LM3549 Datasheet, PDF (1/8 Pages) National Semiconductor (TI) – Evaluation Kit high power LED driver with up to 700mA

LM3549 Evaluation Kit
National Semiconductor
Application Note 2062
Anssi Raisanen
August 6, 2010
General Description
The LM3549 is a high power LED driver with up to 700mA
output current. It has three constant current LED drivers and
a buck boost SMPS for driving RGB LEDs with high efficiency.
LED drivers are designed for sequential drive so only one
driver can be enabled at a time.
LED driver output current settings can be stored to integrated
non-volatile memory which allows stand-alone operation with-
out I²C interface. Non-volatile memory is rewritable so current
setting can be changed if needed.
LM3549 has a fault detection feature that can detect several
different fault conditions. In case of a fault error flags are set
and FAULT output sends interrupt to control logic. Error flags
can be read through I²C interface.
Total brightness can be controlled with PWM input or with
master fader register if I²C interface is used.
LM3549 Evaluation board is designed to help getting famil-
iarized with the LM3549. It can be used to measure key
parameters of the LM3549 and to speed up design in of the
device. The evaluation board has a microcontroller that acts
as an USB to I²C interface. Microcontroller is also used to
manipulate the digital control signals of the LM3549. LM3549
evaluation board can be powered from the USB interface or
from external power supply. If evaluation board is used to
measure the electrical parameters of the LM3549 or used with
high output currents external powersupply needs to be used.
If evalution board is used to check the functionality of the
LM3549 with small output currents or to support software de-
velopment it can be powered directly from USB interface. This
document describes how to get the LM3549 evaluation board
up and running and how to use evaluation software.
What Is Needed
To get started you will need:
• LM3549 evaluation board
• LM3549 evaluation software (LM3549.exe)
• USB Cable
• PC with one free USB port
FIGURE 1.
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