LM3429 Datasheet, PDF (1/8 Pages) National Semiconductor (TI) – N-Channel Controller for Constant Current LED Drivers

LM3429
PRELIMINARY
April 30, 2009
N-Channel Controller for Constant Current LED Drivers
General Description
The LM3429 is a versatile high voltage LED driver controller.
With the capability to be configured in a Buck, Boost, Buck-
Boost (Flyback), or SEPIC topology, and an input and output
operating voltage rating of 75V, the LM3429 is ideal for illu-
minating LEDs in a very diverse, large family of applications.
Adjustable high-side current sense with a typical sense volt-
age of 100 mV allows for tight regulation of the LED current
with the highest efficiency possible. Output LED current reg-
ulation is based on peak current-mode control with predictive
Off-Time Control. This method of control eases the design of
loop compensation while providing inherent input voltage
feed-forward compensation.
The LM3429 includes a high-voltage startup regulator that
operates over a wide input range of 4.5V to 75V. The internal
PWM controller is designed for adjustable switching frequen-
cies of up to 2.0MHz, thus enabling compact solutions. Addi-
tional features include: precision reference, logic compatible
DIM input suitable for fast PWM dimming, cycle-by-cycle cur-
rent limit, and thermal shutdown.
The LM3429 comes in a low profile, thermally efficient TSSOP
EP 14-lead package.
Features
■ ^V_IN ^{range from 4.5V to 75V}
■ ^{2% Internal reference voltage (1.235V)}
■ ^{Current sense voltage adjustable from 20 mV}
■ ^{High-side current sensing}
■ 2Ω MOSFET gate driver
■ ^{Dimming MOSFET gate driver}
■ ^{Input under-voltage protection}
■ ^{Over-voltage protection}
■ ^{Low shutdown current, I}_Q ^{< 1µA}
■ ^{Fast (50kHz) PWM dimming}
■ ^{Cycle-by-cycle current limit}
■ ^{Programmable switching frequency}
■ ^{TSSOP EP 14-lead package}
Applications
■ ^{LED Drivers}
■ ^{Constant-Current Buck-Boost Regulator}
■ ^{Constant-Current Boost Regulator}
■ ^{Constant-Current Flyback Regulator}
■ ^{Constant-Current SEPIC Regulator}
■ ^{Thermo-Electric Cooler (Peltier) Driver}
Typical Application Circuit
Boost LED Driver
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