LM3423MHBKBSTEV/NOPB 产品设计参考手册 - TI（德州仪器）

User's Guide

SNVA376A–December 2008–Revised May 2013

AN-1907 LM3423 Buck-Boost Configuration Evaluation

Board

1 Introduction

This evaluation board has been designed to demonstrate the LM3423 low-side controller as a step-

up/step-down (buck-boost) regulator to deliver constant current to high power LEDs. A complete circuit

schematic and bill of materials for the evaluation board are included at the end of this document. The

printed circuit board consists of two layers of two ounce copper on FR4 material. The LM3423 evaluation

Output voltage regulation is based on peak current-mode control, which eases the design of loop

compensation while providing inherent input voltage feed-forward compensation. The LM3423 includes a

high-voltage start-up regulator that operates over a wide input range of 4.5V to 75V. The PWM controller

is designed for high speed capability including a switching frequency range to 2.0 MHz. Additional features

include “zero” current shutdown, error amplifier, precision reference, logic-compatible DIM input suitable

for fast PWM dimming of the output, cycle-by-cycle current limit, LED ready flag, fault flag, programmable

fault timer, and thermal shutdown.

Standard Evaluation Board Operating Configuration

• f

SW

= 600 kHz

• UVLO set at 8.4V

• I

LED

Available features that can be configured on the standard evaluation board by the user for are listed

below:

• Fixed or programmable LED current

• High-speed PWM high-side or low-side dimming

• User programmable over-voltage protection (OVP)

• Under-voltage lock-out (UVLO) protection

• Fault protection