蒙特卡罗模拟LED并联电路电流降额特性

Monte-Carlo Simulation of Current Derating Characteristics of LED Parallel Circuit

利用蒙特卡罗方法对LED并联电路的电流降额特性进行了模拟,假设分档后的大功率白光LED的正向电压（VF）分布符合正态分布,研究了1×n（2≤n≤15）系列LED并联电路电流降额量（IP）的概率（P）分布。模拟结果表明,IP的概率分布函数偏离了正态分布,密度函数曲线最高值点的两侧不对称,左侧较右侧陡峭;随着LED并联数（n）的增加,概率密度函数沿IP增大的方向移动,并且越来越趋近于正态分布。当n一定时,IP随电路中出现LED承载电流超过其额定电流的概率增大而降低,降低的速度由快转慢;当P为0.01%～1%时,IP大约为20%～30%。当P一定时,IP随n的增加而增大;当n〉6时,IP的增大速度变缓。模拟结果可以推广到m×n阵列化互连大功率LED模组。

Based on Monte-Carlo simulation,the current derating characteristics with LED parallel circuit is studied,especially the probability distribution of current derating of a series （2 ≤n≤15） of LED parallel circuit,given the forward voltage drop values of LED after bin agree with Gaussian distribution.The simulation shows that the probability distribution of current derating deviates Gaussian distribution,namely the left and right of the peak point of probability density function is asymmetric,Of which the left side is more sharp than the right side.The probability distribution of current derating is more and more tend to be Gaussian distribution as the quantity of parallel LED increasing.As the probability of occurrence that the current bearing by LED exceeds its rated current increasing,the current derating needed by the parallel circuit increases gradually but the increase rate tends to be reduced.The current derating is about between 20% and 30% when the probability is between 0.01% and 1%.The current derating needed by the parallel circuit increases gradually but the increase rate tends to be reduced as the quantity of LED increasing （n〉 6）.The simulation results can be applied to the LED interconnection array.