LM3639A Datasheet, PDF (1/28 Pages) Texas Instruments – Single Chip 40V Backlight + 1.5A Flash LED Driver

LM3639A
www.ti.com
SNVS964 – MARCH 2013
LM3639A Single Chip 40V Backlight + 1.5A Flash LED Driver
Check for Samples: LM3639A
FEATURES
1
•2 Single Chip White LED Flash and Backlight
Driver
• 1.5A Flash LED Current
• Dual String Backlight Control (40V Max V_OUT)
• 128 Level Exponential and Linear Brightness
Control
• PWM Input for CABC
• Programmable Over-Voltage Protection
(Backlight)
• Programmable Current Limit (Flash)
• Programmable Switching Frequency
• Optimized Flash Current During Low-Battery
Conditions
APPLICATIONS
• White LED Backlit Display Power
• White LED Camera Flash Power
L(B)
Schottky
L(F)
VOUTB
up to 40V
COUTB
2.5V - 5.5V
CIN
SWF SWB OVP
VIN
OUTF
COUTF
EN
SCL
SDA
STROBE
TX
PWM
BLED1
BLED2
FLED1
FLED2
GND
FLED2
OR
FLED1
DESCRIPTION
The LM3639A is a single-chip white LED Camera
Flash Driver + LCD Display Backlight Driver. The low-
voltage, high-current flash LED driver is a
synchronous boost which provides the power for a
single flash LED at up to 1.5A or dual LEDs at up to
750 mA each. The high-voltage backlight driver is a
dual-output asynchronous boost which powers dual
LED strings at up to 40V and 30 mA per string. An
adaptive regulation method in both boost converters
regulates the headroom voltage across the respective
source/sink to ensure the LED current remains in
regulation while maximizing efficiency. The
LM3639A's flash driver is a 2MHz or 4MHz fixed-
frequency synchronous boost converter plus 1.5A
constant current driver for a high-current white LED.
The high-side current source allows for grounded
cathode LED operation providing Flash current up to
1.5A. An adaptive regulation method ensures the
current source remains in regulation and maximizes
efficiency.
The device is controlled by an I²C-compatible
interface. Features for the flash LED driver include a
hardware flash enable (STROBE) allowing a logic
input to trigger the flash pulse, and a TX input for
synchronization to RF power amplifier events or other
high current conditions. Features for the LCD
backlight driver include a PWM input for content
adjustable backlight control, 128 exponential or linear
brightness levels, programmable over-voltage
protection, and selectable switching frequency (500
kHz or 1 MHz).
The device is available in a tiny 1.790 mm x 2.165
mm x 0.6 mm 20-bump, 0.4 mm pitch DSBGA
package and operates over the −40°C to +85°C
temperature range.
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 © 2013, Texas Instruments Incorporated