mA

powering OLED panels.

•

1% Accurate Current Matching Between

Strings

As a dual output white LED bias supply, the LM3528

adaptively regulates the supply voltage of the LED

•

Internal Soft-Start Limits Inrush Current

strings to maximize efficiency and insure the current

•

True Shutdown Isolation for LED’s

sinks remain in regulation. The maximum current per

•

Wide 2.5V to 5.5V Input Voltage Range

output is set via a single external low power resistor.

•

22V Over-Voltage Protection

adjustment of the LED current in either output from 0

•

1.25MHz Fixed Frequency Operation

to max current in 128 exponential steps. When

•

Dedicated Programmable General Purpose I/O

configured as a white LED + OLED bias supply the

LM3528 can independently and simultaneously drive

•

Active Low Hardware Reset

a string of up to 6 white LED’s and deliver a constant

output voltage of up to 21V for OLED panels.

Figure 1. Typical Application Circuit

Figure 2. Typical PCB Layout

1

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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2

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PRODUCTION DATA information is current as of publication date.

Copyright © 2008–2013, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.