NS LM3450带PFC和相位调光译码器的LED驱动方案
NS 公司的LM3450是具有PFC和相位调光译码器的LED驱动器,PFC在调整输出电压同时保持输入端有极好的功率因素.相位调光70:1 PWM译码,具有过压和反馈短路保护,非常适合离线10-100W的LED驱动,主要用在调光筒灯,平光灯和室内外区域照明以诚相待及电源PFC.本文介绍了LM3450主要特性, 方框图, 典型应用电路图和反激电路图, PFC系统架构图和控制电路图, 调光译码器电路图以及LM3450评估板主要指标,完整电路图和材料清单(BOM).
LED Driver with Active Power Factor Correction and Phase Dimming Decoder
The LM3450 is a power factor controller (PFC) with separate phase dimming decoder. The PFC regulates an accurate output voltage while maintaining excellent power factor at the input. The phase dimming decoder interprets the phase angle and remaps it to a 500Hz PWM output. This combination of features is ideal for implementing a dimmable off-line LED driver for 10-100W loads.
The phase dimming decoder has several unique features. A programmable mapping from input to output increases design flexibility, while a dynamic filter and variable sampling rate provide a fast, smooth response to dimmer movement. A dynamic hold circuit ensures that the phase dimmer angle is decoded properly while minimizing the extra power losses associated with holding current.
LM3450主要特性:
■ Critical conduction mode PFC
■ Over-voltage protection
..
