LM3421_14 Datasheet, PDF (1/65 Pages) Texas Instruments – N-Channel Controllers for Constant Current LED Drivers

www.ti.com
LM3421, LM3421-Q1
LM3423, LM3423-Q1
SNVS574D – JULY 2008 – REVISED SEPTEMBER 2011
LM3421, LM3421Q1, LM3421Q0, LM3423, LM3423Q1, LM3423Q0
N-Channel Controllers for Constant Current LED Drivers
Check for Samples: LM3421, LM3421-Q1, LM3423, LM3423-Q1
FEATURES
1
•2 LM3421Q1/LM3423Q1 are Automotive Grade
Products That are AEC-Q100 Grade 1 Qualified
(-40°C to +125°C Operating Junction
Temperature) and Similarly
LM3421Q0/LM3423Q0 are AEC-Q100 Grade 0
Qualified (-40°C to +150°C Operating Junction
Temperature)
• V_IN Range From 4.5V to 75V
• High-Side Adjustable Current Sense
• 2Ω, 1A Peak MosFET Gate Driver
• Input Under-Voltage and Output Over-Voltage
Protection
• PWM and Analog Dimming
• Cycle-by-Cycle Current Limit
• Programmable Switching Frequency
• "Zero Current" Shutdown and Thermal
Shutdown
• LED Output Status Flag (LM3423/23Q1/23Q0
Only)
• Fault Status Flag and Timer
(LM3423/23Q1/23Q0 Only)
APPLICATIONS
• LED Drivers - Buck, Boost, Buck-Boost, and
SEPIC
• Indoor and Outdoor Area SSL
• Automotive
• General Illumination
• Constant-Current Regulators
DESCRIPTION
The LM3421/23 are versatile high voltage N-channel
MosFET controllers for LED drivers . They can be
easily configured in buck, boost, buck-boost and
SEPIC topologies. This flexibility, along with an input
voltage rating of 75V, makes the LM3421/23 ideal for
illuminating LEDs in a large family of applications.
Adjustable high-side current sense voltage allows for
tight regulation of the LED current with the highest
efficiency possible. The LM3421/23 uses Predictive
Off-time (PRO) control, which is a combination of
peak current-mode control and a predictive off-timer.
This method of control eases the design of loop
compensation while providing inherent input voltage
feed-forward compensation.
The LM3421/23 devices include 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 frequencies of up to
2.0 MHz, thus enabling compact solutions. Additional
features include "zero current" shutdown, analog
dimming, PWM dimming, over-voltage protection,
under-voltage lock-out, cycle-by-cycle current limit,
and thermal shutdown.
The LM3423 also includes an LED output status flag,
a fault flag, a programmable fault timer, and a logic
input to select the polarity of the dimming output
driver.
The LM3421Q1/23Q1 are AEC-Q100 grade 1
qualified and LM3421Q0/23Q0 are AEC-Q100 grade
0 qualified.
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
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 © 2008–2011, Texas Instruments Incorporated