LM3429/-Q1 N-Channel Controller for Constant Current LED Drivers

1 Features

LM3429-Q1 is AEC-Q100 Grade 1 Qualified for Automotive Applications
V_IN Range From 4.5 V to 75 V
Adjustable Current Sense Voltage
High-Side Current Sensing
2-Ω, 1-A Peak MosFET Gate Driver
Input Undervoltage Protection
Overvoltage Protection
PWM Dimming
Analog Dimming
Cycle-by-Cycle Current Limit
Programmable Switching Frequency
Low Profile 14-lead HTSSOP Package
Thermal Shutdown

2 Applications

LED Drivers - Buck, Boost, Buck-Boost, SEPIC
Indoor and Outdoor SSL
Automotive
General Illumination
Constant-Current Regulators

3 Description

The LM3429 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. This flexibility, along with an input voltage rating of 75V, makes the LM3429 ideal for illuminating LEDs in a very diverse, large family of applications.

Adjustable high-side current sense voltage allows for tight regulation of the LED current with the highest efficiency possible. The LM3429 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 LM3429 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 MHz, thus enabling compact solutions. Additional features include analog dimming, PWM dimming, overvoltage protection, undervoltage lock-out, cycle-by-cycle current limit, and thermal shutdown.

Device Information⁽¹⁾

PART NUMBER	PACKAGE	BODY SIZE (NOM)
LM3429	HTSSOP (14)	5.00 mm × 4.40 mm
LM3429-Q1	HTSSOP (14)	5.00 mm × 4.40 mm

For all available packages, see the orderable addendum at the end of the data sheet.

Typical Boost Application Circuit

4 Revision History

Changes from G Revision (April 2013) to H Revision

Added Pin Configuration and Functions section, Handling Rating table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section Go

Changes from F Revision (May 2013) to G Revision

Changed layout of National Data Sheet to TI formatGo

5 Pin Configuration and Functions

PWP Package

14- Pin HTSSOP

Top View

Pin Functions

PIN		I/O	DESCRIPTION	APPLICATION INFORMATION
NO.	NAME	I/O	DESCRIPTION	APPLICATION INFORMATION
1	V_IN	I	Input Voltage	Bypass with 100 nF capacitor to AGND as close to the device as possible in the circuit board layout.
2	COMP	I	Compensation	Connect a capacitor to AGND to set compensation.
3	CSH	I	Current Sense High	Connect a resistor to AGND to set signal current. For analog dimming, connect current source or potentiometer to AGND (see Analog Dimming section).
4	RCT	I	Resistor Capacitor Timing	Connect a resistor from the switch node and a capacitor to AGND to set the switching frequency.
5	AGND	GND	Analog Ground	Connect to PGND through the DAP copper circuit board pad to provide proper ground return for CSH, COMP, and RCT.
6	OVP	I	Overvoltage Protection	Connect to a resistor divider from the output (V_O) or the input to program output overvoltage lockout (OVLO). Turn-off threshold is 1.24 V and hysteresis for turn-on is provided by 20 µA current source.
7	nDIM	I	Not DIM input	Connect a PWM signal for dimming as detailed in the PWM Dimming section and/or a resistor divider from V_IN to program input undervoltage lockout (UVLO). Turn-on threshold is 1.24 V and hysteresis for turn-off is provided by 20 µA current source.
8	NC		No Connection	Leave open.
9	PGND	GND	Power Ground	Connect to AGND through DAP copper pad to provide ground return for GATE.
10	GATE	O	Gate Drive Output	Connect to the gate of the external NFET.
11	V_CC	I	Internal Regulator Output	Bypass with a 2.2 µF–3.3 µF, ceramic capacitor to PGND.
12	IS	I	Main Switch Current Sense	Connect to the drain of the main N-channel MosFET switch for R_DS-ON sensing or to a sense resistor installed in the source of the same device.
13	HSP	I	LED Current Sense Positive	Connect through a series resistor to LED current sense resistor (positive).
14	HSN	I	LED Current Sense Negative	Connect through a series resistor to LED current sense resistor (negative).
DAP (15)	DAP	GND	Thermal pad on bottom of IC	Connect to AGND and PGND.