LM3423 Datasheet, PDF (1/10 Pages) National Semiconductor (TI) – The boost circuit can be easily redesigned for different

LM3423 Boost 2 Layer
Evaluation Board
National Semiconductor
Application Note 2011
James Patterson
September 23, 2010
Introduction
This evaluation board showcases the LM3423 NFET con-
troller used with a boost current regulator. It is designed to
drive 9 to 12 LEDs at a maximum average LED current of
700mA from a DC input voltage of 10 to 26V.
The evaluation board showcases most features of the
LM3423 including PWM dimming, overvoltage protection and
input under-voltage lockout. It also has a connector footprint
(J7) which can mate with an external LED load board allowing
for the LEDs to be mounted close to the driver. Alternatively,
the LED+ and LED- banana jacks can be used to connect the
LED load.
The boost circuit can be easily redesigned for different spec-
ifications by changing only a few components (see the Alter-
nate Designs section found at the end of this application note).
Note that design modifications can change the system effi-
ciency. See the LM3423 datasheet for a comprehensive ex-
planation of the device and application information.
Schematic
EFFICIENCY WITH 9 SERIES LEDS AT 700mA
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