TI(NS )公司的LM3549是输出电流高达700mA的高效大功率RGB LED驱动器,它有三个恒流LED驱动器和一个降压升压开关电源(SMPS),用来高效地驱动RGB LED.LM3459具有过流和超温保护,I2C兼容接口以及欠压锁住, 降压升压转换器的峰值效率95%,主要用在手持视频投映仪和大功率LED驱动.本文介绍了LM3549主要特性和指标,方块图,典型应用电路以及评估板电路图和材料清单. 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主要指标:
■ 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应用:
■ Portable video projectors
■ High power LED driving
图1. LM3549方框图
图2. LM3549典型应用电路图
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