摘要
本文研究了一种采用高边电流检测的滞环控制LED恒流驱动芯片。基于0.5urn5V/18V/40VCDMOS工艺,运用Hspice工具对电路进行仿真,仿真结果显示,在4.5V一28V电源电压范围内,一40°C到+125°C工作温度范围内,电路可为LED提供恒定的350mA驱动电流,LED驱动电流为滞环变化的三角波,最大误差为6.2%。通过调节外部信号DIM的占空比可以调节LED的亮度。
In this paper, a chip which is used in the high-side current sensing topology to drive hysteresis control LED with a constant current is studied. On the basis of the technology of 0.Sum 5V/18V/40V CDMOS, the simulation by using Hspice shows that the chip can provide a driving current of 350mA for LED within the power supply voltage range from 4.5V to 28V, with the working temperatures range from -40~C to +125~C. The LED driving current is of triangular waveform with the hysteresis variation and its maximum control error is less than 6.2%. The luminance of LED can be adjusted by means of regulating the duty ratio of the exter- nal signal DIM.
出处
《自动化信息》
2011年第8期30-32,共3页
Automation Information
关键词
高边电流检测
滞环控制
PWM调光
High Side Current Sensing
Hysteresis Current Control
PWM Dimming