TI(NS )公司的LM3549是輸出電流高達(dá)700mA的高效大功率RGB LED驅(qū)動(dòng)器,它有三個(gè)恒流LED驅(qū)動(dòng)器和一個(gè)降壓升壓開關(guān)電源(SMPS),用來高效地驅(qū)動(dòng)RGB LED.LM3459具有過流和超溫保護(hù),I2C兼容接口以及欠壓鎖住, 降壓升壓轉(zhuǎn)換器的峰值效率95%,主要用在手持視頻投映儀和大功率LED驅(qū)動(dòng).本文介紹了LM3549主要特性和指標(biāo),方塊圖,典型應(yīng)用電路以及評(píng)估板電路圖和材料清單.
The LM3549 is a high power LED driver with up to 700mA output current. It has three constant current LED drivers and a buck boost SMPS for driving RGB LEDs with high efficiency.
LED drivers are designed for sequential drive so only one driver can be enabled at a time.
LED driver output current settings can be stored to integrated non-volatile memory which allows stand-alone operation without I2C interface. Non-volatile memory is rewritable so current setting can be changed if needed.
LM3549 has a fault detection feature that can detect several different fault conditions. In case of a fault error flags are set and FAULT output sends interrupt to control logic. Error flags can be read through I2C interface.
Total brightness can be controlled with PWM input or with master fader register if I2C interface is used.
LM3549主要指標(biāo):
■ Integrated buck-boost converter
■ Programmable LED drivers
■ 700 mA maximum drive current
■ ±6% Current accuracy over temperature
■ 24-pin LLP package
LM3549主要特性:
■ Over-current protection
■ Over-temperature protection
■ I2C compatible interface
■ Under-voltage lockout
■ LED open and short protection and detection
■ 95% peak efficiency buck-boost converter
■ NVM memory for calibration data and standalone usage without I2C control
■ Soft start
LM3549應(yīng)用:
■ Portable video projectors
■ High power LED driving
圖1. LM3549方框圖
圖2. LM3549典型應(yīng)用電路圖
LM3549評(píng)估板
The LM3549 is a high power LED driver with up to 700mA output current. It has three constant current LED drivers and a buck boost SMPS for driving RGB LEDs with high efficiency.
LED drivers are designed for sequential drive so only one driver can be enabled at a time.LED driver output current settings can be stored to integrated non-volatile memory which allows stand-alone operation without I2C interface. Non-volatile memory is rewritable so current setting can be changed if needed.
LM3549 has a fault detection feature that can detect several different fault conditions. In case of a fault error flags are set and FAULT output sends interrupt to control logic. Error flags can be read through I2C interface.
Total brightness can be controlled with PWM input or with master fader register if I2C interface is used.
LM3549 Evaluation board is designed to help getting familiarized with the LM3549. It can be used to measure key parameters of the LM3549 and to speed up design in of the device. The evaluation board has a microcontroller that acts as an USB to I2C interface. Microcontroller is also used to manipulate the digital control signals of the LM3549. LM3549 evaluation board can be powered from the USB interface or from external power supply. If evaluation board is used to measure the electrical parameters of the LM3549 or used with high output currents external power supply needs to be used.
If evalution board is used to check the functionality of the LM3549 with small output currents or to support software development it can be powered directly from USB interface. This document describes how to get the LM3549 evaluation board up and running and how to use evaluation software.
圖3. LM3549評(píng)估板外形圖
圖4. LM3549評(píng)估板電路圖
LM3549評(píng)估板材料清單:
詳情請(qǐng)見:
http://www.national.com/ds/LM/LM3549.pdf
和
http://www.national.com/an/AN/AN-2062.pdf
