AC-LED结温与开启电压关系测量

根据交流发光二极管(AC-LED)的工作特征,提出了一种简单而精准的AC-LED结温测量方法:开启电压法。通过理论分析和实验发现,AC-LED的开启电压会随着结温的上升而下降,且两者之间有良好的线性关系,从而确认将开启电压作为温度变化参数来间接测量AC-LED的结温。实验表明,开启电压法测量结温的重复性最大误差为2.0℃,热阻重复性最大误差为0.6℃/W。经过对比分析,开启电压法得到热阻值比参考脉冲法更接近真实值。

Junction temperature measurement in AC-LED using cut-in voltage

At present,the measurement methods of LED junction temperature are mainly aiming at direct current LED（DC-LED）,and less methods have been proposed for alter current LED（AC-LED）.With regard to this fact,a novel cut-in voltage method was proposed for measuring AC-LED junction temperature.From theoretical analysis and experimental verification,cut-in voltage of AC-LED was found to decrease along with the increase of junction temperature,demonstrating a good linear relationship between the two factors.Therefore,cut-in voltage was confirmed as the temperature variation coefficient （TVC）.Further analysis suggested that the repeatability error of junction temperature and thermal resistance could be narrowed down to 2.0 ℃ and 0.6 ℃/W respectively.By comparison,thermal resistance acquired from cut-in voltage method was closer to real value than that of the reference pulse method.