Allegromicro LC5200离线LED驱动方案

Allegromicro 公司的LC5200是离线LED驱动器集成电路,包括主控制器(MIC)和功率MOSFET.它的高压能直接连接到25V-400V的电源,最大电压可达450V,输出电流为0.5A(LC5205D),1.0A(LC5210D),恒流控制,具有欠压锁住保护(UVLO),过流保护(OCP)和热关断保护(TSD).本文介绍LC5200主要特性和优势, 功能方框图, 典型应用电路图和元件列表, 电流控制电路图与功率因素提升电路图.

LC5200 series is an off-line LED driver IC which includes both a main controller integrated circuit (MIC) and a power MOSFET. Its high voltage capability allows direct connection to a wide range of supply voltages ranging from 25 to 400 V (recommended). The LC5200 uses constant current mode to drive LEDs. The package is a standard 8-pin DIP, with pin 7 removed for greater creepage distance from the supply pin.

LC5200主要特性和优势:

▪ Supply voltage, VBB, 450 V maximum, 25 to 400 V recommended; Note: lowest voltage can vary depending on LED loads

▪ Output current IO(max) options:

▫ 0.5 A, LC5205D

▫ 1.0 A, LC5210D

▪ Constant current control circuit:

▫ Fixed off-time PWM constant current control, off-time adjustable by external components

▫ Externally adjustable output current by input voltage to REF pin

▪ Output current dimming by external PWM signal; low signal to TOFF pin shuts off output current, and PWM signal input to that pin enables dimming

▪ Undervoltage lockout protection (UVLO)

▪ Overcurrent protection (OCP); latched in response to the short-to-GND condition

▪ Thermal Shutdown protection (TSD); protects IC from damage due to excess temperature, auto-restart when temperature drops below threshold

图1.LC5200功能方框图

图2.LC5200典型应用电路图

应用电路图的元件列表:


图3.LC5200电流控制电路图

图4.LC5200功率因素提升电路图