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Reference Design
LM3424
SNVS603D – AUGUST 2009 – REVISED JULY 2019
LM3424 Constant Current N-channel Controller with Thermal Foldback For Driving LEDs
1 Features
•1 VIN range from 4.5 V to 75 V • High-side adjustable current sense • 2-Ω, 1-A peak MOSFET gate driver • Input undervoltage and output overvoltage
protection • PWM and analog dimming • Cycle-by-cycle current limit • Programmable soft-start and slope compensation • Programmable, synchronizable switching
frequency • Programmable thermal foldback • Precision voltage reference • Low-power shutdown and thermal shutdown
2 Applications
• LED Drivers (buck, boost, buck-boost, and SEPIC)
• Indoor and outdoor area SSL • General illumination • Constant-current regulators
3 Description
The LM3424 is a versatile high voltage N-channel MOSFET controller for LED drivers. It can be easily configured in buck, boost, buck-boost and SEPIC topologies. In addition, the LM3424 includes a thermal foldback feature for temperature management of the LEDs. This flexibility, along with an input voltage rating of 75 V, makes the LM3424 ideal for illuminating LEDs in a large family of applications.
Adjustable high-side current sense allows for tight regulation of the LED current with the highest efficiency possible. The LM3424 uses standard peak current-mode control providing inherent input voltage feed-forward compensation for better noise immunity. It is designed to provide accurate thermal foldback with a programmable foldback breakpoint and slope. In addition, a 2.45V reference is provided.
The LM3424 includes a high-voltage startup regulator that operates over a wide input range of 4.5 V to 75 V. The internal PWM controller is designed for adjustable switching frequencies of up to 2.0 MHz and external synchronization is possible. The controller is capable of high speed PWM dimming and analog dimming.
Typical Boost Application Circuit
VIN
1 VIN
LM3424
20 HSP
2 EN
19 HSN
Device Information(1)
PART NUMBER
PACKAGE
BODY SIZE (NOM)
LM3424
HTSSOP (20)
6.50 mm × 4.40 mm
(1) For all available packages, see the orderable addendum at the end of the data sheet.
3 COMP
18 SLOPE
4 CSH
5 RT/SYNC
17 IS
16 VCC
ILED
PWM
6 nDIM
15 GATE
7 SS
14 GND
8 TGAIN
13 DDRV
9
TEMP
TSENSE
10 TREF
DAP
12 OVP
11 VS
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA.
LM3424
SNVS603D – AUGUST 2009 – REVISED JULY 2019
www.ti.com
Table of Contents
1 Features .................................................................. 1 2 Applications ........................................................... 1 3 Description ............................................................. 1 4 Revision History..................................................... 2 5 Pin Configuration and Functions ......................... 3 6 Specifications......................................................... 4
6.1 Absolute Maximum Ratings ...................................... 4 6.2 ESD Ratings.............................................................. 4 6.3 Recommended Operating Conditions....................... 4 6.4 Thermal Information .................................................. 5 6.5 Electrical Characteristics........................................... 5 6.6 Typical Characteristics ............................................. 8 7 Detailed Description ............................................ 11 7.1 Overview ................................................................. 11 7.2 Functional Block Diagram ....................................... 11 7.3 Feature Description................................................. 12
7.4 Device Functional Modes........................................ 25 8 Application and Implementation ........................ 26
8.1 Application Information............................................ 26 8.2 Typical Applications ................................................ 29 9 Power Supply Recommendations...................... 61 9.1 Input Supply Current Limit ...................................... 61 10 Layout................................................................... 61 10.1 Layout Guidelines ................................................. 61 10.2 Layout Example .................................................... 62 11 Device and Documentation Support ................. 63 11.1 Device Support...................................................... 63 11.2 Community Resources.......................................... 63 11.3 Trademarks ........................................................... 63 11.4 Electrostatic Discharge Caution ............................ 63 11.5 Glossary ................................................................ 63 12 Mechanical.