大功率白光LED驱动电路的双环检测方法

A Double Loop Detection Method of the Power White LED Driver Circuit

基于CSMC0.5μm标准CMOS工艺,设计了一种带有双环检测的大功率LED恒流驱动芯片。仿真结果表明,芯片可在2MHz频率下工作,驱动电流最高可达1.5A,在24V电源电压时,电源效率可达95%。当电源电压在6V跳变±10%,驱动1W350mA的LED时,LED电流精度达0.02%。对比单环检测模式,该电路的LED驱动电流响应时间缩短了近2/3。此模式在保持高精度恒流和高效率的同时,有效地缩短了LED驱动电流的响应时间。

A power LED constant-current driver with double loop detection is designed with 0.5 μm standard CMOS process provided by CSMC. The simulation results show that the chip can work under 2 MHz and its driving current can reach 1.5 A. When supply voltage is 24 V,its power efficiency can reach 95 %. While driving a LED of 1 W/350 mA and supply voltage varies ±10 % on 6 V,the LED current changes only 0.02 %. Compared to single loop detection,the response time of LED current is shortened by 2/3. It shortens the response time of LED current while maintaining high precision of constant current driving and high efficiency.