ST公司的VIPer17是离线转换器,包括有800V功率部分,PWM控制,过流保护,过压保护和过载保护以及滞后热保护,软起动和故障消除后自动重起等功能.采用VIPer17的STEVAL-ILL017V1是2W非绝缘离线恒流LED驱动器,输入电压176 V 到264 VAC,LED电流达500mA,电流精度+/-5%,265 VAC时的待机功耗小于50mW,可用作PDA,摄像机,电动剃须刀,手机和视频游戏的适配器,LCD/PDP TV,监视器,音频系统,计算机等辅助电源,机顶盒,DVD播放器/纪录仪和白色家电的开关电源.本文介绍了STEVAL-ILL017V1主要特性和电路图.
STEVAL-ILL017V1: Offline constant current LED driver based on the VIPer17
The STEVAL-ILL017V1 demonstration board is a 2 W non-isolated offline constant current LED driver based on the VIPer17. The board operates with an input ranging from 176 V to 264 VAC and provides 500 mA of constant current from a 7 VDC source, suitable for illuminating two LEDs in series.
The VIPer17 device is an offline converter with an 800 V rugged power section, a PWM control, overcurrent protection, overvoltage and overload protection, hysteretic thermal protection, soft-start and safe auto-restart after the removal of a fault condition. The brown-out protection function is embedded into the high voltage start-up.
Burst mode operation and the very low consumption of the device combine to meet standby energy saving regulations. Advanced frequency jittering reduces EMI filter cost.
STEVAL-ILL017V1主要特性:
Input voltage 220 VAC +/- 20%
800 V avalanche rugged power section
Provides 500 mA constant current for LED
High precision constant current with +/- 5% tolerance (1 sense resistor and 2 resistor bridges with +/- 1% precision)
Overtemperature protection
LED open-circuit protection
LED short-circuit protection
PWM operation with frequency jittering for low EMI
Operating frequency:
– 60 kHz for L type
– 115 kHz for H type
Standby power < 50 mW at 265 VAC
Adjustable and accurate overvoltage protection
On-board soft-start
Safe auto-restart after a fault condition
STEVAL-ILL017V1应用:
Adapters for PDAs, camcorders, electric shavers, cellular phones, videogames
Auxiliary power supply for LCD/PDP TVs, monitors, audio systems, computers, industrial applications
SMPS for set-top boxes, DVD players/ recorders, white goods
图1.STEVAL-ILL017V1应用电路图
