LM3401 Datasheet, PDF (1/18 Pages) National Semiconductor (TI) – Hysteretic PFET Controller for High Power LED Drive

August 2007
LM3401
Hysteretic PFET Controller for High Power LED Drive
General Description
The LM3401 is a switching controller designed to provide
constant current to high power LEDs. The LM3401 drives an
external P-MOSFET switch for step-down (Buck) regulators.
The LM3401 delivers constant current within ±6% accuracy
to a wide variety and number of series connected LEDs. Out-
put current is adjusted with an external current sensing resis-
tor to drive high power LEDs in excess of 1A.
For improved accuracy and efficiency, the LM3401 features
dual-side hysteresis, very low reference voltage, and short
propagation delay. A cycle by cycle current limit provides pro-
tection against over current and short circuit failures. Addi-
tional features include adjustable hysteresis and a CMOS
compatible input pin for PWM dimming.
Features
■ ^{Hysteretic Control for Speed and Simplicity}
■ ^{Input Operating Range of 4.5V-35V}
■ ^{1.5MHz maximum switching frequency}
■ ^{Low 200mV reference voltage}
■ ^{Programmable current limit}
■ ^{High speed CMOS compatible enable/dimming}
■ ^{Adjustable hysteresis}
■ ^{Input UVLO}
■ ^{No output capacitor required}
■ ^{MSOP-8 package}
Applications
■ ^{LED Driver}
■ ^{Battery Charger}
Typical Application Circuit
© 2007 National Semiconductor Corporation 300214
30021401
www.national.com