高可靠、高效率的白光LED高压驱动芯片  

High-reliability and high-efficiency white LED driver with high voltage supply

作　　者：叶益迭[1] 何乐年[1] 

机构地区：[1]浙江大学超大规模集成电路研究所,浙江杭州310027

出　　处：《电路与系统学报》2013年第2期12-19,共8页Journal of Circuits and Systems

摘　　要：根据白光LED(Light Emitting Diode)的特性及其对驱动电路的要求,提出了一种高可靠、高效率的LED高压驱动芯片,具有线性调光和数字调光两种调光功能。芯片采用简化的脉冲宽度调制(PWM,Pulse Width Modulation)峰值电流控制模式控制通过LED的电流,系统稳定性好,抗干扰能力强。振荡器中新型抖频电路模块的加入,提高了系统的电磁干扰(EMI,Electro Magnetic Interference)性能,使系统可靠性进一步增强。驱动芯片的输入电压范围为8.5 V^40V,输出的驱动电压达7.5V,可有效降低NMOS功率开关管的导通损耗。电路设计采用低静态电流、低反馈电压等低功耗设计技术,提高了系统的电能转换效率。芯片采用CSMC公司1μm 40V高压CMOS工艺模型设计,并完成流片。测试结果验证了抖频电路的作用,系统的最高转换效率达到了95.3%。According to the characteristics of the white LEDs（Light Emitting Diode） and the particular requirements on their drivers,a high reliability and high efficiency driver with high voltage supply is proposed with both linear and digital dimming methods.Simplified peak current control mode based on pulse-width modulation（PWM） is adopted to control the current through the LEDs.And the control mode could make the system stable due to its strong anti-interference ability.A novel frequency jitter is added to the oscillator to improve the EMI problem and enhance system reliability.The input voltage range of the driver is expanded to 8.5~40V.The output voltage for driving the NMOS power switch is designed to be 7.5V to reduce the conduction losses.Low-power design techniques,such as low quiescent current,low feedback voltage,etc.,are used to improve the system efficiency.The chip is designed and implemented with the CSMC 1μm 40V BCD process.The testing results have verified the function of the frequency jitter and the maximum efficiency of the system can reach 95.3%.

关 键 词：LED高压驱动芯片 高可靠性 高转换效率 EMI 抖频 

分 类 号：TN432[电子电信—微电子学与固体电子学]